Urban Sewage Treatment Plant Research Articles

Site Selection of Urban Sewage Treatment Plant Based on Hesitant Fuzzy Linguistic Mcdm Model

Site Selection of Urban Sewage Treatment Plant Based on Hesitant Fuzzy Linguistic Mcdm Model

Site Selection of Urban Sewage Treatment Plant Based on Hesitant Fuzzy Linguistic Mcdm Model

Site Selection of Urban Sewage Treatment Plant Based on Hesitant Fuzzy Linguistic Mcdm Model

Basin-Scale Pollution Loads Analyzed Based on Coupled Empirical Models and Numerical Models.

Pollutant source apportionment is of great significance for water environmental protection. However, it is still challenging to accurately quantify pollutant loads at basin-scale. Refined analytical methods combined the pollution discharge coefficient method (PDCM), field observation, and numerical model (Soil & Water Assessment Tool, SWAT) to make quantitative source appointment in the Tuojiang River, a key tributary of the upper Yangtze River. The chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and ammonia nitrogen (N-NH4+) were analyzed. Results showed that the urban sewage treatment plant point source has the largest contribution to COD, TN, and N-NH4+, while TP is mostly from the agricultural sources throughout the year. The total inflowing loads of pollution sources are significantly affected by rainfall. The overall pollution characteristics showed that pollutant loads present in different seasons are as follows: wet season > normal season > dry season. The month with the highest levels of pollutants is July in the wet season. Among the nine cities, the city that contributes the most COD, TN and N-NH4+, is Neijiang, accounting for about 25%, and the city that contributes the most TP is Deyang, accounting for 23%. Among the sub-basins, the Fuxi River subbasin and Qiuxihe River subbasin contribute the most pollutant loads. The technical framework adopted in this paper can be used to accurately identify the types, administrative regions and sub-basins of the main pollution sources in the watershed, which is conducive to management and governance of the environment.

Characterization of Acinetobacter indicus ZJB20129 for heterotrophic nitrification and aerobic denitrification isolated from an urban sewage treatment plant

The Acinetobacter indicus strain ZJB20129 isolated from an urban sewage treatment plant demonstrated the heterotrophic nitrification-aerobic denitrification (HN-AD) ability. Strain ZJB20129 could remove 98.73% of ammonium-N, 97.26% of nitrite-N and 96.55% of nitrate-N, and the maximum removal rate was 3.66, 4.62 and 5.21 mg/L/h, respectively. Ammonium was preferentially used during simultaneous nitrification and denitrification. Strain ZJB20129 exhibited highest ammonium removal capability when carbon source was sodium succinate, C/N ratio was 15, pH was 8.0, and temperature was 35 ℃. Key enzymes involved in HN-AD including hydroxylamine oxidase, periplasmic nitrate reductase and nitrite reductase as well as their encoding genes were detected, and the metabolic pathway of HN-AD was subsequently predicted. Our results suggested that Acinetobacter indicus ZJB20129 displayed superior nitrogen removal performance on actual wastewater and thus made it have a good application prospect in wastewater biological treatment.

Sewage Sludge as Inhibitor of the Formation of Persistent Organic Pollutants during Incineration

With the objective of suppressing dioxins and furans (PCDD/Fs) emission in municipal solid waste incineration plants (MSWI), different chemical inhibitors have been tested. Among these inhibitors, nitrogen and sulphur compounds can significantly suppress PCDD/Fs formation via de novo synthesis, which gives very interesting results with very little capital investment. In recent years, the possibility of using waste rich in nitrogen and/or sulphur as a source of inhibitor compounds has been considered, and thus has reduced the emissions of pollutants while the waste is treated. The effect of adding sludge from urban sewage treatment plants in three variants has been specially studied: directly mixing the waste, using the decomposition gas of the previously dried sludge, and using the decomposition gas of the sludge together with other inhibitors such as thiourea. Reduction of emissions in laboratory tests using model samples indicated the efficiency to be higher than 99%, using sewage sludge (SS) as an inhibitor whereas, in actual MSWI plants, the efficiency can be as high as 90%.

Characterization of a novel micro-pressure double-cycle reactor for low temperature municipal wastewater treatment

ABSTRACT To solve the deterioration of effluent caused by low temperature in urban sewage treatment plant in cold areas, a new type of reactor was proposed, the biochemical environmental and low-temperature operating characteristics of the reactor were studied. Through analysis of flow simulation and dissolved oxygen (DO) distribution when the aeration rate was 0.6 m3/h, it showed that there were many different DO environments in the reactor at the same time, which provided favourable conditions for various biochemical reactions. The operation test showed that the average effluent removal rate of COD, TN, NH4 +-N and TP was 92.53%, 74.57%, 89.61% and 96.04%, respectively. And there were a variety of functional bacteria related to nitrogen and phosphorus removal in the system, most of them with strong adaptability at low temperatures. Among the dominant microorganisms, Flavobacterium and Rhodobacter were related to denitrification, Aeromonas and Thiothrix were related to phosphorous removal. Denitrifying phosphorus removal was the main way of phosphorus removal. Picrust2 results showed that the reactor operated well at low temperature, and the regional difference distribution of nitrification genes further confirmed the existence of functional zones in the reactor. The results showed that the Micro-pressure Double-cycle reactor worked well at low temperature, which provided a new idea and way for the upgrading of urban sewage treatment plants in cold areas.

Environmental Risk Assessment of Active Human Pharmaceutical Ingredients in Urban Rivers in Japan.

Active pharmaceutical ingredients (APIs) have become a public concern owing to their possible adverse effects on aquatic organisms. Ministry of Health, Labor and Welfare in Japan (MHLW) issued "Guidance on the Environmental Risk Assessment (ERA) in new pharmaceutical development" in 2016. To evaluate the validity of phase 1 in the MHLW's ERA guidance, we monitored the measured environmental concentrations (MECs) of approved APIs in urban rivers and sewage treatment plants (STPs) in Japan and compared these MECs with the predicted environmental concentration (PEC). We collected water samples from urban seven rivers and three STPs during each season. Fifty-one APIs for human and veterinary use and the artificial sweetener sucralose were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Forty-four APIs were observed in the rivers and 42 were found in the influent and effluent of STPs, with levels ranging from nanograms to micrograms per liter. The action limit in phase I of the MHLW's guidance was set to 10 ng/L, and there was no API except for ketoprofen, for which PEC of the MHLW's guidance (PECjapan) was lower than 10 ng/L and the maximum MEC (MECmax) was 10 ng/L or greater. Almost all APIs also had median MECs that were lower than those of the respective PECjapan. These results indicate that the PECjapan values in phase I of the MHLW's guidance were appropriate. However, some APIs had MECmax values that were greater than those of the respective PECjapan due to overestimation of the dilution factor of river water and/or underestimation of API production.

Research on Sludge Resource Utilization Technology of Urban Sewage Treatment Plant

Research on Sludge Resource Utilization Technology of Urban Sewage Treatment Plant

Analysis of Economic Benefits of Reclaimed Water Industry Utilization: A Case Study in Tongxiong

Taking the Tongxiang Urban Sewage Treatment Plant Integration Project (Phase 1) as an example, this paper designs three reclaimed water allocation solutions after investigating the water cost, water quality requirement and reclaimed water using willingness of potential reclaimed water users in the surrounding area. The economic cost-benefit calculations for all three options show that under the circumstance that the existing water policy and charging standards remain unchanged, the large-scale use of reclaimed water in industrial production will increase the water intaking cost of industrial water users by 50%∼70%. In order to enhance the enthusiasm of water users for the use of reclaimed water, it is recommended that the government and enterprises could allocate the cost of using reclaimed water reasonably, and the government could provide economic subsidies and preferential policies.

Effect on simultaneous removal of ammonia, nitrate, and phosphorus via advanced stacked assembly biological filter for rural domestic sewage treatment.

The discharge of ammonia-nitrogen (NH3-N), total nitrogen (TN), chemical oxygen demand (COD), and total phosphorus (TP) in rural sewage usually exceeds the Pollutant Discharge Standard for Urban Sewage Treatment Plants (GB18918-2002). Efficient and cost-effective removal of these pollutants cannot be simultaneously realized using conventional rural sewage treatment methods. Thus, an assembled biological filter (D50 × W50 × H113 cm), including a phosphorus removal layer filled with solid polymeric ferric sulfate and alternating aerobic-anaerobic layers, is proposed herein. The aerobic (anerobic) layers were filled with zeolite (zeolite and composite soil) at different intervals. This system was used for the treatment of synthetic sewage having COD: 122.0-227.0mg/L; NH3-N: 29.1-47.0mg/L; TN: 28.0-58.0mg/L; and TP: 2.0-3.8mg/L. Based on optimal operation conditions (40L/h reflow rate, without artificial aeration, and 12-h operation cycle), the system showed NH3-N, TN, COD, and TP removal efficiencies of 87.1 ± 8.1, 83.4 ± 7.9, 91.0 ± 9.4, and 80.0 ± 6.4%, respectively. Further, in the pilot-scale test, under the same optimal parameters, the removal efficiencies of NH3-N, TN, COD, and TP were 78.9 ± 8.1, 75.4 ± 7.9, 82 ± 9.4, and 76 ± 6.4%, respectively. Furthermore, in the different functional units of the system, a large number of functional bacteria capable of efficiently facilitating the simultaneous removal of the different pollutants from sewage were identified. Therefore, this proposed system, which complies with current environmental discharge regulations, can be a more sustainable approach for the treatment of unattended rural sewage.

Characteristics of Sludge and Associated Risk Assessment of Urban Sewage Treatment Plants

In urban solid waste management, the scientific and reasonable disposal and utilization of sewage sludge is becoming more and more important. It can be said that the pollution status and chemical properties of sewage sludge in urban sewage treatment plants can provide a basis for the scientific disposal and utilization of sludge. In this study, the characteristics of pH, moisture content, Cd, Cr, Cu, Zn, Pb, As, Hg, Ni, mineral oil, volatile phenol, PAHs, organic matter, nitrogen, phosphorus, and potassium were evaluated in sewage sludge collected from 49 sewage treatment plants in a certain city. The pollution status of heavy metals and organic pollutants, the frequency distribution of pollutant concentrations, and changes in the nutrient content were analyzed. The Nemero index and Hakanson potential ecological hazard index were used to assess the potential ecological risks of heavy metals in the agricultural utilization process of sludge. The results showed that under the condition of neutral pH values and high moisture content, the order of heavy metal content was Zn > Cu > Cr > Pb > Ni > As > Hg > Cd. The principal component analysis (PCA) results indicated that Cd, Pb, Hg, Ni, and As constituted the main load factors of the first main component of heavy metal sources. The most concentrated contents of 8 heavy metal frequency distributions among the 49 samples were 38.9-1380.0, 62.6-182.7, 63.6-181.3, 0.0-97.8, 19.3-68.4, 0.8-29.2, 0.3-8.7, and 0.01-0.96 mg·kg-1. In addition, the most concentrated frequency distribution of mineral oil, volatile phenol, and PAH concentration were 87.0%, 87.9%, and 77.6%, respectively. Moreover, the nutrient content of sludge was higher than the average level in China, and the organic matter content was 67.4%, 75.9%, and 92.5% of that of pig manure, cow dung, and chicken manure, while the content of nitrogen, phosphorus, and potassium was not very different. The Nemero index and Hakanson ecological hazard index results showed that the sludge of urban sewage treatment plant in the city has certain ecological risks. However, four sewage treatment plants were heavily polluted or highly ecologically hazardous among the 44 plants in this study, which were in line with the Standards for pollutant control of agricultural sludge. In summary, there are certain potential ecological risks for the agricultural utilization of sludge in the city, and it is necessary to reduce the heavy metal content before resourcing. More importantly, on the premise that the sludge meets the agricultural standards, a comprehensive ecological risk assessment is required to select a reasonable sludge recycling method.

Antibiotic resistance: Global health crisis and metagenomics

Antibiotic resistance is a global problem which affects human health. The imprudent use of antibiotics (medicine, agriculture, aquaculture, and food industry) has resulted in the broader dissemination of resistance. Urban wastewater & sewage treatment plants act as the hotspot for the widespread of antimicrobial resistance. Natural environment also plays an important role in the dissemination of resistance. Mapping of antibiotic resistance genes (ARGS) in environment is essential for mitigating antimicrobial resistance (AMR) widespread. Therefore, the review article emphasizes on the application of metagenomics for the surveillance of antimicrobial resistance. Metagenomics is the next generation tool which is being used for cataloging the resistome of diverse environments. We summarize the different metagenomic tools that can be used for mining of ARGs and acquired AMR present in the metagenomic data. Also, we recommend application of targeted sequencing/ capture platform for mapping of resistome with higher specificity and selectivity.

Occurrence and removal of emerging pollutants in urban sewage treatment plants using LC-QToF-MS suspect screening and quantification

Urban wastewaters (WW) are a major vector of many emerging pollutants (EPs) to aquatic ecosystems, as urban wastewater treatment plants (WWTPs) are not designed to abate them. New methods are now critically necessary for a more comprehensive analysis of WW samples and for the assessment of the WWTP efficiency in EP removal. To this end, the present study aims to develop a methodology to identify and quantify EPs, especially pharmaceutical residues and pesticides, in the raw and treated wastewater of 10 heterogeneous WWTPs in a highly urbanized territory in France over three sampling campaigns, through the following steps: (1) development and implementation of a suspect screening of EPs in WW samples, based on a solid phase extraction followed by an LC-QToF-MS analysis; (2) confirmation of their identification by reinjection of WW samples spiked with authentic analytical standards; (3) quantification of previously identified compounds by targeted LC-QToF-MS analysis in raw and treated effluents and assessment of their removal efficiency by WWTPs. Forty-one EPs, including 37 pharmaceutical residues (such as anti-depressive, anti-hypertensive, or antipsychotic drugs) and 4 pesticides, were identified by suspect screening. Some of them (e.g. milnacipran) are reported for the first time in urban WWTPs in this study. High variability in detection frequency and concentrations were observed in function of the EP and WWTP. Nevertheless, median removal rates were considered negative or low for more than 50% of the EPs (respectively 4 and 17), leading to a quantification of significant concentrations in treated WW. Their release into receiving streams may thus lead to ecotoxicological risks that should be evaluated in order to prevent any degradation of the exposed ecosystems.

Analysis and Discussion on Operation Stability of Urban Sewage Treatment Plant

Based on the acceleration of the development of the national economy and the overall progress of urbanization, the discharge of domestic sewage has increased significantly, and the characteristics of domestic sewage within each city are significantly different. Therefore, the design and operational stability of urban sewage treatment plants are proposed higher requirements. In this case, the urban domestic sewage treatment plant should follow the basic principles of adapting measures to local conditions, taking into account the characteristics of domestic sewage drainage and water quality in different areas to ensure the rationality of the sewage treatment process design and the safer and more stable subsequent operations. Based on this, the article takes the urban domestic sewage treatment plant as the main research object, and focuses on the related content of its operational stability.

Optimizing the system-wide layout of sewage treatment plants based on enumeration and the orthogonal test.

Optimizing the locations of sewage treatment plants has enormous practical significance. In this study, a large-system mathematical model was developed for optimizing the locations of sewage treatment plants within a system and designing the associated pumping station pipe network. Head loss of pipe segments in the pipe network was the coupling constraint, the economic flow rate of pipe segments was determined by the feasible region constraints of decision variables, and the design variables were the sewage treatment plant locations, the design head of the pumping stations, the pipeline economic life, and the pipe diameter of divided pipe segments. The minimum total annual cost of the sewage treatment plant(s) and the pumping station pipe network was the objective function. A large-system quadratic orthogonal test-based selection method was used with a discrete enumeration comparison and selection method to determine pipeline economic life. A dynamic programming method was used to determine the pipe diameter of the divided pipe segments. By comparing the total annual cost of the sewage treatment plants and the associated pumping station pipe network corresponding to different pipeline economic lifetimes, the optimal solution that generates the minimum total annual cost can be identified. The sewage treatment plant and pumping station pipe network in Taizhou, China, was used as an example to compare and analyze optimization results. The new optimization method would have produced much lower annual cost than that of the existing system. This study provides valuable theoretical references for probing the layout design of urban sewage treatment plants corresponding to different pipeline economic lifetimes.

Fluctuation of phosphorus concentration in Lake Taihu in the past 70 years and future control strategy

分析湖泊中磷浓度的变化特征，揭示其变化的驱动机制，是有效实施湖泊水体磷浓度控制的前提.本文整理分析了太湖70年来（1949—2020年）水体磷浓度监测历史资料，对比了太湖不同湖区、不同时间尺度水体磷浓度的差异性及波动性，发现影响太湖磷浓度变化的原因既有人为的因素，也有自然的因素.无论是污染较轻的1950年，还是污染负荷相对较重的近30年，太湖水体磷浓度一直存在较大时空差异性.暴雨引发入湖河流携带磷污染的扩散、风浪扰动引起的内源释放及蓝藻水华期间藻类生物量的大幅时空变化，都加剧了太湖水体磷浓度的不稳定性.近20年的太湖水污染治理对磷浓度的时空分布影响明显，1998年的太湖水污染治理“零点行动”，2007年以来的水利调度等系列水污染治理工程，以及2017年以来的藻情变化等，都对太湖水体磷浓度的时空格局产生了影响.然而，高强度治理投入下太湖水体磷浓度依然偏高，其原因与流域建设用地比例增加、人口增加、耕地种植结构变化等外源负荷因素发生变化有关，也与湖体沉水植被退化、出入流结构发生变化、气候变化引发的蓝藻水华扩张等内源强度及水体表观磷浓度决定因素的生态环境变化有关.近70年来太湖水体磷浓度的变化过程对类似大型浅水湖泊的磷控制策略具有启示意义：大型浅水湖泊存在磷浓度较大波动的自然属性，在水环境保护目标考核中应充分考虑其不确定性，制定切实可行的控制目标；在控制策略上应将外源负荷控制放在首位，在流域污水处理厂深度除磷及流域土地利用调整等方面采取措施，实现入湖磷负荷的大幅削减，同时实施湖体生态修复与食物链调控措施，才能逐步实现湖泊水体磷浓度的控制目标.;Understanding the changing mechanism of phosphorus concentration in lakes is the precondition of strategic decision for lake restoration. Based on the 70 years (1949-2020) phosphorus concentration monitoring data at Lake Taihu, a large shallow lake, it is found that the phosphorus concentration was highly fluctuated temporally and spatially, owing to both human pollution and natural limnological changes. Phosphorus concentrations was largely different both in the relatively clean 1950 and in the relatively polluted recent 30 years. Heavy rain storm discharge plenty of external phosphorus into the lake, causing large spatial difference of water phosphorus concentration. Strong wind causing lots of phosphorus released from lake sediment, causing large temporal fluctuation of phosphorus concentration. And algal bloom materials re- distribution by wind driving also bring about large uncertainty of phosphorus concentrations. In the recent 20 years, pollution abatement projects have significantly changed the spatial-temporal change of phosphorus concentration in Lake Taihu. Zero Action of water pollution control in Taihu catchment since 1998, water resource diversion engineering since 2007, and the bloom situation aggravate since 2017 have significantly influenced the fluctuation intensity, spatial distribution and mean value of phosphorus in Lake Taihu. However, phosphorus concentrations in the whole Lake Taihu still keep high level even plenty of pollution treatment investigation. Its reasons are owing to both external loading factors, such as largely increase of construction land use ratios, population increases, and crop planting structure change in farmlands, and internal loading factors, such as submerged vegetation degradations, hydrological structure changes, and algal bloom aggravates under climatic change. The seventy years variation characteristic of phosphorus concentration in Lake Taihu should provide lessons for large shallow lakes management. Relatively large fluctuation of phosphorus concentration in lake water is the nature of large shallow lakes. Decision-maker should consider the natural characteristic when they formulate the protection target of large shallow lakes. External loading abatement should give priority, such as land use adjustment in Lake Taihu basin and deeply phosphorus removal in tail-water of urban sewage treatment plants. At the same time, internal loading control measures, such as submerged vegetation restoration and top-down food-web control of algal biomass by bio-manipulation of fishery should be undertaken to make sure the highly fluctuation of phosphorus being largely controlled.

Reaproveitamento energético do lodo de estação de tratamento de esgoto – uma revisão

Este trabalho teve como objetivo avaliar a capacidade do reaproveitamento energético do lodo de uma estação de tratamento de esgoto (ETE) urbana, a fim de determinar a viabilidade técnica e econômica deste destino final do lodo, em comparação com a disposição final em aterro sanitário. A análise bibliográfica efetuada mostra que do ponto de vista energético, o lodo proveniente de uma ETE, digerido anaeróbio, possui elevada carga orgânica e elevado poder calorífico em relação a outras biomassas combustíveis. Sendo assim, seu reaproveitamento pode ser vantajoso econômica e ambientalmente. A disposição de lodo em aterros, apesar da simplicidade, apresenta problemas ambientais, como a possibilidade de contaminação do lençol freático, do solo e emissão de poluentes. A investigação mostra que no reaproveitamento energético, os processos de conversão do lodo em energia como pirólise e incineração, apresentaram resultados satisfatórios, porém são processos de elevados custos de operação e manutenção.

Prevention and control of the novel coronavirus in urban sewage treatment plants in Jiangsu

Prevention and control of the novel coronavirus in urban sewage treatment plants in Jiangsu

Urban sewage treatment odor gas release characteristics and regional differences

At present, more and more urban sewage treatment plants are put into construction and operation in China. While improving the quality of the water environment, the urban sewage plant has brought new problems to its surrounding environment, the most typical of which is the problem of odor pollution. In this study, the urban sewage treatment plant is taken as the object to study the discharge rule of typical odorous substances, which provides theoretical guidance for the evaluation and control of odor pollution in the urban sewage treatment plant. The results of studies on typical odorous substance discharge concentrations indicate that H2S is the main odorous pollutant in the wastewater treatment plant, and treatment units with higher odorous substance discharge concentrations include grids, aeration grit tanks, and mud storage tanks. The H2S emission concentration of the inlet pump house, grille and aeration grit tank is low in winter and high in summer, and will be significantly reduced during rainfall. The H2S discharge concentration of the inlet pump room, grille and aeration grit tank is significantly positively correlated with the sewage temperature.

Comprehensive Evaluation on the Bio-Toxicity of Three Advanced Wastewater Treatment Processes

Water quality and safety of tailwater is crucial to achieve sustainability of water resources. However, the traditional monitoring method based on chemical and physical indicators cannot reflect the actual biological effects. The objective of this study was to provide effective biological indicators in water quality monitoring and the safe discharge of sewage. The influent, secondary effluent, and tailwater were sampled from three sewage treatment plants with different advanced-treatment processes (wetland, ozone + ultraviolet, and filter + ultraviolet), and the removal efficiencies of the tail water on acute toxicity and genotoxicity were assessed by Vicia faba micronucleus test, acute comprehensive evaluation (TU), and genotoxicity test. The results showed that physical and chemical indicators could meet the national standards of pollutant discharge in urban sewage treatment plants, and the biological toxicity of the tail water after each treatment process significantly reduced. According to TU method, the biological acute toxicity of the treated effluent had obvious decrease by 25.49%, 30.43%, and 30.85% in the deep treatment process of wetland, ozone + ultraviolet, and filter + ultraviolet respectively, and Selenastrum capricornutum was not suitable for the comprehensive acute toxicity evaluation. The treated effluents by ozone + ultraviolet had the highest degree of genetic toxicity reduction (35.9%) compared to undercurrent wetland (33.63%), and filter + ultraviolet (11.19%). Correlation analysis demonstrated that TP concentration was significantly negative correlation with the toxicity of Selenastrum capricornutum and the growth inhibition of Selenastrum capricornutum, which can act as indicator species represented by TP concentrations.