1
|
Xiong W, Jin Y, Wang Y, Wang S, Chen B, Su H. Novel insights into the biological state in algal-bacterial granular sludge granulation: Armor-like protection provided by the algal barrier. WATER RESEARCH 2024; 262:122087. [PMID: 39024667 DOI: 10.1016/j.watres.2024.122087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 07/10/2024] [Accepted: 07/11/2024] [Indexed: 07/20/2024]
Abstract
Algal-bacterial granular sludge (ABGS) composed of microalgae and aerobic granular sludge, is a sustainable and promising technology for wastewater treatment. However, the formation mechanism of ABGS has not been clearly defined, and the direct formation of ABGS in saline wastewater has rarely been investigated. This study proposed novel insights into the granulation process of ABGS by assembling the algal barrier, which was successfully cultivated directly in saline wastewater. The results concluded that ABGS with the algal barrier maintained a higher biomass (MLSS of 7046 ± 61 mg/L), larger particle sizes (1.21 ± 0.06 mm), and better settleability (SVI30 of 46 ± 1 mL/g), enabling efficient pollutants removal. Soluble microbial products (SMP) were found to be closely related to the emergence of the algal barrier. In addition, under salinity stress, the high production of extracellular polymeric substances (EPS, 133.70 ± 1.40 mg/g VSS), specifically TB-EPS (90.29 ± 1.12 mg/g VSS), maintained a crucial role in the formation of ABGS. Further analysis indicated that biofilm producing bacteria Pseudofulvimonas and filamentous eukaryote Streptophyta were the key players in ABGS formation with the algal barrier. Furthermore, the enhancement of key genes and enzymes involved in nitrogen metabolism, TCA cycle, and polysaccharide metabolism suggested a more robust protective effect provided by the algal barrier. This study is expected to advance the application of simultaneous ABGS formation and pollutant removal in wastewater.
Collapse
Affiliation(s)
- Wei Xiong
- State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Yu Jin
- State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Yaoqiang Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Shaojie Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
| | - Biqiang Chen
- State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Haijia Su
- State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
| |
Collapse
|
2
|
Ye Q, Gong X, Li A, Shao S, Ji B. A typical acidic extracellular polysaccharide alludes to algae-bacteria-collaboration in microalgal-bacterial symbiosis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 929:172545. [PMID: 38636868 DOI: 10.1016/j.scitotenv.2024.172545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/12/2024] [Accepted: 04/15/2024] [Indexed: 04/20/2024]
Abstract
Microalgal-bacterial symbioses are prevalent in aquatic ecosystems and play a pivotal role in carbon sequestration, significantly contributing to global carbon cycling. The understanding of the contribution of exopolysaccharides (EPSs), a crucial carbon-based component, to the structural integrity of microalgal-bacterial symbioses remains insufficiently elucidated. To address this gap, our study aims to enhance our comprehension of the composition and primary structure of EPSs within a specific type of granular microalgal-bacterial symbiosis named microalgal-bacterial granular sludge (MBGS). Our investigation reveals that the acidic EPSs characteristic of this symbiosis have molecular weights ranging from several hundred thousand to over one million Daltons, including components like glucopyranose, galactopyranose, mannose, and rhamnose. Our elucidation of the backbone linkage of a representative exopolysaccharide revealed a →3)-β-D-Galp-(1→4)-β-D-Glcp-(1→ glycosidic linkage. This linear structure closely resembles bacterial xanthan, while the branched chain structure bears similarities to algal EPSs. Our findings highlight the collaborative synthesis of acidic EPSs by both microalgae and bacteria, emphasizing their joint contribution in the production of macromolecules within microalgal-bacterial symbiosis. This collaborative synthesis underscores the intricate molecular interactions contributing to the stability and function of these symbiotic relationships.
Collapse
Affiliation(s)
- Qinyi Ye
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Xiping Gong
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Anjie Li
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Senlin Shao
- School of Civil Engineering, Wuhan University, Wuhan 430072, China
| | - Bin Ji
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China.
| |
Collapse
|
3
|
Garieri T, Allen DG, Gao W, Liao B. A review of emerging membrane-based microalgal-bacterial processes for wastewater treatment: Process configurations, biological and membrane performance, and perspectives. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172141. [PMID: 38580119 DOI: 10.1016/j.scitotenv.2024.172141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 03/15/2024] [Accepted: 03/30/2024] [Indexed: 04/07/2024]
Abstract
Microalgal-bacterial (MB) consortia create an excellent eco-system for simultaneous COD/BOD and nutrients (N and P) removals in a single step with significant reduction in or complete elimination of aeration and carbonation in the biological wastewater treatment processes. The integration of membrane separation technology with the MB processes has created a new paradigm for research and development. This paper focuses on a comprehensive and critical literature review of recent advances in these emerging processes. Novel membrane process configurations and process conditions affecting the biological performance of these novel systems have been systematically reviewed and discussed. Membrane fouling issues and control of MB biofilm formation and thickness associated with these emerging suspended growth or immobilized biofilm processes are addressed and discussed. The research gaps, challenges, outlooks of these emerging processes are identified and discussed in-depth. The findings from the literature suggest that the membrane-based MB processes are advanced biotechnologies with a significant reduction in energy consumption and process simplification and high process efficiency that are not achievable with current technologies in wastewater treatment. There are endless opportunities for research and development of these novel and emerging membrane-based MB processes.
Collapse
Affiliation(s)
- Teralyn Garieri
- Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1, Canada
| | - D Grant Allen
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada
| | - Wa Gao
- Department of Civil Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1, Canada
| | - Baoqiang Liao
- Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1, Canada.
| |
Collapse
|
4
|
Tang CC, Hu YR, Zhang M, Chen SL, He ZW, Li ZH, Tian Y, Wang XC. Role of phosphate in microalgal-bacterial symbiosis system treating wastewater containing heavy metals. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 349:123951. [PMID: 38604305 DOI: 10.1016/j.envpol.2024.123951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 02/19/2024] [Accepted: 04/08/2024] [Indexed: 04/13/2024]
Abstract
Phosphorus is one of the important factors to successfully establish the microalgal-bacterial symbiosis (MABS) system. The migration and transformation of phosphorus can occur in various ways, and the effects of phosphate on the MABS system facing environmental impacts like heavy metal stress are often ignored. This study investigated the roles of phosphate on the response of the MABS system to zinc ion (Zn2+). The results showed that the pollutant removal effect in the MABS system was significantly reduced, and microbial growth and activity were inhibited with the presence of Zn2+. When phosphate and Zn2+ coexisted, the inhibition effects of pollutants removal and microbial growth rate were mitigated compared to that of only with the presence of Zn2+, with the increasing rates of 28.3% for total nitrogen removal, 48.9% for chemical oxygen demand removal, 78.3% for chlorophyll-a concentration, and 13.3% for volatile suspended solids concentration. When phosphate was subsequently supplemented in the MABS system after adding Zn2+, both pollutants removal efficiency and microbial growth and activity were not recovered. Thus, the inhibition effect of Zn2+ on the MABS system was irreversible. Further analysis showed that Zn2+ preferentially combined with phosphate could form chemical precipitate, which reduced the fixation of MABS system for Zn2+ through extracellular adsorption and intracellular uptake. Under Zn2+ stress, the succession of microbial communities occurred, and Parachlorella was more tolerant to Zn2+. This study revealed the comprehensive response mechanism of the co-effects of phosphate and Zn2+ on the MABS system, and provided some insights for the MABS system treating wastewater containing heavy metals, as well as migration and transformation of heavy metals in aquatic ecosystems.
Collapse
Affiliation(s)
- Cong-Cong Tang
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | - Ya-Ru Hu
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Min Zhang
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Sheng-Long Chen
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Zhang-Wei He
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Zhi-Hua Li
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Yu Tian
- State Key Laboratory of Urban Water Resource & Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Xiaochang C Wang
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an, 710055, China
| |
Collapse
|
5
|
Chen B, Shen Y, Zhang X, Ji B. Influence mechanism of sludge bed position on microalgal-bacterial granular sludge process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:168118. [PMID: 37884157 DOI: 10.1016/j.scitotenv.2023.168118] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/16/2023] [Accepted: 10/23/2023] [Indexed: 10/28/2023]
Abstract
Sludge bed position in the reactor is one of the key parameters for microalgal-bacterial granular sludge (MBGS) process, which lacks of study. To fill this gap, this study investigated the influence of sludge bed position on MBGS. The sludge bed located closer to the bottom of the bioreactor demonstrated the optimal pollutant removal performance due to a close synergistic effect between microalgae and bacteria, resulting in the high growth rate as well as agglomeration rate of MBGS. Specifically, organics and ammonia removals were closely related to the sludge bed position. For the bottom bed position, the removals of organic matter, ammonia, and phosphate were 75.1 %, 73.1 %, and 82.5 %, whereas for the top bed position, they were only 13.2 %, 9.6 %, and 68.9 %, respectively. Additionally, a significant correlation between the position of the sludge bed and the relative abundance of Rotifera (R2 = 0.931) and Chlorophyta (R2 = 0.733) was observed, while the microbial communities at the lower sludge bed positions underwent rapider succession. It can be inferred that that a sludge bed located closer to the bottom of the bioreactor ensures that the light source and substrate matrix are transmitted in the same direction, thereby resulting in a close synergistic effect between microalgae and bacteria for achieving the excellent performance of MBGS. These results can provide basis knowledge for engineering application of MBGS process.
Collapse
Affiliation(s)
- Bingheng Chen
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Yao Shen
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Xiaoyuan Zhang
- Engineering Laboratory of Low-Carbon Unconventional Water Resources Utilization and Water Quality Assurance, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Bin Ji
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China; Hubei Provincial Engineering Research Center of Urban Regeneration, Wuhan University of Science and Technology, Wuhan 430065, China.
| |
Collapse
|
6
|
Zhang JT, Wang JX, Liu Y, Zhang Y, Wang JH, Chi ZY, Kong FT. Microalgal-bacterial biofilms for wastewater treatment: Operations, performances, mechanisms, and uncertainties. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:167974. [PMID: 37884155 DOI: 10.1016/j.scitotenv.2023.167974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/28/2023] [Accepted: 10/18/2023] [Indexed: 10/28/2023]
Abstract
Microalgal-bacterial biofilms have been increasingly considered of great potential in wastewater treatment due to the advantages of microalgal-bacterial synergistic pollutants removal/recovery, CO2 sequestration, and cost-effective biomass-water separation. However, such advantages may vary widely among different types of microalgal-bacterial biofilms, as the biofilms could be formed on different shapes and structures of attachment substratum, generating "false hope" for certain systems in large-scale wastewater treatment if the operating conditions and pollutants removal properties are evaluated based on the general term "microalgal-bacterial biofilm". This study, therefore, classified microalgal-bacterial biofilms into biofilms formed on 2D substratum, biofilms formed on 3D substratum, and biofilms formed without substratum (i.e. microalgal-bacterial granular sludge, MBGS). Biofilms formed on 2D substratum display higher microalgae fractions and nutrients removal efficiencies, while the adopted long hydraulic retention times were unacceptable for large-scale wastewater treatment. MBGS are featured with much lower microalgae fractions, most efficient pollutants removal, and acceptable retention times for realistic application, yet the feasibility of using natural sunlight should be further explored. 3D substratum systems display wide variations in operating conditions and pollutants removal properties because of diversified substratum shapes and structures. 2D and 3D substratum biofilms share more common in eukaryotic and prokaryotic microbial community structures, while MGBS biofilms are more enriched with microorganisms favoring EPS production, biofilm formation, and denitrification. The specific roles of stratified extracellular polymeric substances (EPS) in nutrients adsorption and condensation still require in-depth exploration. Nutrients removal uncertainties caused by microalgal-bacterial synergy decoupling under insufficient illumination, limited microbial community control, and possible greenhouse gas emission exacerbation arising from microalgal N2O generation were also indicated. This review is helpful for revealing the true potential of applying various microalgal-bacterial biofilms in large-scale wastewater treatment, and will provoke some insights on the challenges to the ideal state of synergistic pollutants reclamation and carbon neutrality via microalgal-bacterial interactions.
Collapse
Affiliation(s)
- Jing-Tian Zhang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| | - Jian-Xia Wang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| | - Yang Liu
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| | - Ying Zhang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| | - Jing-Han Wang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China; Key Laboratory of Environment Controlled Aquaculture, Dalian Ocean University, Dalian 116023, PR China.
| | - Zhan-You Chi
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| | - Fan-Tao Kong
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| |
Collapse
|
7
|
Asghar N, Hussain A, Nguyen DA, Ali S, Hussain I, Junejo A, Ali A. Advancement in nanomaterials for environmental pollutants remediation: a systematic review on bibliometrics analysis, material types, synthesis pathways, and related mechanisms. J Nanobiotechnology 2024; 22:26. [PMID: 38200605 PMCID: PMC10777661 DOI: 10.1186/s12951-023-02151-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 10/09/2023] [Indexed: 01/12/2024] Open
Abstract
Environmental pollution is a major issue that requires effective solutions. Nanomaterials (NMs) have emerged as promising candidates for pollution remediation due to their unique properties. This review paper provides a systematic analysis of the potential of NMs for environmental pollution remediation compared to conventional techniques. It elaborates on several aspects, including conventional and advanced techniques for removing pollutants, classification of NMs (organic, inorganic, and composite base). The efficiency of NMs in remediation of pollutants depends on their dispersion and retention, with each type of NM having different advantages and disadvantages. Various synthesis pathways for NMs, including traditional synthesis (chemical and physical) and biological synthesis pathways, mechanisms of reaction for pollutants removal using NMs, such as adsorption, filtration, disinfection, photocatalysis, and oxidation, also are evaluated. Additionally, this review presents suggestions for future investigation strategies to improve the efficacy of NMs in environmental remediation. The research so far provides strong evidence that NMs could effectively remove contaminants and may be valuable assets for various industrial purposes. However, further research and development are necessary to fully realize this potential, such as exploring new synthesis pathways and improving the dispersion and retention of NMs in the environment. Furthermore, there is a need to compare the efficacy of different types of NMs for remediating specific pollutants. Overall, this review highlights the immense potential of NMs for mitigating environmental pollutants and calls for more research in this direction.
Collapse
Affiliation(s)
- Nosheen Asghar
- Department of Global Smart City, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea.
| | - Alamdar Hussain
- Department of Botany, University of Baltistan, Skardu 16400, Gilgit-Baltistan, Pakistan
| | - Duc Anh Nguyen
- Department of Global Smart City, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea
| | - Salar Ali
- Department of Environmental Science, University of Baltistan, Skardu 16400, Gilgit-Baltistan, Pakistan
| | - Ishtiaque Hussain
- Department of Environmental Science, University of Baltistan, Skardu 16400, Gilgit-Baltistan, Pakistan
- Department of Environmental Science, Quaid-i-Azam University of Islamabad, Islamabad, 15320, Pakistan
| | - Aurangzeb Junejo
- Department of Global Smart City, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea
| | - Attarad Ali
- Department of Environmental Science, University of Baltistan, Skardu 16400, Gilgit-Baltistan, Pakistan.
- Directorate of Quality Enhancement Cell, University of Baltistan, Skardu 16400, Gilgit-Baltistan, Pakistan.
| |
Collapse
|
8
|
Zhang L, Yang G, Hasan HA, Fan J, Ji B. Adaptation mechanisms of microalgal-bacterial granular sludge to outdoor light-limited conditions. ENVIRONMENTAL RESEARCH 2023; 239:117244. [PMID: 37783330 DOI: 10.1016/j.envres.2023.117244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/21/2023] [Accepted: 09/23/2023] [Indexed: 10/04/2023]
Abstract
Microalgal-bacterial granular sludge (MBGS) has attached attention for sustainable wastewater treatment, but it remains elusive whether it can adapt to outdoor light-limited conditions. This paper investigated the biological adaptation mechanisms of MBGS to outdoor light-limited diel conditions using real municipal wastewater. The results indicated that MBGS still had excellent pollutants removal performance, and that both the extracellular polymeric substances and glycogen content of MBGS increased significantly. The main functional microalgae and bacteria were revealed to be Leptolyngbyaceae and Rhodanobacteria, respectively. Further analyses indicated that the abundance of genes encoding PsbA, PsbD, PsbE, PsbJ, PsbP, Psb27, Psb28-2, PsaC, PsaE, PsaL, PsbX, PetB, PetA, and PetE increased in photosystem. Meanwhile, the abundance of gene encoding Rubisco decreased but the gene abundance regarding to crassulacean acid metabolism cycle increased. These suggested that MBGS could adjust the photosynthetic pathway to ensure the completion of photosynthesis. This study is anticipated to add fundamental insights for the MBGS process operated under outdoor light-limited conditions.
Collapse
Affiliation(s)
- Lingyang Zhang
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Genji Yang
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Hassimi Abu Hasan
- Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Malaysia; Research Centre for Sustainable Process Technology (CESPRO), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Malaysia
| | - Jie Fan
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, China; Hubei Provincial Engineering Research Center of Urban Regeneration, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Bin Ji
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, China; Hubei Provincial Engineering Research Center of Urban Regeneration, Wuhan University of Science and Technology, Wuhan, 430065, China.
| |
Collapse
|
9
|
Kong L, Feng Y, Du W, Zheng R, Sun J, Rong K, Sun W, Liu S. Cross-Feeding between Filamentous Cyanobacteria and Symbiotic Bacteria Favors Rapid Photogranulation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16953-16963. [PMID: 37886803 DOI: 10.1021/acs.est.3c04867] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Photogranules are dense algal-bacterial aggregates used in aeration-free and carbon-negative wastewater treatment, wherein filamentous cyanobacteria (FC) are essential components. However, little is known about the functional role of symbiotic bacteria in photogranulation. Herein, we combined cyanobacterial isolation, reactor operation, and multiomics analysis to investigate the cyanobacterial-bacterial interaction during photogranulation. The addition of FC to the inoculated sludge achieved a 1.4-fold higher granule size than the control, and the aggregation capacity of FC-dominant photogranules was closely related to the extracellular polysaccharide (PS) concentration (R = 0.86). Importantly, we found that cross-feeding between FC and symbiotic bacteria for macromolecular PS synthesis is at the heart of photogranulation and substantially enhanced the granular stability. Chloroflexi-affiliated bacteria intertwined with FC throughout the photogranules and promoted PS biosynthesis using the partial nucleotide sugars produced by FC. Proteobacteria-affiliated bacteria were spatially close to FC, and highly expressed genes for vitamin B1 and B12 synthesis, contributing the necessary cofactors to promote FC proliferation. In addition, Bacteroidetes-affiliated bacteria degraded FC-derived carbohydrates and influenced granules development. Our metabolic characterization identified the functional role of symbiotic bacteria of FC during photogranulation and shed light on the critical cyanobacterial-bacterial interactions in photogranules from the viewpoint of cross-feeding.
Collapse
Affiliation(s)
- Lingrui Kong
- Department of Environmental Engineering, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Water and Sediment Sciences, Ministry of Education of China, Peking University, Beijing 100871, China
| | - Yiming Feng
- Department of Environmental Engineering, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Water and Sediment Sciences, Ministry of Education of China, Peking University, Beijing 100871, China
| | - Wenran Du
- Key Laboratory of Water and Sediment Sciences, Ministry of Education of China, Peking University, Beijing 100871, China
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Ru Zheng
- Department of Environmental Engineering, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Water and Sediment Sciences, Ministry of Education of China, Peking University, Beijing 100871, China
| | - Jingqi Sun
- Department of Environmental Engineering, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Water and Sediment Sciences, Ministry of Education of China, Peking University, Beijing 100871, China
| | - Kaiyu Rong
- Department of Environmental Engineering, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Water and Sediment Sciences, Ministry of Education of China, Peking University, Beijing 100871, China
| | - Weiling Sun
- Department of Environmental Engineering, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Water and Sediment Sciences, Ministry of Education of China, Peking University, Beijing 100871, China
| | - Sitong Liu
- Department of Environmental Engineering, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Water and Sediment Sciences, Ministry of Education of China, Peking University, Beijing 100871, China
| |
Collapse
|
10
|
Shen Y, Chen B, Wang S, Li A, Ji B. Necessity of stirring for outdoor microalgal-bacterial granular sludge process. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118816. [PMID: 37598492 DOI: 10.1016/j.jenvman.2023.118816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/02/2023] [Accepted: 08/12/2023] [Indexed: 08/22/2023]
Abstract
As a green process, microalgal-bacterial granular sludge (MBGS) process shows talents in achieving pollutant removal, resource recovery and carbon neutralization. However, when it comes to application, the adequate mixing of MBGS and substrate should be adopted theoretically. Therefore, this study devoted to address the necessity of stirring for MBGS in municipal wastewater treatment. Outdoor performances showed that stirring significantly enhanced both of the photosynthetic efficiency and biomass productivity of MBGS with almost 2-fold increase as compared to non-stirred MBGS, while the average pore size and microalgae-to-bacteria ratio also increased. Consequently, stirring acted as a pivotal role in accelerating pollutants removal, with removals of organics (89.89% COD) and nutrients (99.22% NH4+-N, 92.15% PO43--P) reaching peak levels at 2 h and 6 h, respectively, while removals of organics (87.50% COD) and nutrients (86.11% NH4+-N, 86.76% PO43--P) removal peaked at 8 h for non-stirred MBGS. The improved granule characteristics and microbial compositions due to the stirring were found to be favorable for MBGS to adapting to the changeable weather. Based on the above results, the possible underlying mechanisms of stirring for improving MBGS were illustrated. Overall, stirring positively impacted the photosynthetic efficiency, biomass productivity, pollutant removal and microbial structure for MBGS. This study gains knowledge on stirred MBGS process under outdoor conditions for its future practical application.
Collapse
Affiliation(s)
- Yao Shen
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan, 430065, China; Hubei Provincial Engineering Research Center of Urban Regeneration, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Bingheng Chen
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan, 430065, China; Hubei Provincial Engineering Research Center of Urban Regeneration, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Shuo Wang
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China
| | - Anjie Li
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Bin Ji
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan, 430065, China; Hubei Provincial Engineering Research Center of Urban Regeneration, Wuhan University of Science and Technology, Wuhan, 430065, China.
| |
Collapse
|
11
|
Amaro HM, Salgado EM, Nunes OC, Pires JCM, Esteves AF. Microalgae systems - environmental agents for wastewater treatment and further potential biomass valorisation. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 337:117678. [PMID: 36948147 DOI: 10.1016/j.jenvman.2023.117678] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/25/2023] [Accepted: 03/03/2023] [Indexed: 06/18/2023]
Abstract
Water is the most valuable resource on the planet. However, massive anthropogenic activities generate threatening levels of biological, organic, and inorganic pollutants that are not efficiently removed in conventional wastewater treatment systems. High levels of conventional pollutants (carbon, nitrogen, and phosphorus), emerging chemical contaminants such as antibiotics, and pathogens (namely antibiotic-resistant ones and related genes) jeopardize ecosystems and human health. Conventional wastewater treatment systems entail several environmental issues: (i) high energy consumption; (ii) high CO2 emissions; and (iii) the use of chemicals or the generation of harmful by-products. Hence, the use of microalgal systems (entailing one or several microalgae species, and in consortium with bacteria) as environmental agents towards wastewater treatment has been seen as an environmentally friendly solution to remove conventional pollutants, antibiotics, coliforms and antibiotic resistance genes. In recent years, several authors have evaluated the use of microalgal systems for the treatment of different types of wastewater, such as agricultural, municipal, and industrial. Generally, microalgal systems can provide high removal efficiencies of: (i) conventional pollutants, up to 99%, 99%, and 90% of total nitrogen, total phosphorus, and/or organic carbon, respectively, through uptake mechanisms, and (ii) antibiotics frequently found in wastewaters, such as sulfamethoxazole, ciprofloxacin, trimethoprim and azithromycin at 86%, 65%, 42% and 93%, respectively, through the most desirable microalgal mechanism, biodegradation. Although pathogens removal by microalgal species is complex and very strain-specific, it is also possible to attain total coliform and Escherichia coli removal of 99.4% and 98.6%, respectively. However, microalgal systems' effectiveness strongly relies on biotic and abiotic conditions, thus the selection of operational conditions is critical. While the combination of selected species (microalgae and bacteria), ratios and inoculum concentration allow the efficient removal of conventional pollutants and generation of high amounts of biomass (that can be further converted into valuable products such as biofuels and biofertilisers), abiotic factors such as pH, hydraulic retention time, light intensity and CO2/O2 supply also have a crucial role in conventional pollutants and antibiotics removal, and wastewater disinfection. However, some rationale must be considered according to the purpose. While alkaline pH induces the hydrolysis of some antibiotics and the removal of faecal coliforms, it also decreases phosphates solubility and induces the formation of ammonium from ammonia. Also, while CO2 supply increases the removal of E. coli and Pseudomonas aeruginosa, as well as the microalgal growth (and thus the conventional pollutants uptake), it decreases Enterococcus faecalis removal. Therefore, this review aims to provide a critical review of recent studies towards the application of microalgal systems for the efficient removal of conventional pollutants, antibiotics, and pathogens; discussing the feasibility, highlighting the advantages and challenges of the implementation of such process, and presenting current case-studies of different applications of microalgal systems.
Collapse
Affiliation(s)
- Helena M Amaro
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465, Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Eva M Salgado
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465, Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Olga C Nunes
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465, Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - José C M Pires
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465, Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
| | - Ana F Esteves
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465, Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal; LSRE-LCM - Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465, Porto, Portugal
| |
Collapse
|
12
|
Microalgal-bacterial granular sludge under constant dark and weak light conditions: Morphology, performance and microbial community. ALGAL RES 2023. [DOI: 10.1016/j.algal.2023.103050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
|
13
|
Ren HY, Song X, Kong F, Song Q, Ren NQ, Liu BF. Lipid production characteristics of a newly isolated microalga Asterarcys quadricellulare R-56 as biodiesel feedstock. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:48339-48350. [PMID: 36757593 DOI: 10.1007/s11356-023-25728-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 01/31/2023] [Indexed: 02/10/2023]
Abstract
In this study, a new microalgal strain, Asterarcys quadricellulare R-56, was isolated for biomass and lipid production. The effects of carbon and nitrogen sources and initial pH on the cell growth and lipid accumulation of strain R-56 were investigated. At 10 g L-1 glucose, 0.6 g L-1 sodium nitrate, and pH 7, the highest biomass of 4.18 g L-1 and lipid content of 43.66% were obtained. Microalgae had a broad pH tolerance in the range of 5-11, and the pH of the culture medium was close to neutral at the end of cultivation. The maximum contents of chlorophyll, carbohydrate, and protein under the recommended culture conditions were 19.47 mg mL-1, 21.80%, and 29.94%, respectively. Palmitic and palmitoleic acid contents in strain R-56 accounted for as high as 83.73% of total fatty acids. This study suggested that strain R-56 was a promising lipid producer for high-quality biodiesel production.
Collapse
Affiliation(s)
- Hong-Yu Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
| | - Xueting Song
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
| | - Fanying Kong
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China. .,School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, 150030, China.
| | - Qingqing Song
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
| | - Nan-Qi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
| | - Bing-Feng Liu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
| |
Collapse
|
14
|
Zhang Z, Ahmed AIS, Malik MZ, Ali N, Khan A, Ali F, Hassan MO, Mohamed BA, Zdarta J, Bilal M. Cellulose/inorganic nanoparticles-based nano-biocomposite for abatement of water and wastewater pollutants. CHEMOSPHERE 2023; 313:137483. [PMID: 36513201 DOI: 10.1016/j.chemosphere.2022.137483] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/25/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Nanostructured materials offer a significant role in wastewater treatment with diminished capital and operational expense, low dose, and pollutant selectivity. Specifically, the nanocomposites of cellulose with inorganic nanoparticles (NPs) have drawn a prodigious interest because of the extraordinary cellulose properties, high specific surface area, and pollutant selectivity of NPs. Integrating inorganic NPs with cellulose biopolymers for wastewater treatment is a promising advantage for inorganic NPs, such as colloidal stability, agglomeration prevention, and easy isolation of magnetic material after use. This article presents a comprehensive overview of water treatment approaches following wastewater remediation by green and environmentally friendly cellulose/inorganic nanoparticles-based bio-nanocomposites. The functionalization of cellulose, functionalization mechanism, and engineered hybrid materials were thoroughly discussed. Moreover, we also highlighted the purification of wastewater through the composites of cellulose/inorganic nanoparticles via adsorption, photocatalytic and antibacterial approach.
Collapse
Affiliation(s)
- Zhen Zhang
- Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou, 318000, Zhejiang Province, China
| | - Abdulrazaq Ibrahim Said Ahmed
- Key Laboratory of Regional Resource Exploitation and Medicinal Research, Faculty of Chemical Engineering, Huaiyin Institute of Technology, Huai'an, Jiangsu Province, China
| | - Muhammad Zeeshan Malik
- School of Electronics and Information Engineering, Taizhou University, Taizhou, 318000, Zhejiang Province, China.
| | - Nisar Ali
- Key Laboratory of Regional Resource Exploitation and Medicinal Research, Faculty of Chemical Engineering, Huaiyin Institute of Technology, Huai'an, Jiangsu Province, China
| | - Adnan Khan
- Institute of Chemical Sciences, University of Peshawar, Khyber Pakhtunkhwa, 25120, Pakistan
| | - Farman Ali
- Department of Chemistry, Hazara University, KPK, Mansehra, 21300, Pakistan
| | - Mohamed Osman Hassan
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Badr A Mohamed
- Department of Agricultural Engineering, Cairo University, El-Gamma Street, Giza 12613, Egypt
| | - Jakub Zdarta
- Institute of Chemical Technology and Engineering, Faculty of Chemical Technology, Poznan University of Technology, Berdychowo 4, PL-60965, Poznan, Poland
| | - Muhammad Bilal
- Institute of Chemical Technology and Engineering, Faculty of Chemical Technology, Poznan University of Technology, Berdychowo 4, PL-60965, Poznan, Poland
| |
Collapse
|
15
|
Shi Y, Ji B, Zhang X, Liu Y. Auto-floating oxygenic microalgal-bacterial granular sludge. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159175. [PMID: 36191702 DOI: 10.1016/j.scitotenv.2022.159175] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 06/16/2023]
Abstract
As an emerging green wastewater treatment technology, the microalgal-bacterial granular sludge (MBGS) process has attracted increasing interest under the current situation of global climate change. However, little information is available for its performance in treating municipal wastewater under outdoor conditions. Thus, this study evaluated the behaviors of MBGS for treating simulated and real municipal wastewater under natural diel conditions. The results showed that a significant accumulation of oxygen bubbles during daily operation led to the auto-floating of the conventional settable MBGS. The removal of organics was relatively stable during day-night cycles, while the removals of total nitrogen and total phosphorus were dependent on the saturated oxygen concentration over 10 mg/L in MBGS system. Furthermore, oxygen bubbles generated by photosynthesis of microalgae (Scenedesmaceae and Cyanobacteria) due to microalgae phototaxis were found to be attached onto the surface of granules, causing the auto-flotation of MBGS. The formation process of the auto-floating oxygenic MBGS was clarified and further analysis suggested that the non-aerated settable MBGS would be able to auto-float at an average outdoor light intensity of 140 μ mol/m2/s. Overall, the auto-floating oxygenic MBGS process was demonstrated to be feasible for real municipal wastewater treatment, even under rainy and cloudy days, advancing the knowledge and adding theoretical basis for its further applications.
Collapse
Affiliation(s)
- Yuting Shi
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Bin Ji
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China.
| | - Xiaoyuan Zhang
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
| | - Yu Liu
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| |
Collapse
|
16
|
Rafeeq H, Afsheen N, Rafique S, Arshad A, Intisar M, Hussain A, Bilal M, Iqbal HMN. Genetically engineered microorganisms for environmental remediation. CHEMOSPHERE 2023; 310:136751. [PMID: 36209847 DOI: 10.1016/j.chemosphere.2022.136751] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 09/12/2022] [Accepted: 10/02/2022] [Indexed: 06/16/2023]
Abstract
In the recent era, the increasing persistence of hazardous contaminants is badly affecting the globe in many ways. Due to high environmental contamination, almost every second species on earth facing the worst issue in their survival. Advances in newer remediation approaches may help enhance bioremediation's quality, while conventional procedures have failed to remove hazardous compounds from the environment. Chemical and physical waste cleanup approaches have been used in current circumstances; however, these methods are costly and harmful to the environment. Thus, there has been a rise in the use of bioremediation due to an increase in environmental contamination, which led to the development of genetically engineered microbes (GEMs). It is safer and more cost-effective to use engineered microorganisms rather than alternative methods. GEMs are created by introducing a stronger protein into bacteria through biotechnology or genetic engineering to enhance the desired trait. Biodegradation of oil spills, halobenzoates naphthalenes, toluenes, trichloroethylene, octanes, xylenes etc. has been accomplished using GEMs such bacteria, fungus, and algae. Biotechnologically induced microorganisms are more powerful than naturally occurring ones and may degrade contaminants faster because they can quickly adapt to new pollutants they encounter or co-metabolize. Genetic engineering is a worthy process that will benefit the environment and ultimately the health of our people.
Collapse
Affiliation(s)
- Hamza Rafeeq
- Department of Biochemistry, Riphah International University, Faisalabad Campus, Faisalabad, 38000, Pakistan
| | - Nadia Afsheen
- Department of Biochemistry, Riphah International University, Faisalabad Campus, Faisalabad, 38000, Pakistan
| | - Sadia Rafique
- Departement of Pharmacy, Riphah International University, Faisalabad Campus, Faisalabad, 38000, Pakistan
| | - Arooj Arshad
- Department of Biochemistry, University of Agriculture Faisalabad, 38000, Pakistan
| | - Maham Intisar
- Department of Biochemistry, University of Agriculture Faisalabad, 38000, Pakistan
| | - Asim Hussain
- Department of Biochemistry, University of Agriculture Faisalabad, 38000, Pakistan
| | - Muhammad Bilal
- Institute of Chemical Technology and Engineering, Faculty of Chemical Technology, Poznan University of Technology, Berdychowo 4, PL-60695 Poznan, Poland.
| | - Hafiz M N Iqbal
- Tecnologico de Monterrey, School of Engineering and Sciences, Monterrey, 64849, Mexico.
| |
Collapse
|
17
|
Ghaffar I, Deepanraj B, Sundar LS, Vo DVN, Saikumar A, Hussain A. A review on the sustainable procurement of microalgal biomass from wastewaters for the production of biofuels. CHEMOSPHERE 2023; 311:137094. [PMID: 36334745 DOI: 10.1016/j.chemosphere.2022.137094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/22/2022] [Accepted: 10/30/2022] [Indexed: 06/16/2023]
Abstract
The feasibility of microalgal biomass as one of the most promising and renewable sources for the production of biofuels is being studied extensively. Microalgal biomass can be cultivated under photoautotrophic, heterotrophic, photoheterotrophic, and mixotrophic cultivation conditions. Photoautotrophic cultivation is the most common way of microalgal biomass production. Under mixotrophic cultivation, microalgae can utilize both organic carbon and CO2 simultaneously. Mixotrophic cultivation depicts higher biomass productivity as compared to photoautotrophic cultivation. It is evident from the literature that mixotrophic cultivation yields higher quantities of polyunsaturated fatty acids as compared to that photoautotrophic cultivation. In this context, for economical biomass production, the organic carbon of industrial wastewaters can be valorized for the mixotrophic cultivation of microalgae. Following the way, contaminants' load of wastewaters can be reduced while concomitantly producing highly productive microalgal biomass. This review focuses on different aspects covering the sustainable cultivation of different microalgal species in different types of wastewaters.
Collapse
Affiliation(s)
- Imania Ghaffar
- Applied and Environmental Microbiology Laboratory, Department of Wildlife and Ecology, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Balakrishnan Deepanraj
- Department of Mechanical Engineering, College of Engineering, Prince Mohammad Bin Fahd University, Al Khobar, Saudi Arabia.
| | - Lingala Syam Sundar
- Department of Mechanical Engineering, College of Engineering, Prince Mohammad Bin Fahd University, Al Khobar, Saudi Arabia
| | - Dai-Viet N Vo
- Institute of Applied Technology and Sustainable Development, Nguyen Tat Thanh University, Ho Chi Minh City, Viet Nam
| | - Algam Saikumar
- Department of Aeronautical Engineering, MLR Institute of Technology, Hyderabad, Telangana, India
| | - Ali Hussain
- Applied and Environmental Microbiology Laboratory, Institute of Zoology, University of the Punjab, Lahore, Pakistan.
| |
Collapse
|
18
|
Sun P, Liu C, Li A, Ji B. Using carbon dioxide-added microalgal-bacterial granular sludge for carbon-neutral municipal wastewater treatment under outdoor conditions: Performance, granule characteristics and environmental sustainability. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 848:157657. [PMID: 35907521 DOI: 10.1016/j.scitotenv.2022.157657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/21/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
Microalgal-bacterial granular sludge (MBGS) process has a gorgeous prospect for municipal wastewater treatment, but the research on the treatment of complex organic wastewater by MBGS process with CO2 addition under outdoor conditions is not enough. Therefore, this paper evaluated the feasibility of CO2-added MBGS process for complex organic wastewater disposal under natural day-night cycles. The results showed that the addition of CO2 overall improved the removal efficiency of pollutants. Typically, the removal efficiency of total phosphorus increased averagely from 88.5 % to 95.0 % in 12-h day cycle and from 26.2 % to 45.3 % in 12-h night cycle. The addition of CO2 increased the size of MBGS from 1.0 mm to 16.5 mm within 30 days due to extracellular polymeric substances secretion and the dominant filamentous microalgae on granules. The decrease of catalase activity and malondialdehyde content indicated that CO2 reduced oxidative damage and maintained the normal growth of MBGS. Further estimates of the collected gas showed that CO2-added MBGS process could reduce global CO2 emissions by one hundred million tons per year. This study is expected to contribute to the goal of carbon neutrality in the area of wastewater treatment by MBGS process.
Collapse
Affiliation(s)
- Penghui Sun
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Cheng Liu
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Anjie Li
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Bin Ji
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China.
| |
Collapse
|
19
|
Jiang Q, Chen H, Fu Z, Fu X, Wang J, Liang Y, Yin H, Yang J, Jiang J, Yang X, Wang H, Liu Z, Su R. Current Progress, Challenges and Perspectives in the Microalgal-Bacterial Aerobic Granular Sludge Process: A Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:13950. [PMID: 36360829 PMCID: PMC9655209 DOI: 10.3390/ijerph192113950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/18/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Traditional wastewater treatment technologies have become increasingly inefficient to meet the needs of low-consumption and sustainable wastewater treatment. Researchers are committed to seeking new wastewater treatment technologies, to reduce the pressure on the environment caused by resource shortages. Recently, a microalgal-bacterial granular sludge (MBGS) technology has attracted widespread attention due to its high efficiency wastewater treatment capacity, low energy consumption, low CO2 emissions, potentially high added values, and resource recovery capabilities. This review focused primarily on the following aspects of microalgal-bacterial granular sludge technology: (1) MBGS culture and maintenance operating parameters, (2) MBGS application in different wastewaters, (3) MBGS additional products: biofuels and bioproducts, (4) MBGS energy saving and consumption reduction: greenhouse gas emission reduction, and (5) challenges and prospects. The information in this review will help us better understand the current progress and future direction of the MBGS technology development. It is expected that this review will provide a sound theoretical basis for the practical applications of a MBGS technology in environmentally sustainable wastewater treatment, resource recovery, and system optimization.
Collapse
Affiliation(s)
- Qianrong Jiang
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Honglei Chen
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
| | - Zeding Fu
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114, China
| | - Xiaohua Fu
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
| | - Jiacheng Wang
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
| | - Yingqi Liang
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
| | - Hailong Yin
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
| | - Junbo Yang
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
| | - Jie Jiang
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Xinxin Yang
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
| | - He Wang
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
| | - Zhiming Liu
- Department of Biology, Eastern New Mexico University, Portales, NM 88130, USA
| | - Rongkui Su
- Ecological Environment Management and Assessment Center, Central South University of Forestry and Technology, Changsha 410004, China
- School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
| |
Collapse
|
20
|
Xiao M, Xin J, Fan J, Ji B. Response mechanisms of microalgal-bacterial granular sludge to zinc oxide nanoparticles. BIORESOURCE TECHNOLOGY 2022; 361:127713. [PMID: 35926556 DOI: 10.1016/j.biortech.2022.127713] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
Currently, zinc oxide nanoparticles (ZnO-NPs) with their widespread applications lead to their increasing dosages in wastewater, posing an urgent threat to wastewater treatment. Herein, the responses of the emerging microalgal-bacterial granular sludge (MBGS) to ZnO-NPs were investigated. The results showed that the performance of MBGS was significantly affected when the concentration of ZnO-NPs reached 10 mg/L, especially for the removal of ammonia and phosphorus. ZnO-NPs on the granular surface could affect microalgae photosynthesis by shading, while antioxidant enzymes could be generated against overproduced reactive oxygen species. Specifically, ZnO-NPs addition to MBGS systems altered the microbial community structure (e.g. Cyanobacteria) and function (e.g. biosynthesis) of prokaryotes rather than eukaryotes. Overall, the MBGS could exhibit multiple mechanisms to alleviate the ZnO-NPs toxicity. This study is expected to add knowledge on MBGS in the treatment of wastewater containing nanoparticles.
Collapse
Affiliation(s)
- Meixing Xiao
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Jiayi Xin
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Jie Fan
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Bin Ji
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China.
| |
Collapse
|
21
|
Re-cultivation of dry microalgal-bacterial granular sludge. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
|
22
|
Activated Carbon-Loaded Titanium Dioxide Nanoparticles and Their Photocatalytic and Antibacterial Investigations. Catalysts 2022. [DOI: 10.3390/catal12080834] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Activated carbon doping TiO2 nanoparticles were synthesised by zapota leaf extract using the co-precipitation method. The bio-constituents of plant compounds were used in the reactions of stabilization and reductions. The carbon loading on the TiO2 nanoparticles was characterised by XRD, FTIR, UV-DRS, SEM with EDX, and TEM analysis. The loading of activated carbon onto the TiO2 nanoparticles decreased the crystallite size and optical bandgap, and their doping improved the surface structure of AC/TiO2 nanoparticles. Mesoporous/microporous instability was remodified from the activated carbon, which was visualised using SEM and TEM analysis, respectively. The photocatalytic dye degradation of Rh-B dye was degraded in TiO2 and AC/TiO2 nanoparticles under visible light irradiation. The degradation efficiencies of TiO2 and AC/TiO2 nanoparticles were 73% and 91%, respectively. The bacterial abilities of TiO2 and AC/TiO2 nanoparticles were examined by E. coli and S. aureus. The water reclamation efficiency and bactericidal effect of TiO2 and AC/TiO2 nanoparticles were examined via catalytic dye degradation and bacterial efficiency of activated carbon-doped titanium dioxide nanoparticles.
Collapse
|
23
|
Chen Z, Xie Y, Qiu S, Li M, Yuan W, Ge S. Granular indigenous microalgal-bacterial consortium for wastewater treatment: Establishment strategy, functional microorganism, nutrient removal, and influencing factor. BIORESOURCE TECHNOLOGY 2022; 353:127130. [PMID: 35398536 DOI: 10.1016/j.biortech.2022.127130] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/02/2022] [Accepted: 04/05/2022] [Indexed: 06/14/2023]
Abstract
Granular indigenous microalgal-bacterial consortium (G-IMBC) system integrates the advantages of the MBC and granular activated sludge technologies, also with superior microalgal wastewater adaptation capacity. In this review, the concept of IMBC was firstly described, followed by its establishment and acclimation strategies. Characteristics and advantages of G-IMBC system compared to other IMBC systems (i.e., attached and floc IMBC systems) were then introduced. Moreover, the involved functional microorganisms and their interactions, as well as nutrient removal mechanisms were systematically and critically reviewed. Finally, the influencing factors including wastewater characteristics and operation factors were discussed. This study aims to provide a comprehensive up-to-date summary of the G-IMBC system for sustainable wastewater treatment.
Collapse
Affiliation(s)
- Zhipeng Chen
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Yue Xie
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Shuang Qiu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Mengting Li
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Wenqi Yuan
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China
| | - Shijian Ge
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China.
| |
Collapse
|
24
|
Sun Y, Chang H, Zhang C, Xie Y, Ho SH. Emerging biological wastewater treatment using microalgal-bacterial granules: A review. BIORESOURCE TECHNOLOGY 2022; 351:127089. [PMID: 35358672 DOI: 10.1016/j.biortech.2022.127089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 06/14/2023]
Abstract
Aiming at deepening the understanding of the formation and evolution of emerging microalgal-bacterial granule (MBG)-based wastewater treatment systems, the recent advances regarding the formation processes, transfer phenomena, innovative bioreactors development and wastewater treatment performance of MBG-based systems are comprehensively reviewed in this work. Particularly, the successful establishments of MBG-based systems with various inocula are summarized. Besides, as the indispensable factors for biochemical reactions in MBGs, the light and substrates (organic matters, inorganic nutrients, etc) need to undergo complicated and multi-scale transfer processes before being assimilated by microorganisms within MBGs. Therefore, the involved transfer phenomena and mechanisms in MBG-based bioreactors are critically discussed. Subsequently, some recent advances of MBG-based bioreactors, the application of MBG-based systems in treating various synthetic and real wastewater, and the future development directions are discussed. In short, this review helps in promoting the development of MBG-based systems by presenting current research status and future perspectives.
Collapse
Affiliation(s)
- Yahui Sun
- School of Energy and Mechanical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Haixing Chang
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, China
| | - Chaofan Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Youping Xie
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China
| | - Shih-Hsin Ho
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
| |
Collapse
|
25
|
Ji B, Fan S, Liu Y. A continuous-flow non-aerated microalgal-bacterial granular sludge process for aquaculture wastewater treatment under natural day-night conditions. BIORESOURCE TECHNOLOGY 2022; 350:126914. [PMID: 35231593 DOI: 10.1016/j.biortech.2022.126914] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/20/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
This study developed a continuous-flow non-aerated microalgal-bacterial granular tubular reactor for aquaculture wastewater treatment under natural day-night conditions. Results showed that daytime was favorable for ammonia removal while nighttime for nitrate removal. Over 99% of nitrite-N could be removed over the day-night cycles at a hydraulic retention time of 6 h. However, the phosphorus removal was found to be sensitive to the weather condition, ranging from 35.0% to 96.6%. It was also observed that dissolved oxygen produced by microalgae in daytime was sufficient for creating a 6-h aerobic condition in nighttime for sustaining heterotrophic activity. Chlorella and Leptolyngbya were identified as the most abundant algae related to weather changes. Metagenomics analysis revealed that the high nitrite removal relied mainly on nitrite reduction. These experimental findings offer new insights into the non-aerated microalgal-bacterial granular sludge for environmentally sustainable aquaculture wastewater treatment.
Collapse
Affiliation(s)
- Bin Ji
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan 430065, PR China.
| | - Siqi Fan
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan 430065, PR China
| | - Yu Liu
- Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| |
Collapse
|
26
|
Enhanced Nitrogen Removal from Domestic Wastewater by Partial-Denitrification/Anammox in an Anoxic/Oxic Biofilm Reactor. Processes (Basel) 2022. [DOI: 10.3390/pr10010109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
A partial-denitrification coupling with anaerobic ammonium oxidation (anammox) process (PD/A) in a continuous-flow anoxic/oxic (A/O) biofilm reactor was developed to treat carbon-limited domestic wastewater (ammonia (NH4+-N) of 55 mg/L and chemical oxygen demand (COD) of 148 mg/L in average) for about 200 days operation. Satisfactory NH4+-N oxidation efficiency above 95% was achieved with rapid biofilm formation in the aerobic zone. Notably, nitrite (NO2−-N) accumulation was observed in the anoxic zone, mainly due to the insufficient electron donor for complete nitrate (NO3−-N) reduction. The nitrate-to-nitrite transformation ratio (NTR) achieved was as high as 64.4%. After the inoculation of anammox-enriched sludge to anoxic zones, total nitrogen (TN) removal was significantly improved from 37.3% to 78.0%. Anammox bacteria were effectively retained in anoxic biofilm utilizing NO2−-N produced via the PD approach and NH4+-N in domestic wastewater, with the relative abundance of 5.83% for stable operation. Anammox pathway contributed to TN removal by a high level of 38%. Overall, this study provided a promising method for mainstream nitrogen removal with low energy consumption and organic carbon demand.
Collapse
|
27
|
Machine Learning Approach to Predict Quality Parameters for Bacterial Consortium-Treated Hospital Wastewater and Phytotoxicity Assessment on Radish, Cauliflower, Hot Pepper, Rice and Wheat Crops. WATER 2022. [DOI: 10.3390/w14010116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Raw hospital wastewater is a source of excessive heavy metals and pharmaceutical pollutants. In water-stressed countries such as Pakistan, the practice of unsafe reuse by local farmers for crop irrigation is of major concern. In our previous work, we developed a low-cost bacterial consortium wastewater treatment method. Here, in a two-part study, we first aimed to find what physico-chemical parameters were the most important for differentiating consortium-treated and untreated wastewater for its safe reuse. This was achieved using a Kruskal–Wallis test on a suite of physico-chemical measurements to find those parameters which were differentially abundant between consortium-treated and untreated wastewater. The differentially abundant parameters were then input to a Random Forest classifier. The classifier showed that ‘turbidity’ was the most influential parameter for predicting biotreatment. In the second part of our study, we wanted to know if the consortium-treated wastewater was safe for crop irrigation. We therefore carried out a plant growth experiment using a range of popular crop plants in Pakistan (Radish, Cauliflower, Hot pepper, Rice and Wheat), which were grown using irrigation from consortium-treated and untreated hospital wastewater at a range of dilutions (turbidity levels) and performed a phytotoxicity assessment. Our results showed an increasing trend in germination indices and a decreasing one in phytotoxicity indices in plants after irrigation with consortium-treated hospital wastewater (at each dilution/turbidity measure). The comparative study of growth between plants showed the following trend: Cauliflower > Radish > Wheat > Rice > Hot pepper. Cauliflower was the most adaptive plant (PI: −0.28, −0.13, −0.16, −0.06) for the treated hospital wastewater, while hot pepper was susceptible for reuse; hence, we conclude that bacterial consortium-treated hospital wastewater is safe for reuse for the irrigation of cauliflower, radish, wheat and rice. We further conclude that turbidity is the most influential parameter for predicting bio-treatment efficiency prior to water reuse. This method, therefore, could represent a low-cost, low-tech and safe means for farmers to grow crops in water stressed areas.
Collapse
|