Integration of sulphate reduction, autotrophic denitrification and nitrification to achieve low-cost excess sludge minimisation for Hong Kong sewage.

An integrated anaerobic-aerobic treatment system of sulphate-laden wastewater was proposed here to achieve low sludge production, low energy consumption and effective sulphide control. Before integrating the whole system, the feasibility of autotrophic denitrification utilising dissolved sulphide produced during anaerobic treatment of sulphate rich wastewater was studied here. An upflow anaerobic sludge blanket reactor was operated to treat sulphate-rich synthetic wastewater (TOC=100 mg/L and sulphate=500 mg/L) and its effluent with dissolved sulphide and external nitrate solution were fed into an anoxic biofilter. The anaerobic reactor was able to remove 77-85% of TOC at HRT of 3 h and produce 70-90 mg S/L sulphide in dissolved form for the subsequent denitrification. The performance of anoxic reactor was stable, and the anoxic reactor could remove 30 mg N/L nitrate at HRT of 2 h through autotrophic denitrification. Furthermore, sulphur balance for the anoxic filter showed that more than 90% of the removed sulphide was actually oxidised into sulphate, thereby there was no accumulation of sulphur particles in the filter bed. The net sludge productions were approximately 0.15 to 0.18 g VSS/g COD in the anaerobic reactor and 0.22 to 0.31 g VSS/g NO3- -N in the anoxic reactor. The findings in this study will be helpful in developing the integrated treatment system to achieve low-cost excess sludge minimisation.     

香港岛污水管网系统总体规划概述

阐述了在香港岛污水管网系统总体规划工作中建立和使用水力模型的基本步骤,主要包括利用InfoWorks建立、校核和调整水力模型,根据模拟结果辅助规划设计以及建立管网的GIS系统等。     

Multistage wastewater treatment using separated storage driven denitrification and nitrification biofilms.

The feasibility of combining a previously reported storage driven denitrification biofilm, where 80% of influent acetate can be converted to poly-beta-hydroxybutyrate (PHB), with a suitable nitrification reactor, either submerged or trickling filter design, to achieve complete biological nitrogen removal was tested. The reactor system showed the potential of complete biological nitrogen removal of waste streams with a C/N ratio as low as 3.93 kg COD/kg N-NH3 at an overall nitrogen removal rate of 1.1 mmole NH3/L/h. While the efficiency and the rates of nitrogen removal were higher than what is observed in traditional or simultaneous nitrification and denitrification (SND) systems, there were two problems that require further development: (a) the incomplete draining of the reactor caused ammonia retention and release in the effluent, limiting the overall N-removal and (b) pH drifts in the nitrification step slowed down the rate of nitrification if not corrected by appropriate pH adjustment or buffering.     

Sediment nitrification and denitrification in a Lake Superior estuary

Inorganic nitrogen (N) transformations and removal in aquatic sediments are microbially mediated, and rates influence N-transport. In this study we related physicochemical properties of a large Great Lakes embayment, the St. Louis River Estuary (SLRE) of western Lake Superior, to sediment N-transformation rates. We tested for associations among rates and N-inputs, vegetation biomass, and temperature. We measured rates of nitrification (NIT), unamended base denitrification (DeNIT), and potential denitrification [denitrifying enzyme activity (DEA)] in 2011 and 2012 across spatial and depth zones. In vegetated habitats, NIT and DeNIT rates were highest in deep (ca. 2 m) water (249 and 2111 mg N m^− 2 d^− 1, respectively) and in the upper and lower reaches of the SLRE (> 126 and 274 mg N m^− 2 d^− 1, respectively). Rates of DEA were similar among zones. In 2012, NIT, DeNIT, and DEA rates were highest in July, May, and June, respectively. System-wide, we observed highest NIT (223 and 287 mg N m^− 2 d^− 1) and DeNIT (77 and 64 mg N m^− 2 d^− 1) rates in the harbor and from deep water, respectively. Amendment with NO₃⁻ enhanced DeNIT rates more than carbon amendment; however, DeNIT and NIT rates were inversely related, suggesting the two processes are decoupled in sediments. Average proportion of N₂O released during DEA (23–54%) was greater than from DeNIT (0–41%). Nitrogen cycling rates were spatially and temporally variable, but we modeled how alterations to water depth and N-inputs may impact DeNIT rates. A large flood occurred in 2012 which temporarily altered water chemistry and sediment nitrogen cycling.     

A novel wastewater treatment process: simultaneous nitrification, denitrification and phosphorus removal.

Simultaneous nitrification and denitrification (SND) via the nitrite pathway and anaerobic-anoxic enhanced biological phosphorus removal (EBPR) are two processes that can significantly reduce the COD demand for nitrogen and phosphorus removal. The combination of these two processes has the potential of achieving simultaneous nitrogen and phosphorus removal with a minimal requirement for COD. A lab-scale sequencing batch reactor (SBR) was operated in alternating anaerobic-aerobic mode with a low dissolved oxygen concentration (DO, 0.5 mg/L) during the aerobic period, and was demonstrated to accomplish nitrification, denitrification and phosphorus removal. Under anaerobic conditions, COD was taken up and converted to polyhydroxyalkanoates (PHA), accompanied with phosphorus release. In the subsequent aerobic stage, PHA was oxidized and phosphorus was taken up to less than 0.5 mg/L at the end of the cycle. Ammonia was also oxidised during the aerobic period, but without accumulation of nitrite or nitrate in the system, indicating the occurrence of simultaneous nitrification and denitrification. However, off-gas analysis found that the final denitrification product was mainly nitrous oxide (N2O) not N2. Further experimental results demonstrated that nitrogen removal was via nitrite, not nitrate. These experiments also showed that denitrifying glycogen-accumulating organisms rather than denitrifying polyphosphate-accumulating organisms were responsible for the denitrification activity.     

海宁市污水处理工程污水排放口位置选择

为适应海宁市经济的持续发展，促进城市环境综合整治，拟建污水处理工程。通过大量实测资料对选址河床进行分析，根据其演变特点并综合考虑其它因素，提出了较为可行的排放口位置方案。     

曝气生物滤池内同步硝化反硝化的研究进展

笔者以1984—2009年发表在国内外期刊上的关于BAF研究与应用的多篇文献为基础,对曝气生物滤池中的同步硝化反硝化作用从宏观、微观和微生物角度进行机理分析,并从DO、C/N、pH以及滤料角度对影响脱氮过程的因素进行探讨,最后对曝气生物滤池同步硝化反硝化研究进行展望。     

淡水湖泊微生物硝化反硝化过程与影响因素研究

简述了参与硝化反硝化过程的微生物类型及其影响因素,指出湖泊中底栖动物提高了沉积物中氨氧化菌的丰度,加快了沉积物和上覆水反硝化过程,同时底栖动物的肠道也是反硝化场所并释放N2O。研究淡水湖泊中硝化反硝化微生物群落结构组成及多样性,阐述硝化反硝化的分子生物学机制,探索底栖动物对参与氮循环微生物群落结构与功能影响。     

鄂西山区农村生活污水处理及排放状况调查研究

以鄂西山区某饮用水源水库周边农村福善场村为例,通过现场调查分析和水质检测对鄂西山区农村生活污水处理及排放状况进行了调查研究。结果表明：鄂西山区农村生活污水主要通过集中微动力污水处理站、三户联排小型微动力污水处理设施和三格式化粪池3种方式处理后排入地表沟渠、堰塘或下渗至地下;经3种污水处理方式处理后的出水水质均未达到农村生活污水排放水质要求,对邻近饮用水源水库水质具有一定影响;农村微动力污水处理设施存在运行成本高、运维程序复杂、疏于管理、有效运行时间短等问题,致使其难以达到相应的污水处理效果;根据当地农村地势及生活污水排放特点研究新型农村生活污水处理方式是保障鄂西山区农村水环境安全与质量的当务之急。     

香港城市给排水现状

介绍了香港的城市供水和排水处理现状 ,污水处理回用技术 ,节水措施及环保等方面的情况。     

Impact of sewage treatment plants and combined sewer overflow basins on the microbiological quality of surface water.

In a small river catchment, microbiological quality of different sewage treatment plants under regular conditions and in case of heavy rainfall, when combined sewage overflow basins (CSOs) are activated, was examined regarding microbial indicators and pathogens. In the watercourse, no self-cleaning effects could be observed. Small compact treatment plants discharge treated wastewater with a poor microbiological quality compared to river water quality and the quality of treated wastewater of larger plants. During storm water events, concentrations of microorganisms downstream of sewer overflows were approximately two logs higher than during dry weather conditions. Concentrations of parasites decreased slowly during the overflow, in parallel to filterable matter and particle-bound substances. The annual load of microorganisms originating from CSOs significantly exceeds the load from treated effluent of the sewage plants. Thus, an improved hygienic quality of the water course could be achieved by preventing overflows and by enhancing sewage treatment plants.     

香港水质模型研究及其应用

近年来,香港地区对于水质模型研究极为活跃,包括在数学模型和物理模型方面,本文综述香港在水质模型研究方面的一些成果,及其在城市污水治理,港口与机场建设、海洋渔业养殖等方面的应用。     

城镇污水处理厂污染物排放标准修改完善的思考

正在水资源、水环境、水生态三水共治目标下,制定削减水域污染大户城镇污水的技术经济政策,对建立现代环境治理体系非常重要。城镇污水处理厂污染物排放标准控制对象是全国每天1.8亿t的城镇污水,影响范围是不同气候带的大小水域和不同城市的污水回用要求,所以污染物排放标准指标应体现不同污染物控制的最佳技术经济效益。2016年《城镇污水处理厂污染物排放标准》(征求意见稿)却废除了排污去向,以膜技术为依据提出了各项标准值。环保部发现问题,叫停了该标准制定工作,至今,城镇污水处理厂污染物排放标准的修正完     

Comparison of membrane biofouling in nitrification and denitrification for the membrane bioreactor (MBR).

Batch filtration tests were conducted to compare the characteristics of membrane biofouling with regard to nitrification and denitrification. A Modified Fouling Index (MFI) was obtained using a stirred cell tester. The denitrification assays showed higher membrane fouling rates than the nitrification assays. The fouling became worse, not only due to pore blocking resistance, but also from cake layer resistance after denitrification. The Extracellular Polymeric Substances (EPS) concentration and relative hydrophobicity were decreased after denitrification, resulting in floc deterioration. The floc deterioration was assumed to have increased the cake layer resistance in the filtration test. The protein Soluble Microbial Products (SMP) concentration, portion of high molecular weight in carbohydrate SMP and relative hydrophobicity were increased after denitrification, which was assumed to cause membrane pore blocking. The changes in the EPS and SMP characteristics were the main fouling parameters in denitrification.     

Simultaneous nitrification and autotrophic denitrification in fluidized bed reactors using pyrite and elemental sulfur as electron donors

In this study, simultaneous nitrification and autotrophic denitrification (SNAD) with either elemental sulfur or pyrite were investigated in fluidized bed reactors in mesophilic conditions. The reactor performance was evaluated at different ammonium (12-40 mg/L of NH₄⁺-N), nitrate (35-45 mg/L of NO₃^--N), and dissolved oxygen (DO) (0.1-1.5 mg/L) concentrations, with a hydraulic retention time of 12 h. The pyrite reactor supported the SNAD process with a maximum nitrogen removal efficiency of 139.5 mg/(L·d) when the DO concentration was in the range of 0.8-1.5 mg/L. This range, however, limited the denitrification efficiency of the reactor, which decreased from 90.0% ± 5.3% in phases II-V to 67.9% ± 7.2% in phases VI and VII. Sulfate precipitated as iron sulfate (FeSO₄/Fe₂(SO₄)₃) and sodium sulfate (Na₂SO₄) minerals during the experiment. The sulfur reactor did not respond well to nitrification with a low and unstable ammonium removal efficiency, while denitrification occurred with a nitrate removal efficiency of 97.8%. In the pyrite system, the nitrifying bacterium Nitrosomonas sp. was present, and its relative abundance increased from 0.1% to 1.1%, while the autotrophic denitrifying genera Terrimonas, Ferruginibacter, and Denitratimonas dominated the community. Thiobacillus, Sulfurovum, and Trichlorobacter were the most abundant genera in the sulfur reactor during the entire experiment.     

低地坪高潮位地区的雨水管道淹没出流计算

根据水力学理论,阐述了重力流雨水管道淹没出流的水力计算方法,并结合工程实例,介绍了低地坪高潮位地区雨水管道淹没出流的简化计算方法。提出低地坪高潮位地区的重力流雨水管道应优先采用小坡降、低流速、大管径系统,以尽可能降低水位壅高对管道的不利影响。     

加强入河排污口的监督管理探讨

入河排污口的监督管理是<水法>赋予水行政主管部门的一项重要工作,如何做好入河排污口的监督管理工作,是加强水功能区管理和水资源保护工作的基础.本文主要探讨入河排污口监督管理的内容和方法,并针对此项工作所遇到的部分问题提出今后工作的一些设想,希望对规范和健全入河排污口监督管理工作能提供借鉴、参考.     

关于建立流域排污权交易制度的探讨

在当前的流域排污、治污管理中,存在诸多弊端,而各流域水污染形势严峻,因此提出建立流域排污权交易制度的构思,并对可能存在的问题提出对策.     

Theoretical and practical identifiability of a reduced order model in an activated sludge process doing nitrification and denitrification

This paper deals with the structural identifiability and the identification of the parameters of a reduced order model used for control of a single reactor activated sludge process doing nitrification and denitrification. This reduced order model is splitted into two submodels, one 3-dimensional state submodel in aerobic conditions and one 2-dimensional state submodel in anoxic conditions. The identifiability analysis is based on on-line oxygen and nitrate concentrations data. It has been shown that the reduced order model is structurally identifiable. The parameter identification has been carried out by using the simplex method of Neider and Mead. Simulation results performed over a range of six hours (two aerobic/anoxic cycles), show that there exists a good fit between the simulated solution and the actual behavior of a lab scale pilot plant.     

污水处理厂尾水排放对圩区河道水环境影响预测

以芜湖市长江沿线澛港圩区内污水处理厂尾水排放为例,充分考虑圩区内水利工程的调度规则、受纳水体的环境保护目标、污水处理厂运行工况等因素制定预测方案,分别采用一维稳态数学模型和二维水量水质数学模型对内河和外河的影响进行预测,根据预测结果提出了对受纳水体影响最小的排放方案,为决策部门提供了科学依据.