Prediction and Analysis of Total Nitrogen in a Sewage Treatment Plant Effluent

Total nitrogen was an important indicator for characterizing eutrophication of polluted water. Although the use of water quality online monitoring instrument can monitor water quality changes in real time, the degree of intelligence was low, so it was urgent to predict the water quality and take precautions in advance. A predictive model for total nitrogen levels in a sewage treatment plant utilizing the Anaerobic-Anoxic-Oxic (AAO) process was investigated in this paper. This model demonstrated significant practical application value. Based on the ARIMA (Autoregressive Integrated Moving Average) model and taking into account the impact of Biochemical Oxygen Demand (BOD), a prediction model for effluent total nitrogen was developed. However, the initial results exhibited significant deviations. To address this issue, seasonal factors were further considered. Then, the dataset was divided into winter and Non-winter sub-samples, leading to a reconstruction of the prediction model. Additionally, in developing the Non-winter prediction model, life cycle considerations were incorporated, and consequently, a SARIMA (Seasonal Autoregressive Integrated Moving Average) model was established. The predicting deviation associated with both the winter and Non-winter forecasting models showed a significant reduction.

Levels and distributions of polychlorinated biphenyls in sewage sludge of urban wastewater treatment plants

Concentrations of polychlorinated biphenyls （PCBs） have been measured in sewage sludge samples from 8 urban wastewater treatment plants in Beijing, China. The PCB congeners were analyzed by isotope dilution high resolution gas chromatography/high resolution mass spectrometry method. The concentration of PCBs ranged from 65.6 to 157 ng/g dry weight （dw）, with a mean value of 101 ng/g dw. The dioxin-like PCB WHO-TEQs （World Health Organization-Toxic Equivalents） of the sludge were lower than 1 pg /g dw. Consequently, all the concentrations of PCBs in sludge samples were below the upper limit for land application according to the Chinese legislation law for agriculture use. The PCB homologue profiles in sludge samples were dominated by tri-CBs and tetra- CBs. Similar distributions have been found in one of the Chinese PCB commercial products. The patterns of dioxin-like and indicator congeners observed in this study were quite similar in all samples. The predominant congener for dioxin-like and indicator PCBs were PCB-118 and PCB-28, respectively, while PCB-126 had the highest TEQ value.

Current Seasonal Variations in Physicochemical and Heavy Metals Parameters of Sewage Treatment Plant Effluent and Suitability for Irrigation

The study aims to investigate the current extent of physicochemical parameters and heavy metal contamination in the effluent of the Jaganpur sewage treatment plant (STP), Dayalbagh, Agra India. Majority of the nearby farmers have access to use of STP effluent in irrigation purposes for growing major edible crops. The problems of using STP effluent for irrigation purpose, continuous water quality analysis required. To check the quality of irrigation water, substantial physicochemical parameters accordance to Indian Standards (IS-Reaffirmed 2002/2003) analysed to calculate Sodium absorption ratio (SAR) and Residual sodium carbonate (RSC). To estimate the heavy metal pollution index (HPI) and metal quality index (MQI), toxic Heavy metals such as As, Cr, Mn, Fe, Ni, Cu, Zn, Pd, Cd, Co, and B also determined in the STP effluent with an AAS and results verified with ICP-OES against certified standards. The high value of SAR (range 13 to 20) and RSC (range -10 to 11) in STP effluent exceeded the permissible limit for irrigation purpose. On the other hand, HPI and MQI values (1692.4 and 58.1, respectively) show that high metal contamination mainly due to industrial and domestic wastewater does not treat appropriately in the sewage treatment plant. Thus it is suggested that further studies are carried out on the STP effluents to improve the water quality through proper treatment. Treated wastewater used for irrigation purposes needs to analyse the contamination like heavy metals and pinpoint the pollution sources.

Deep learning-based intelligent management for sewage treatment plants

It is generally believed that intelligent management for sewage treatment plants(STPs) is essential to the sustainable engineering of future smart cities.The core of management lies in the precise prediction of daily volumes of sewage.The generation of sewage is the result of multiple factors from the whole social system.Characterized by strong process abstraction ability,data mining techniques have been viewed as promising prediction methods to realize intelligent STP management.However,existing data mining-based methods for this purpose just focus on a single factor such as an economical or meteorological factor and ignore their collaborative effects.To address this challenge,a deep learning-based intelligent management mechanism for STPs is proposed,to predict business volume.Specifically,the grey relation algorithm(GRA) and gated recursive unit network(GRU) are combined into a prediction model(GRAGRU).The GRA is utilized to select the factors that have a significant impact on the sewage business volume,and the GRU is set up to output the prediction results.We conducted a large number of experiments to verify the efficiency of the proposed GRA-GRU model.

Discussion on the Problems and Developing Trend of Construction of Sewage Treatment Plants in Small Towns

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.

Advances in Research of Characteristics and Removal of Microplastics in Sewage Treatment Plants

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.

Behavior of Antibiotic-Resistant Fecal Coliforms in the Stream of a Sewage Treatment Plant in Tokyo

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 β-lactamase (ESBL)-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.

Sewage Sludge： A Sustainable Source for Plant Nutrient

Sludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly handled and disposed, it may produce extensive health hazards. On the other hand, this sludge has benefit for plants and soils. Sludge samples were collected over a 12 month period from sewage treatment plants （STP＇s）, i.e, Khairathabad and Meeralam Tank, Hyderabad, India and analyzed for C, H, N, S by elementar analyzer, P, K, Ca, Mg by spectrophotometer and heavy metals like Zn, Pb, Ni, Cu, Cd by atomic absorption spectrophotometer. The sludge contained approximately 50% organic matter and 1-4% inorganic carbon. Organic and inorganic carbon, organic nitrogen, inorganic phosphorous, Ca and Mg were found to be present in sludge at a relatively constant concentration with respect to sampling time. Inorganic N, organic P, K, and all metals were found to be quite variable with time when sludge produced from different STP＇s.

Advances in the Medicinal Value of Constructed Wetland Plants for Treating Rural Domestic Sewage

Firstly,the advantages and disadvantages of constructed wetlands for treating rural domestic sewage are introduced.Secondly,the types of constructed wetland plants are introduced.Thirdly,the suitability of using medicinal wetland plants to treat rural domestic sewage is analyzed.Fourthly,the principles of selecting wetland plants with medicinal value are studied.Finally,commonly used constructed wetland plants and their medicinal value are introduced.

添加微藻的水生动植物组合对畜禽养殖场污水净化效应

用正交试验方法研究了添加微藻后的不同水生动植物组合对畜禽养殖场污水的净化效果。结果表明微藻的添加对污水的脱氮除磷效果有促进作用,当小球藻的添加量为1000 mL时,对总氮、硝态氮、总磷的去除效果最好,比未添加小球藻组去除率提高4.8%、32.63%、22.18%;当小球藻的添加量为4.4×10^(6)cell·mL^(-1)时,对氨氮、COD的去除效果较好,比未添加小球藻组去除率提高25.77%、13.30%。其中去除水体总氮、硝态氮效果最佳组合为红鲫鱼270 g·m^(-2),小球藻2.2×10^(6)cell·mL^(-1),田螺400 g·m^(-2),黑藻200 g·m^(-2)。去除氨氮最佳组合为红鲫鱼540 g·m^(-2),小球藻4.4×10^(6)cell·mL^(-1),田螺200 g·m^(-2),添加黑藻和苦草(种植比例1∶1,密度200 g·m^(-2))。去除总磷TP最佳组合为红鲫鱼540 g·m^(-2),小球藻2.2×10^(6)cell·mL^(-1),田螺400 g·m^(-2),黑藻(种植密度200 g·m^(-2))。研究表明,应用正交试验可以优化水生植物组合对畜禽污水净化处理工艺,对于不同的目标污染物,具有不同的最优参数组合,综合考虑各因素对各目标污染物的去除效果的影响,可以选择污水净化工艺的最优参数组合,通过回收沼液养殖的微藻用于水生动植物组合进一步净化养殖场污水,实现废弃物资源化循环利用,对于污水深度处理技术具有良好的应用前景。

“双碳”目标下燃煤电厂灵活性改造及政策建议

双碳目标下,以新能源为主的可再生能源将实现规模化发展,煤电将向基础保障性和系统调节性电源并重转型。推动燃煤电厂灵活性改造,是增加新能源消纳能力、推动新能源高质量发展的重要举措。本文系统介绍了中国的煤电现状及新定位,梳理了中国“三改联动”中煤电灵活性改造进展情况,评价了灵活性改造实施效果,聚焦影响煤电机组灵活性运行的主要技术问题,研究分析了灵活性改造典型技术路线及其经济性。借鉴欧美提升煤电灵活性的市场经验,从加强规划引导、完善支持政策、发挥市场作用、确保运行安全等方面提出了推进灵活性改造、促进煤电产业转型发展的政策建议。

泰国、马来西亚和印度天然橡胶产业支持政策及启示

天然橡胶是重要的战略物资和战略资源,2023年中央一号文件要求完善天然橡胶产业扶持政策。为了更好地借鉴天然橡胶主产国的经验,从生产、市场、贸易等角度对泰国、马来西亚和印度天然橡胶产业政策进行了较为系统的梳理,并进行对比分析,对完善我国天然橡胶产业政策提出了建议。

污水处理厂温室气体排放特征与减排技术研究

污水处理厂是温室气体的重要排放源,必须探索和应用有效的减排技术,提升温室气体减排能力。深入分析污水处理厂温室气体排放特征,有助于更好地应用减排技术。直接排放与间接排放是污水处理厂温室气体的两种主要排放形式。结合污水处理厂温室气体的来源,以山东省某污水处理厂为例,核算2018-2020年温室气体直接排放量与间接排放量,然后根据污水处理厂温室气体排放特征,分析污水处理厂温室气体的减排措施。总体来说,要科学选择污水处理工艺,合理调节工艺运行参数,有效减少温室气体排放量。

污水厂尾水对河流水质和底泥细菌群落的影响

污水厂的出水即尾水,其排放关系到受纳水体的水质和生态状况。分析了武汉市某污水厂尾水排放指标,采用水槽试验探究了污水厂尾水对河流水质指标和底泥细菌群落的影响。结果表明:尾水排放促进了河水中硝酸盐氮的降解,总磷去除更加稳定;尾水使河水pH值提高了0.3、电导率上升幅度55%、溶解氧降低了0.6 mg/L。尾水排放之后,底泥细菌群落的丰富度升高、多样性降低,抑制厌氧菌Anaerolineaceae和SBR1031,促进好氧菌Pseudomonas;反硝化菌Azospira、Dechloromonas、Pseudomonas、Sphingomonas增多,促进了NO_(3)^(-)-N的降解。底泥中致病菌奈瑟菌属、军团菌属、消毒残生细菌相对丰度上升。

施用堆肥污泥对土壤肥力及植物生长的影响

土地利用有望成为市政污泥处置的主要途径。本研究以好氧堆肥的市政污泥为研究对象,通过田间试验,设置不同堆肥污泥施用量:0%、30%、50%、70%、100%(堆肥污泥与土壤体积配比),研究堆肥污泥施用对土壤肥力、植物生长以及土壤重金属含量的影响。结果表明:堆肥污泥施用未造成土壤酸碱化,土壤肥力等级由三级一般土壤提升为二级肥沃土壤,土壤主要营养组分含量随污泥施用量的增加均显著提高,其中堆肥污泥添加比例为50%时土壤有机质增加1.9倍、碱解氮增加3.0倍、有效磷增加9.5倍、速效钾增加3.7倍。堆肥污泥添加比例为50%时木春菊组长势最好,添加比例为30%时鼠尾草组和高羊茅&黑麦草组长势最佳,但是不同添加比例下早樱组生长并无显著差异。尽管施用堆肥污泥会导致试验区土壤重金属含量略有升高,但远低于《城镇污水处理厂污泥处置林地用泥质》(CJ/T 362-2011)所规定的污染物指标及其限值,未造成土壤重金属污染。本研究将为堆肥污泥的土地利用提供理论依据和数据支撑。

Total concentrations and different fractions of heavy metals in sewage sludge from Guangzhou, China

Dewatered municipal sludge samples were collected from five municipal wastewater treatment plants （WWTPs） and one industrial WWTP in Guangzhou, China. A number of agricultural parameters and total metal concentrations in the sludge were determined. Metal speciation was also studied. The results showed that sewage sludge had high organic carbon, and was rich in such nutrients as N and P. The concentrations of Mn, Zn, and Cu were the highest, followed by Ni, Pb, and Cr, Cd had the lowest concentration. In addition, the concentrations of the aforementioned heavy metals in the sludge samples were higher than those recorded in the background data for crop soils. With the exception of Cu and Cd from site S1, and Ni from sites S1, $2, and $5, all other metal concentrations conformed to permissible levels prescribed by the national application standard of acid soil in China （GB 18918--2002）. The results of the BCR sequential extraction showed that the concentrations of Mn and Zn were predominant in acid-soluble/exchangeable and reducible fractions. Cu was principally distributed in oxidizable and residual fractions, whereas Cr was present in oxidizable and residual fractions, Pb was found in the state of residual fractions, and the distribution of Ni and Cd did not show significant characteristics.

财政支持的粮食增产效应及其空间溢出效应——以水稻为例

粮食生产是保障国家粮食安全战略的基石,而与其相关的适度财政支持可以兼顾公共财政资金有效利用、国家安全战略实施。结合水稻在粮食生产中的重要地位,基于2006-2021年中国省际面板数据,采用固定效应模型、中介效应模型和空间杜宾模型,实证分析财政支持对水稻总产量的影响机制及其空间溢出效应。研究发现:财政支持能够促进水稻总产量增长,但这种增产效应存在时滞;财政支持对水稻增产的中介效应主要通过扩大区域水稻生产规模实现;财政支持的增产效应存在负向空间溢出效应,导致水稻生产在空间分布上呈集聚趋势。鉴于水稻生产的空间异质性,从是否为粮食主产区来看,财政支持的增产效应在粮食主产区更显著;从经济发展水平来看,增产效应在东北地区更显著。因此,需要保持对粮食生产的财政支持力度,促进经营的规模化、效益化、可持续化的良性循环,防控财政支持政策的负向抑制作用,增量资金向包括东北地区的主产区倾斜。

东北地区某城镇污水处理厂碳源投加策略分析

低C/N进水条件造成的生物处理系统反硝化脱氮能力不足已成为我国污水处理厂运行面临的主要挑战。文章应用文献计量学对目前碳源投加策略进行了总结,并以东北地区某城镇污水处理厂为考察对象,结合各碳源的实际应用情况介绍了目前常用的几种主流外加碳源的优缺点,分析了甲醇、乙酸钠、葡萄糖和麦可碳4种碳源投加公式计算理论值与实际碳源投加量之间存在差异的原因,旨在为城镇污水处理厂实现经济、高效、低碳运行碳源投加策略提供技术指导。

长江大保护试点城市某污水处理厂尾水湿地净化效果研究

为探寻污水处理厂配套尾水湿地净化效果,以长江大保护试点城市某污水处理厂尾水湿地为例,通过现场调查与采样,分析湿地出水水质特征,探讨影响湿地污染物去除效率因素。结果表明:尾水湿地出水COD、NH_(3)-N及TP浓度满足设计目标,潜流湿地对COD去除率较高,表流湿地对氨氮及磷的去除率较高,优于涵养塘;湿地实际运行水力负荷、水力停留时间和污染物负荷与设计值不符,影响污染物去除效果;据此提出湿地运行优化建议,促进湿地深度脱氮除磷,提升尾水湿地效能;运行优化可提高潜流湿地污染物去除率,同时污水处理厂减少碳排放94.74 gCO_(2)m^(3)。研究结果可为该尾水湿地运行管理及长江大保护试点城市系列污水处理厂配套尾水湿地设计与运维提供参考。

雨污合流制地区溢流污染影响因素及管控建议

雨污合流制地区汛期溢流成为城市河流返黑返臭的重要原因,溢流污染的有效控制,对改善水环境,提升人民幸福感、获得感与安全感有着重要作用。针对雨污合流制地区汛期溢流污染防控,总结了合流制溢流污染的特点、对水环境质量的影响以及合流制溢流污染的影响因素等内容,分析了我国溢流污染严重区域的分布特征并提出管控建议。研究发现,我国合流制溢流污水呈现出成分复杂、水量水质变化大、初期雨水水质差等特点,且合流制溢流污染会导致城市面源污染,加重地表水质恶化程度。通过分析合流制溢流污染的2个主要影响因素(降水量和管网条件),初步识别出我国溢流污染严重区域主要集中在东部、南部地区,且相关性分析结果表明汛期降水量及管网密度与区域水质存在中等相关关系。为加强合流制地区溢流污染防控,提出要因地制宜制订汛期雨污溢流污染排放管控标准、开展溢流污染控制技术更新行动、加强汛期雨污溢流污染的全过程管理、加强汛期雨污溢流污染治理成效考核等具体建议,以期为有效控制合流制溢流污染,推动水环境质量持续改善提供参考。