1
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Deng L, Zakaria BS, Zhang J, Dhar BR. Utilizing waste eggshells as a calcium precursor for contact precipitation of phosphorus from digested sludge centrate. Sci Total Environ 2024; 919:170906. [PMID: 38350578 DOI: 10.1016/j.scitotenv.2024.170906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 02/09/2024] [Accepted: 02/09/2024] [Indexed: 02/15/2024]
Abstract
Phosphorus (P) recovery from wastewater is an essential component of the global P cycle. A contact precipitation process using chicken eggshells as a calcium (Ca) precursor was used to recover P from synthetic wastewater and real digested sludge centrate. Up to 96.4 % of P could be recovered from the digested sludge centrate after three repeated cycles of the contact precipitation process. In addition, 36.1 % of total chemical oxygen demand and 37.6 % of total ammonia nitrogen were removed from the centrate. Finally, most of the precipitates could be collected by a simple washing step. Scanning electron microscopy-energy dispersive spectroscopy and x-ray diffraction results indicated that the eggshells played three roles in this process: Ca source, precipitation substrate, and filter medium. Precipitates were mainly brushite. This research provides a new perspective on P recovery from wastewater using waste eggshells, and if further optimized, has a potential for practical future applications.
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Affiliation(s)
- Linyu Deng
- Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China; Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada; Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley 94720, CA, United States
| | - Jianfeng Zhang
- Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
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2
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Azizi SMM, Dhar BR. Can low-temperature thermal hydrolysis mitigate the oxidative stress of polystyrene nanoplastics on anaerobic digestion? Chemosphere 2024; 353:141516. [PMID: 38387654 DOI: 10.1016/j.chemosphere.2024.141516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/29/2024] [Accepted: 02/20/2024] [Indexed: 02/24/2024]
Abstract
The presence of micro/nanoplastics (MPs/NPs) in sewage sludge has sparked considerable apprehensions over their potential negative effects on anaerobic digestion (AD) performance. The occurrence of MPs/NPs can trigger oxidative stress on the anaerobic microbiome, leading to potential inhibition of the AD process. While the thermal hydrolysis process (THP) is an extensively utilized sludge pretreatment method for AD, its impact on stress induced by MPs/NPs during AD remains poorly understood. In this study, we assessed the impacts of low-temperature THP (90 °C, 90 min) on AD of sewage sludge in the presence of 150 μg/L of polystyrene nanoplastics (PsNPs) under different solid retention times (SRTs) of 20, 15, and 10 d. The presence of PsNPs resulted in a higher reactive oxygen species (ROS) production and a higher abundance of antibiotic resistance genes (ARGs). Additionally, their presence caused a significant inhibition of methane production by 28.2%, 29.3%, and 38.8% for SRTs of 20, 15, and 10 d, respectively. Introducing low-temperature THP prior to the AD could partially recover methane production by mitigating ROS-induced stress and curbing the propagation of ARGs during the AD process. These results shed light on the potential benefits of THP and further optimization opportunities in alleviating the adverse effects of MPs/NPs-induced stress during sewage sludge AD.
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Affiliation(s)
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB, T6G 1H9, Canada.
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3
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Mirsoleimani Azizi SM, Zakaria BS, Dhar BR. Low-temperature thermal hydrolysis for enhancing sludge anaerobic digestion and antibiotic resistance management: Significance of digester solids retention time. Sci Total Environ 2024; 917:170392. [PMID: 38281633 DOI: 10.1016/j.scitotenv.2024.170392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 01/03/2024] [Accepted: 01/21/2024] [Indexed: 01/30/2024]
Abstract
Recently, there has been a growing inclination towards utilizing primary sludge (PS) fermentation prior to anaerobic digestion (AD) in water resource recovery facilities (WRRFs), where sludge liquor containing volatile fatty acids is used for biological nutrient removal. Nevertheless, using a low-temperature thermal hydrolysis process (THP) to improve AD in WRRFs adopting PS fermentation remains an area that has received limited research attention. Here, we studied the impact of THP (90 °C, 90 min) on anaerobic co-digestion of thickened waste activated sludge (TWAS) and fermented primary sludge (FPS) under varying solids retention times (SRTs) in semi-continuous mode. The study involved two THP schemes: scheme 1, where THP was done for both TWAS and FPS, and scheme 2, where THP was applied to TWAS only. The results demonstrated that reducing SRT from 20 to 15 and 10 d leads to decreased methane yield in both schemes. However, THP significantly enhances methane production, showing improvements of up to 37.9 % (scheme 1) and 31.2 % (scheme 2) under a 15-d SRT. Furthermore, while decreasing SRT increased the proliferation of antibiotic resistance genes (ARGs), thermal hydrolysis could effectively reduce most ARGs, indicating its potential to mitigate antibiotic resistance in the AD process. Overall, these results provide useful perceptions regarding the potential adoption of low-temperature THP in WRRFs with PS fermentation.
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Affiliation(s)
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada; Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, United States
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
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4
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Zakaria BS, Azizi SMM, Pramanik BK, Hai FI, Elbeshbishy E, Dhar BR. Responses of syntrophic microbial communities and their interactions with polystyrene nanoplastics in a microbial electrolysis cell. Sci Total Environ 2023; 903:166082. [PMID: 37544438 DOI: 10.1016/j.scitotenv.2023.166082] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/18/2023] [Accepted: 08/03/2023] [Indexed: 08/08/2023]
Abstract
Microbial electrochemical technologies are promising for simultaneous energy recovery and wastewater treatment. Although the inhibitory effects of emerging pollutants, particularly micro/nanoplastics (MPs/NPs), on conventional wastewater systems have been extensively studied, the current understanding of their impact on microbial electrochemical systems is still quite limited. Microplastics are plastic particles ranging from 1 μm to 5 mm. However, nanoplastics are smaller plastic particles ranging from 1 to 100 nm. Due to their smaller size and greater surface area, they can penetrate deeper into biofilm structures and cell membranes, potentially disrupting their integrity and leading to changes in biofilm composition and function. This study first reports the impact of polystyrene nanoplastics (PsNPs) on syntrophic anode microbial communities in a microbial electrolysis cell. Low concentrations of PsNPs (50 and 250 μg/L) had a minimal impact on current density and hydrogen production. However, 500 μg/L of PsNPs decreased the maximum current density and specific hydrogen production rate by ∼43 % and ∼48 %, respectively. Exposure to PsNPs increased extracellular polymeric substance (EPS) levels, with a higher ratio of carbohydrates to proteins, suggesting a potential defense mechanism through EPS secretion. The downregulation of genes associated with extracellular electron transfer was observed at 500 μg/L of PsNPs. Furthermore, the detrimental impact of 500 μg/L PsNPs on the microbiome was evident from the decrease in 16S rRNA gene copies, microbial diversity, richness, and relative abundances of key electroactive and fermentative bacteria. For the first time, this study presents the inhibitory threshold of any NPs on syntrophic electroactive biofilms within a microbial electrochemical system.
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Affiliation(s)
- Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, Canada
| | | | | | - Faisal I Hai
- Strategic Water Infrastructure Laboratory, School of Civil, Mining, Environmental and Architectural Engineering, University of Wollongong, Wollongong, Australia
| | - Elsayed Elbeshbishy
- Civil Engineering, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, Canada.
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5
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Alam M, Dhar BR. Boosting thermophilic anaerobic digestion with conductive materials: Current outlook and future prospects. Chemosphere 2023; 343:140175. [PMID: 37714472 DOI: 10.1016/j.chemosphere.2023.140175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 08/15/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023]
Abstract
Thermophilic anaerobic digestion (TAD) can provide superior process kinetics, higher methane yields, and more pathogen destruction than mesophilic anaerobic digestion (MAD). However, the broader application of TAD is still very limited, mainly due to process instabilities such as the accumulation of volatile fatty acids and ammonia inhibition in the digesters. An emerging technique to overcome the process disturbances in TAD and enhance the methane production rate is to add conductive materials (CMs) to the digester. Recent studies have revealed that CMs can promote direct interspecies electron transfer (DIET) among the microbial community, increasing the TAD performance. CMs exhibited a high potential for alleviating the accumulation of volatile fatty acids and inhibition caused by high ammonia levels. However, the types, properties, sources, and dosage of CMs can influence the process outcomes significantly, along with other process parameters such as the organic loading rates and the type of feedstocks. Therefore, it is imperative to critically review the recent research to understand the impacts of using different CMs in TAD. This review paper discusses the types and properties of CMs applied in TAD and the mechanisms of how they influence methanogenesis, digester start-up time, process disturbances, microbial community, and biogas desulfurization. The engineering challenges for industrial-scale applications and environmental risks were also discussed. Finally, critical research gaps have been identified to provide a framework for future research.
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Affiliation(s)
- Monisha Alam
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB, T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB, T6G 1H9, Canada.
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6
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Mohammad Mirsoleimani Azizi S, Zakaria BS, Haffiez N, Kumar A, Ranjan Dhar B. Pilot-scale investigation of conductive carbon cloth amendment for enhancing high-solids anaerobic digestion and mitigating antibiotic resistance. Bioresour Technol 2023; 385:129411. [PMID: 37394042 DOI: 10.1016/j.biortech.2023.129411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 07/04/2023]
Abstract
This study examined the effectiveness of introducing conductive carbon cloth into a pilot-scale high-solids anaerobic digestion (HSAD) system. Adding carbon cloth increased methane production by 22 % and improved the maximum methane production rate by 39 %. Microbial community characterization indicated a possible direct interspecies electron transfer-based syntrophic association among microbes. Using carbon cloth also enhanced microbial richness, diversity, and evenness. Carbon cloth effectively reduced the total abundance of antibiotic resistance genes (ARGs) by 44.6 %, mainly by inhibiting horizontal gene transfer, as shown by the significant decrease in the relative abundance of integron genes (particularly intl1). The multivariate analysis further demonstrated strong correlations of intl1 with most of the targeted ARGs. These findings suggest that carbon cloth amendment can promote efficient methane production and attenuate the spread of ARGs in HSAD systems.
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Affiliation(s)
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Nervana Haffiez
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Amit Kumar
- Mechanical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada.
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7
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Deng L, Dhar BR. Phosphorus recovery from wastewater via calcium phosphate precipitation: A critical review of methods, progress, and insights. Chemosphere 2023; 330:138685. [PMID: 37060960 DOI: 10.1016/j.chemosphere.2023.138685] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/06/2023] [Accepted: 04/11/2023] [Indexed: 05/14/2023]
Abstract
Phosphorus (P) is one of the important elements for human, animal, and plant life. Due to the development of the circular economy in recent years, the recovery of P from wastewater has received more attention. Recovery of P from domestic, industrial, and agricultural wastewater in the form of calcium phosphate (CaP) by precipitation/crystallization process presents a low-cost and effective method. Recovered CaP could be used as P fertilizer and for other industrial applications. This review summarizes the effects of supersaturation, pH, seed materials, calcium (Ca) source, and wastewater composition, on the precipitation/crystallization process. The recovery efficiency and value proposition of recovered CaP were assessed. This in-depth analysis of the literature reports identified the process parameters that are worth further optimization. The review also provides perspectives on future research needs on expanding the application field of recovered CaP and finding other more economical and environmentally friendly Ca sources.
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Affiliation(s)
- Linyu Deng
- Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB, T6G 1H9, Canada.
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB, T6G 1H9, Canada
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8
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Mohammad Mirsoleimani Azizi S, Zakaria BS, Haffiez N, Ranjan Dhar B. Granular activated carbon remediates antibiotic resistance propagation and methanogenic inhibition induced by polystyrene nanoplastics in sludge anaerobic digestion. Bioresour Technol 2023; 377:128938. [PMID: 36948429 DOI: 10.1016/j.biortech.2023.128938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/14/2023] [Accepted: 03/18/2023] [Indexed: 06/18/2023]
Abstract
Nano/microplastics (NPs/MPs) in sewage sludge can induce oxidative stress to the anaerobic digestion (AD) and also proliferate antibiotic resistance genes (ARGs). Recently, granular activated carbon (GAC) has been used as an additive to enhance methane production in AD via direct interspecies electron transfer (DIET); however, its impact on AD exposed to NPs/MPs is yet to be studied. This study examined the effect of GAC (5 and 15 g/L) on sludge AD exposed to 150 µg/L of polystyrene nanoplastics (PsNPs). PsNPs decreased methane yield by 32.3% due to elevated levels of reactive oxygen species. However, GAC addition counteracted this adverse effect and improved methane production, attributed to the potential enrichment of DIET-active microbes and the adsorption of PsNPs by GAC. Moreover, GAC reduced the total abundance of ARGs, which was increased by PsNPs exposure. Thus, GAC can provide dual benefits in mitigating methanogenic inhibition caused by PsNPs and ARG spread.
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Affiliation(s)
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Nervana Haffiez
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
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9
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Monira S, Roychand R, Hai FI, Bhuiyan M, Dhar BR, Pramanik BK. Nano and microplastics occurrence in wastewater treatment plants: A comprehensive understanding of microplastics fragmentation and their removal. Chemosphere 2023; 334:139011. [PMID: 37230299 DOI: 10.1016/j.chemosphere.2023.139011] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/12/2023] [Accepted: 05/21/2023] [Indexed: 05/27/2023]
Abstract
Nano/microplastic (NP/MP) pollution is a growing concern for the water environment. Wastewater treatment plants (WWTPs) are considered the major recipients of MP before discharging into local waterbodies. MPs enter WWTPs mainly from synthetic fibers through washing activities and personal care products. To control and prevent NP/MP pollution, it is essential to have a comprehensive understanding of their characteristics, fragmentation mechanisms, and the effectiveness of the current treatment processes used in WWTPs for NP/MP removal. Therefore, the objectives of this study are to (i) understand the detailed mapping of NP/MP in the WWTP, (ii) understand the fragmentation mechanisms of MP into NP, and (iii) investigate the removal efficiency of NP/MP by existing processes in the WWTP. This study found that fiber is the dominant shape of MP, and polyethylene, polypropylene, polyethylene terephthalate, and polystyrene are the major polymer type of MP in wastewater samples. Crack propagation and mechanical breakdown of MP due to water shear forces induced by treatment facilities (e.g., pumping, mixing, and bubbling) could be the major causes for NP generation in the WWTP. Conventional wastewater treatment processes are ineffective for the complete removal of MPs. Although these processes are capable of removing ∼95% of MPs, they tend to accumulate in sludge. Thus, a significant number of MPs may still be released into the environment from WWTPs on a daily basis. Therefore, this study suggested that using DAF process in the primary treatment unit can be an effective strategy to control MP in the initial stage before it goes to the secondary and tertiary stage.
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Affiliation(s)
- Sirajum Monira
- School of Engineering, RMIT University, Melbourne, VIC, 3000, Australia
| | - Rajeev Roychand
- School of Engineering, RMIT University, Melbourne, VIC, 3000, Australia
| | - Faisal Ibney Hai
- School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Muhammed Bhuiyan
- School of Engineering, RMIT University, Melbourne, VIC, 3000, Australia
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
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10
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Huang Q, Liu Y, Ranjan Dhar B. Boosting resilience of microbial electrolysis cell-assisted anaerobic digestion of blackwater with granular activated carbon amendment. Bioresour Technol 2023; 381:129136. [PMID: 37169203 DOI: 10.1016/j.biortech.2023.129136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/13/2023]
Abstract
Poor hydrolysis and methanogenesis efficiencies remain the main challenges for blackwater anaerobic digestion. This study investigated the performance of a granular activated carbon (GAC) amended microbial electrolysis cell-assisted anaerobic digester (MEC-AD) treating blackwater. Due to hydrolysis limitation, both MEC-AD and control reactors experienced performance declines as the organic loading rate increased from 3.0 to 4.5 g COD/L-d. Then, adding GAC without mixing formed GAC-sludge aggregates that improved methane yield to 38.3% and 32.3% in the MEC-AD and control reactor, respectively, and enhanced hydrolysis efficiency. The amended MEC-AD also successfully overcame the performance deterioration due to a temperature drop. Biomarker identification revealed the crucial roles of GAC biofilms and settled sludge in promoting methanogenesis and hydrolysis, respectively. This study demonstrated the GAC addition and the electrochemical environment could have a reciprocal influence, leading to more robust syntrophic microbial interactions, which could guide the future application of conductive materials in MEC-AD systems.
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Affiliation(s)
- Qi Huang
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, T6G 1H9, Canada
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, T6G 1H9, Canada.
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, T6G 1H9, Canada
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11
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Haffiez N, Zakaria BS, Mohammad Mirsoleimani Azizi S, Ranjan Dhar B. Antibiotic resistance genes proliferation under anaerobic degradation of polylactic acid and polyhydroxy butyrate bioplastics. Environ Int 2023; 175:107938. [PMID: 37120980 DOI: 10.1016/j.envint.2023.107938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/14/2023] [Accepted: 04/14/2023] [Indexed: 05/22/2023]
Abstract
As the global concern over plastic pollution grows, efforts are underway to find environmentally friendly alternatives to traditional plastics. Bioplastics are being extensively researched and developed as a possible solution. This study compared the impact of two bioplastics, polylactic acid (PLA) and polyhydroxy butyrate (PHB), on the proliferation of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) during anaerobic digestion (AD). Both bioplastics (250-500 particles) could be degraded to a certain extent over 79 days, as indicated by higher methane production than the control without bioplastic particles. The PHB 500 reactor showed the highest methane yield along with the highest biodegradation efficiency (91 %) than other reactors amended with PHB and PLA particles. The highest ARG and MGE abundances were also observed in PLA 500, and the lowest ARG abundance was in PLA 250. Conversely, PHB reactors showed a relatively lower ARG abundance than the control. The correlation analysis suggested that most ARGs were positively correlated with PLA and negatively correlated with PHB (except for tetA, tetB, and tetX). Moreover, a correlation between MGEs and ARGs in PLA and PHB reactors was revealed by correlation analysis. These results show that AD responds differently to the different types/levels of bioplastics, which can ultimately influence the behavior of ARG proliferation. Thus, bioplastics may also pose a potential risk for spreading antibiotic resistance. These findings can be used as a basis for setting environmental standards for bioplastics and creating monitoring and control measures to prevent potential negative impacts on public health.
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Affiliation(s)
- Nervana Haffiez
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada
| | | | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
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12
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Chung TH, Shahidi M, Mezbahuddin S, Dhar BR. Ensemble machine learning approach for examining critical process parameters and scale-up opportunities of microbial electrochemical systems for hydrogen peroxide production. Chemosphere 2023; 324:138313. [PMID: 36878371 DOI: 10.1016/j.chemosphere.2023.138313] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/23/2023] [Accepted: 03/03/2023] [Indexed: 06/18/2023]
Abstract
Hydrogen peroxide (H2O2) production in microbial electrochemical systems (MESs) is an attractive option for enabling a circular economy in the water/wastewater sector. Here, a machine learning algorithm was developed, using a meta-learning approach, to predict the H2O2 production rates in MES based on the seven input variables, including various design and operating parameters. The developed models were trained and cross-validated using the experimental data collected from 25 published reports. The final ensemble meta-learner model (combining 60 models) demonstrated a high prediction accuracy with very high R2 (0.983) and low root-mean-square error (RMSE) (0.647 kg H2O2 m-3 d-1) values. The model identified the carbon felt anode, GDE cathode, and cathode-to-anode volume ratio as the top three most important input features. Further scale-up analysis for small-scale wastewater treatment plants indicated that proper design and operating conditions could increase the H2O2 production rate to as high as 9 kg m-3 d-1.
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Affiliation(s)
- Tae Hyun Chung
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada
| | - Manjila Shahidi
- 4S Analytics & Modelling Ltd., Edmonton, AB, T6W 3V6, Canada
| | | | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
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13
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Allam NE, Zakaria BS, Kuznetsov PV, Dhar BR, Ulrich AC. Mitigating methane emission from oil sands tailings using enzymatic and lime treatments. Chemosphere 2023; 313:137455. [PMID: 36470354 DOI: 10.1016/j.chemosphere.2022.137455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 06/17/2023]
Abstract
Engineering strategies to reduce greenhouse gases (GHGs) emissions by inhibiting methanogenesis in oil sands tailings have rarely been examined. In this study, we explored the potential impact of chemical treatment (lime) and biological treatment using enzymes (lysozyme and protease) on inhibiting methane emissions from tailings. Overall, treatment with protease 3%, lysozyme 3%, and lime 5000 ppm reduced CH4 production (by 52%, 28%, and 25%, respectively) and were weakly associated with the archaeal abundance. Enzymes treatment resulted in a higher reduction in CH4 production compared with lime treatment. A 3% lysozyme treatment suppressed CH4 production (the change in methane was 0.48 mmol) and reduced the degradation of hexane throughout the experiment. Similarly, 3% protease suppressed CH4 production throughout the experiment (the change in methane was 0.78 mmol), which could be attributed to the pH reduction to pH 4.9 at week 23 resulting from the formation of volatile fatty acids. Another possible mechanism could be the formation of toxic compounds, such as high nitrogen content, after protease treatment that inhibited the microbial community. The toxicity effect to Vibrio fischeri was greater with lysozyme 3% and protease 3% treatment than with lime treatment (124 TU and 76 TU, respectively). Lime treatment resulted in the highest reduction in 16S rRNA gene copies from 5.7 × 106 cells g-1 (control) to 2.7 × 105, 1.71 × 105, and 1.4 × 105 cells g-1 for 1600, 3500, and 5000 ppm treatments, respectively. This study supports further work to examine and determine the optimum conditions (e.g., enzyme and lime dosages) for CH4 inhibition.
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Affiliation(s)
- Nesma Eltoukhy Allam
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Petr V Kuznetsov
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Ania C Ulrich
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
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14
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Haffiez N, Zakaria BS, Azizi SMM, Dhar BR. Fate of intracellular, extracellular polymeric substances-associated, and cell-free antibiotic resistance genes in anaerobic digestion of thermally hydrolyzed sludge. Sci Total Environ 2023; 855:158847. [PMID: 36126703 DOI: 10.1016/j.scitotenv.2022.158847] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/11/2022] [Accepted: 09/14/2022] [Indexed: 06/15/2023]
Abstract
Thermal hydrolysis of sludge is a promising approach to mitigate antibiotic resistance genes (ARGs) propagation in anaerobic digestion (AD). Although ARGs in sludge may be fractioned into intracellular, extracellular polymeric substance (EPS)-associated, and cell-free ARGs, the fate of these different fractions in AD has never been investigated. This study presents a detailed characterization of intracellular and extracellular ARGs in AD of sludge thermally hydrolyzed at 90 °C and 140 °C. EPS-associated ARGs represented the major fraction of the total extracellular ARGs in all samples, while its lowest abundance was observed for thermal hydrolysis at 140 °C along with the lowest EPS levels. The results suggested a positive correlation between EPS-associated ARGs with intracellular and cell-free ARGs. Furthermore, various EPS components, such as proteins and e-DNA, were positively correlated with β-lactam resistance genes. sul1 dominated all samples as an EPS-associated resistance gene. These results provide new insights into the significance of different ARGs fractions in their overall dissemination in AD integrated with thermal hydrolysis.
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Affiliation(s)
- Nervana Haffiez
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada
| | | | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
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15
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de Albuquerque FP, Dastyar W, Mirsoleimani Azizi SM, Zakaria BS, Kumar A, Dhar BR. Carbon cloth amendment for boosting high-solids anaerobic digestion with percolate recirculation: Spatial patterns of microbial communities. Chemosphere 2022; 307:135606. [PMID: 35810875 DOI: 10.1016/j.chemosphere.2022.135606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 06/30/2022] [Accepted: 07/02/2022] [Indexed: 06/15/2023]
Abstract
The addition of conductive materials in anaerobic digestion (AD) is a promising method for boosting biomethane recovery from organic waste. However, conductive additives have rarely been investigated for the high-solids anaerobic digestion (HSAD). Here, the impact of adding carbon cloth in the solid phase of an HSAD system with percolate recirculation was investigated. Furthermore, spatial patterns of microbial communities in suspended biomass, percolate, and carbon cloth attached biofilm were assessed. Carbon cloth increased biomethane yield from source-separated organics (SSO) by 20% more than the unamended control by shortening the lag phase (by 15%) and marginally improving the methanogenesis rate constant (by ∼8%) under a batch operation for 50 days. Microbial community analysis demonstrated higher relative abundances of the archaeal population in the carbon cloth amended reactor than in unamended control (12%-21% vs. 5%-15%). Compared to percolate and suspension, carbon cloth attached microbial community showed higher enrichment of known electroactive Pseudomonas species along with Methanosarcina and Methanobacterium species, indicating the possibility of DIET-based syntrophy among these species.
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Affiliation(s)
| | - Wafa Dastyar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada
| | | | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada
| | - Amit Kumar
- Mechanical Engineering, University of Alberta, University of Alberta, Edmonton, AB, T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
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16
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Haffiez N, Chung TH, Zakaria BS, Shahidi M, Mezbahuddin S, Maal-Bared R, Dhar BR. Exploration of machine learning algorithms for predicting the changes in abundance of antibiotic resistance genes in anaerobic digestion. Sci Total Environ 2022; 839:156211. [PMID: 35623518 DOI: 10.1016/j.scitotenv.2022.156211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/29/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
The land application of digestate from anaerobic digestion (AD) is considered a significant route for transmitting antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) to ecosystems. To date, efforts towards understanding complex non-linear interactions between AD operating parameters with ARG/MGE abundances rely on experimental investigations due to a lack of mechanistic models. Herein, three different machine learning (ML) algorithms, Random Forest (RF), eXtreme Gradient Boosting (XGBoost), and Artificial Neural Network (ANN), were compared for their predictive capacities in simulating ARG/MGE abundance changes during AD. The models were trained and cross-validated using experimental data collected from 33 published literature. The comparison of model performance using coefficients of determination (R2) and root mean squared errors (RMSE) indicated that ANN was more reliable than RF and XGBoost. The mode of operation (batch/semi-continuous), co-digestion of food waste and sewage sludge, and residence time were identified as the three most critical features in predicting ARG/MGE abundance changes. Moreover, the trained ANN model could simulate non-linear interactions between operational parameters and ARG/MGE abundance changes that could be interpreted intuitively based on existing knowledge. Overall, this study demonstrates that machine learning can enable a reliable predictive model that can provide a holistic optimization tool for mitigating the ARG/MGE transmission potential of AD.
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Affiliation(s)
- Nervana Haffiez
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Tae Hyun Chung
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | | | | | | | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
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17
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Huang Q, Liu Y, Ranjan Dhar B. A multifaceted screening of applied voltages for electro-assisted anaerobic digestion of blackwater: Significance of temperature, hydrolysis/acidogenesis, electrode corrosion, and energy efficiencies. Bioresour Technol 2022; 360:127533. [PMID: 35764278 DOI: 10.1016/j.biortech.2022.127533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
A microbial electrolysis cell-assisted anaerobic digester (MEC-AD) was operated with vacuum toilet blackwater at different applied voltages (0-1.6 V) at room temperature (R20). A parallel MEC-AD was operated at 35 °C (R35) to provide a kinetics index at mesophilic temperature. Both reactors failed at 1.6 V due to the alkaline pH created by anodic corrosion. In R20, the best performance was observed at 1.2 V, with methane yield, COD removal, hydrolysis and acidogenesis efficiency increased by 59.9%, 27.0%, 52.0%, and 44.9%, respectively, compared to those of 0 V. Enrichment of hydrolytic and syntrophic bacteria (e.g., Clostridium, Bacteroidales, Sedimentibacter, Syntrophomonas) and increased abundance of genes encoding complex organics (e.g., proteins, carbohydrates, lipids) metabolism in R20 at 1.2 V corresponded to the enhanced hydrolysis/acidogenesis processes. R20 at 1.2 V generated 1.16 times more net energy than R35 at the optimum voltage for methane yield (0.8 V), indicating ambient temperature operation of MEC-AD systems would be a more sustainable strategy.
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Affiliation(s)
- Qi Huang
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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18
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Zakaria BS, Guo H, Kim Y, Dhar BR. Molecular biology and modeling analysis reveal functional roles of propionate to acetate ratios on microbial syntrophy and competition in electro-assisted anaerobic digestion. Water Res 2022; 216:118335. [PMID: 35358877 DOI: 10.1016/j.watres.2022.118335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 03/08/2022] [Accepted: 03/19/2022] [Indexed: 06/14/2023]
Abstract
This study examined the significance of propionate to acetate (HPr/HAc) ratios on microbial syntrophy and competition in microbial electrolysis cell-assisted anaerobic digestion (MEC-AD). In addition to molecular biology and phylogenetic analysis, a numerical MEC-AD model was developed by modifying Anaerobic Digestion Model No.1 to predict the effects of different HPr/HAc ratios (0.5, 1.5, 2.5, and 5). The HPr/HAc ratios of 0.5 and 1.5 maintained efficient syntrophy among electroactive bacteria, hydrogenotrophic methanogens, and homoacetogens, leading to higher methane yields. In contrast, higher HPr/HAc ratios of 2.5 and 5 were detrimental to methanogenesis. Both microbial community analysis and numerical modeling results suggested that higher propionate levels could promote the enrichment of H2-utilizing acetogens, thereby triggering their competition with hydrogenotrophic methanogens. Moreover, protein fraction in extracellular polymeric substances and the relative expression of genes associated with extracellular electron transfer in both anode and cathode biofilms were markedly decreased with increasing HPr/HAc ratios, indicating partial inhibition of microbial electroactivity. Overall, these results illuminate deep insight into anaerobic syntrophy, contributing to the process kinetics and methane yields in MEC-AD systems. Furthermore, from a practical viewpoint, the results can also be helpful in effective control of MEC-AD operation without propionate accumulation.
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Affiliation(s)
- Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Hui Guo
- Civil Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Younggy Kim
- Civil Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
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19
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Haffiez N, Chung TH, Zakaria BS, Shahidi M, Mezbahuddin S, Hai FI, Dhar BR. A critical review of process parameters influencing the fate of antibiotic resistance genes in the anaerobic digestion of organic waste. Bioresour Technol 2022; 354:127189. [PMID: 35439559 DOI: 10.1016/j.biortech.2022.127189] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/13/2022] [Accepted: 04/15/2022] [Indexed: 06/14/2023]
Abstract
The overuse and inappropriate disposal of antibiotics raised severe public health risks worldwide. Specifically, the incomplete antibiotics metabolism in human and animal bodies contributes to the significant release of antibiotics into the natural ecosystems and the proliferation of antibiotic-resistant bacteria carrying antibiotic-resistant genes. Moreover, the organic feedstocks used for anaerobic digestion are often highly-rich in residual antibiotics and antibiotic-resistant genes. Hence, understanding their fate during anaerobic digestion has become a significant research focus recently. Previous studies demonstrated that various process parameters could considerably influence the propagation of the antibiotic-resistant genes during anaerobic digestion and their transmission via land application of digestate. This review article scrutinizes the influences of process parameters on antibiotic-resistant genes propagation in anaerobic digestion and the inherent fundamentals behind their effects. Based on the literature review, critical research gaps and challenges are summarized to guide the prospects for future studies.
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Affiliation(s)
- Nervana Haffiez
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Tae Hyun Chung
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Manjila Shahidi
- 4S Analytics & Modelling Ltd., Edmonton, AB, T6W 3V6, Canada
| | | | - Faisal I Hai
- Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
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20
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Haffiez N, Azizi SMM, Zakaria BS, Dhar BR. Propagation of antibiotic resistance genes during anaerobic digestion of thermally hydrolyzed sludge and their correlation with extracellular polymeric substances. Sci Rep 2022; 12:6749. [PMID: 35468927 PMCID: PMC9038762 DOI: 10.1038/s41598-022-10764-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/12/2022] [Indexed: 12/27/2022] Open
Abstract
The positive impact of the thermal hydrolysis process (THP) of sewage sludge on antibiotic resistance genes (ARGs) removal during anaerobic digestion (AD) has been reported in the literature. However, little information is available on how changes in different extracellular polymeric substances (EPS) due to THP can influence ARG propagation during AD. This study focused on systematically correlating EPS components and ARG abundance in AD of sewage sludge pretreated with THP (80 °C, 110 °C, 140 °C, 170 °C). THP under different conditions improved sludge solubilization followed by improved methane yields in the biochemical methane potential (BMP) test. The highest methane yield of 275 ± 11.5 ml CH4/g COD was observed for THP-140 °C, which was 40.5 ± 2.5% higher than the control. Increasing THP operating temperatures showed a non-linear response of ARG propagation in AD due to the rebound effect. The highest ARGs removal in AD was achieved with THP at 140 °C. The multivariate analysis showed that EPS polysaccharides positively correlated with most ARGs and integrons, except for macrolides resistance genes. In contrast, EPS protein was only strongly correlated with β-lactam resistance genes. These results suggest that manipulating THP operating conditions targeting specific EPS components will be critical to effectively mitigating the dissemination of particular ARG types in AD.
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21
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Chung TH, Zakaria BS, Meshref MNA, Dhar BR. Enhancing quorum sensing in biofilm anode to improve biosensing of naphthenic acids. Biosens Bioelectron 2022; 210:114275. [PMID: 35447397 DOI: 10.1016/j.bios.2022.114275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 11/18/2022]
Abstract
The feasibility of enhancing quorum sensing (QS) in anode biofilm to improve the quantifications of commercial naphthenic acid concentrations (9.4-94 mg/L) in a microbial electrochemical cell (MXC) based biosensor was demonstrated in this study. First, three calibration methods were systematically compared, and the charging-discharging operation was selected for further experiments due to its 71-227 folds higher electrical signal outputs than the continuous closed-circuit operation and cyclic voltammetry modes. Then, the addition of acylase (5 μg/L) as an exogenous QS autoinducer (acylase) was investigated, which further improved the biosensor's electrical signal output by ∼70%, as compared to the control (without acylase). The addition of acylase increased the relative expression of QS-associated genes (lasR, lasI, rhlR, rhlI, lasA, and luxR) by 7-100%, along with increased abundances of known electroactive bacterial genera, such as Geobacter (from 42% to 47%) and Desulfovibrio (from 6% to 11%). Furthermore, toxicities of different NAs concentrations measured with the Microtox bioassay test were correlated with corresponding electrical signals, indicating that MXC-biosensor can provide a dual platform for rapid assessment of both NA concentrations and NA-associated toxicity.
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Affiliation(s)
- Tae Hyun Chung
- Civil and Environmental Engineering, University of Alberta, 9211-116, Street NW, Edmonton, AB, T6G 1H9, Canada
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, 9211-116, Street NW, Edmonton, AB, T6G 1H9, Canada
| | - Mohamed N A Meshref
- Civil and Environmental Engineering, University of Alberta, 9211-116, Street NW, Edmonton, AB, T6G 1H9, Canada; Public Works Department, Faculty of Engineering, Ain Shams University, 1 El Sarayat St., Abbassia, Cairo, 11517, Egypt
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 9211-116, Street NW, Edmonton, AB, T6G 1H9, Canada.
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22
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Hyun Chung T, Ranjan Dhar B. A multi-perspective review on microbial electrochemical technologies for food waste valorization. Bioresour Technol 2021; 342:125950. [PMID: 34852436 DOI: 10.1016/j.biortech.2021.125950] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/08/2021] [Accepted: 09/12/2021] [Indexed: 06/13/2023]
Abstract
The worldwide generation of food waste (FW) has been increasing enormously due to the growing food industry and population. However, FW contains a large amount of biodegradable organics that can be converted to clean energy, which can potentially minimize the utilization of fossil fuels. Conventional biowaste valorization technologies, such as anaerobic digestion and composting, have been adopted for FW management for recovering useful biogas and compost. However, they are often limited by high capital and operation costs, low recovery efficiency, slow process kinetics, and system instability. On the other hand, microbial electrochemical technologies (METs) have been highly promising for efficiently harvesting bioenergy and high value-added products from FW. Hence, this article critically reviews up-to-date studies on applying various METs regarding their value-added products recovery efficiencies from FW. Moreover, this review lists existing challenges, ways to optimize the system performance and provides perspectives on future research needs.
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Affiliation(s)
- Tae Hyun Chung
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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23
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Shekhar Bose R, Chowdhury B, Zakaria BS, Kumar Tiwari M, Ranjan Dhar B. Significance of different mixing conditions on performance and microbial communities in anaerobic digester amended with granular and powdered activated carbon. Bioresour Technol 2021; 341:125768. [PMID: 34469818 DOI: 10.1016/j.biortech.2021.125768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/06/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Conductive materials amendment in anaerobic digestion (AD) is a promising strategy for boosting the methanogenesis process. Despite mixing is a critical parameter, the behavior of digesters amended with conductive additives upon different mixing conditions has rarely been investigated. This study investigated continuous mixing, intermittent mixing (10 min in every 12 h), and non-mixing conditions for digesters amended with granular activated carbon (GAC) and powdered activated carbon (PAC). The non-mixed GAC digester provided the highest methane yield (318 ± 28 mL/g COD) from synthetic blackwater, while intermittently mixed GAC and control exhibited similar methane yields (290-294 mL/g COD). For non-mixed systems, microbial richness and diversity increased with GAC and PAC amendment. In contrast, continuous and intermittent mixing increased microbial diversity and richness in control reactors while reduced the same in GAC and PAC amended reactors. Overall, various mixing conditions distinctly changed the degree of enrichment/retention of microbes and consequently influenced methane recovery.
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Affiliation(s)
- Raj Shekhar Bose
- Civil and Environmental Engineering, University of Alberta, Edmonton AB, Canada; School of Water Resources, Indian Institute of Technology Kharagpur, WB, India
| | - Bappi Chowdhury
- Civil and Environmental Engineering, University of Alberta, Edmonton AB, Canada
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton AB, Canada
| | - Manoj Kumar Tiwari
- School of Water Resources, Indian Institute of Technology Kharagpur, WB, India
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton AB, Canada.
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24
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Dastyar W, Mohammad Mirsoleimani Azizi S, Dhadwal M, Ranjan Dhar B. High-solids anaerobic digestion of organic fraction of municipal solid waste: Effects of feedstock to inoculum ratio and percolate recirculation time. Bioresour Technol 2021; 337:125335. [PMID: 34139557 DOI: 10.1016/j.biortech.2021.125335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/23/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
The effects of feedstock to inoculum (F:I) ratio and percolate recirculation time (PRT) were studied for the high-solids anaerobic digestion (HSAD) of the organic fraction of municipal solid waste (OFMSW). Six mesophilic HSAD systems were operated at different F:I ratios (1 to 3 kg VS/kg VS; PRT = 2.5 h/d) and PRTs (1.5 to 3.5 h/d; F:I = 2 kg VS/kg VS). The F:I ratio of 1 provided up to 86% of the theoretical methane potential of OFMSW. In contrast, F:I ratio of 3 provided only 34% methane recovery due to volatile fatty acids (VFAs) accumulation and pH drop. Despite F:I ratio of 2 could provide 70% methane recovery, it could enable almost 45% higher organics processing capacity (VS basis) and lower solids washout during percolate recirculation, as compared to the F:I ratio of 1. However, different examined PRTs showed marginal impacts on methane yields with comparable changes in profiles of percolate characteristics.
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Affiliation(s)
- Wafa Dastyar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
| | | | - Mayank Dhadwal
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.
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25
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Meshref MNA, Azizi SMM, Dastyar W, Maal-Bared R, Dhar BR. Low-temperature thermal hydrolysis of sludge prior to anaerobic digestion: Principal component analysis (PCA) of experimental data. Data Brief 2021; 38:107323. [PMID: 34522731 PMCID: PMC8426196 DOI: 10.1016/j.dib.2021.107323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/12/2021] [Indexed: 11/05/2022] Open
Abstract
Here, we report data of the principal component analysis (PCA) assessment and clustering analysis related to low-temperature thermal hydrolysis process (THP) for enhancing the anaerobic digestion (AD) of sludge in wastewater treatment plants (WWTPs) with primary sludge fermentation (Azizi et al., 2021). The PCA was examined to pinpoint the influence of different THP schemes on the variations of macromolecular compounds solubilization after low-temperature THP and the relative performances in enhancing methane potential in AD. We established 2 experimental setups with a total of 18 treatment conditions (3 exposure times, 30, 60, and 90 min at three temperature levels 50, 70 and 90 °C) in comparison to the untreated control samples. Scheme-1 comprises the THP of a mixture of (1:1 vol ratio) fermented primary sludge (FPS) and thickened waste activated sludge (TWAS); while scheme-2 comprised the THP of TWAS only. The factors employed in the assessment of the PCA encompassed the variations in the macromolecular compounds and other solubilization metrics. This included the variations in the levels of carbohydrates, lipids, proteins, and solubilization of chemical oxygen demand (COD) and volatile suspended solids (VSS). Furthermore, the evaluation considered the changes of volatile fatty acids (VFAs) and total ammonia nitrogen (TAN) with respect to time and temperature. The assessment of PCA classified the THP based on their differences and alterations that occurred after the treatment. The indices of the PCA assessments differed based on the factors of concern and the focus of each individual PCA assessment. In every individual PCA assessment, the respective contribution to the total variance in PCA analysis was calculated and manifested by the highest distribution of the principal components (PCs) axis PC1 and PC2. The differences in distributions of PCs after various PCA examinations can describe the relative influence of THP schemes and the most significant variables that can trigger major differences among THP conditions. The comparative differences demonstrated by PCA support the potential investigations of the efficiency of THPs conditions and their performance categories.
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Affiliation(s)
- Mohamed N A Meshref
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada.,Public Works Department, Faculty of Engineering, Ain Shams University, 1 El Sarayat St., Abbassia, Cairo, 11517, Egypt
| | | | - Wafa Dastyar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Rasha Maal-Bared
- EPCOR Water Utilities, 2000-10423 101 Street NW, Edmonton, Alberta T5H 0E8, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 116 Street NW, Edmonton, AB T6G 1H9, Canada
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26
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Huang Q, Liu Y, Dhar BR. Pushing the organic loading rate in electrochemically assisted anaerobic digestion of blackwater at ambient temperature: Insights into microbial community dynamics. Sci Total Environ 2021; 781:146694. [PMID: 33812109 DOI: 10.1016/j.scitotenv.2021.146694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/17/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Decentralized blackwater treatment by anaerobic digestion is being considered as a sustainable sanitation concept. However, the low biodegradability and complex composition restrictedly limited the treatability of blackwater, resulting in requirements of low operational organic loading rates (OLRs). In this study, a microbial electrolysis cell assisted anaerobic digester (MEC-AD) treating vacuum toilet blackwater was successfully operated for 420 days at OLRs ranging from 0.77 to 3.03 g COD/L-d in 6 stages (including an open-circuit Stage 5) at ambient temperature. Based on the steady-state results from different stages, the highest methane yield (42.4% out of 45% biochemical methane potential value) was achieved in Stage 1 with an OLR of 0.77 g COD/L-d. At the same OLR of ~3.0 g COD/L-d, Stage 4 (32.4%) and Stage 6 (35.2%) showed significantly higher methane yield (p < 0.01) than open-circuit Stage 5 (24.1%). The lowest COD removal efficiency of 31.8% was observed in Stage 5 with short-chain volatile fatty acids (SCVFAs) accumulated to ~1000 mg/L, which was more than double the values of Stage 4 and 6. The microbial community analysis revealed that the applied potential did not significantly affect archaeal diversity but largely increased the archaeal abundance on the cathode, and led the bacterial community shift with the enrichment of specific electroactive bacteria. Microbial co-occurrence network analysis further confirmed the positive correlations between known electroactive bacteria and electrotrophic methanogens. Moreover, electric energy consumed by the MEC-AD system was fully recovered as biomethane.
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Affiliation(s)
- Qi Huang
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
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Chung TH, Dhar BR. Paper-based platforms for microbial electrochemical cell-based biosensors: A review. Biosens Bioelectron 2021; 192:113485. [PMID: 34274625 DOI: 10.1016/j.bios.2021.113485] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/30/2021] [Accepted: 07/02/2021] [Indexed: 12/13/2022]
Abstract
The development of low-cost analytical devices for on-site water quality monitoring is a critical need, especially for developing countries and remote communities in developed countries with limited resources. Microbial electrochemical cell-based (MXC) biosensors have been quite promising for quantitative and semi-quantitative (often qualitative) measurements of various water quality parameters due to their low cost and simplicity compared to traditional analytical methods. However, conventional MXC biosensors often encounter challenges, such as the slow establishment of biofilms, low sensitivity, and poor recoverability, making them unable to be applied for practical cases. In response, MXC biosensors assembled with paper-based materials demonstrated tremendous potentials to enhance sensitivity and field applicability. Furthermore, the paper-based platforms offer many prominent features, including autonomous liquid transport, rapid bacterial adhesion, lowered resistance, low fabrication cost (<$1 in USD), and eco-friendliness. Therefore, this review aims to summarize the current trend and applications of paper-based MXC biosensors, along with critical discussions on their field applicability. Moreover, future advancements of paper-based MXC biosensors, such as developing a novel paper-based biobatteries, increasing the system performance using an unique biocatalyst, such as yeast, and integrating the biosensor system with other advanced tools, such as machine learning and 3D printing, are highlighted.
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Affiliation(s)
- Tae Hyun Chung
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, T6G 1H9, Canada.
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Shekhar Bose R, Zakaria BS, Kumar Tiwari M, Ranjan Dhar B. High-rate blackwater anaerobic digestion under septic tank conditions with the amendment of biosolids-derived biochar synthesized at different temperatures. Bioresour Technol 2021; 331:125052. [PMID: 33812134 DOI: 10.1016/j.biortech.2021.125052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Septic tanks have been widely used for blackwater treatment in developing countries, while high-rate septic tanks with improved methane recovery are yet to be achieved. This study investigated biosolids-derived biochar (synthesized at 300℃, 425℃, and 550℃) as an additive for developing high-rate septic tanks. The experiments were conducted with anaerobic bioreactors operated with synthetic blackwater under septic tank conditions. All biochar amended reactors demonstrated a steady increase in daily methane production for increasing OLR from 0.08 to 3 g COD/L/d. The control reactor showed significant process disturbances at OLRs ≥ 2 g COD/L/d with an accumulation of volatile fatty acids followed by pH drop. At OLR of 3 g COD/L/d, the daily methane production from biochar amended reactors was ~ 4.3 times higher than the control (300 vs. 70 mL per day). Biochar addition established a robust microbiome consisted of a higher abundance of hydrogenotrophic and acetoclastic methanogens and hydrogen-producing fermentative bacteria.
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Affiliation(s)
- Raj Shekhar Bose
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada; School of Water Resources, Indian Institute of Technology Kharagpur, WB, India
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Manoj Kumar Tiwari
- School of Water Resources, Indian Institute of Technology Kharagpur, WB, India
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada.
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29
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Pereira de Albuquerque F, Dhadwal M, Dastyar W, Mirsoleimani Azizi SM, Karidio I, Zaman H, Dhar BR. Fate of disposable face masks in high-solids anaerobic digestion: Experimental observations and review of potential environmental implications. Case Stud Chem Environ Eng 2021; 3:100082. [PMID: 38620309 PMCID: PMC7816893 DOI: 10.1016/j.cscee.2021.100082] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/12/2021] [Accepted: 01/16/2021] [Indexed: 05/18/2023]
Abstract
Face masks became a part of our daily life amid the global COVID-19 (SARS-CoV-2) pandemic. Most of the face masks are made for single-use and primarily disposed of in garbage bins with other non-recyclable wastes. To date, little is known about how disposable face masks in municipal solid waste (MSW) would interfere with high-solids anaerobic digestion (HSAD) in waste management facilities. Here, we first report preliminary results from a lab experiment conducted with the organic fraction of municipal solid waste (OFMSW) amended with used disposable face masks. The lab-scale HSAD systems were operated with percolate recirculation comparable to commercial HSAD systems typically used for full-scale processing of OFMSW. The results suggested that the presence of face masks in OFMSW could negatively affect methane productivity and kinetics. In the digesters amended with face masks, total cumulative methane production decreased by up to 18%, along with a 12-29% decrease in maximum methane production rates than the control digester (without face masks). Moreover, lag phases increased by 7-14%. The results also suggested that the type of polymeric materials used in face masks would be more critical than their total number/loading in the digester, which warrants further investigation. The visual inspection of digestate showed that the face masks were mostly undegraded after 40 days of operation. Much remains unknown about how the undegraded face masks will affect the digestate management practices, such as composting, land application, and landfilling. However, the review of existing literature suggested that they can be a potential source of plastic and microplastic pollution and amplify transmission of antibiotic resistance genes to the ecosystem. In summary, this study underscores the importance of developing safe and reliable disposal guidelines and management plans for single-use face masks.
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Affiliation(s)
| | - Mayank Dhadwal
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Wafa Dastyar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | | | - Ibrahim Karidio
- Edmonton Waste Management Centre, City of Edmonton, Edmonton, AB, Canada
| | - Hamid Zaman
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
- Edmonton Waste Management Centre, City of Edmonton, Edmonton, AB, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
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30
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Mohammad Mirsoleimani Azizi S, Hai FI, Lu W, Al-Mamun A, Ranjan Dhar B. A review of mechanisms underlying the impacts of (nano)microplastics on anaerobic digestion. Bioresour Technol 2021; 329:124894. [PMID: 33662851 DOI: 10.1016/j.biortech.2021.124894] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
The presence of (nano)microplastics in domestic wastewater and their subsequent release to the aquatic environment via the discharge of treated sewage has raised significant concerns. Previous studies have also identified their excessive accumulation in sewage sludge. Anaerobic digestion is one of the most used sludge stabilization methods in wastewater treatment plants. Therefore, understanding the potential effects of (nano)microplastics on anaerobic digestion has been receiving increasing attention from researchers. This article provides a comprehensive review of mechanisms underlying the impacts of (nano)microplastics on anaerobic digestion. Notably, this review covers mechanisms of inhibition/enhancement of anaerobic digestion by (nano)microplastics and their potential impacts on biochemical pathways, key enzymes, functional genes, and microbial communities investigated to date. Moreover, potential environmental risks of biosolids contaminated with (nano)microplastics were highlighted. Finally, knowledge gaps and future research needs were outlined. This review will guide more standardized studies in the future, covering both fundamental and engineering aspects.
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Affiliation(s)
| | - Faisal I Hai
- Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Wenjing Lu
- Environmental Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Abdullah Al-Mamun
- Civil and Architectural Engineering, Sultan Qaboos University, P.O. Box 33, Al-Khoud 123, Muscat, Oman
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, Canada.
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31
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Zakaria BS, Dhar BR. Characterization and significance of extracellular polymeric substances, reactive oxygen species, and extracellular electron transfer in methanogenic biocathode. Sci Rep 2021; 11:7933. [PMID: 33846480 PMCID: PMC8041852 DOI: 10.1038/s41598-021-87118-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 03/24/2021] [Indexed: 02/01/2023] Open
Abstract
The microbial electrolysis cell assisted anaerobic digestion holds great promises over conventional anaerobic digestion. This article reports an experimental investigation of extracellular polymeric substances (EPS), reactive oxygen species (ROS), and the expression of genes associated with extracellular electron transfer (EET) in methanogenic biocathodes. The MEC-AD systems were examined using two cathode materials: carbon fibers and stainless-steel mesh. A higher abundance of hydrogenotrophic Methanobacterium sp. and homoacetogenic Acetobacterium sp. appeared to play a major role in superior methanogenesis from stainless steel biocathode than carbon fibers. Moreover, the higher secretion of EPS accompanied by the lower ROS level in stainless steel biocathode indicated that higher EPS perhaps protected cells from harsh metabolic conditions (possibly unfavorable local pH) induced by faster catalysis of hydrogen evolution reaction. In contrast, EET-associated gene expression patterns were comparable in both biocathodes. Thus, these results indicated hydrogenotrophic methanogenesis is the key mechanism, while cathodic EET has a trivial role in distinguishing performances between two cathode electrodes. These results provide new insights into the efficient methanogenic biocathode development.
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Affiliation(s)
- Basem S. Zakaria
- grid.17089.37Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9 Canada
| | - Bipro Ranjan Dhar
- grid.17089.37Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9 Canada
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32
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Fida Z, Price WE, Pramanik BK, Dhar BR, Kumar M, Jiang G, Hai FI. Reduction of excess sludge production by membrane bioreactor coupled with anoxic side-stream reactors. J Environ Manage 2021; 281:111919. [PMID: 33418384 DOI: 10.1016/j.jenvman.2020.111919] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 12/14/2020] [Accepted: 12/27/2020] [Indexed: 06/12/2023]
Abstract
While cleaning wastewater, biological wastewater treatment processes such as membrane bioreactors (MBR) produce a significant amount of sludge that requires costly management. In the oxic-settling-anoxic (OSA) process, sludge is retained for a temporary period in side-stream reactors with low oxygen and substrate, and then it is recirculated to the main reactor. In this way, excess sludge production is reduced. We studied the influence of the rate of sludge exchange between MBR and side-stream anoxic reactors on sludge yield reduction within MBR. Two MBRs, namely, MBROSA and MBRcontrol, each coupled with separate external anoxic side-stream reactors, were run in parallel for 350 days. Unlike MBRcontrol, MBROSA had sludge exchange with the external reactors connected to it. During the investigation over a sludge interchange rate (SIR) range of 0-22%, an SIR of 11% achieved the highest sludge reduction (58%). Greater volatile solids destruction i.e., bacterial cell lysis and extracellular polymeric substance (EPS) destruction occurred at the SIR of 11%, which helped to achieve the highest sludge reduction. The enhanced volatile solids destruction was evident by the release of nutrients in the external anoxic reactors. It was confirmed that the sludge yield reduction was achieved without compromising the wastewater treatment quality, sludge settleability and hydraulic performance of the membrane in MBR.
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Affiliation(s)
- Zulqarnain Fida
- Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - William E Price
- Strategic Water Infrastructure Laboratory, School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | | | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116, Street NW, Edmonton, AB T6G 1H9, Canada
| | - Manish Kumar
- Discipline of Earth Sciences, Indian Institute of Technology Gandhinagar, Gujarat, 382355, India
| | - Guangming Jiang
- School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Faisal I Hai
- Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia.
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33
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Zhou P, Meshref MNA, Dhar BR. Optimization of thermal hydrolysis process for enhancing anaerobic digestion in a wastewater treatment plant with existing primary sludge fermentation. Bioresour Technol 2021; 321:124498. [PMID: 33316702 DOI: 10.1016/j.biortech.2020.124498] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/27/2020] [Accepted: 11/28/2020] [Indexed: 06/12/2023]
Abstract
Many wastewater treatment plants (WWTPs) adopted primary sludge fermentation to produce sludge liquor for the biological denitrification process. The fermented primary sludge (FPS) is usually co-digested with thickened waste activated sludge (TWAS) in the anaerobic digestion (AD) process. To date, there has been limited information on how the sludge thermal hydrolysis process (THP) could be retrofitted for enhancing AD in WWTPs with the existing primary sludge fermentation process. This study assessed two THP retrofitting schemes, (FPS + TWAS and TWAS alone) combining different exposure times (15, 30, and 60 min) and temperatures (140, 160, and 180 °C). The results suggested that temperature had more impact on sludge solubilization than exposure times. Notably, 180 °C was the most effective for sludge solubilization under both schemes. However, a higher degree of solubilization did not necessarily lead to higher methane yields. The THP of FPS + TWAS attained considerably higher methane yield than the pretreatment of TWAS alone.
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Affiliation(s)
- Peijun Zhou
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Mohamed N A Meshref
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada; Public Works Department, Faculty of Engineering, Ain Shams University, 1 El Sarayat St., Abbassia, Cairo 11517, Egypt
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
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34
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Zakaria BS, Ranjan Dhar B. An intermittent power supply scheme to minimize electrical energy input in a microbial electrolysis cell assisted anaerobic digester. Bioresour Technol 2021; 319:124109. [PMID: 33035866 DOI: 10.1016/j.biortech.2020.124109] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 06/11/2023]
Abstract
From the perspective of energy saving in the operation of microbial electrolysis cell assisted anaerobic digester (MEC-AD), this study focused on developing an intermittent power supply scheme. The applied potential was switched off for 12 and 6 hours/day during the operation of a laboratory-scale MEC-AD system fed with glucose. The results from the operation under continuous applied potential served as the control. The overall biomethane generation and net energy income from the process were unaffected when the applied potential turned off for 6 hours/day. Both quantitative and qualitative analyses of microbial communities suggested that a balanced microbiome could be maintained under short-term switching-off the applied potential. However, performance substantially deteriorated when the applied potential turned off for 12 hours/day. Overall, the results of this study suggest that MEC-AD operation does not need a continuous power supply, and higher energy efficiency can be effectively achieved by intermittently powering the reactor.
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Affiliation(s)
- Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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35
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Ting HNJ, Lin L, Cruz RB, Chowdhury B, Karidio I, Zaman H, Dhar BR. Transitions of microbial communities in the solid and liquid phases during high-solids anaerobic digestion of organic fraction of municipal solid waste. Bioresour Technol 2020; 317:123951. [PMID: 32822895 DOI: 10.1016/j.biortech.2020.123951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/28/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
This study presents a microbiological diagnosis of a mesophilic high-solids anaerobic digestion (HSAD) system with percolate recirculation. The results demonstrated a significant decrease in microbial diversity in both the solid digestate and the liquid percolate. Also, the digestate from the top and middle sections of the digester had similar diversity, whereas the digestate from the bottom of the tank had a slightly lower diversity. These results suggest that despite percolate recirculation, substrate gradients might have developed across the system. Archaeal communities showed shifts towards known hydrogenotrophic and ammonia-tolerant methanogens (genera Methanocelleus, Methanolinea, Methanosarcina, vadin CA11, etc.), which was a consequence of decreased volatile fatty acids and increased ammonia-nitrogen levels over time. Compared to initial solid and liquid inoculum, the relative abundances of some bacteria (phyla Proteobacteria and Firmicutes) and archaea of the genus Methanosarcina changed between two phases in the opposite direction, indicating a shift of microbes between two phases.
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Affiliation(s)
- Hok Nam Joey Ting
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Long Lin
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Raul Bello Cruz
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Bappi Chowdhury
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada
| | - Ibrahim Karidio
- Edmonton Waste Management Centre, City of Edmonton, Edmonton, AB, Canada
| | - Hamid Zaman
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada; Edmonton Waste Management Centre, City of Edmonton, Edmonton, AB, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada.
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36
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Chung TH, Meshref MNA, Hai FI, Al-Mamun A, Dhar BR. Microbial electrochemical systems for hydrogen peroxide synthesis: Critical review of process optimization, prospective environmental applications, and challenges. Bioresour Technol 2020; 313:123727. [PMID: 32646578 DOI: 10.1016/j.biortech.2020.123727] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 06/19/2020] [Accepted: 06/20/2020] [Indexed: 06/11/2023]
Abstract
Hydrogen peroxide (H2O2) is an industrial chemical that has been widely adopted for various industrial applications, including water and wastewater treatment. Currently, the majority of H2O2 is being produced through the anthraquinone oxidation process, which is disadvantageous due to the requirement of toxic raw materials and high energy input. Recently, microbial electrochemical cells (MXCs), such as microbial fuel cells and microbial electrolysis cells, have demonstrated great potential for effective H2O2 production via cathodic oxygen-reduction reaction (ORR). Previous studies have specified key operational parameters for scaling-up of H2O2-producing MXCs, where improvements in production rate, conversion efficiency, product concentration and stability are attainable. Moreover, various systems have demonstrated their value proposition in the contaminant removal aspects through direct removal of various environmental pollutants, water disinfection, and many more. This review is intended to highlight promising ways of H2O2 production with MXCs and on-site environmental applications of bioelectrochemically-produced H2O2.
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Affiliation(s)
- Tae Hyun Chung
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Mohamed N A Meshref
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada; Public Works Department, Faculty of Engineering, Ain Shams University, 1 El Sarayat St., Abbassia, 11517 Cairo, Egypt
| | - Faisal I Hai
- Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Abdullah Al-Mamun
- Department of Civil and Architectural Engineering, Sultan Qaboos University, Al-Khoud 123, Muscat, Oman
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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Zakaria BS, Dhar BR. Changes in syntrophic microbial communities, EPS matrix, and gene-expression patterns in biofilm anode in response to silver nanoparticles exposure. Sci Total Environ 2020; 734:139395. [PMID: 32454336 DOI: 10.1016/j.scitotenv.2020.139395] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/10/2020] [Accepted: 05/10/2020] [Indexed: 05/25/2023]
Abstract
Understanding the toxic effect of silver nanoparticles (AgNPs) on various biological wastewater treatment systems is of significant interest to researchers. In recent years, microbial electrochemical technologies have opened up new opportunities for bioenergy and chemicals production from organic wastewater. However, the effects of AgNPs on microbial electrochemical systems are yet to be understood fully. Notably, no studies have investigated the impact of AgNPs on a microbial electrochemical system fed with a complex fermentable substrate. Here, we investigated the impact of AgNPs (50 mg/L) exposure to a biofilm anode in a microbial electrolysis cell (MEC) fed with glucose. The volumetric current density was 29 ± 2.0 A/m3 before the AgNPs exposure, which decreased to 20 ± 2.2 A/m3 after AgNPs exposure. The biofilms produced more extracellular polymeric substances (EPS) to cope with the AgNPs exposure, while carbohydrate to protein ratio in EPS considerably increased from 0.4 to 0.7. Scanning electron microscope (SEM) imaging also confirmed the marked excretion of EPS, forming a thick layer covering the anode biofilms after AgNPs injection. Transmission electron microscope (TEM) imaging showed that AgNPs still penetrated some microbial cells, which could explain the deterioration of MEC performance after AgNPs exposure. The relative expression level of the quorum signalling gene (LuxR) increased by 30%. Microbial community analyses suggested that various fermentative bacterial species (e.g., Bacteroides, Synergistaceae_vadinCA02, Dysgonomonas, etc.) were susceptible to AgNPs toxicity, which led to the disruption of their syntrophic partnership with electroactive bacteria. The abundance of some specific electroactive bacteria (e.g., Geobacter species) also decreased. Moreover, decreased relative expressions of various extracellular electron transfer associated genes (omcB, omcC, omcE, omcZ, omcS, and pilA) were observed. However, the members of family Enterobacteriaceae, known to perform a dual function of fermentation and anodic respiration, became dominant after biofilm anode exposed to AgNPs. Thus, EPS extraction provided partial protection against AgNPs exposure.
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Affiliation(s)
- Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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Chung TH, Meshref MN, Dhar BR. Microbial electrochemical biosensor for rapid detection of naphthenic acid in aqueous solution. J Electroanal Chem (Lausanne) 2020. [DOI: 10.1016/j.jelechem.2020.114405] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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39
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Chowdhury B, Lin L, Dhar BR, Islam MN, McCartney D, Kumar A. Enhanced biomethane recovery from fat, oil, and grease through co-digestion with food waste and addition of conductive materials. Chemosphere 2019; 236:124362. [PMID: 31323554 DOI: 10.1016/j.chemosphere.2019.124362] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/25/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
In this study, the effect of conductive additives on co-digestion of fat, oil, and grease (FOG) and food waste (FW) was evaluated. Initially, biochemical methane potential (BMP) test was conducted for optimization of mixing ratio of FW and FOG. The optimal methane production (800 L (kg VS)-1) was obtained from co-digestion of 70% FW + 30% FOG (w/w), which was 1.2 times and 12 times of that obtained from mono-digestion of FW and FOG, respectively. This optimal mixing ratio was used for subsequent fed-batch studies with the addition of two conductive additives, granular activated carbon (GAC) and magnetite. The addition of GAC significantly shortened the lag phase (from 7 to 3 d), reduced accumulation of various volatile fatty acids (VFAs), and enhanced methane production rate (50-80% increase) compared to the control and magnetite-amended bioreactor. Fourier transformation infrared (FTIR) analysis suggested that the degradation of lipids, protein and carbohydrates was the highest in GAC amended reactor, followed by magnetite and control reactors. GAC addition also enriched more abundant and diverse bacteria and methanogens than control. Magnetite addition also showed similar trends but to a lesser degree. The substantial enrichment of syntrophic LCFA β-oxidizing bacteria (e.g. Syntrophomonas) and methanogenic archaea in the GAC-amended bioreactor likely attributed to the superior methanogenesis kinetics in GAC amended bioreactor. Our findings suggest that the addition of GAC could provide a sustainable strategy to enrich kinetically efficient syntrophic microbiome to favor methanogenesis kinetics in co-digestion of FW and FOG.
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Affiliation(s)
- Bappi Chowdhury
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - Long Lin
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.
| | | | - Daryl McCartney
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - Amit Kumar
- Department of Mechanical Engineering, University of Alberta, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
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Zakaria BS, Lin L, Dhar BR. Shift of biofilm and suspended bacterial communities with changes in anode potential in a microbial electrolysis cell treating primary sludge. Sci Total Environ 2019; 689:691-699. [PMID: 31280150 DOI: 10.1016/j.scitotenv.2019.06.519] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/29/2019] [Accepted: 06/29/2019] [Indexed: 06/09/2023]
Abstract
This study, for the first time, documented microbial community shifts in response to the changes in anode potential in a microbial electrolysis cell (MEC) operated with primary sludge. At an anode potential of -0.4 V vs. Ag/AgCl, the MEC showed COD and VSS removal efficiencies of 73 ± 1% and 75 ± 2%, respectively. The volumetric current density and specific hydrogen production rate were 23 ± 1.2 A/m3, and 145 ± 4.1 L/m3-d, respectively. The anodic microbial community was consisted of various fermentative/hydrolytic bacteria (e.g., Bacteroides and Dysgonomonas) and anode-respiring bacteria (Geobacter), while different hydrolytic/fermentative bacteria were abundant in suspension. The MEC showed substantially inferior performance along with a higher accumulation of various volatile fatty acids when the anode potential was switched to more positive values (0 V and +0.4 V). Both biofilms and suspended communities were also shifted when the anode potential was changed. Notably, at +0.4 V, Geobacter genus entirely disappeared from the biofilms, while Paludibacter species (known fermentative bacteria) were selectively enriched in biofilms. Also, the relative abundance of genus Bacteroides (known hydrolytic bacteria) substantially decreased in both biofilms and suspension, which was correlated with the inferior hydrolysis of VSS. Quantitative comparison of biofilms and suspended microbial communities at different anode potentials revealed a sharp decrease in bacterial cell numbers in anode biofilms after changing anode potential from -0.4 V to +0.4 V. By contrast, bacterial cell numbers in suspension were slightly decreased. Collectively, these results provide new insights into the role of anode potential in shaping key microbial players associated with hydrolysis/fermentation and anodic respiration processes when MECs are operated with real biowastes.
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Affiliation(s)
- Basem S Zakaria
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Long Lin
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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Zakaria BS, Dhar BR. Progress towards catalyzing electro-methanogenesis in anaerobic digestion process: Fundamentals, process optimization, design and scale-up considerations. Bioresour Technol 2019; 289:121738. [PMID: 31300305 DOI: 10.1016/j.biortech.2019.121738] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/26/2019] [Accepted: 06/30/2019] [Indexed: 06/10/2023]
Abstract
Electro-methanogenesis represents an emerging bio-methane production pathway that can be achieved through integrating microbial electrolysis cell (MEC) with conventional anaerobic digester (AD). Since 2009, a significant number of publications have reported superior methane productivity and kinetics from MEC-AD integrated systems. The overall objective of this review is to communicate the recent advances towards promoting electro-methanogenesis in the anaerobic digestion process. Firstly, the electro-methanogenesis pathways and functional roles of key microbial members are summarized. Secondly, various extrinsic process parameters, such as applied voltage/potential, pH, and temperature are discussed with emphasis on process optimization. Moreover, available methods for the inoculation and start-up of MEC-AD process are critically reviewed. Finally, system design and scale-up considerations, such as the selection of electrode materials, surface area and surface chemistry of electrode materials, and electrode spacing are summarized.
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Affiliation(s)
- Basem S Zakaria
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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Ryue J, Lin L, Liu Y, Lu W, McCartney D, Dhar BR. Comparative effects of GAC addition on methane productivity and microbial community in mesophilic and thermophilic anaerobic digestion of food waste. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2019.03.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Barua S, Zakaria BS, Lin L, Dhar BR. Shaping microbial communities with conductive carbon fibers to enhance methane productivity and kinetics. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2018.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Zakaria BS, Barua S, Sharaf A, Liu Y, Dhar BR. Impact of antimicrobial silver nanoparticles on anode respiring bacteria in a microbial electrolysis cell. Chemosphere 2018; 213:259-267. [PMID: 30223131 DOI: 10.1016/j.chemosphere.2018.09.060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 09/08/2018] [Accepted: 09/10/2018] [Indexed: 06/08/2023]
Abstract
This study assessed the impact of antimicrobial AgNPs (50 mg L-1, 30-50 nm) on the electrocatalytic activity of a mixed-culture anode biofilm enriched with Geobacter species. The current densities and electrochemical kinetics were maintained after exposure to AgNPs in consecutive fed-batch cycles, despite significant changes in morphological structures and bacterial communities. Bacterial community analysis showed a substantial increase in the Geobacter population in response to AgNPs exposure, indicating their higher tolerance to AgNPs. In contrast, the population of other anode respiring bacteria (ARB) belongs to Acinetobacter, Dysgonomonas, and Cloacibacillus genera appeared to be very sensitive to AgNPs toxicity as their relative abundance significantly decreased. Microscopic imaging showed that AgNPs were accumulated within anode biofilm matrix without penetration inside the cells. Moreover, the anode biofilm became denser because of enhanced extracellular polymeric substances (EPSs) production by ARB after exposure of AgNPs, implying that EPS could protect ARB against AgNPs toxicity.
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Affiliation(s)
- Basem S Zakaria
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, T6G 1H9, Canada
| | - Sajib Barua
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, T6G 1H9, Canada
| | - Ahmed Sharaf
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, T6G 1H9, Canada
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB, T6G 1H9, Canada.
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Barua S, Zakaria BS, Dhar BR. Enhanced methanogenic co-degradation of propionate and butyrate by anaerobic microbiome enriched on conductive carbon fibers. Bioresour Technol 2018; 266:259-266. [PMID: 29982046 DOI: 10.1016/j.biortech.2018.06.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 06/13/2018] [Accepted: 06/16/2018] [Indexed: 05/10/2023]
Abstract
Recent studies have shown that the addition of conductive materials can promote direct interspecies electron transfer (DIET) between bacteria and methanoarchaea. This study demonstrated that carbon fibers could significantly stimulate methanogenic conversion of propionate and butyrate as co-substrate, while only butyrate was completely degraded in the unamended control bioreactor. In the carbon fibers-amended bioreactor, specific methane production (mL-CH4/g CODInitial) and methanogenesis rate (d-1) increased by around 2.4 and 6.7 times, respectively. Various electroactive bacteria were abundant in the carbon fibers-amended bioreactor, whereas different known fermentative bacteria were abundant in the control. Moreover, carbon fibers substantially increased the abundance of Methanosaeta species. These results suggest that electroactive bacteria could be involved in DIET with Methanosaeta species enabling co-degradation of propionate and butyrate. Additionally, electrical conductivities of the biomass were comparable in both configurations, indicating that carbon fibers were the primary route for DIET.
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Affiliation(s)
- Sajib Barua
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Basem S Zakaria
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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Dhar BR, Sim J, Ryu H, Ren H, Santo Domingo JW, Chae J, Lee HS. Microbial activity influences electrical conductivity of biofilm anode. Water Res 2017; 127:230-238. [PMID: 29055828 PMCID: PMC7321815 DOI: 10.1016/j.watres.2017.10.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 10/11/2017] [Accepted: 10/12/2017] [Indexed: 05/14/2023]
Abstract
This study assessed the conductivity of a Geobacter-enriched biofilm anode in a microbial electrochemical cell (MxC) equipped with two gold anodes (25 mM acetate medium), as different proton gradients were built throughout the biofilm. There was no pH gradient across the biofilm anode at 100 mM phosphate buffer (current density 2.38 A/m2) and biofilm conductivity (Kbio) was as high as 0.87 mS/cm. In comparison, an inner biofilm became acidic at 2.5 mM phosphate buffer in which dead cells were accumulated at ∼80 μm of the inner biofilm anode. At this low phosphate buffer, Kbio significantly decreased by 0.27 mS/cm, together with declined current density of 0.64 A/m2. This work demonstrates that biofilm conductivity depends on the composition of live and dead cells in the conductive biofilm anode.
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Affiliation(s)
- Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, Alberta, T6G 1H9, Canada; Civil and Environmental Engineering, University of Waterloo, 200 University Avenue, West Waterloo, Ontario, N2L 3G, Canada.
| | - Junyoung Sim
- Civil and Environmental Engineering, University of Waterloo, 200 University Avenue, West Waterloo, Ontario, N2L 3G, Canada.
| | - Hodon Ryu
- National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Hao Ren
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA.
| | - Jorge W Santo Domingo
- National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Junseok Chae
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA.
| | - Hyung-Sool Lee
- Civil and Environmental Engineering, University of Waterloo, 200 University Avenue, West Waterloo, Ontario, N2L 3G, Canada.
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Al-Mamun A, Baawain MS, Dhar BR, Kim IS. Improved recovery of bioenergy and osmotic water in an osmotic microbial fuel cell using micro-diffuser assisted marine aerobic biofilm on cathode. Biochem Eng J 2017. [DOI: 10.1016/j.bej.2017.09.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Barua S, Dhar BR. Advances towards understanding and engineering direct interspecies electron transfer in anaerobic digestion. Bioresour Technol 2017; 244:698-707. [PMID: 28818798 DOI: 10.1016/j.biortech.2017.08.023] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/03/2017] [Accepted: 08/05/2017] [Indexed: 05/16/2023]
Abstract
Direct interspecies electron transfer (DIET) is a recently discovered microbial syntrophy where cell-to-cell electron transfer occurs between syntrophic microbial species. DIET between bacteria and methanogenic archaea in anaerobic digestion can accelerate the syntrophic conversion of various reduced organic compounds to methane. DIET-based syntrophy can naturally occur in some anaerobic digester via conductive pili, however, can be engineered via the addition of various non-biological conductive materials. In recent years, research into understanding and engineering DIET-based syntrophy has emerged with the aim of improving methanogenesis kinetics in anaerobic digestion. This article presents a state-of-art review focusing on the fundamental mechanisms, key microbial players, the role of electrical conductivity, the effectiveness of various conductive additives, the significance of substrate characteristics and organic loading rates in promoting DIET in anaerobic digestion.
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Affiliation(s)
- Sajib Barua
- Department of Civil and Environmental Engineering, School of Mining & Petroleum Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, School of Mining & Petroleum Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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Dhar BR, Ryu H, Ren H, Domingo JWS, Chae J, Lee HS. High Biofilm Conductivity Maintained Despite Anode Potential Changes in a Geobacter-Enriched Biofilm. ChemSusChem 2016; 9:3485-3491. [PMID: 27870324 PMCID: PMC7377214 DOI: 10.1002/cssc.201601007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 08/25/2016] [Indexed: 05/25/2023]
Abstract
This study systematically assessed intracellular electron transfer (IET) and extracellular electron transfer (EET) kinetics with respect to anode potential (Eanode ) in a mixed-culture biofilm anode enriched with Geobacter spp. High biofilm conductivity (0.96-1.24 mS cm-1 ) was maintained during Eanode changes from -0.2 to +0.2 V versus the standard hydrogen electrode (SHE), although the steady-state current density significantly decreased from 2.05 to 0.35 A m-2 in a microbial electrochemical cell. Substantial increase of the Treponema population was observed in the biofilm anode at Eanode =+0.2 V, which reduced intracellular electron-transfer kinetics associated with the maximum specific substrate-utilization rate by a factor of ten. This result suggests that fast EET kinetics can be maintained under dynamic Eanode conditions in a highly conductive biofilm anode as a result of shift of main EET players in the biofilm anode, although Eanode changes can influence IET kinetics.
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Affiliation(s)
- Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, Alberta, T6G 1H9, Canada
| | - Hodon Ryu
- National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, USA
| | - Hao Ren
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Jorge W Santo Domingo
- National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, USA
| | - Junkseck Chae
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Hyung-Sool Lee
- Civil and Environmental Engineering, University of Waterloo, 200 University Avenue, West Waterloo, Ontario, N2L 3G, Canada
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Lee HS, Dhar BR, An J, Rittmann BE, Ryu H, Santo Domingo JW, Ren H, Chae J. The Roles of Biofilm Conductivity and Donor Substrate Kinetics in a Mixed-Culture Biofilm Anode. Environ Sci Technol 2016; 50:12799-12807. [PMID: 27797183 PMCID: PMC7388032 DOI: 10.1021/acs.est.6b04168] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We experimentally assessed the kinetics and thermodynamics of electron transfer (ET) from the donor substrate (acetate) to the anode for a mixed-culture biofilm anode. We interpreted the results with a modified biofilm-conduction model consisting of three ET steps in series: (1) intracellular ET, (2) non-Ohmic extracellular ET (EET) from an outer membrane protein to an extracellular cofactor (EC), and (3) ET from the EC to the anode by Ohmic-conduction in the biofilm matrix. The steady-state current density was 0.82 ± 0.03 A/m2 in a miniature microbial electrochemical cell operated at fixed anode potential of -0.15 V versus the standard hydrogen electrode. Illumina 16S-rDNA and -rRNA sequences showed that the Geobacter genus was less than 30% of the community of the biofilm anode. Biofilm conductivity was high at 2.44 ± 0.42 mS/cm, indicating that the maximum current density could be as high as 270 A/m2 if only Ohmic-conduction EET was limiting. Due to the high biofilm conductivity, the maximum energy loss for Ohmic-conduction EET was negligible, 0.085 mV. The energy loss in the second ET step also was small, only 20 mV, and the potential for the EC involved in the second ET was -0.15 V, a value documenting that >99% of the EC was in the oxidized state. Monod kinetics for utilization of acetate were relatively slow, and at least 87% of the energy loss was in the intracellular step. Thus, intracellular ET was the main kinetic and thermodynamic bottleneck to ET from donor substrate to the anode for a highly conductive biofilm.
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Affiliation(s)
- Hyung-Sool Lee
- Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L3G1, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L3G1, Canada
| | - Junyeong An
- Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L3G1, Canada
| | - Bruce E. Rittmann
- Swette Center for Environmental Biotechnology, The Biodesign Institute at Arizona State University, P.O. Box 875701, Tempe, Arizona 85287-5701, United States
| | - Hodon Ryu
- National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, Ohio 45268, United States
| | - Jorge W. Santo Domingo
- National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, Ohio 45268, United States
| | - Hao Ren
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, United States
| | - Junseok Chae
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, United States
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