Applications of AOPs in wastewater treatment.

As Advanced Oxidation Processes (AOPs) are based on radical reactions that are very fast, non-selective and can completely oxidise substances, they have great potential for the removal of non-biodegradable pollutants from municipal and industrial wastewater. However, although there has been much progress in understanding AOPs, most work has been limited to laboratory or pilot-plant scale; there are few reports on industrial applications of AOP for wastewater treatment and hardly any disclose costs. Publication of such studies is needed if AOPs are to gain wide application as an alternative to more conventional treatment methods.     

Nutrients removal in MBRs for municipal wastewater treatment.

Owing to increasingly stringent effluent quality requirements, intensifications of the conventional activated sludge process (ASP) are required. Due to high biomass concentrations employed, higher metabolic rates and better nutrient removal are possible in membrane bioreactors (MBRs). Decoupling of hydraulic and solids residence times offers additional possibilities for process design and optimisation. Recently, unconventional concepts like post-denitrification and enhanced biological phosphorus removal in MBRs have emerged. The objective of this paper is to present current knowledge on nutrients removal in MBRs and trends in process optimisation in comparison with conventional ASP.     

Dimensioning of membrane bioreactors for municipal wastewater treatment.

A basic procedure is proposed for dimensioning membrane bioreactors that is generally applicable. It evaluates the required membrane surface with particular consideration of loading combinations and hydraulic loading characteristics; it also takes into account ranges of minimum temperatures and corresponding fluxes as given by suppliers. The procedures, while likely to require further improvement, should make MBR design more transparent and aid the comparison of design variants.     

城镇污水处理领域的碳减排

温室气体增加导致的气候变化正在对人类社会产生日益明显的影响,减少温室气体排放、控制气候变化已经成为国际社会的共识,绝大部分行业都在进行碳排放评价研究及碳减排对策的制定.城镇污水处理虽然是人类社会活动中一个很小的行业,但却是一个重要的碳排放源,发达国家已经越来越重视城镇污水处理行业的碳减排.碳排放是关于温室气体排放的一个总称或简称.能在大气中吸收红外线产生温室效应的气体有30多种,京都议定书确定需对其中的二氧化碳(CO2)、甲烷(CH4)、一氧化二氮(N2O)、氢氟碳化物(HFCs)、全氟碳化物(PFCs)及六氟化硫(SF6)六种气体进行消减,以有效控制气候变化.     

Biosensor-based control of nitrification inhibitor in municipal wastewater treatment plants.

The effect of potassium cyanide (KCN) on nitrification processes in municipal wastewater treatment plants was studied by batch nitrification tests, which indicated that nitrification processes tend to be inhibited at a lower KCN concentration than the present discharge standard to sewerage. The experiment of the biosensor using nitrifying bacteria was also conducted for continuous monitoring of nitrification inhibitor in influent wastewater, and demonstrated that the biosensor can detect KCN at as low as EC10 of the abovementioned batch nitrification test. Moreover, to determine the effectiveness of application of the biosensor to avoid the impact of KCN due to an accidental spillage in a sewerage system, KCN was intentionally injected into the experimental models of activated sludge process equipped both with and without the biosensor. The model with the biosensor that could detect KCN could divert the wastewater including KCN to a refuge tank, which resulted in the avoidance of upset of the activated sludge process. On the other hand, the model without the biosensor was upset in the nitrification process due to KCN. Such differences demonstrate the effectiveness of the biosensor applied to countermeasures of an accidental spillage of toxic chemicals to avoid upset of nitrification in municipal wastewater treatment plants.     

溶气气浮技术的发展及其在城市污水处理厂中的应用

介绍了溶气气浮 (DAF)技术发展的三个阶段 (早期DAF ,普通DAF ,紊流DAF) ,及各自的技术特点。通过实例分析了DAF在城市污水处理领域中几个方面的应用 :强化一级处理中的应用 ,三级处理固液分离中的应用 ,厌氧处理出水及污泥浓缩中的应用。     

Occurrence of benzothiazoles in municipal wastewater and their fate in biological treatment.

A number of 2-substituted benzothiazoles that are known to be used as fungicides, corrosion inhibitors and vulcanization accelerators in industry have been analyzed in municipal wastewater and the effluents of activated sludge and membrane bioreactor (MBR) treatment over a three month period. All six analytes were regularly detected in the municipal wastewater by liquid chromatography-mass spectrometry and amount to a total concentration of 3.4 microg/L. Of these compounds benzothiazole-2-sulfonic acid (1,700 ng/L), benzothiazole (850 ng/L) and 2-hydroxybenzothiazole (500 ng/L) were most prominent. The source of the benzothiazole emission is yet unknown. Activated sludge treatment did not reduce total benzothiazole concentration significantly. Removals of the individual compounds ranged from 90% for 2-mercaptobenzothiazole and 70% for hydroxybenzothiazole to 40% for benzothiazole. The concentration of benzothiazole-2-sulfonic acid increased by 20%, whereas 2-methylthiobenzothiazole increased by 160% during activated sludge treatment, likely due to the methylation of mercaptobenzothiazole. Total benzothiazole removal in two parallely operated MBRs was significantly better (43%) than in the conventional activated sludge treatment. Namely benzothiazole and benzothiazole-2-sulfonic acid were more effectively removed. This first systematic study on the occurrence of benzothiazoles in municipal wastewater has shown that this is a relevant class of trace contaminants in municipal wastewater which is only incompletely removed in biological wastewater treatment. Emission from sewage treatment is dominated by the most polar benzothiazole-2-sulfonic acid. MBR treatment may reduce but cannot avoid this emission.     

ANAMMOX工艺在生活污水深度处理中的应用研究

随着水环境质量的恶化,高能低耗的污水深度处理技术成为当前研究热点,尤其是对于低C/N比的城市生活污水脱氮技术的研究。试验以城市生活污水的二级出水为研究对象,采用ANAMMOX下向流生物滤池,当二级出水NH3-N=15-35mg/L,CODCr=25-45mg/L,TOC=9-12mg/L,水温=25-28℃时,ANAMMOX下向流生物滤池脱氨率达80%-100%,不仅适用于处理高氨废水,也可用于城市生活污水深度处理中。试验发现pH可以用来指示ANAMMOX反应的进行,同时也可以用来指示ANAMMOX反应进程的快慢。试验中还发现,厌氧氨氧化反应速率与NO2--N含量有关,原水中NO2--N含量的增多有利于ANAMMOX工艺处理效果。     

城市污水再生利用中病原菌指示微生物及其限值研究

在对目前国内外再生水中病原菌指示微生物进行调研的基础上,结合再生水厂运行数据对再生水中病原菌指示微生物及其限值进行了探讨。研究结果表明,以粪大肠菌群作为再生水病原菌指示微生物更能够反映出水体中病原菌的存在状况,目前的再生水处理和消毒技术要达到《城市污水再生利用城市杂用水水质》(GB/T 18920—2002)对总大肠菌群≤3个/L的要求需要投加大量的消毒剂,增加了再生水的处理成本以及再生水中的消毒副产物。     

Tracking influent inorganic suspended solids through wastewater treatment plants.

From an experimental and theoretical investigation of the continuity of influent inorganic suspended solids (ISS) along the links connecting the primary settling tank (PST), fully aerobic or N removal activated sludge (AS) and anaerobic and aerobic sludge digestion unit operations, it was found that the influent wastewater (fixed) ISS concentration is conserved through primary sludge anaerobic digestion, activated sludge and aerobic digestion unit operations. However, the measured ISS flux at different stages through a series of wastewater treatment plant (WWTP) unit operations is not equal to the influent ISS flux, because the ordinary heterotrophic organisms (OHO) biomass contributes to the ISS flux by differing amounts depending on the active fraction of the VSS solids at that stage.     

Mathematical modelling of small wastewater treatment plants: power and limitations.

Although mathematical modelling of biological wastewater treatment processes has proved to be valuable for large-scale WWTPs (wastewater treatment plants) little experience has been acquired in the mathematical modelling of small wastewater treatment plants. This paper seeks to evaluate the applicability of mathematical modelling on small systems, which are characterized by high fluctuations in organic and hydraulic loads and little possibility for control. In order to achieve this, the paper examines the different steps in a general modelling protocol. One important bottleneck for the general use of mathematical modelling of small systems that emerges is the frequent sampling and many analyses needed for characterization of the flows while its applicability is limited. On the other hand, the determination of the model structure of a small WWTP can be quite valuable. Experiments show that tracer tests should include tests with a highly varying influent flow rate to spot independent small internal flows as these can have a significant impact on the behaviour of peak concentrations throughout the system. In addition, the model structure determination can provide useful information on dead zones, short-circuiting and mixing behaviour in the plant.     

城市污水处理CASS工艺模拟与优化

以中山市大涌污水处理厂的CASS工艺为例,介绍了如何利用工艺模拟工具解决实际工程问题的方法。利用BioWin软件所构建的大涌污水处理厂模型,通过对该厂历史数据和补充采样数据进行模拟和校正。经校正后的模型用于现有污水处理厂在不同运行方案下的情景分析和优化,同时,对模型在节能降耗方面的应用也进行了探讨。     

我国城镇污水处理发展的状况和面临的挑战

1 我国城镇污水处理目前处于快速发展阶段 (1)与2000年相比,我国城镇污水排放量略有增长,过去九年增长了14%,但是同期的污水处理量大幅度增加,累计增加了140%.从国际经验来看,我国是世界上唯一一个十年内污水处理量翻番的大国.     

可持续发展的新型、高效城市污水处理技术探讨

对国内外城市污水处理工艺的发展进行了回顾,提出我国目前所采用的以氧化沟技术和SBR反应器为主体的城市污水处理技术是西方发达国家在一定历史时期和技术发展水平下的产物,与西方国家的自然条件和经济发展水平是相适应的。从可持续发展方面进行考察认为这些技术(特别是延时曝气)是不适合我国国情的高物质消耗和高能耗的污水处理技术。同时,提出我国城市污水可持续发展的处理技术的关键是要在新工艺开发方面进行不断的探索,同时解决污泥处理技术方面的问题。并就工艺创新、技术创新和体制创新对城市污水处理厂降低投资和运行管理费用的作用进行了分析。对沉淀和分离性能改进,生物的量和质的提高以及充氧性能的改善是高效反应器发展的要点。     

城市污水处理中砂的影响及对策

污水处理厂在日常运行中常会受到一些外来因素的影响,污水中含砂量的增加就是其中之一。这一问题给污水处理厂的运行带来了极大的困难。1　污水处理中砂量增加对运行的影响一般城市污水的沉砂量可按10 0万m3污水沉砂30m3计算,其含水率为6 0 % ,密度为15 0 0kg/m3,但有些污水处理厂进水口水样检测中经常高于上述数值,甚至是设计含砂量的2～3倍。污水中含砂量的增加给运行中各道工序带来影响。1 1　对沉砂池前道工序的影响进水泵房前池是泵房的集水区域,且成了污水中粗颗粒的沉砂池。在进水通道中有扩散和死角处积砂更严重,使水泵进水的水量受…     

硅藻土在城市污水处理中的应用研究

采用硅藻土对污水处理厂进水进行混凝处理,尝试将硅藻土混凝和微滤分离膜处理技术相结合对污水进行处理。试验结果表明,硅藻土用于城市污水处理,效果显著。当硅藻土用量为300mg/L时,结合微滤分离膜系统,能够满足生活杂用和市政杂用所需水质要求。应用环境扫描电镜表征硅藻土混凝前后的组分和表观特征,初步提出了硅藻土的污水处理机理为吸附、混凝和中和三个协同作用。     

Design and operation of an eco-system for municipal wastewater treatment and utilization.

An eco-system consisting of integrated ponds and constructed wetland systems is employed in Dongying City, Shandong Province for the treatment and utilization of municipal wastewater with design capacity of 100,000 m(3)/d. The total capital cost of this system is 680 Yuan (RMB) or US dollars 82/m(3)/d, or about half that of the conventional system based on activated sludge process, and the O/M cost is 0.1 Yuan (RMB) or US dollars 0.012/m(3), only one fifth that of conventional treatment systems. The performance of the wastewater treatment and utilization eco-system is quite good with a final effluent COD, BOD, SS, NH3-N and TP of 45-65 mg/l, 7-32 mg/l, 12-35 mg/l, 2-13 mg/l and 0.2-1.8mg/l respectively and the annual average removals of COD, BOD, SS, NH3-N and TP are 69.1%, 78.3%, 76.4%, 62.1% and 52.9%o respectively, which is much better than that of conventional pond system or constructed wetland used separately and illustrates that the artificial and integrated eco-system is more effective and efficient than the simple natural eco-system.     

城市污水处理厂恶臭污染及其评价体系

城市污水处理厂的恶臭问题正在成为环境领域的一个重要研究课题。在阐述了城市污水处理厂恶臭气体的来源、主要组成成分及其浓度的基础上,进一步概述了我国城市污水处理厂的恶臭污染现状,并提出了针对我国城市污水处理厂恶臭污染的评价体系。该体系从恶臭物质的产生、迁移和所产生的影响三方面进行评价,能够较全面地反映城市污水处理厂的恶臭污染状况及其对周边环境的影响程度。     

漓江流域城市污水处理技术研究

运用系统分析的方法,从流域水污染控制角度出发,对漓江流域的城市污水处理有关问题进行了系统研究。结合漓江流域城镇经济、技术水平特点,对流域的城镇排水的体制、出路进行了分析;根据污水排放和污染物排放情况以及水环境容量分布,确定了流域内城市污水处理厂规模;在分析了几种适合中小城市特点的典型城市污水处理工艺后,提出了4种城市污水处理工艺作为流域不同类型城镇的城市污水处理的优选技术;为保证流域水污染有效控制,建议实行流域水环境的统一管理。     

城市污水处理工程设计中值得探讨的几个问题

对污水处理厂设计过程中涉及到的内容和问题进行了全面系统的分析介绍。首先对污水处理厂设计基本条件及影响因素 ,如进出水水质、水量、管网系统及规划年限等进行了分析 ;然后对几种常用的污水处理工艺进行分析比较 ,指出各自特点及适用范围 ;最后对设计中可能遇到的一些热点问题进行了探讨