[Objectives] By reasonable water distribution and air supply to soil, soil water permeability is maintained, and the nutrient conditions of degrading bacteria in soil are improved to effectively prevent soil clogging....[Objectives] By reasonable water distribution and air supply to soil, soil water permeability is maintained, and the nutrient conditions of degrading bacteria in soil are improved to effectively prevent soil clogging. [Methods] Through the innovation and improvement of traditional soil sewage treatment technology, the physical, chemical and biological characteristics of soil for sewage purification are utilized to enhance the pollutant decomposition ability of soil microorganisms and maintain soil water permeability.[Results] It has no secondary pollution, and can effectively remove pollutants such as COD_(Cr), TN, TP, NH_3-N, etc. in sewage. [Conclusions] The operation and maintenance cost is low, and the land can be reused, while water and nutrients can be restored to the land.展开更多
Rural domestic sewage treatment is an important part of the rural revitalization strategy and a key action to build a livable, livable and beautiful countryside. This paper composes and summarizes the relevant studies...Rural domestic sewage treatment is an important part of the rural revitalization strategy and a key action to build a livable, livable and beautiful countryside. This paper composes and summarizes the relevant studies on rural domestic sewage treatment from the governance techniques and modes of governance subjects and research perspectives, in order to provide reference for the implementation of rural revitalization strategy and rural domestic sewage treatment research and action implementation.展开更多
Biotransformation of nonylphenol ethoxylates (NPEOs) during continuous anaerobic sewage treatment was compared with the aerobic treatment of sewage spiked with 23 μmol/L technical NPEOs over a period of 90 d. Immed...Biotransformation of nonylphenol ethoxylates (NPEOs) during continuous anaerobic sewage treatment was compared with the aerobic treatment of sewage spiked with 23 μmol/L technical NPEOs over a period of 90 d. Immediate degradation of NPEOs was observed under both anaerobic and aerobic conditions, indicating that the enzymes and bacteria required for NPEO degradation existed abundantly in both aerobic and anaerobic sludge. Both treatments achieved high removal (〉 92%) of the spiked NPEO9 mixture. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that short-chain NPEOs (NPEO1-NPEO3) accumulated in anaerobic (2.01-2.56 μmol/L) and aerobic (1.62-2.03 μmol/L) effluents, with nonylphenol (NP) (0.24-0.31 μmol/L) as another group of metabolites in the anaerobic effluent, and nonylphenoxy carboxylates (NPECs) (2.79-3.30 μmol/L) in the aerobic effluent. Significant accumulation of NP in the anaerobic sludge and NPEO1-3 in the sludge of two reactors was observed. These results indicated that it was difficult to control these harmful metabolites in the conventional treatment processes. Denaturing gradient gel electrophoresis profiles of sludge samples support the speculation that the NPEO degradation bacteria might be the dominant indigenous species.展开更多
The problem of water pollution is one of the long-term difficulties in the process of rural environmental construction and economic development in China.In order to meet the requirements of the country’s green and su...The problem of water pollution is one of the long-term difficulties in the process of rural environmental construction and economic development in China.In order to meet the requirements of the country’s green and sustainable development,many regions actively promote the construction of rural sewage treatment and fill in the shortcomings of the rural habitat environment to accelerate the construction of beautiful and livable villages.Through a lot of literature and case studies,this paper explores the environmental problems that are common in rural sewage treatment in the northern region of China,explores advanced domestic and foreign cases and technologies on this topic,and summarizes the landscape design strategies on this issue.From the perspective of ecological landscape design,the thesis seeks the theoretical and technical support for rural sewage treatment in river valley areas,and establishes a bridge between rural sewage treatment technology and ecological landscape.Finally,combining theory with practice,taking the project of Lushi sewage treatment in Sanmenxia as an example,team completed the landscape design of ecological sewage purification display area in Zhangjiacun.The design focuses on presenting the application of internal sewage treatment technology and external landscape aesthetics.According to the main points of ecological landscape design and the theory of ecological edge effect,the local ecological system is effectively protected,and a rural domestic sewage purification display area with economic benefits is constructed.展开更多
Existing problems of sewage treatment plants in small towns were summarized firstly,and then the developing trend of construction of sewage treatment plants in small towns was discussed from the aspects of project dec...Existing problems of sewage treatment plants in small towns were summarized firstly,and then the developing trend of construction of sewage treatment plants in small towns was discussed from the aspects of project decision,site selection,design,processing technology and construction financing models. Finally,outlooks for its future development were proposed to provide reference for the construction of sewage treatment plants in small towns in future.展开更多
[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dos...[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dosing lime and influence of the constraint factor were stud- ied. [ Result] Lime precipitation method treating high-concentration phosphorus wastewater could not only decline cost of phosphorus removal by chemical method, but also reach better treatment effect under suitable stirring and precipitation conditions by controlling alkalinity and pH. Phosphor- us content of chemical sludge after treatment could reach 9% -12%, with higher recyclable value. E Conclusion] Lime method treating phosphorus- rich sewage was more economic than low-concentration phosphorus sewage, and had very great potential for recycling phosphorus.展开更多
Microplastic pollution has become a worldwide issue.The discharge of sewage treatment plants(STPs)or wastewater treatment plant(WWTPs)is an important way for microplastics to enter the environment.This study reviewed ...Microplastic pollution has become a worldwide issue.The discharge of sewage treatment plants(STPs)or wastewater treatment plant(WWTPs)is an important way for microplastics to enter the environment.This study reviewed the sources and occurrence characteristics(type,size,color and components)of microplastics in domestic and foreign sewage plants.It elaborated the removal principles of microplastics by primary,secondary and tertiary treatments.In addition,the removal effects of various treatment units and different processes on microplastics were summarized.In the future,the removal mechanism of microplastics in sewage treatment plants should be discussed in more depth,so as to further improve the removal rate of microplastics by optimizing and transforming traditional sewage treatment processes.Therefore,it is necessary to develop new technologies/processes specifically for the removal of microplastics and promote them to practical applications.展开更多
Based on the principle of selective permeability of cell membrane,a new urban sewage treatment device and urban sewage recycling system are designed.The new urban sewage treatment device consists of 10 parts,namely:in...Based on the principle of selective permeability of cell membrane,a new urban sewage treatment device and urban sewage recycling system are designed.The new urban sewage treatment device consists of 10 parts,namely:inlet pipe,secondary filter screen,tertiary rectifier,gravity separation chamber,floating material collection chamber,sewage shunt pipes,cell membrane filtration chamber,cell membrane purification device,sediment collection chamber and purified water collection chamber.The urban sewage recycling system consists of 6 parts,namely:urban sewage collection device,filtration and sedimentation separation device,floating matter collection device,cell membrane sewage purification device,sediment collection device and urban water pool.展开更多
In this paper,from the three dimensions of development quality,sustainable development and public satisfaction,the index system of government performance evaluation of wastewater treatment in Beijing City was construc...In this paper,from the three dimensions of development quality,sustainable development and public satisfaction,the index system of government performance evaluation of wastewater treatment in Beijing City was constructed by conversion of critical success factor method.Using comprehensive evaluation method based on entropy weight method and principal component analysis method,the sewage treatment effect of Beijing municipal government from 2010 to 2017 was quantified,and the government s sewage treatment work was comprehensively evaluated.The evaluation results showed that the government has achieved remarkable results in sewage treatment,but it should continue to optimize the countermeasures in promoting the transformation and upgrading of economic structure,strengthening the management of urban sewage treatment and strict management system of water environment.展开更多
<span style="font-family:Verdana;">We are confronting a new threat in the prevalence of antibiotic-resistant bacteria followed by epidemic spread in aquatic environments in metropolitan areas because d...<span style="font-family:Verdana;">We are confronting a new threat in the prevalence of antibiotic-resistant bacteria followed by epidemic spread in aquatic environments in metropolitan areas because damage from river floods is increasing remarkably in Japan due to global extreme weather. The sewer penetration rate is about 100% in Tokyo and reclaimed water from sewage treatment plants accounts for over 50% of all water in both the down- and mid-stream areas of local rivers. The water quality of these rivers, which contain microflora, seems to be seriously affected by reclaimed water. In this study, we collected water samples on July 17, 2018 and examined the behavior of antibiotic-resistant fecal coliforms in the stream of a sewage treatment plant in Tokyo. Extended-spectrum </span><i><span style="font-family:Verdana;">β</span></i><span style="font-family:Verdana;">-lactamase (ESBL)</span><span style="font-family:Verdana;">-producing fecal coliforms with encoding genes were found;the CTX-M-1, CTX-M-9, TEM, and SHV groups were found to have survived in the final effluent to the river after sterilization with sodium hypochlorite.展开更多
In recent years,the construction of rural sewage treatment in Beijing City has developed rapidly,but there are still many problems in some rural domestic sewage treatment. In this paper,the current situation of rural ...In recent years,the construction of rural sewage treatment in Beijing City has developed rapidly,but there are still many problems in some rural domestic sewage treatment. In this paper,the current situation of rural domestic sewage in Beijing City is combed,and its characteristics are summarized. Meanwhile,the current situation of rural domestic sewage treatment in Zhejiang Province,Hunan Province and Shandong Province is summarized by consulting relevant data. By comparing with current situation of rural domestic sewage treatment in Beijing City,it is found that there are some problems in the treatment of rural domestic sewage in Beijing City,such as unsuitable treatment mode,unreasonable discharge requirements and inadequate treatment technology. Therefore,some countermeasures and suggestions are proposed,such as strengthening the investigation,research and planning,and differential formulation of the sewage treatment discharge standards,and establishing modular treatment technology system. It is hoped that this paper will be helpful to the treatment of rural domestic sewage in Beijing City.展开更多
These days, water and wastewater treatment are one of the most important issues regarding to the human health. Wastewaters are one of the most environmental pollutants and a wide range of adverse effects linked to the...These days, water and wastewater treatment are one of the most important issues regarding to the human health. Wastewaters are one of the most environmental pollutants and a wide range of adverse effects linked to the effect of untreated wastewaters or wastewaters that treat improperly. The aim of this present study was to evaluate performance of the wastewater treatment plant at Al-Diwaniyah City according to the national standards. Therefore, data of the most common parameters (PH, BOD<sub>5</sub>, COD, TSS, PO<sub>4</sub>, NO<sub>3</sub>, Cl, and Oil and Grease) were collected from the wastewater treatment plant. The study revealed that the wastewater treatment plant was receiving medium to strong influent with a BOD<sub>5</sub>/COD ratio of between (0.4 - 0.7). Regression analysis was achieved to approximate the influent of BOD<sub>5</sub> and TSS. While the effluent quality was exceeded the Iraq standards for disposing treated wastewater to the water bodies with a fluctuation in the ratio of BOD5to COD as a consequence of the operational problems. Therefore, these results would be of help to planners and policy makers in the City to combat such this problem and to take the necessary actions to reduce the impact of these pollutants.展开更多
Rural sewage treatment is in need of more capital investment,in which the financing model of PPP(public-private partnership)is able to encourage the investment of social capital in this sector.Risk sharing is one of t...Rural sewage treatment is in need of more capital investment,in which the financing model of PPP(public-private partnership)is able to encourage the investment of social capital in this sector.Risk sharing is one of the core features in the PPP model.In view that the risk loss of projects cannot be accurately estimated,this article describes the uncertainty of risk loss with fuzzy numbers and allocates the distribution of risk loss among the participants of rural sewage treatment PPP projects with interval fuzzy Shapley value to ensure a more reasonable and effective risk distribution.展开更多
The combination of PCR amplification of 16S rRNA genes with denaturing gradient gel electrophoresis (DGGE) analysis was used to reveal the compositions and dynamics of bacterial communities in a sewage treatment pla...The combination of PCR amplification of 16S rRNA genes with denaturing gradient gel electrophoresis (DGGE) analysis was used to reveal the compositions and dynamics of bacterial communities in a sewage treatment plant with two systems, i.e., an anoxic- anaerobic-aerobic system (inverted A2O) and an anaerobic-anoxic-aerobic one (conventional A2O) over a period from February to July 2009, during which both systems experienced serious sludge bulking problems. The DGGE patterns showed that there were many common bands in both systems, suggesting the high similarity of bacterial communities of the two systems. Meanwhile, the moving window correlation analysis showed that the two systems experienced different microbial community structure changes during the period, which might be related with the different situations of the occurrence and disappearance of sludge bulking, as being reflected by sludge volume index (SVI) values. Major bands of DGGE patterns of sludge samples were further sequenced. Phylogenetic affiliation indicated that the majority of the sequences obtained were affiliated with Actinobacteria, Firmicutes, Bacteroidetes/Chlorobi group and α- and β-Proteobacteria. Two sequences showed high similarities to typical filamentous bacteria Microthrix parvicella and Nostocoida limicola I, indicating that these bacterial species have been involved in the sludge bulking problems.展开更多
Characterization, treatment and releases of eight polybrominated diphenyl ethers (PBDEs) congeners and sixteen polycyclic aromatic hydrocarbons (PAHs) in wastewater were evaluated along the treatment processes of ...Characterization, treatment and releases of eight polybrominated diphenyl ethers (PBDEs) congeners and sixteen polycyclic aromatic hydrocarbons (PAHs) in wastewater were evaluated along the treatment processes of a typical secondary treatment municipal sewage treatment plant (STP) (in Hefei City) situated the beside Nanfei River, East China. The findings showed that the average concentrations of the total PBDEs in raw wastewater and treated effluent were 188.578 and 36.884 ng/L respectively. Brominated diphenyl ether (BDE) 209 congener, the predominant PBDE in the STP and Nanfei River, could be related to the discharge of car-industry-derived wastes. For PAHs, the average concentrations in raw wastewater and treated effluent were 5758.8 and 2240.4 ng/L respectively, with naphthalene, benzo[a]pyrene and indeno[1,2,3-c,d]pyrene being detected at the highest concentrations. PAHs mainly originate from the combustion of biomass/coal and petroleum. The STP reduced about 80% of the PBDEs and 61% of the PAHs, which were eliminated mainly by sedimentation processes. The removal rates of PBDEs/PAHs increased with the increase of their solid-water partitioning coefficients. Accordingly, the STP's effluent, containing some PBDE congeners (e.g., BDE 47, 99 and 209, etc.) and low-molecular-weight PAHs, could be an important contributor of these contaminants' input to Nanfei River. It resulted in a significant increase of PBDE/PAH concentrations and PAH toxicological risk in the river water downstream. About 4.040 kg/yr of PBDEs and 245.324 kg/yr of PAHs could be released into the Nanfei River. The current conventional wastewater treatment processes should be improved to remove the relatively low-molecular-weight PBDEs/PAHs more effectively.展开更多
The distribution of antibiotic resistance genes(ARGs)has been intensively studied in large-scale wastewater treatment plants and livestock sources.However,small-scale decentralized sewage treatment facilities must als...The distribution of antibiotic resistance genes(ARGs)has been intensively studied in large-scale wastewater treatment plants and livestock sources.However,small-scale decentralized sewage treatment facilities must also be explored due to their possible direct exposure to residents.In this study,six wastewater treatment facilities in developed rural areas in eastern China were investigated to understand their risks of spreading ARGs.Using metagenomics and network analysis tools,ARGs and bacterial and viral communities were identified in the influent(INF)and effluent(EFF)samples.The dominant ARGs belonged to the bacitracin class,which are different from most of municipal wastewater treatment plants(WWTPs).The dominant hosts of ARGs are Acidovorax in bacterial communities and Prymnesiovirus in viral communities.Furthermore,a positive relationship was found between ARGs and phages.The ARGs significantly correlated with phages were all hosted by specific genera of bacteria,indicating that phages had contributed to the ARG’s proliferation in sewage treatment facilities.Paying significant concern on the possible enhanced risks caused by bacteria,viruses and their related ARGs in decentralized sewage treatment facilities is necessary.展开更多
Sewage discharge could be a major source of polycyclic aromatic hydrocarbons (PAHs) in the coastal waters. Stonecutters Island and Shatin Sewage Treatment Works (SCISTW and STSTW) in Hong Kong, adopted chemically ...Sewage discharge could be a major source of polycyclic aromatic hydrocarbons (PAHs) in the coastal waters. Stonecutters Island and Shatin Sewage Treatment Works (SCISTW and STSTW) in Hong Kong, adopted chemically enhanced primary treatment and biological treatment, respectively. This study aimed at (1) determining the removal efficiencies of PAHs, (2) comparing the capabilities in removing PAHs, and (3) characterizing the profile of each individual PAHs, in the two sewage treatment plants (STPs). Quantification of 16 PAHs was conducted by a Gas Chromatography. The concentrations of total PAHs decreased gradually along the treatment processes (from 301 ± 255 and 307 ± 217 ns/L to 14.9 ± 12.1 and 63.3 ± 54.1 ng/L in STSTW and SCISTW, respectively). It was noted that STSTW was more capable in removing total PAHs than SCISTW with average total removal effidency 94.4% ± 4.12% us. 79.2% ± 7.48% (p 〈 0.05). The removal of PAHs was probably due to sorption in particular matter, confirmed by the higher distribution coefficient of individual and total PAHs in solid samples (dewatered sludge contained 92.5% and 74.7% of total PAHs in SCISTW and STSTW, respectively) than liquid samples (final efffluent-total contained 7.53% and 25.3% of total PAHs in STSTW and SCISTW, respectively). Despite the impressive capability of STSTW and SCISTW in removing PAHs, there was still a considerable amount of total PAHs (1.85 and 39.3 ks/year, respectively for the two STPs) being discharged into Hone Kon coastal waters, which would be an environmental concern.展开更多
In this study, we investigated the occurrence and fate of nonylphenol(NP), nonylphenol monoethoxylate(NP1EO) and nonylphenol diethoxylate(NP2EO) in a full scale sewage treatment plant, which applied an Anaerobic...In this study, we investigated the occurrence and fate of nonylphenol(NP), nonylphenol monoethoxylate(NP1EO) and nonylphenol diethoxylate(NP2EO) in a full scale sewage treatment plant, which applied an Anaerobic/Oxic process. Concentrations of NP, NP1 EO and NP2 EO in the wastewater were measured during the period spanning a whole year.The results showed remarkable seasonal variation in the concentrations of the compounds.The NPn EO compounds were most abundant in winter, with the total concentrations of influent NP, NP1 EO and NP2 EO ranging from 3900 to 7000 ng/L, 4000 to 4800 ng/L and 5200 to 7200 ng/L, respectively. Regarding the total removal efficiencies of the three types of short-chain NPn EO compounds, different trends were exhibited according to different seasons. The average removal efficiency of NP for the different seasons ranked as follows:winter 〉 summer 〉 autumn 〉 spring; NP2 EO concentrations decreased as follows: summer 〉autumn 〉 winter 〉 spring, while NP1 EO concentrations reduced according to: spring 〉summer 〉 autumn 〉 winter. We also investigated the contribution ratio of individual treatment units in the A/O process, with the findings suggesting that the anaerobic treatment unit plays an important role in the elimination of short-chain NPn EOs from the wastewater.展开更多
Activated sludge was monthly sampled from a saline sewage treatment plant of Hong Kong(China)during June 2007 to May 2008 to analyze the microbial community shift along with environmental variations using denaturing g...Activated sludge was monthly sampled from a saline sewage treatment plant of Hong Kong(China)during June 2007 to May 2008 to analyze the microbial community shift along with environmental variations using denaturing gradient gel electrophoresis of polymerase chain reaction amplified 16S rDNA fragments.Environmental changes resulted into a seasonal microbial community shift characterized by alterations in species number and abundance in the sewage treatment plant.Correspondence analysis and cluster analysis on community structure profile showed that the 12 monthly samples fell into four groups,which is in accordance with season changing in Hong Kong.Canonical correspondence analysis revealed that PO_(4)^(3-)-P and NH_(4)^(+)-N posed more significant effects on community structure than total phosphorus and total nitrogen,respectively.Compared with sludge retention time,influent total phosphorus had an inverse effect on the community structure shift,and chemical oxygen demand and NH_(4)^(+)-N showed a similar effects.Results of this study may contribute to the development of new knowledge involving the microbial community shift in sewage treatment plants.展开更多
The concentration and distribution of nonylphe-nol polyethoxylates(NPEOs represents the mixture,and NPnEO represents the monomer)and its metabolites in the influent and effluent of four municipal sewage treatment plan...The concentration and distribution of nonylphe-nol polyethoxylates(NPEOs represents the mixture,and NPnEO represents the monomer)and its metabolites in the influent and effluent of four municipal sewage treatment plants(STPs)in the north of China were measured.Moreover,the concentration and distribution of the above chemicals in the sludge of two STPs were also determined,and the transfer and fate of NPEOs in the sewage treatment process were discussed primarily by analyzing the distribu-tion of the products in the effluent and the sludge.The results showed that NPEOs and its metabolites existed in all the samples of the influent,effluent,and sludge.NPEOs were degraded in the sewage treatment process with the removal efficiency in the range of 23.38%-77.11%,or an average of 52.86%.However,the large analogs of NPnEO were only degraded to small ones,whose degradation rate was rather slow,and consequently the degradation was not complete.Hence,the concentrations of some small metabolites,such as nonylphenol(NP),nonylphenol monoethoxylate(NP1EO),and nonylphenol diethoxylate(NP2EO)were elevated in the effluent.These small metabolites are more toxic than the large NPnEO analogs,and some of them were reported to exhibit environmental endocrine disrupting activity.From this point of view,the process of sewage treatment does not reduce but elevate the risk of NPEOs,which becomes the main source of these small NPnEO in the environment.The sludge exhibited good adsorption ability for NPEOs,especially for the small analogs,which led to the high level of NPEOs in the sludge.Hence,reasonable disposal of the surplus sludge to avoid re-pollution is very important.展开更多
文摘[Objectives] By reasonable water distribution and air supply to soil, soil water permeability is maintained, and the nutrient conditions of degrading bacteria in soil are improved to effectively prevent soil clogging. [Methods] Through the innovation and improvement of traditional soil sewage treatment technology, the physical, chemical and biological characteristics of soil for sewage purification are utilized to enhance the pollutant decomposition ability of soil microorganisms and maintain soil water permeability.[Results] It has no secondary pollution, and can effectively remove pollutants such as COD_(Cr), TN, TP, NH_3-N, etc. in sewage. [Conclusions] The operation and maintenance cost is low, and the land can be reused, while water and nutrients can be restored to the land.
文摘Rural domestic sewage treatment is an important part of the rural revitalization strategy and a key action to build a livable, livable and beautiful countryside. This paper composes and summarizes the relevant studies on rural domestic sewage treatment from the governance techniques and modes of governance subjects and research perspectives, in order to provide reference for the implementation of rural revitalization strategy and rural domestic sewage treatment research and action implementation.
基金This work was supported by the National Natural Science Foundation of China (No. 50578153, 50525824, 20307010).
文摘Biotransformation of nonylphenol ethoxylates (NPEOs) during continuous anaerobic sewage treatment was compared with the aerobic treatment of sewage spiked with 23 μmol/L technical NPEOs over a period of 90 d. Immediate degradation of NPEOs was observed under both anaerobic and aerobic conditions, indicating that the enzymes and bacteria required for NPEO degradation existed abundantly in both aerobic and anaerobic sludge. Both treatments achieved high removal (〉 92%) of the spiked NPEO9 mixture. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that short-chain NPEOs (NPEO1-NPEO3) accumulated in anaerobic (2.01-2.56 μmol/L) and aerobic (1.62-2.03 μmol/L) effluents, with nonylphenol (NP) (0.24-0.31 μmol/L) as another group of metabolites in the anaerobic effluent, and nonylphenoxy carboxylates (NPECs) (2.79-3.30 μmol/L) in the aerobic effluent. Significant accumulation of NP in the anaerobic sludge and NPEO1-3 in the sludge of two reactors was observed. These results indicated that it was difficult to control these harmful metabolites in the conventional treatment processes. Denaturing gradient gel electrophoresis profiles of sludge samples support the speculation that the NPEO degradation bacteria might be the dominant indigenous species.
文摘The problem of water pollution is one of the long-term difficulties in the process of rural environmental construction and economic development in China.In order to meet the requirements of the country’s green and sustainable development,many regions actively promote the construction of rural sewage treatment and fill in the shortcomings of the rural habitat environment to accelerate the construction of beautiful and livable villages.Through a lot of literature and case studies,this paper explores the environmental problems that are common in rural sewage treatment in the northern region of China,explores advanced domestic and foreign cases and technologies on this topic,and summarizes the landscape design strategies on this issue.From the perspective of ecological landscape design,the thesis seeks the theoretical and technical support for rural sewage treatment in river valley areas,and establishes a bridge between rural sewage treatment technology and ecological landscape.Finally,combining theory with practice,taking the project of Lushi sewage treatment in Sanmenxia as an example,team completed the landscape design of ecological sewage purification display area in Zhangjiacun.The design focuses on presenting the application of internal sewage treatment technology and external landscape aesthetics.According to the main points of ecological landscape design and the theory of ecological edge effect,the local ecological system is effectively protected,and a rural domestic sewage purification display area with economic benefits is constructed.
文摘Existing problems of sewage treatment plants in small towns were summarized firstly,and then the developing trend of construction of sewage treatment plants in small towns was discussed from the aspects of project decision,site selection,design,processing technology and construction financing models. Finally,outlooks for its future development were proposed to provide reference for the construction of sewage treatment plants in small towns in future.
文摘[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dosing lime and influence of the constraint factor were stud- ied. [ Result] Lime precipitation method treating high-concentration phosphorus wastewater could not only decline cost of phosphorus removal by chemical method, but also reach better treatment effect under suitable stirring and precipitation conditions by controlling alkalinity and pH. Phosphor- us content of chemical sludge after treatment could reach 9% -12%, with higher recyclable value. E Conclusion] Lime method treating phosphorus- rich sewage was more economic than low-concentration phosphorus sewage, and had very great potential for recycling phosphorus.
基金Supported by Project of National Natural Science Foundation of China(42007317)Project of Guangdong Basic and Applied Basic Research Foundation(2019A1515110272)+1 种基金Outstanding Young Teachers'Scientific Research Ability Improvement Program Funding Project of Zhaoqing University(YQ202105)Innovation and Entrepreneurship Training Program for College Students(202210580015).
文摘Microplastic pollution has become a worldwide issue.The discharge of sewage treatment plants(STPs)or wastewater treatment plant(WWTPs)is an important way for microplastics to enter the environment.This study reviewed the sources and occurrence characteristics(type,size,color and components)of microplastics in domestic and foreign sewage plants.It elaborated the removal principles of microplastics by primary,secondary and tertiary treatments.In addition,the removal effects of various treatment units and different processes on microplastics were summarized.In the future,the removal mechanism of microplastics in sewage treatment plants should be discussed in more depth,so as to further improve the removal rate of microplastics by optimizing and transforming traditional sewage treatment processes.Therefore,it is necessary to develop new technologies/processes specifically for the removal of microplastics and promote them to practical applications.
基金Supported by Undergraduate Innovation and Enterpreneurship Training Program of Dalian University(202111258202).
文摘Based on the principle of selective permeability of cell membrane,a new urban sewage treatment device and urban sewage recycling system are designed.The new urban sewage treatment device consists of 10 parts,namely:inlet pipe,secondary filter screen,tertiary rectifier,gravity separation chamber,floating material collection chamber,sewage shunt pipes,cell membrane filtration chamber,cell membrane purification device,sediment collection chamber and purified water collection chamber.The urban sewage recycling system consists of 6 parts,namely:urban sewage collection device,filtration and sedimentation separation device,floating matter collection device,cell membrane sewage purification device,sediment collection device and urban water pool.
基金Supported by the Collaborative Innovation Project of Chaoyang District(cyxc1819).
文摘In this paper,from the three dimensions of development quality,sustainable development and public satisfaction,the index system of government performance evaluation of wastewater treatment in Beijing City was constructed by conversion of critical success factor method.Using comprehensive evaluation method based on entropy weight method and principal component analysis method,the sewage treatment effect of Beijing municipal government from 2010 to 2017 was quantified,and the government s sewage treatment work was comprehensively evaluated.The evaluation results showed that the government has achieved remarkable results in sewage treatment,but it should continue to optimize the countermeasures in promoting the transformation and upgrading of economic structure,strengthening the management of urban sewage treatment and strict management system of water environment.
文摘<span style="font-family:Verdana;">We are confronting a new threat in the prevalence of antibiotic-resistant bacteria followed by epidemic spread in aquatic environments in metropolitan areas because damage from river floods is increasing remarkably in Japan due to global extreme weather. The sewer penetration rate is about 100% in Tokyo and reclaimed water from sewage treatment plants accounts for over 50% of all water in both the down- and mid-stream areas of local rivers. The water quality of these rivers, which contain microflora, seems to be seriously affected by reclaimed water. In this study, we collected water samples on July 17, 2018 and examined the behavior of antibiotic-resistant fecal coliforms in the stream of a sewage treatment plant in Tokyo. Extended-spectrum </span><i><span style="font-family:Verdana;">β</span></i><span style="font-family:Verdana;">-lactamase (ESBL)</span><span style="font-family:Verdana;">-producing fecal coliforms with encoding genes were found;the CTX-M-1, CTX-M-9, TEM, and SHV groups were found to have survived in the final effluent to the river after sterilization with sodium hypochlorite.
基金Supported by the Collaborative Innovation Project of Chaoyang District。
文摘In recent years,the construction of rural sewage treatment in Beijing City has developed rapidly,but there are still many problems in some rural domestic sewage treatment. In this paper,the current situation of rural domestic sewage in Beijing City is combed,and its characteristics are summarized. Meanwhile,the current situation of rural domestic sewage treatment in Zhejiang Province,Hunan Province and Shandong Province is summarized by consulting relevant data. By comparing with current situation of rural domestic sewage treatment in Beijing City,it is found that there are some problems in the treatment of rural domestic sewage in Beijing City,such as unsuitable treatment mode,unreasonable discharge requirements and inadequate treatment technology. Therefore,some countermeasures and suggestions are proposed,such as strengthening the investigation,research and planning,and differential formulation of the sewage treatment discharge standards,and establishing modular treatment technology system. It is hoped that this paper will be helpful to the treatment of rural domestic sewage in Beijing City.
文摘These days, water and wastewater treatment are one of the most important issues regarding to the human health. Wastewaters are one of the most environmental pollutants and a wide range of adverse effects linked to the effect of untreated wastewaters or wastewaters that treat improperly. The aim of this present study was to evaluate performance of the wastewater treatment plant at Al-Diwaniyah City according to the national standards. Therefore, data of the most common parameters (PH, BOD<sub>5</sub>, COD, TSS, PO<sub>4</sub>, NO<sub>3</sub>, Cl, and Oil and Grease) were collected from the wastewater treatment plant. The study revealed that the wastewater treatment plant was receiving medium to strong influent with a BOD<sub>5</sub>/COD ratio of between (0.4 - 0.7). Regression analysis was achieved to approximate the influent of BOD<sub>5</sub> and TSS. While the effluent quality was exceeded the Iraq standards for disposing treated wastewater to the water bodies with a fluctuation in the ratio of BOD5to COD as a consequence of the operational problems. Therefore, these results would be of help to planners and policy makers in the City to combat such this problem and to take the necessary actions to reduce the impact of these pollutants.
文摘Rural sewage treatment is in need of more capital investment,in which the financing model of PPP(public-private partnership)is able to encourage the investment of social capital in this sector.Risk sharing is one of the core features in the PPP model.In view that the risk loss of projects cannot be accurately estimated,this article describes the uncertainty of risk loss with fuzzy numbers and allocates the distribution of risk loss among the participants of rural sewage treatment PPP projects with interval fuzzy Shapley value to ensure a more reasonable and effective risk distribution.
基金supported by the National Research Foundation, China (No. 20921140094)the Chinese Academy of Sciences, Knowledge innovation Project(No. KSCX2-YW-G-054, KZCX2-YW-JC407)CASTWAS Postdoctoral Fellowships 2009
文摘The combination of PCR amplification of 16S rRNA genes with denaturing gradient gel electrophoresis (DGGE) analysis was used to reveal the compositions and dynamics of bacterial communities in a sewage treatment plant with two systems, i.e., an anoxic- anaerobic-aerobic system (inverted A2O) and an anaerobic-anoxic-aerobic one (conventional A2O) over a period from February to July 2009, during which both systems experienced serious sludge bulking problems. The DGGE patterns showed that there were many common bands in both systems, suggesting the high similarity of bacterial communities of the two systems. Meanwhile, the moving window correlation analysis showed that the two systems experienced different microbial community structure changes during the period, which might be related with the different situations of the occurrence and disappearance of sludge bulking, as being reflected by sludge volume index (SVI) values. Major bands of DGGE patterns of sludge samples were further sequenced. Phylogenetic affiliation indicated that the majority of the sequences obtained were affiliated with Actinobacteria, Firmicutes, Bacteroidetes/Chlorobi group and α- and β-Proteobacteria. Two sequences showed high similarities to typical filamentous bacteria Microthrix parvicella and Nostocoida limicola I, indicating that these bacterial species have been involved in the sludge bulking problems.
基金supported by the Mega-projects of Science Research for Water Environment Improvement(No.2009ZX07106-001,2012ZX07101-002)the National Natural Science Foundation of China(No.40901248)the China Basic Research Program(No.2008CB418206)
文摘Characterization, treatment and releases of eight polybrominated diphenyl ethers (PBDEs) congeners and sixteen polycyclic aromatic hydrocarbons (PAHs) in wastewater were evaluated along the treatment processes of a typical secondary treatment municipal sewage treatment plant (STP) (in Hefei City) situated the beside Nanfei River, East China. The findings showed that the average concentrations of the total PBDEs in raw wastewater and treated effluent were 188.578 and 36.884 ng/L respectively. Brominated diphenyl ether (BDE) 209 congener, the predominant PBDE in the STP and Nanfei River, could be related to the discharge of car-industry-derived wastes. For PAHs, the average concentrations in raw wastewater and treated effluent were 5758.8 and 2240.4 ng/L respectively, with naphthalene, benzo[a]pyrene and indeno[1,2,3-c,d]pyrene being detected at the highest concentrations. PAHs mainly originate from the combustion of biomass/coal and petroleum. The STP reduced about 80% of the PBDEs and 61% of the PAHs, which were eliminated mainly by sedimentation processes. The removal rates of PBDEs/PAHs increased with the increase of their solid-water partitioning coefficients. Accordingly, the STP's effluent, containing some PBDE congeners (e.g., BDE 47, 99 and 209, etc.) and low-molecular-weight PAHs, could be an important contributor of these contaminants' input to Nanfei River. It resulted in a significant increase of PBDE/PAH concentrations and PAH toxicological risk in the river water downstream. About 4.040 kg/yr of PBDEs and 245.324 kg/yr of PAHs could be released into the Nanfei River. The current conventional wastewater treatment processes should be improved to remove the relatively low-molecular-weight PBDEs/PAHs more effectively.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07202-003)National Natural Science Foundation of China(51778325)+1 种基金the Fundamental Research Fund for the Central Universities(FRF-TP-20-011A)the Research Fund Program of Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology(2020B 1212060022).
文摘The distribution of antibiotic resistance genes(ARGs)has been intensively studied in large-scale wastewater treatment plants and livestock sources.However,small-scale decentralized sewage treatment facilities must also be explored due to their possible direct exposure to residents.In this study,six wastewater treatment facilities in developed rural areas in eastern China were investigated to understand their risks of spreading ARGs.Using metagenomics and network analysis tools,ARGs and bacterial and viral communities were identified in the influent(INF)and effluent(EFF)samples.The dominant ARGs belonged to the bacitracin class,which are different from most of municipal wastewater treatment plants(WWTPs).The dominant hosts of ARGs are Acidovorax in bacterial communities and Prymnesiovirus in viral communities.Furthermore,a positive relationship was found between ARGs and phages.The ARGs significantly correlated with phages were all hosted by specific genera of bacteria,indicating that phages had contributed to the ARG’s proliferation in sewage treatment facilities.Paying significant concern on the possible enhanced risks caused by bacteria,viruses and their related ARGs in decentralized sewage treatment facilities is necessary.
基金Financial support from the Drainage Services Department,the Government of the Hong Kong SAR(nos.DEMP/2011/04,DEMP/2014/03 and DEMP/2015/01)the Open Science Research Fund of State Key Laboratory in Marine Pollution(no.OSRF/0001)+1 种基金the Start-up Research Grant for Newly Recruited Professors/(Research)Chair ProfessorsThe Education University of Hong Kong(no.RG24/13-14R)is gratefully acknowledged
文摘Sewage discharge could be a major source of polycyclic aromatic hydrocarbons (PAHs) in the coastal waters. Stonecutters Island and Shatin Sewage Treatment Works (SCISTW and STSTW) in Hong Kong, adopted chemically enhanced primary treatment and biological treatment, respectively. This study aimed at (1) determining the removal efficiencies of PAHs, (2) comparing the capabilities in removing PAHs, and (3) characterizing the profile of each individual PAHs, in the two sewage treatment plants (STPs). Quantification of 16 PAHs was conducted by a Gas Chromatography. The concentrations of total PAHs decreased gradually along the treatment processes (from 301 ± 255 and 307 ± 217 ns/L to 14.9 ± 12.1 and 63.3 ± 54.1 ng/L in STSTW and SCISTW, respectively). It was noted that STSTW was more capable in removing total PAHs than SCISTW with average total removal effidency 94.4% ± 4.12% us. 79.2% ± 7.48% (p 〈 0.05). The removal of PAHs was probably due to sorption in particular matter, confirmed by the higher distribution coefficient of individual and total PAHs in solid samples (dewatered sludge contained 92.5% and 74.7% of total PAHs in SCISTW and STSTW, respectively) than liquid samples (final efffluent-total contained 7.53% and 25.3% of total PAHs in STSTW and SCISTW, respectively). Despite the impressive capability of STSTW and SCISTW in removing PAHs, there was still a considerable amount of total PAHs (1.85 and 39.3 ks/year, respectively for the two STPs) being discharged into Hone Kon coastal waters, which would be an environmental concern.
基金supported by Heilongjiang Natural Science Fund for Distinguished Young Scientists(No.JC200909)
文摘In this study, we investigated the occurrence and fate of nonylphenol(NP), nonylphenol monoethoxylate(NP1EO) and nonylphenol diethoxylate(NP2EO) in a full scale sewage treatment plant, which applied an Anaerobic/Oxic process. Concentrations of NP, NP1 EO and NP2 EO in the wastewater were measured during the period spanning a whole year.The results showed remarkable seasonal variation in the concentrations of the compounds.The NPn EO compounds were most abundant in winter, with the total concentrations of influent NP, NP1 EO and NP2 EO ranging from 3900 to 7000 ng/L, 4000 to 4800 ng/L and 5200 to 7200 ng/L, respectively. Regarding the total removal efficiencies of the three types of short-chain NPn EO compounds, different trends were exhibited according to different seasons. The average removal efficiency of NP for the different seasons ranked as follows:winter 〉 summer 〉 autumn 〉 spring; NP2 EO concentrations decreased as follows: summer 〉autumn 〉 winter 〉 spring, while NP1 EO concentrations reduced according to: spring 〉summer 〉 autumn 〉 winter. We also investigated the contribution ratio of individual treatment units in the A/O process, with the findings suggesting that the anaerobic treatment unit plays an important role in the elimination of short-chain NPn EOs from the wastewater.
基金This research was supported by Hong Kong General Research Fund(HKU7195/06E)the authors would like to thank HKU Faculty of Engineering to support Dr.X.X.Zhang with the PostDoctoral Fellowship.
文摘Activated sludge was monthly sampled from a saline sewage treatment plant of Hong Kong(China)during June 2007 to May 2008 to analyze the microbial community shift along with environmental variations using denaturing gradient gel electrophoresis of polymerase chain reaction amplified 16S rDNA fragments.Environmental changes resulted into a seasonal microbial community shift characterized by alterations in species number and abundance in the sewage treatment plant.Correspondence analysis and cluster analysis on community structure profile showed that the 12 monthly samples fell into four groups,which is in accordance with season changing in Hong Kong.Canonical correspondence analysis revealed that PO_(4)^(3-)-P and NH_(4)^(+)-N posed more significant effects on community structure than total phosphorus and total nitrogen,respectively.Compared with sludge retention time,influent total phosphorus had an inverse effect on the community structure shift,and chemical oxygen demand and NH_(4)^(+)-N showed a similar effects.Results of this study may contribute to the development of new knowledge involving the microbial community shift in sewage treatment plants.
基金This work was supported by Kurita Water Environ-ment Foundation of Japan(14701)the National Natural Science Foundation of China(Grant No.20277022).
文摘The concentration and distribution of nonylphe-nol polyethoxylates(NPEOs represents the mixture,and NPnEO represents the monomer)and its metabolites in the influent and effluent of four municipal sewage treatment plants(STPs)in the north of China were measured.Moreover,the concentration and distribution of the above chemicals in the sludge of two STPs were also determined,and the transfer and fate of NPEOs in the sewage treatment process were discussed primarily by analyzing the distribu-tion of the products in the effluent and the sludge.The results showed that NPEOs and its metabolites existed in all the samples of the influent,effluent,and sludge.NPEOs were degraded in the sewage treatment process with the removal efficiency in the range of 23.38%-77.11%,or an average of 52.86%.However,the large analogs of NPnEO were only degraded to small ones,whose degradation rate was rather slow,and consequently the degradation was not complete.Hence,the concentrations of some small metabolites,such as nonylphenol(NP),nonylphenol monoethoxylate(NP1EO),and nonylphenol diethoxylate(NP2EO)were elevated in the effluent.These small metabolites are more toxic than the large NPnEO analogs,and some of them were reported to exhibit environmental endocrine disrupting activity.From this point of view,the process of sewage treatment does not reduce but elevate the risk of NPEOs,which becomes the main source of these small NPnEO in the environment.The sludge exhibited good adsorption ability for NPEOs,especially for the small analogs,which led to the high level of NPEOs in the sludge.Hence,reasonable disposal of the surplus sludge to avoid re-pollution is very important.