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Wang Z, Liao Y, Yan L, Liao B. Biological performance and membrane fouling of a microalgal-bacterial membrane photobioreactor for wastewater treatment without external aeration and carbonation. Environ Res 2024; 247:118272. [PMID: 38246292 DOI: 10.1016/j.envres.2024.118272] [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: 11/23/2023] [Revised: 01/10/2024] [Accepted: 01/18/2024] [Indexed: 01/23/2024]
Abstract
Biological nutrient removal processes involving the use of activated sludge (AS) to treat municipal wastewater normally result in high aeration energy consumption and significant greenhouse gas (GHG) emissions. Therefore, developing cost-efficient and environmentally friendly processes for wastewater treatment is vital. In this work, a novel non-aerated microalgal-bacterial membrane photobioreactor (MB-MPBR) was proposed, and its feasibility for organic contaminant and nutrient removals was evaluated, for the first time. The effects of inoculation ratio (microalgae to bacteria (M/B)) on the biological performance and membrane fouling were systematically investigated. The results showed that 95.9% of the chemical oxygen demand (COD), 74.5% of total nitrogen (TN), 98.5% of NH4+-N and 42.0% of total phosphorus (TP) were removed at an inoculation M/B ratio of 3:2 at steady state, representing a significant improvement compared to the M/B inoculation ratio of 1:3. Additionally, the higher inoculation M/B ratio (3:2) significantly promoted the biomass production owing to the favorable mutual exchange of oxygen and carbon dioxide between microalgae and bacteria. Cake layer formation was the primary fouling mechanism owing to the absence of aeration scouring on the membrane surface. The membrane fouling rate was slightly higher at the higher inoculation ratio (M/B = 3:2) owing to the increased biomass and extracellular polymeric substances (EPS) productions, despite the larger particle size. These results demonstrated that the non-aerated MB-MPBR could achieve superior biological performance, of which the inoculation M/B ratio was of critical importance for the initiation and maintenance of microalgal-bacterial symbiotic system, yet possibly caused severer membrane fouling in the absence of external aeration and carbonation. This study provides a new perspective for further optimizing and applying non-aerated MB-MPBR to enhance municipal wastewater treatment.
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Affiliation(s)
- Zhaozhao Wang
- College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, 063210, PR China; College of Energy and Environmental Engineering, Hebei University of Engineering, Handan, 056038, PR China; Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada.
| | - Yichen Liao
- Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada
| | - Lina Yan
- College of Chemical Engineering, North China University of Science and Technology, Tangshan, 063210, PR China
| | - Baoqiang Liao
- Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada.
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Ma J, Zhang S, Liu X, Wang J. Machine learning prediction of biochar yield based on biomass characteristics. Bioresour Technol 2023; 389:129820. [PMID: 37805089 DOI: 10.1016/j.biortech.2023.129820] [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: 08/12/2023] [Revised: 10/01/2023] [Accepted: 10/01/2023] [Indexed: 10/09/2023]
Abstract
Slow pyrolysis is a widely used thermochemical pathway that can convert organic waste into biochar. We employed six machine learning models to predictively model 13 selected variables using pearson feature selection. Additionally, partial dependence analysis is used to reveal the deep relationship between feature variables. Both the gradient boosting decision tree and the Levenberg-Marquardt backpropagation neural network achieved training set R2 > 0.9 and testing set R2 > 0.8. But the other models displayed lower performance on the testing set, with R2 < 0.8. The partial dependence plot demonstrates that pyrolysis conditions have greater impact on biochar yield than biomass composition. Furthermore, the highest treatment temperature, being the sole consistently changing feature, can serve as a guiding factor for regulating biochar yield. This study highlights the immense potential of machine learning in experimental prediction, providing a scientific reference for reducing time and economic costs in pyrolysis experiments and process development.
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Affiliation(s)
- Jingjing Ma
- School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, 710049, China
| | - Shuai Zhang
- School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, 710049, China
| | - Xiangjun Liu
- School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, 710049, China
| | - Junqi Wang
- School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, 710049, China.
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Su S, Wang J. Machine learning prediction of contents of oxygenated components in bio-oil using extreme gradient boosting method under different pyrolysis conditions. Bioresour Technol 2023; 379:129040. [PMID: 37037334 DOI: 10.1016/j.biortech.2023.129040] [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: 02/23/2023] [Revised: 04/05/2023] [Accepted: 04/07/2023] [Indexed: 05/03/2023]
Abstract
This work aims to develop a prediction model for the contents of oxygenated components in bio-oil based on machine learning according to different pyrolysis conditions and biomass characteristics. The prediction model was constructed using the extreme gradient boosting (XGB) method, and the prediction accuracy was evaluated using the test dataset. The partial dependence analysis (PDA) method was used to derive the pattern of influence of each input feature individually or in combination on the output variable. The results show that the prediction models constructed from biomass ultimate analysis and pyrolysis conditions can predict the contents of oxygenated components in bio-oil more accurately than the models constructed from biomass proximate analysis. Moderate C and O contents, higher H content of biomass, lower flow rate, and higher pyrolysis temperature can improve bio-oil quality.
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Affiliation(s)
- Sheng Su
- National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics, School of Energy and Power Engineering, Beihang University, Beijing 100191, China
| | - Juan Wang
- National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics, School of Energy and Power Engineering, Beihang University, Beijing 100191, China.
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Biliani SE, Manariotis ID. Wastewater treatment by high density algal flocs for nutrient removal and biomass production. J Appl Phycol 2023; 35:1237-1250. [PMID: 37249918 PMCID: PMC9990567 DOI: 10.1007/s10811-023-02931-2] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 02/15/2023] [Accepted: 02/15/2023] [Indexed: 05/31/2023]
Abstract
The present work investigated the efficiency of algal flocs biomass for the treatment of primary and secondary effluent in static and mixing conditions under different hydraulic retention time (HRT). Primary effluent fed cultures created a high-density biomass of 2.8 and 3.8 g L-1 under static and mixing conditions, respectively. Secondary effluent was more effective in order to create even higher density biomass of 7.8 and 6 g L-1 under static and mixing conditions, respectively. The algal floc biomass developed was quite effective for organic matter and nutrient removal. Primary effluent fed cultures seemed to be more efficient for chemical oxygen demand (COD) and ammonia nitrogen removal, while secondary effluent fed cultures for nitrates removal. At an HRT of 8 days using primary effluent, the removal of COD, ammonia nitrogen and total phosphorus was 86.2, 100 and 97.4%, respectively. The cultures fed with secondary effluent, even at low HRT of 1.2 days, achieved removals of 88.4, 77.5, 100 and 98.6% for COD, nitrates, ammonia, and total phosphorus, respectively. Supplementary Information The online version contains supplementary material available at 10.1007/s10811-023-02931-2.
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Affiliation(s)
- Styliani E. Biliani
- Environmental Engineering Laboratory, Department of Civil Engineering, University of Patras, 26504 Rio, Greece
| | - Ioannis D. Manariotis
- Environmental Engineering Laboratory, Department of Civil Engineering, University of Patras, 26504 Rio, Greece
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Ismail S, Elreedy A, Fujii M, Ni SQ, Tawfik A, Elsamadony M. Fatigue of anammox consortia under long-term 1,4-dioxane exposure and recovery potential: N-kinetics and microbial dynamics. J Hazard Mater 2021; 414:125533. [PMID: 34030408 DOI: 10.1016/j.jhazmat.2021.125533] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [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: 11/18/2020] [Revised: 01/22/2021] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
Long-term exposure of anammox process to 1,4-dioxane was investigated using periodic anammox baffled reactor (PABR) under different 1,4-dioxane concentrations. The results generally indicated that PABR (composed of 4 compartments) has robust resistance to 10 mg-dioxane/L. The 1st compartment acted as a shield to protect subsequent compartments from 1,4-dioxane toxicity through secretion of high extracellular polymeric substance (EPS) of 152.9 mg/gVSS at 10 mg-dioxane/L. However, increasing 1,4-dioxane to 50 mg/L significantly inhibited anammox bacteria; e.g., ~ 93% of total nitrogen removal was lost within 14 days. The inhibition of anammox process at this dosage was most likely due to bacterial cell lysis, resulting in the decrease of EPS secretion and specific anammox activity (SAA) to 105.9 mg/gVSS and 0.04 mg N/gVSS/h, respectively, in the 1st compartment. However, anammox bacteria were successfully self-recovered within 41 days after the cease of 1,4-dioxane exposure. The identification of microbial compositions further emphasized the negative impacts of 1,4-dioxane on abundance of C. Brocadia among samples. Furthermore, the development of genus Planococcus in the 1st compartment, where removal of 1,4-dioxane was consistently observed, highlights its potential role as anoxic 1,4-dioxane degrader. Overall, long-term exposure to 1,4-dioxane should be controlled not exceeding 10 mg/L for a successful application.
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Affiliation(s)
- Sherif Ismail
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China; Environmental Engineering Department, Zagazig University, Zagazig 44519, Egypt; Suzhou Research Institute, Shandong University, Suzhou, Jiangsu 215123, China
| | - Ahmed Elreedy
- Sanitary Engineering Department, Alexandria University, Alexandria 21544, Egypt; Department of Applied Biology, Institute for Applied Biosciences, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Manabu Fujii
- Civil and Environmental Engineering Department, Tokyo Institute of Technology, Meguro-Ku, Tokyo 152-8552, Japan
| | - Shou-Qing Ni
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China; Suzhou Research Institute, Shandong University, Suzhou, Jiangsu 215123, China.
| | - Ahmed Tawfik
- Water Pollution Research Department, National Research Centre, Giza 12622, Egypt
| | - Mohamed Elsamadony
- Civil and Environmental Engineering Department, Tokyo Institute of Technology, Meguro-Ku, Tokyo 152-8552, Japan; Department of Public Works Engineering, Faculty of Engineering, Tanta University, 31521 Tanta City, Egypt
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Zkeri E, Iliopoulou A, Katsara A, Korda A, Aloupi M, Gatidou G, Fountoulakis MS, Stasinakis AS. Comparing the use of a two-stage MBBR system with a methanogenic MBBR coupled with a microalgae reactor for medium-strength dairy wastewater treatment. Bioresour Technol 2021; 323:124629. [PMID: 33421834 DOI: 10.1016/j.biortech.2020.124629] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 11/26/2020] [Revised: 12/22/2020] [Accepted: 12/25/2020] [Indexed: 05/05/2023]
Abstract
Two systems were compared for medium-strength dairy wastewater treatment. The first comprised a methanogenic Moving Bed Biofilm Reactor (AnMBBR) and an aerobic MBBR (AeMBBR), while the second an AnMBBR and a sequencing batch reactor (SBR) with Chlorella sorokiniana. The AnMBBR, under ambient conditions, achieves biogas production sufficient enough to attain energy autonomy. The produced energy was 0.538 kWh m-3, whereas the energy consumption 0.025 kWh m-3. Its coupling with the AeMBBR removed COD, NH4-N TKN, and PO4-P by 93 ± 4%, 97 ± 3%, 99 ± 1% and 49 ± 15%, respectively, while the use of the SBR as a second step eliminated totally COD but partially the other pollutants. The higher nitrogen removal in the first system was due to nitrification occurring in the AeMBBR. The acclimatization of microalgae to dairy wastewater enhanced their growth. Their protein content was 54.56%, while starch and lipids were 3.39% and 23.1%, respectively.
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Affiliation(s)
- Eirini Zkeri
- Water and Air Quality Laboratory, Department of Environment, University of the Aegean, 81100, Greece
| | - Athanasia Iliopoulou
- Water and Air Quality Laboratory, Department of Environment, University of the Aegean, 81100, Greece
| | - Alexandra Katsara
- Water and Air Quality Laboratory, Department of Environment, University of the Aegean, 81100, Greece
| | - Angeliki Korda
- Water and Air Quality Laboratory, Department of Environment, University of the Aegean, 81100, Greece
| | - Maria Aloupi
- Water and Air Quality Laboratory, Department of Environment, University of the Aegean, 81100, Greece
| | - Georgia Gatidou
- Water and Air Quality Laboratory, Department of Environment, University of the Aegean, 81100, Greece
| | - Michail S Fountoulakis
- Water and Air Quality Laboratory, Department of Environment, University of the Aegean, 81100, Greece
| | - Athanasios S Stasinakis
- Water and Air Quality Laboratory, Department of Environment, University of the Aegean, 81100, Greece.
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Agustini CB, da Costa M, Gutterres M. Biogas from Tannery Solid Waste Anaerobic Digestion Is Driven by the Association of the Bacterial Order Bacteroidales and Archaeal Family Methanosaetaceae. Appl Biochem Biotechnol 2020; 192:482-93. [PMID: 32399839 DOI: 10.1007/s12010-020-03326-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/23/2020] [Indexed: 10/24/2022]
Abstract
The search for renewable energies has been one of the biggest challenges of the last decades. Sludge and solid wastes of many sources have been used to produce biogas of high calorific value. Thus, this work aimed to evaluate the biogas production of solid waste originating from a tannery that uses chromium salts as a tanning agent and to characterize the physicochemical parameters and microbial composition of the biogas-producing biomass. Wastes were collected and the parameters were evaluated at the initial and final time points of the anaerobic incubation process. At the end of 150 days, there was a production of 26.1 mL g-1 VSS of biogas with 52% of methane. The highest amount of biomethane observed was related to the archaeal family Methanosaetaceae and bacterial order Bacteroidales. Knowledge about changes in the microbial composition can provide tools for manipulation, isolation, and inoculation of the microorganisms inside the bioreactors to maximize methane production.
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Luo W, Hai FI, Kang J, Price WE, Guo W, Ngo HH, Yamamoto K, Nghiem LD. Effects of salinity build-up on biomass characteristics and trace organic chemical removal: implications on the development of high retention membrane bioreactors. Bioresour Technol 2015; 177:274-281. [PMID: 25496948 DOI: 10.1016/j.biortech.2014.11.084] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [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: 10/15/2014] [Revised: 11/18/2014] [Accepted: 11/20/2014] [Indexed: 06/04/2023]
Abstract
This study investigated the impact of salinity build-up on the performance of membrane bioreactor (MBR), specifically in terms of the removal and fate of trace organic chemicals (TrOCs), nutrient removal, and biomass characteristics. Stepwise increase of the influent salinity, simulating salinity build-up in high retention MBRs, adversely affected the metabolic activity in the bioreactor, thereby reducing organic and nutrient removal. The removal of hydrophilic TrOCs by MBR decreased due to salinity build-up. By contrast, with the exception of 17α-ethynylestradiol, the removal of all hydrophobic TrOCs was not affected at high salinity. Moreover, salinity build-up had negligible impact on the residual accumulation of TrOCs in the sludge phase except for a few hydrophilic compounds. Additionally, the response of the biomass to salinity stress also dramatically enhanced the release of both soluble microbial products (SMP) and extracellular polymeric substances (EPS), leading to severe membrane fouling.
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Affiliation(s)
- Wenhai Luo
- Strategic Water Infrastructure Laboratory, 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
| | - Jinguo Kang
- Strategic Water Infrastructure Laboratory, School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia
| | - William E Price
- Strategic Water Infrastructure Laboratory, School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Wenshan Guo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Hao H Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Kazuo Yamamoto
- Environmental Science Center, The University of Tokyo, Tokyo 113-0033, Japan
| | - Long D Nghiem
- Strategic Water Infrastructure Laboratory, School of Civil Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia.
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