市政污水厂尾水处理人工湿地施工工艺技术要点

随着现代城市化进程加快,城市基础建设也越来越完善,其中市政污水尾水处理人工湿地工程的建设施工中涉及到多项关键工艺技术。文章阐述了市政污水尾水处理人工湿地工程的特征,结合邹城市一污尾水人工湿地工程,具体从地基、挡墙、防渗、填料、管道等施工环节,对相关工艺技术的实施要点进行了分析,希望能为相关工程的施工管理提供参考。

高效人工湿地技术在污水厂尾水处理中的应用

人工湿地技术是新时期社会发展下一种新型的尾水处理技术,具有处理效果好,运行成本低且对生态环境相对较为友好的诸多应用优势,因此,人工湿地技术深受社会大众的广泛关注。而尾水处理作为污水厂的重点工作内容,深受社会大众的广泛关注,通过切实发挥人工湿地技术的优势价值并实现在污水厂尾水处理中的有效应用,不仅能够切实提高污水厂尾水处理效果,提升尾水处理质量,更能从根本上缓解我国水资源压力,提高水资源利用效率。所以,需要以高效人工湿地技术为核心对其展开积极探究,以有效的应用策略提高污水厂尾水处理效果。

人工湿地在污水厂尾水处理方面的应用分析

尾水的处理与回收利用有利于减轻我国水污染问题的严重程度,对于促进水资源的可持续发展具有至关重要的意义。人工湿地的应用有利于提高污水厂对尾水处理的效率。本文分析人工湿地的原理以及其在污水厂尾水处理中应用的优势,阐述人工湿地在污水厂尾水处理方面应用存在的问题,并提出了具体应用的策略,从而有效实现我国水资源与经济的协调发展。

集成式铁基质生物膜反应器自养反硝化深度脱氮

以污水厂处理水为研究对象,采用铁基质生物载体与生物膜耦合实现高效自养反硝化脱氮。考察停留时间(HRT)对系统脱氮效能的影响,通过动力学及微生物群落结构分析,揭示耦合技术的脱氮机理。结果表明:HRT为8 h,对一级A和一级B污水厂处理水,总氮(TN)平均去除率分别为95.41%和92.55%,TN处理负荷分别为0.48 kg TN/(m^3·d)和0.58 kg TN/(m^3·d),硝化过程氨氮(NH4^+-N)饱和常数分别为1.17 mg/L和0.72 mg/L,反硝化过程硝氮(NO3^--N)饱和常数分别为0.87 mg/L和0.67 mg/L。出水水质分别达到《地表水环境质量标准》Ⅲ类、Ⅴ类水质标准。铁基质生物载体与生物膜耦合系统中微生物优势菌属为Maritimimonas、Rhodobacter和Sphaerotilus,均为自养反硝化菌,证实了铁基质生物载体可为自养反硝化菌提供电子,实现生物自养反硝化脱氮。

Advances in Energy-Producing Anaerobic Biotechnologies for Municipal Wastewater Treatment

Municipal wastewater treatment has long been known as a high-cost and energy-intensive process that destroys most of the energy-containing molecules by spending energy and that leaves little energy and few nutrients available for reuse, Over the past few years, some wastewater treatment plants have tried to revamp themselves as ＂resource factories,＂ enabled by new technologies and the upgrading of old technologies. In particular, there is an renewed interest in anaerobic biotechnologies, which can convert organic matter into usable energy and preserve nutrients for potential reuse. However, considerable technological and economic limitations still exist. Here, we provide an overview of recent advances in several cutting-edge anaerobic biotechnologies for wastewater treatment, including enhanced side- stream anaerobic sludge digestion, anaerobic membrane bioreactors, and microbial electrochemical systems, and discuss future challenges and opportunities for their applications. This review is intended to provide useful information to guide the future design and optimization of municipal wastewater treatment processes.

Experimental Study on Hydrothermal Drying for Sewage Sludge in Large-Scale Commercial Plant

The study was conducted to demonstrate the performance of the large-scale commercial plant of the hydrothermal drying of sewage sludge. Its performance was compared with that of the small-scale pilot facility to confirm the scaling effect of the facility. It has been shown that the optimum reaction temperature was 190℃ and reaction time was 30 minutes for both facilities. The dehydration performance of the products of the hydrothermal treatment and the natural drying performance of the dehydrated residue were almost the same for both facilities, which demonstrated that the small-scale pilot facility could simulate the commercial-scale plant well. With these optimum hydrothermal reaction conditions, the moisture content of the dehydrated product was less than 40% by the use of the frame filter, which had better dehydration performance than the centrifuge dehydrator. The moisture content of the dehydrated solid residue could be reduced less than 20% and 10% after 24 hours and 48 hours natural drying, respectively. The solubilization rate of sludge into the dehydrated liquid was 10% and 90% of the solid content in the raw sludge could be recovered as a dry solid fuel by this process with reduced energy requirement compared with conventional thermal drying processes. Too high reaction temperature or too long reaction time increased the content of solid material in the dehydrated liquid （solubilization rate of sludge） and reduced the yield of the dry solid fuel.

Full scale application of combined SBF-AS process for municipal wastewater treatment in small towns and cities in China

The combined submerged biofilm （ SBF）-activated sludge （AS） process for treatment of municipal wastewater in a small city in China is described in this paper. The process exhibited high removal efficiencies for carbonaceous substances, nitrogen and phosphorus which mainly took place in the combined SBF-AS biore- actor. The SBF-AS bioreactor was divided into pre-anoxic, anaerobic, anoxic and aerobic zones from inlet to outlet, in which fixed biofilm carriers were packed. Excellent performance had been obtained under normal operating conditions in more than one year of operation in Dong＇ e municipal WWTP, Shandong province, with mean removal efficiencies of BOD5 93.4%, COD 88%, SS 92%, NH4 - N 82. 1%, TP 75% and TN 66.7%, and quite high effluent quality such as BOD5 6 to 10 rag/L, COD 20 to 40 rag/L, SS 5 to 10 rag/L, TN 10 to 20 rag/L, NH4 - N 4 to 8 mg/L and TP 0. 6 to 1.0 mg/L. The effluent was reused multi-purposely, such as toilet flushing, green belt watering and artificial lake pounding. Simultaneous nitrification and denitrification took place due to the DO gradient in biofilm in aerobic zone of the SBF-AS bioreactor, which made TN removal efficiency improved remarkably in system. Some activated sludge was returned from final clarifiers to the bioreactor for phosphorus removal. The process had the advantages of low investment and low operational/ maintenance （O/M） costs, low sludge yield and was preferably employed in small towns and cities.

Wastewater Quality Assessment of a Petroleum Refinery in Ghana

TOR （Tema oil refinery） is the only petroleum refinery in Ghana. To assess the quality of the wastewater, wastewater samples taken from three points of discharge into the treatment plant and the treated effluent were analyzed for physico-chemical characteristics. The levels of the pH, temperature, conductivity, COD （Chemical Oxygen Demand）, TDS （Total Dissolved Solids）, TSS （Total Suspended Solids） and phenol were assessed from January to June, 2011. The results obtained indicate varied levels of contaminants in both the untreated and treated wastewater. The average values of the treated effluent parameters analyzed were 38 ℃, 6,258 μs.cm-1, 314 mg-L-1, 115 mg.L-1, 2,689 mg-L-1 and 1 mg.L-1 for the temperature, conductivity, COD, TDS, TSS and phenol, respectively. The results suggest that both the raw wastewater and the treated effluent did not meet the discharge limit set by Ghana Environmental Protection Agency. Therefore, the treated effluent required additional treatment before it can be discharged into the environment. This suggests that the wastewater treatment plant of TOR is ineffective for the type of wastewater produced.

Impact of Suspended Particles and Enhancement Techniques on Ultraviolet Disinfection of a Secondary Effluent

The concentration of suspended solids in the secondary effluent often varies widely, leading to frequent adjustment of the UV dosage to meet the disinfection criterion. In addition, a desired disinfection rate is difficult to achieve sometimes. The authors studied the particle size distribution, contribution of particle-associated Fecal Coliform (F.C.), and their influences on UV disinfection. A combined disinfection process (chlorination with a subsequent UV disinfection) was tested to improve the disinfection effect. The results indicated that the content of suspended solids, especially that of large particles, has a strong impact on UV disinfection efficiency; D>10 μm particles associated F.C. are difficult to be disinfected and are the main part of the tailings of F.C. inactivation curves. Pre-chlorination could decrease the number of particles in the secondary effluent and transform the large particles into small ones, reducing the influence of particles on UV disinfection and enhancing the resistance ability of the combined process to particle loading.

Environmental Assessment of AI-Hilla City Wastewater Treatment Plants

Iraq is one of the countries that is suffering from water shortage problems and, for this reason, wastewater treatment plants become a necessity to minimize this problem. In this study, the impact of A1-Hilla WWTP （wastewater treatment plant） on the environment has been studied. This was achieved using SimaPro software package. This software is a powerful tool for analyzing the environmental impact on products during their whole life cycle. A huge amount of knowledge about the environment is built into the program and database, enabling to analyze a product with a minimum of specialized knowledge. The results of LCA （life cycle assessment） showed that the impact and damage on the environment by A1-Hilla WWTP was 41 bad points for each 1 m3 of treated wastewater. The most environmental impacts potentially were global warming, respiratory inorganics and non-renewable energy. The study also showed that most of the effects were the result of the use of cement, steel and electricity consumption.

Technological Feasibility of Biodiesel Production from Bioaugmented Hydrolysate of Waste Sludge in a Municipal Wastewater Treatment Plant

The hydrolysate of waste sludge was used as the feedstock of biodiesel production,and its technological feasibility was investigated.Waste sludge,collected from No.3 Municipal Wastewater Treatment Plant of Xi’an,was hydrolyzed in two parallel reactors firstly.Yeast was added into one reactor for bioaugmentation,and the other reactor without yeast was used as a control.Then an acid-catalyzed in situ esterification process was carried out to convert the hydrolysate to biodiesel.The results of hydrolysis showed that the reactor bioaugmented with yeast could promote hydrolysis compared with the control one because of an obvious variance in total suspended solid(TSS),volatile suspended solid(VSS)and soluble chemical oxygen demand(SCOD).Furthermore,gas chromatography(GC)analysis exhibited that the total volatile fatty acid(VFA)was low in the hydrolysate of bioaugmentation reactor;however,its yield of the fatty acid methyl esters(FAMEs)by in situ esterification was obviously higher when compared with the control one.Therefore,it may be inferred that the hydrolysate of bioaugmentation was mainly inclined to longer-chain fatty acid rather than to VFA.Anyway,an FAMEs yield of 9.24%(wt%)from dried sludge was attained after the 12-d bioaugmentation hydrolysis and succedent esterification.This value was not only higher than that of the control one but also higher than that reported in previous literature.The above results illuminated that it was feasible to produce biodiesel from the bioaugmented hydrolysate of waste sludge.

Evaluation and improvement of wastewater treatment plant performance using BioWin

In this study,the activated sludge model implemented in the BioWin software was validated against full-scale wastewater treatment plant data. Only two stoichiometric parameters(Y p /acetic and the heterotrophic yield(Y H)) required calibration. The value 0.42 was used for Yp /acetic in this study,while the default value of the BioWin software is 0.49,making it comparable with the default values of the corresponding parameter(yield of phosphorus release to substrate uptake(YPO4)) used in ASM2,ASM2 d,and ASM3 P,respectively. Three scenarios were evaluated to improve the performance of the wastewater treatment plant,the possibility of wasting sludge from either the aeration tank or the secondary clarifier,the construction of a new oxidation ditch,and the construction of an equalization tank. The results suggest that construction of a new oxidation ditch or an equalization tank for the wastewater treatment plant is not necessary. However,sludge should be wasted from the aeration tank during wet weather to reduce the solids loading of the clarifiers and avoid effluent violations. Therefore,it is recommended that the design of wastewater treatment plants(WWTPs) should include flexibility to operate the plants in various modes. This is helpful in selection of the appropriate operating mode when necessary,resulting in substantial reductions in operating costs.

Discussion on nitrogen and phosphorus removal process characteristics of improved oxidation ditch

In order to enhance efficiency of the nitrogen and phosphorus removal of sewage treatment plant, Taking Wu Long kou sewage treatment plant project in Zhengzhou as an example, this article introduces the structure, the working principle, the craft character, as well as the problems existed in the practical application of the improved oxidation ditch, and raises some corresponding processing countermeasures. Looked from the running situation of Wu Long kou sewage treatment plant, the improved oxidation ditch have certain advantages in city sewage treatment, such as high organic removing efficiency, good removing effect of nitrogen and phosphorus, low investing expenses and operating cost and so on. It is a craft that is worth promoting in urban sewage treatment.

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.

Removal of Nitrogen and Phosphorus from Animal and Municipal Wastewaters as Dittmarite

Phosphorus and nitrogen are known causes of eutrophication in rivers, lakes streams and estuaries. The sources of these nutrients are diverse and they include chemical fertilizers, CAFOs （Confmed Animal Feeding Operations）, land application of animal and municipal as well as industrial wastewaters. Application of manure slurries to crop land beyond allowable limits could result in high levels of phosphorus and nitrogen in runoff that negatively impact aquatic animals. Municipal wastewater treatment plants are setup to remove these nutrients from domestic and industrial wastewater through a network of treatment processes. Controlling the discharge of phosphorus and nitrogen in wastewater is a key factor in preventing eutrophication. This paper presents work done to enhance a chemical precipitation process that removes over 90% of dissolved phosphorus and nearly 20% of dissolved nitrogen from both synthetic and municipal wastewaters. The objective of the study is to remove nitrogen and phosphorus from wastewater as dittmarite, a value-added mineral fertilizer found in nature. A laboratory procedure was developed that generated significant quantities of dittmarite from various wastewaters. Pure dittrnarite contains nitrogen, phosphorus and magnesium in approximate molar ratios of 1：1.2：1.2 that can support plant growth. It is produced as a wet precipitate from chemical reactions that occur in the wastewater treatment process; it can be dried for proper handling and utilization. Municipal wastewater treatment plants, high volume fish producers, CAFOs and individual rural homeowners could all benefit from this technology for on-site removal of nitrogen and phosphorus from produced wastewaters.

武汉市光谷三路湿地公园景观设计

城市建设,环保先行。为美化城市环境及保障其可持续发展,生态建设越来越提前。根据《武汉科技新城排水专项规划》环保先行的原则,片区的发展需依托相关环保基础设施项目的建设(如污水处理厂),在环保基础设施项目运营之前,城市的发展会受到制约。此外,污水处理厂的尾水排放需满足环保要求,需经人工强化湿地处理后方能排向周边自然水体。本项目因此应运而生,设计对周边环境需求、污水厂尾水流量、公园自身功能及后期运营管理等诸多方面进行了统筹考虑。并结合现状植被、水体及地形进行了针对性设计。使之真正能够成为集科教、生态、自然、功能于一体的综合型特色公园。

CANON Process for Nitrogen Removal from Effluents of Municipal Sewage Treatment Plants

The feasibility and performance of nitrogen removal from municipal sewage were investigated through the completely autotrophic nitrogen removal over nitrite (CANON) process in a continuous reactor. CANON process was successfully started up with the transformation of nitrogen into gas by mass-balance analysis. For the synthetic waste-water (up to 480 mg NH4+-N/(L·d)), removal rates of the ammonia nitrogen and total nitrogen (TN) were about 80% and 55%, respectively, at 1.25 h hydraulic retention time (HRT). For the secondary effluent of municipal sewage, the effluent concentrations of NH4+-N and TN were below 5 mg/L and 9 mg/L, respectively. It is in accordance with the water quality standard for scenic environment with the reuse of urban recycling water (GB/T 18921-2002).

Urban Services Delivery in Limbo： A Provisional Assessment of Gweru＇s Water Supply System

This study sought to assess Gweru＇s water supply system from the source to the consumer to find out whether the water is safe for domestic purposes, mainly consumption. Water samples were taken from Gwenoro dam （raw water）, Gwenoro treatment plant （treated water） as well as from GIS-generated random points of residential areas closest to Gwenoro and furthest from both the dam and the treatment plant. These were taken for laboratory testing where parameters like pH, hardness, turbidity and DO （dissolved oxygen） were tested. Questionnaires were used to solicit the views of the consumers on water quality and water service delivery from eight randomly selected residential suburbs. Interviews were also administered to Gwenoro Water Treatment Plant superintendent and deputy to get insight into the day to day challenges that they have to grapple with. Results generally show that treated water from Gwenoro treatment plant is relatively safe to drink for those who have access to it. However, some consumer points like Mkoba 13 and Mkoba 18 receive water whose DO is out of the recommended range. Suburbs which lie on higher ground like Mkoba 19 and Mkoba 14 however rarely receive water from Gwenoro with some residents of Mkoba 19 having had no water from their taps for more than three years now. The study recommends that new equipment be bought for the treatment plant so that treated water reaches all parts of the city. Newly resettled farmers in the Upper Runde Catchment must be resettled elsewhere while urban stream bank cultivation must be banned to reduce water pollution as well as possible sedimentation of Gwenoro dam.

Interplay Factors Involved in the Inadequate Performance of Four Activated Sludge Systems in Northern Gauteng-South Africa

A recent study conducted on the four activated systems serving the surrounding communities in the Northern Gauteng revealed the failure of three of these wastewater treatment plants to remove enteric pathogenic bacteria and protozoan parasites such as Cryptosporidium and Giardia spp. To determine the factors involved in the inadequate performance of the plants, the following parameters were considered： the design characteristic of the plants, the microbiological structure and the physical characteristics of the plants. The results revealed that higher than optimal influent loadings and inadequate aeration systems, observed in Baviaanspoort, Refilwe and Rayton Water Care Works （WCW） increased the composition of filamentous bacteria in flocs and decreased the diversity of protozoan species in the sludge. Sequentially, these resulted in the poor settling properties of the sludge at these plants. However, Zeekoegat WCW showed optimum influent loads and adequate aeration systems. This maintained balance in the microbial community, resulting in good clarification of the sludge.

Phosphorus Reduction from Urban Wastewater Treatment Plant with Trickling Filters

The purpose of this research is to investigate a biofilm system with trickling filter as a biological alternative process during low cost treatment connection with the possibility of reducing nutrients such as phosphorus. Given that nitrogen with phosphorus that are leading causes of algal bloom resulting in increased eutrophication or chemical nutrients are the basis of this document analysis. This increase in organisms results in less oxygen in water bodies and at times, slow decay leads many fresh water ponds, lakes and rivers. The process of eutrophication unfortunately tends to favor pollution and algae, which reduce the quality of the water. Kosovo has not a long tradition in the treatment of wastewater, especially in removing phosphorus, since the country has only a plant for wastewater treatment. The present plant is intended to protect the Klina river from eutrophication from wastewater discharged after treatment. This plant currently reduced phosphorus efficiently, but the goal of this paper is to increase the percentage of removal of phosphorus to 40% through trickling filters, presenting options for optimizing work on plant Skenderaj.