Pub Date : 2024-08-03DOI: 10.1016/j.wroa.2024.100248
The use of polymers for water storage or distribution is closely monitored, especially with regard to the possible contamination with substances coming from the material's surfaces. Different standards are practiced across countries according to type of applied materials and such test methods are prevalently based on constant temperature conditions. However, these polymers systems could be located in diverse environment which does not necessarily provide constant conditions. Experimental findings show that exposure of liquid inside polymeric materials to specific temperature gradients, and consequently to emerging organized flows, can result in an accelerated leaching of undesirable substances from the solid surface. In presented work model steady-state and organized flow conditions are used to compare release of contaminates from polyethylene by measuring of surface tension, UV–Vis spectroscopy, FTIR, scanning electron microscopy and elemental analysis of polymer surfaces and water leachates. The pilot study shows that convective flow generated via temperature gradient significantly affects contaminant release in comparison to a steady state and mixing flow conditions.
{"title":"Release of contaminants from polymer surfaces under condition of organized fluid flows","authors":"","doi":"10.1016/j.wroa.2024.100248","DOIUrl":"10.1016/j.wroa.2024.100248","url":null,"abstract":"<div><p>The use of polymers for water storage or distribution is closely monitored, especially with regard to the possible contamination with substances coming from the material's surfaces. Different standards are practiced across countries according to type of applied materials and such test methods are prevalently based on constant temperature conditions. However, these polymers systems could be located in diverse environment which does not necessarily provide constant conditions. Experimental findings show that exposure of liquid inside polymeric materials to specific temperature gradients, and consequently to emerging organized flows, can result in an accelerated leaching of undesirable substances from the solid surface. In presented work model steady-state and organized flow conditions are used to compare release of contaminates from polyethylene by measuring of surface tension, UV–Vis spectroscopy, FTIR, scanning electron microscopy and elemental analysis of polymer surfaces and water leachates. The pilot study shows that convective flow generated via temperature gradient significantly affects contaminant release in comparison to a steady state and mixing flow conditions.</p></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589914724000380/pdfft?md5=509de9eab7440517f2bb9894b5a8766a&pid=1-s2.0-S2589914724000380-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141979302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-02DOI: 10.1016/j.wroa.2024.100246
Aquaculture, producing half of global fish production, offers a high-quality protein source for humans. Improving nitrogen use efficiency (NUE) through microbial protein recovery is crucial for increasing fish production and reducing environmental footprint. However, the poor palatability and high moisture content of microbial protein make its utilization challenging. Here, a biofloc-worm reactor was integrated into a recirculating aquaculture system (BW_RAS) for the first time to convert microbial protein into Tubificidae (Oligochaeta) biomass, which was used as direct feed for culturing fish. Batch experiments indicated that an aeration rate of 0.132 m3L−1h−1 and a worm density of 0.3 g cm−2 on the carrier were optimal for microbial biomass growth and worm predation, respectively. Compared to the biofloc reactor-based recirculating aquaculture system (B_RAS), the BW_RAS improved water quality, NUE, and fish production by 17.1 % during a 120-day aquaculture period. The abundance of heterotrophic aerobic denitrifier Deinococcus in BW_RAS was one order of magnitude higher than in B_RAS, while heterotrophic bacteria Mycobacterium was more abundant in B_RAS. Denitrifiers cooperated with organic matter degraders and nitrogen assimilation bacteria for protein recovery and gaseous nitrogen loss while competing with predatory bacteria. Function prediction and qPCR indicated greater aerobic respiration, nitrate assimilation, nitrification (AOB-amoA), and denitrification (napA, nirK, nirS, nosZI), but lower fermentation in BWR compared to BR. This study demonstrated that BW_RAS increased microbial protein production and aerobic nitrogen cycling through ongoing worm predation, further enhancing fish production to a commercially viable level.
{"title":"Increasing fish production in recirculating aquaculture system by integrating a biofloc-worm reactor for protein recovery","authors":"","doi":"10.1016/j.wroa.2024.100246","DOIUrl":"10.1016/j.wroa.2024.100246","url":null,"abstract":"<div><p>Aquaculture, producing half of global fish production, offers a high-quality protein source for humans. Improving nitrogen use efficiency (NUE) through microbial protein recovery is crucial for increasing fish production and reducing environmental footprint. However, the poor palatability and high moisture content of microbial protein make its utilization challenging. Here, a biofloc-worm reactor was integrated into a recirculating aquaculture system (BW_RAS) for the first time to convert microbial protein into Tubificidae (Oligochaeta) biomass, which was used as direct feed for culturing fish. Batch experiments indicated that an aeration rate of 0.132 m<sup>3</sup> <em>L</em><sup>−1</sup> <em>h</em><sup>−1</sup> and a worm density of 0.3 g cm<sup>−2</sup> on the carrier were optimal for microbial biomass growth and worm predation, respectively. Compared to the biofloc reactor-based recirculating aquaculture system (B_RAS), the BW_RAS improved water quality, NUE, and fish production by 17.1 % during a 120-day aquaculture period. The abundance of heterotrophic aerobic denitrifier <em>Deinococcus</em> in BW_RAS was one order of magnitude higher than in B_RAS, while heterotrophic bacteria <em>Mycobacterium</em> was more abundant in B_RAS. Denitrifiers cooperated with organic matter degraders and nitrogen assimilation bacteria for protein recovery and gaseous nitrogen loss while competing with predatory bacteria. Function prediction and qPCR indicated greater aerobic respiration, nitrate assimilation, nitrification (AOB-<em>amoA</em>), and denitrification (<em>napA, nirK, nirS, nosZI</em>), but lower fermentation in BWR compared to BR. This study demonstrated that BW_RAS increased microbial protein production and aerobic nitrogen cycling through ongoing worm predation, further enhancing fish production to a commercially viable level.</p></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589914724000367/pdfft?md5=03789b8d1a27121c8f9a0b57ba65c23f&pid=1-s2.0-S2589914724000367-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141962887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-30DOI: 10.1016/j.wroa.2024.100245
Advanced controllers often offer an innovative solution to proper quality control in wastewater treatment processes (WWTPs). However, nonlinearity and uncertain disturbances usually make the conventional control strategies inadequate or impossible for the stable operations of WWTPs. To guarantee the stability of ammonia nitrogen concentration () control in WWTPs, a direct adaptive neural networks-based sliding mode control (ANNSMC) strategy has been proposed in this article. A sliding mode controller is designed and implemented with the help of an adaptive Neural Network (ANN), named Radial Basis Function Neural Network (RBFNN), which can approach the desired control law accurately. Also, the stability of a system installed with the ANNSMC is analyzed by using the Lyapunov theorem, which ensures system robustness and adaptability. Additionally, to deal with high energy consumption and low treatment efficiency problems in the wastewater denitrification processes, this paper proposes a dual-loop denitrification control strategy and validates it in the Benchmark Simulation Model No.2 (BSM2) platform. The strategy can strengthen the denitrification efficiency by collaborating the with nitrate nitrogen () concentration in the WWTPs properly. The experimental results demonstrate that the proposed strategy can obtain remarkable stability and robustness, reducing energy consumption effectively compared with other standard and advanced control strategies.
{"title":"Towards Stable and Efficient Nitrogen Removal in Wastewater Treatment Processes Via an Adaptive Neural Network Based Sliding Mode Controller","authors":"","doi":"10.1016/j.wroa.2024.100245","DOIUrl":"10.1016/j.wroa.2024.100245","url":null,"abstract":"<div><p>Advanced controllers often offer an innovative solution to proper quality control in wastewater treatment processes (WWTPs). However, nonlinearity and uncertain disturbances usually make the conventional control strategies inadequate or impossible for the stable operations of WWTPs. To guarantee the stability of ammonia nitrogen concentration (<span><math><msub><mi>S</mi><mrow><mi>N</mi><mi>H</mi></mrow></msub></math></span>) control in WWTPs, a direct adaptive neural networks-based sliding mode control (ANNSMC) strategy has been proposed in this article. A sliding mode controller is designed and implemented with the help of an adaptive Neural Network (ANN), named Radial Basis Function Neural Network (RBFNN), which can approach the desired control law accurately. Also, the stability of a system installed with the ANNSMC is analyzed by using the Lyapunov theorem, which ensures system robustness and adaptability. Additionally, to deal with high energy consumption and low treatment efficiency problems in the wastewater denitrification processes, this paper proposes a dual-loop denitrification control strategy and validates it in the Benchmark Simulation Model No.2 (BSM2) platform. The strategy can strengthen the denitrification efficiency by collaborating the <span><math><msub><mi>S</mi><mrow><mi>N</mi><mi>H</mi></mrow></msub></math></span> with nitrate nitrogen (<span><math><msub><mi>S</mi><mrow><mi>N</mi><mi>O</mi></mrow></msub></math></span>) concentration in the WWTPs properly. The experimental results demonstrate that the proposed strategy can obtain remarkable stability and robustness, reducing energy consumption effectively compared with other standard and advanced control strategies.</p></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589914724000355/pdfft?md5=1ce9f584cf8205423e62e081c01ae36d&pid=1-s2.0-S2589914724000355-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141962886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-28DOI: 10.1016/j.wroa.2024.100239
Per- and polyfluoroalkyl substances (PFASs) are emerging contaminants detected ubiquitously and have negative impacts on human health and ecosystem; thus, developing in-situ sensing technique is important to ensure safety. Herein, we report a novel colorimetric-based sensor with perfluoroalkyl receptor attached to citrate coated gold nanoparticles (Citrate-Au NPs) that can detect several PFASs including perfluorocarboxylates with different chain lengths (PFHxA, PFOA, PFNA, PFDA), perfluorooctanoic sulfonate (PFOS), and perfluorooctanoic phosphonate (PFOPA). The sensor detects PFASs utilizing fluorous interaction between PFASs and the perfluoroalkyl receptor of Citrate-Au NPs in a solution at a fixed salt concentration, inducing changes in nanoparticle dispersity and the solution color. The rate of spectrum shift was linearly dependent on PFASs concentrations. Citrate-Au NPs with size between 29 – 109 nm were synthesized by adjusting citrate/Au molar ratios, and 78 nm showed the best sensitivity to PFOA concentration (with level of detection of 4.96 µM). Citrate-Au NPs only interacted with PFASs with perfluoroalkyl length > 4 and not with non-fluorinated alkyl compound (nonanoic acid). The performance of Citrate-Au NP based sensor was strongly dependent on the chain length of the perfluoroalkyl group and the head functional group; higher sensitivity was observed with longer chain over shorter chain, and with sulfonate functional group over carboxylate and phosphonate. The sensor was tested using real water samples (i.e., tap water, filtered river water), and it was found that the sensor is capable of detecting PFASs in these conditions if calibrated with the corresponding water matrix. While further optimization is needed, this study demonstrated new capability of Citrate-Au NPs based sensor for detection of PFASs in water.
{"title":"Perfluoroalkyl functionalized-Au nanoparticle sensor: Employing rate of spectrum shifting for highly selective and sensitive detection of per- and polyfluoroalkyl substances (PFASs) in aqueous environments","authors":"","doi":"10.1016/j.wroa.2024.100239","DOIUrl":"10.1016/j.wroa.2024.100239","url":null,"abstract":"<div><p>Per- and polyfluoroalkyl substances (PFASs) are emerging contaminants detected ubiquitously and have negative impacts on human health and ecosystem; thus, developing <em>in-situ</em> sensing technique is important to ensure safety. Herein, we report a novel colorimetric-based sensor with perfluoroalkyl receptor attached to citrate coated gold nanoparticles (Citrate-Au NPs) that can detect several PFASs including perfluorocarboxylates with different chain lengths (PFHxA, PFOA, PFNA, PFDA), perfluorooctanoic sulfonate (PFOS), and perfluorooctanoic phosphonate (PFOPA). The sensor detects PFASs utilizing fluorous interaction between PFASs and the perfluoroalkyl receptor of Citrate-Au NPs in a solution at a fixed salt concentration, inducing changes in nanoparticle dispersity and the solution color. The rate of spectrum shift was linearly dependent on PFASs concentrations. Citrate-Au NPs with size between 29 – 109 nm were synthesized by adjusting citrate/Au molar ratios, and 78 nm showed the best sensitivity to PFOA concentration (with level of detection of 4.96 µM). Citrate-Au NPs only interacted with PFASs with perfluoroalkyl length > 4 and not with non-fluorinated alkyl compound (nonanoic acid). The performance of Citrate-Au NP based sensor was strongly dependent on the chain length of the perfluoroalkyl group and the head functional group; higher sensitivity was observed with longer chain over shorter chain, and with sulfonate functional group over carboxylate and phosphonate. The sensor was tested using real water samples (i.e., tap water, filtered river water), and it was found that the sensor is capable of detecting PFASs in these conditions if calibrated with the corresponding water matrix. While further optimization is needed, this study demonstrated new capability of Citrate-Au NPs based sensor for detection of PFASs in water.</p></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S258991472400029X/pdfft?md5=8ac9eb812d5e44d71307e45861d57dbd&pid=1-s2.0-S258991472400029X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141843961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-26DOI: 10.1016/j.wroa.2024.100244
People spend most of their time indoors and are exposed to numerous contaminants in the built environment. Water management plans implemented in buildings are designed to manage the risks of preventable diseases caused by drinking water contaminants such as opportunistic pathogens (e.g., Legionella spp.), metals, and disinfection by-products (DBPs). However, specialized training required to implement water management plans and heterogeneity in building characteristics limit their widespread adoption. Implementation of machine learning and artificial intelligence (ML/AI) models in building water settings presents an opportunity for faster, more widespread use of data-driven water quality management approaches. We demonstrate the utility of Random Forest and Long Short-Term Memory (LSTM) ML models for predicting a key public health parameter, free chlorine residual, as a function of data collected from building water quality sensors (ORP, pH, conductivity, and temperature) as well as WiFi signals as a proxy for building occupancy and water usage in a “green” Leadership in Energy and Environmental Design (LEED) commercial and institutional building. The models successfully predicted free chlorine residual declines below 0.2 ppm, a common minimum reference level for public health protection in drinking water distribution systems. The predictions were valid up to 5 min in advance, and in some cases reasonably accurate up to 24 h in advance, presenting opportunities for proactive water quality management as part of a sense-analyze-decide framework. An online data dashboard for visualizing water quality in the building is presented, with the potential to link these approaches for real-time water quality management.
{"title":"High resolution data visualization and machine learning prediction of free chlorine residual in a green building water system","authors":"","doi":"10.1016/j.wroa.2024.100244","DOIUrl":"10.1016/j.wroa.2024.100244","url":null,"abstract":"<div><p>People spend most of their time indoors and are exposed to numerous contaminants in the built environment. Water management plans implemented in buildings are designed to manage the risks of preventable diseases caused by drinking water contaminants such as opportunistic pathogens (e.g., <em>Legionella</em> spp<em>.</em>), metals, and disinfection by-products (DBPs). However, specialized training required to implement water management plans and heterogeneity in building characteristics limit their widespread adoption. Implementation of machine learning and artificial intelligence (ML/AI) models in building water settings presents an opportunity for faster, more widespread use of data-driven water quality management approaches. We demonstrate the utility of Random Forest and Long Short-Term Memory (LSTM) ML models for predicting a key public health parameter, free chlorine residual, as a function of data collected from building water quality sensors (ORP, pH, conductivity, and temperature) as well as WiFi signals as a proxy for building occupancy and water usage in a “green” Leadership in Energy and Environmental Design (LEED) commercial and institutional building. The models successfully predicted free chlorine residual declines below 0.2 ppm, a common minimum reference level for public health protection in drinking water distribution systems. The predictions were valid up to 5 min in advance, and in some cases reasonably accurate up to 24 h in advance, presenting opportunities for proactive water quality management as part of a sense-analyze-decide framework. An online data dashboard for visualizing water quality in the building is presented, with the potential to link these approaches for real-time water quality management.</p></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589914724000343/pdfft?md5=9bbb00daa0ee30e2833e3440fc3a810e&pid=1-s2.0-S2589914724000343-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141847893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-26DOI: 10.1016/j.wroa.2024.100241
Given that many organic pollutants have been reported to facilitate the plasmid-mediated conjugative transfer of antibiotic resistance genes (ARGs), it was naturally deduced that nonylphenol (NP) can also have this kind of effect. Whereas, this study demonstrates an entirely different result that environmentally relevant concentrations of NP attenuate plasmid-mediated ARGs conjugative transfer (maximum inhibition rate 64 %), further study show that NP exposure had no significant effect on bacterial growth, cell vitality, oxidative stress response, and expression of conjugation-relevant genes, which were reported to closely relate to the conjugative transfer in numerous studies. Conclusively, it was found that the dispersant function of NP impeded the occurrence of cell mating, thus was responsible for the decline of conjugative transfer. This study shows a new perspective on understanding the effect of organic pollutants like NP on the ARGs horizontal dissemination in environment.
{"title":"A maverick: Environmentally relevant concentrations of nonylphenol attenuate the plasmid-mediated conjugative transfer of antibiotic resistance genes","authors":"","doi":"10.1016/j.wroa.2024.100241","DOIUrl":"10.1016/j.wroa.2024.100241","url":null,"abstract":"<div><p>Given that many organic pollutants have been reported to facilitate the plasmid-mediated conjugative transfer of antibiotic resistance genes (ARGs), it was naturally deduced that nonylphenol (NP) can also have this kind of effect. Whereas, this study demonstrates an entirely different result that environmentally relevant concentrations of NP attenuate plasmid-mediated ARGs conjugative transfer (maximum inhibition rate 64 %), further study show that NP exposure had no significant effect on bacterial growth, cell vitality, oxidative stress response, and expression of conjugation-relevant genes, which were reported to closely relate to the conjugative transfer in numerous studies. Conclusively, it was found that the dispersant function of NP impeded the occurrence of cell mating, thus was responsible for the decline of conjugative transfer. This study shows a new perspective on understanding the effect of organic pollutants like NP on the ARGs horizontal dissemination in environment.</p></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589914724000318/pdfft?md5=825587c1d724f818a79ffb6684271469&pid=1-s2.0-S2589914724000318-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141852706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-25DOI: 10.1016/j.wroa.2024.100243
The goal of this study was to assess the impacts or benefits of sludge in situ reduction (SIR) within wastewater treatment processes with relation to global warming potential in wastewater treatment plants, with a comprehensive consideration of wastewater and sludge treatment. The anaerobic side-stream reactor (ASSR) and the sludge process reduction activated sludge (SPRAS), two typical SIR technologies, were used to compare the carbon footprint analysis results with the conventional anaerobic - anoxic - oxic (AAO) process. Compared to the AAO, the ASSR with a typical sludge reduction efficiency (SRE) of 30 % increased greenhouse gas (GHG) emissions by 1.1 - 1.7 %, while the SPRAS with a SRE of 74 % reduced GHG emissions by 12.3 - 17.6 %. Electricity consumption (0.025 - 0.027 kg CO2-eq/m3), CO2 emissions (0.016 - 0.059 kg CO2-eq/m3), and N2O emissions (0.009 - 0.023 kg CO2-eq/m3) for the removal of secondary substrates released from sludge decay in the SIR processes were the major contributor to the increased GHG emissions from the wastewater treatment system. By lowering sludge production and the organic matter content in the sludge, the SIR processes significantly decreased the carbon footprints associated with sludge treatment and disposal. The threshold SREs of the ASSR for GHG reduction were 27.7 % and 34.6 % for the advanced dewatering - sanitary landfill and conventional dewatering - drying-incinerating routes, respectively. Overall, the SPRAS process could be considered as a cost-effective and sustainable low-carbon SIR technology for wastewater treatment.
本研究的目的是评估污泥原位减量(SIR)在废水处理工艺中对废水处理厂全球变暖潜能值的影响或益处,并对废水和污泥处理进行综合考虑。厌氧侧流反应器(ASSR)和污泥工艺减量活性污泥(SPRAS)是两种典型的 SIR 技术,碳足迹分析结果与传统的厌氧-缺氧-缺氧(AAO)工艺进行了比较。与 AAO 相比,典型污泥减量效率(SRE)为 30% 的 ASSR 增加了 1.1 - 1.7% 的温室气体(GHG)排放量,而 SRE 为 74% 的 SPRAS 则减少了 12.3 - 17.6% 的温室气体排放量。SIR 工艺中去除污泥腐烂释放的二次基质所消耗的电力(0.025 - 0.027 kg CO2-eq/m3)、二氧化碳排放量(0.016 - 0.059 kg CO2-eq/m3)和一氧化二氮排放量(0.009 - 0.023 kg CO2-eq/m3)是污水处理系统温室气体排放量增加的主要原因。通过降低污泥产量和污泥中的有机物含量,SIR 工艺显著减少了与污泥处理和处置相关的碳足迹。对于高级脱水-卫生填埋和传统脱水-干燥-焚烧路线,ASSR 的温室气体减排阈值 SRE 分别为 27.7% 和 34.6%。总体而言,SPRAS 工艺可被视为一种成本效益高且可持续的低碳 SIR 废水处理技术。
{"title":"Carbon footprint analysis of wastewater treatment processes coupled with sludge in situ reduction","authors":"","doi":"10.1016/j.wroa.2024.100243","DOIUrl":"10.1016/j.wroa.2024.100243","url":null,"abstract":"<div><p>The goal of this study was to assess the impacts or benefits of sludge in situ reduction (SIR) within wastewater treatment processes with relation to global warming potential in wastewater treatment plants, with a comprehensive consideration of wastewater and sludge treatment. The anaerobic side-stream reactor (ASSR) and the sludge process reduction activated sludge (SPRAS), two typical SIR technologies, were used to compare the carbon footprint analysis results with the conventional anaerobic - anoxic - oxic (AAO) process. Compared to the AAO, the ASSR with a typical sludge reduction efficiency (SRE) of 30 % increased greenhouse gas (GHG) emissions by 1.1 - 1.7 %, while the SPRAS with a SRE of 74 % reduced GHG emissions by 12.3 - 17.6 %. Electricity consumption (0.025 - 0.027 kg CO<sub>2-eq</sub>/m<sup>3</sup>), CO<sub>2</sub> emissions (0.016 - 0.059 kg CO<sub>2-eq</sub>/m<sup>3</sup>), and N<sub>2</sub>O emissions (0.009 - 0.023 kg CO<sub>2-eq</sub>/m<sup>3</sup>) for the removal of secondary substrates released from sludge decay in the SIR processes were the major contributor to the increased GHG emissions from the wastewater treatment system. By lowering sludge production and the organic matter content in the sludge, the SIR processes significantly decreased the carbon footprints associated with sludge treatment and disposal. The threshold SREs of the ASSR for GHG reduction were 27.7 % and 34.6 % for the advanced dewatering - sanitary landfill and conventional dewatering - drying-incinerating routes, respectively. Overall, the SPRAS process could be considered as a cost-effective and sustainable low-carbon SIR technology for wastewater treatment.</p></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589914724000331/pdfft?md5=2de9b0c83b367b3abb143647d9212f29&pid=1-s2.0-S2589914724000331-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141848269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-23DOI: 10.1016/j.wroa.2024.100240
Wastewater treatment plants produce large amounts of sludge requiring stabilization before safe disposal. Traditional biological stabilization approaches are cost-effective but generally require either an extended retention time (10–40 days), or elevated temperatures (40–80 °C) for effective pathogens inactivation. This study overcomes these limitations via a novel acidic aerobic digestion process, leveraging an acid-tolerant ammonia-oxidizing bacterium (AOB) Candidatus Nitrosoglobus. To retain this novel but slowly growing AOB, we proposed the first-ever application of a classical wastewater configuration—moving bed biofilm reactor (MBBR)—for sludge treatment. The AOB in biofilm maintains acidic pH and high nitrite levels in sludge, generating free nitrous acid in situ to expedite sludge stabilization. This process was tested in two laboratory-scale aerobic digesters processing full-scale anaerobically digested sludge. At an ambient temperature of 20 °C, pathogens were reduced to levels well below the threshold specified for the highest stabilization level (Class A), within a retention time of 3.5 days. A high volatile solids reduction of 27.4 ± 5.2% was achieved. Through drastically accelerating stabilization and enhancing reduction, this process substantially saves capital and operational costs for sludge disposal.
{"title":"Quadrupling the capacity of post aerobic digestion treating anaerobically digested sludge using a moving-bed biofilm (MBBR) configuration","authors":"","doi":"10.1016/j.wroa.2024.100240","DOIUrl":"10.1016/j.wroa.2024.100240","url":null,"abstract":"<div><p>Wastewater treatment plants produce large amounts of sludge requiring stabilization before safe disposal. Traditional biological stabilization approaches are cost-effective but generally require either an extended retention time (10–40 days), or elevated temperatures (40–80 °C) for effective pathogens inactivation. This study overcomes these limitations via a novel acidic aerobic digestion process, leveraging an acid-tolerant ammonia-oxidizing bacterium (AOB) <em>Candidatus</em> Nitrosoglobus. To retain this novel but slowly growing AOB, we proposed the first-ever application of a classical wastewater configuration—moving bed biofilm reactor (MBBR)—for sludge treatment. The AOB in biofilm maintains acidic pH and high nitrite levels in sludge, generating free nitrous acid in situ to expedite sludge stabilization. This process was tested in two laboratory-scale aerobic digesters processing full-scale anaerobically digested sludge. At an ambient temperature of 20 °C, pathogens were reduced to levels well below the threshold specified for the highest stabilization level (Class A), within a retention time of 3.5 days. A high volatile solids reduction of 27.4 ± 5.2% was achieved. Through drastically accelerating stabilization and enhancing reduction, this process substantially saves capital and operational costs for sludge disposal.</p></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589914724000306/pdfft?md5=40ed91b99cf87da03a8c29e628fdcd57&pid=1-s2.0-S2589914724000306-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141850418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-16DOI: 10.1016/j.wroa.2024.100238
Water disinfection by copper vessels has been prevalent over thousands of years. Unfortunately, people are still suffering from the bacterial pollution in drinking water. Here we show that, only through steeping with tiny amounts of common plant leaves, the room-temperature water in copper pots has unexpectedly high antibacterial ability. Remarkably, copper ions released from copper pots into water are in concentrations lower than the WHO safety threshold for drinking water, and have effective antibacterial ability when water contains specific leave components (polyphenols and/or lignin). Our computations show that the key to enhance antibacterial ability is the great increase in the proportion of Cu+ induced by aromatic rings in these leave components, which has been demonstrated by our experiments. The findings may disclose the mystery of copper vessels for water disinfection, and more importantly, provide effective antibacterial applications in industries and daily lives, by safely using copper ions together with biocompatible natural substances.
{"title":"Unexpectedly high antibacterial ability of water in copper pot with tiny amount of plant leaves","authors":"","doi":"10.1016/j.wroa.2024.100238","DOIUrl":"10.1016/j.wroa.2024.100238","url":null,"abstract":"<div><p>Water disinfection by copper vessels has been prevalent over thousands of years. Unfortunately, people are still suffering from the bacterial pollution in drinking water. Here we show that, only through steeping with tiny amounts of common plant leaves, the room-temperature water in copper pots has unexpectedly high antibacterial ability. Remarkably, copper ions released from copper pots into water are in concentrations lower than the WHO safety threshold for drinking water, and have effective antibacterial ability when water contains specific leave components (polyphenols and/or lignin). Our computations show that the key to enhance antibacterial ability is the great increase in the proportion of Cu<sup>+</sup> induced by aromatic rings in these leave components, which has been demonstrated by our experiments. The findings may disclose the mystery of copper vessels for water disinfection, and more importantly, provide effective antibacterial applications in industries and daily lives, by safely using copper ions together with biocompatible natural substances.</p></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589914724000288/pdfft?md5=78fdaf6596718360d9424d0a61897d31&pid=1-s2.0-S2589914724000288-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141702863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-10DOI: 10.1016/j.wroa.2024.100237
Nitrite-oxidizing bacteria (NOB) are undesirable in the anaerobic ammonium oxidation (anammox)-driven nitrogen removal technologies in the modern wastewater treatment plants (WWTPs). Diverse strategies have been developed to suppress NOB based on their physiological properties that we have understood. But our knowledge of the diversity and mechanisms employed by NOB for survival in the modern WWTPs remains limited. Here, Three NOB species (NOB01–03) were recovered from the metagenomic datasets of a full-scale WWTP treating duck breeding wastewater. Among them, NOB01 and NOB02 were classified as newly identified lineage VII, tentatively named Candidatus (Ca.) Nitrospira NOB01 and Ca. Nitrospira NOB02. Analyses of genomes and in situ transcriptomes revealed that these two novel NOB were active and showed a high metabolic versatility. The transcriptional activity of Ca. Nitrospira could be detected in all tanks with quite different dissolved oxygen (DO) (0.01–5.01 mg/L), illustrating Ca. Nitrospira can survive in fluctuating DO conditions. The much lower Ca. Nitrospira abundance on the anammox bacteria-enriched sponge carrier likely originated from the intensification substrate (NO2−) competition from anammox and denitrifying bacteria. In particular, a highlight is that Ca. Nitrospira encoded and treanscribed cyanate hydratase (CynS), amine oxidase, urease (UreC), and copper-containing nitrite reductase (NirK) related to ammonium and NO production, driving NOB to interact with the co-existed AOB and anammox bacteria. Ca. Nitrospira strains NOB01 and NOB02 showed quite different niche preference in the same aerobic tank, which dominanted the NOB communities in activated sludge and biofilm, respectively. In addition to the common rTCA cycle for CO2 fixation, a reductive glycine pathway (RGP) was encoded and transcribed by NOB02 likely for CO2 fixation purpose. Additionally, a 3b group hydrogenase and respiratory nitrate reductase were uniquely encoded and transcribed by NOB02, which likely confer a survival advantage to this strain in the fluctuant activated sludge niche. The discovery of this new genus significantly broadens our understanding of the ecophysiology of NOB. Furthermore, the impressive metabolic versatility of the novel NOB revealed in this study advances our understanding of the survival strategy of NOB and provides valuable insight for suppressing NOB in the anammox-based WWTP.
{"title":"A positive contribution to nitrogen removal by a novel NOB in a full-scale duck wastewater treatment system","authors":"","doi":"10.1016/j.wroa.2024.100237","DOIUrl":"10.1016/j.wroa.2024.100237","url":null,"abstract":"<div><p>Nitrite-oxidizing bacteria (NOB) are undesirable in the anaerobic ammonium oxidation (anammox)-driven nitrogen removal technologies in the modern wastewater treatment plants (WWTPs). Diverse strategies have been developed to suppress NOB based on their physiological properties that we have understood. But our knowledge of the diversity and mechanisms employed by NOB for survival in the modern WWTPs remains limited. Here, Three NOB species (NOB01–03) were recovered from the metagenomic datasets of a full-scale WWTP treating duck breeding wastewater. Among them, NOB01 and NOB02 were classified as newly identified lineage VII, tentatively named <em>Candidatus</em> (<em>Ca.</em>) Nitrospira NOB01 and <em>Ca.</em> Nitrospira NOB02. Analyses of genomes and in situ transcriptomes revealed that these two novel NOB were active and showed a high metabolic versatility. The transcriptional activity of <em>Ca.</em> Nitrospira could be detected in all tanks with quite different dissolved oxygen (DO) (0.01–5.01 mg/L), illustrating <em>Ca.</em> Nitrospira can survive in fluctuating DO conditions. The much lower <em>Ca.</em> Nitrospira abundance on the anammox bacteria-enriched sponge carrier likely originated from the intensification substrate (NO<sub>2</sub><sup>−</sup>) competition from anammox and denitrifying bacteria. In particular, a highlight is that <em>Ca.</em> Nitrospira encoded and treanscribed cyanate hydratase (CynS), amine oxidase, urease (UreC), and copper-containing nitrite reductase (NirK) related to ammonium and NO production, driving NOB to interact with the co-existed AOB and anammox bacteria. <em>Ca.</em> Nitrospira strains NOB01 and NOB02 showed quite different niche preference in the same aerobic tank, which dominanted the NOB communities in activated sludge and biofilm, respectively. In addition to the common rTCA cycle for CO<sub>2</sub> fixation, a reductive glycine pathway (RGP) was encoded and transcribed by NOB02 likely for CO<sub>2</sub> fixation purpose. Additionally, a 3b group hydrogenase and respiratory nitrate reductase were uniquely encoded and transcribed by NOB02, which likely confer a survival advantage to this strain in the fluctuant activated sludge niche. The discovery of this new genus significantly broadens our understanding of the ecophysiology of NOB. Furthermore, the impressive metabolic versatility of the novel NOB revealed in this study advances our understanding of the survival strategy of NOB and provides valuable insight for suppressing NOB in the anammox-based WWTP.</p></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":null,"pages":null},"PeriodicalIF":7.2,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2589914724000276/pdfft?md5=04648454e6f8c75310c750db6732638e&pid=1-s2.0-S2589914724000276-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141706652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}