Influence of vacuum pressure,pH, and potential gradient on the vacuum electro-osmosis dewatering of drinking water treatment sludge

This paper describes research that evaluated the influence of vacuum pressure, pH, and potential gradient on the vacuum electro-osmosis dewatering (VEOD) of drinking water treatment sludge (DWTS). In the first phase of the VEOD process, a vacuum pressure of ?0.05 MPa was applied alone to DWTS for 30 min, removing almost all free water and part of pore water. In phase two, electro-osmosis was applied in combination with intermittent vacuum filtration, further reducing pore water and surface adhesion water in DWTS. However, statistical analysis indicated that the optimum dewatering parameter values were vacuum pressure at ?0.06 MPa, pH at 6.2, and potential gradient at 2.5 V/cm, which resulted in a relevant energy consumption of 0.35 kW.h/kg removed water.     

Dewatering effect of vacuum preloading incorporated with electro-osmosis in different ways

The dredger fill dewatering effect of vacuum preloading incorporated with electro-osmosis in different ways was evaluated by implementing six laboratory tests. The results of these tests show that the asynchronous consolidation effect of vacuum preloading incorporated with electro-osmosis was better than the other tests. However, vacuum preloading and electro-osmosis will not be able to give full play to the drainage effect, if the alternate time is too short. Alternatively, the energy provided by vacuum preloading and electro-osmosis will not be able to make full use, if the alternate time is too long. There are some advantages when using vacuum preloading and electro-osmosis asynchronous reinforcement. The alternate time of vacuum preloading and electro-osmosis has to constantly adjust according to the water discharge or drainage rate in engineering application.     

Integration of immersed membrane ultrafiltration with the reuse of PAC and alum sludge (RPAS) process for drinking water treatment

Effects of PAC and alum sludge generated from water treatment process on the effluent quality and fouling of immersed UF membrane were systematically investigated with representative source of natural water and the efficiency of coagulation, PAC adsorption and RPAS to treat natural surface water prior to UF were compared. It was found that the average turbidity removal by RPAS could reach up to 80.2%, and the turbidity removal of immersed membrane UF was independent of the influent, which could be kept at 99%. Particulates were reduced after being pre-treated by different processes, and particles with sizes ranging from 0.5 to 3.5 μm and larger than 13.5 μm were effectively removed by RPAS. UF coupled with RPAS pre-treatment got the best removal for DOM compared to other processes with average DOC and UV₂₅₄ removal 54.1% and 47.2% due to the high removal in the influent of UF. The residual alum content in the effluent of RPAS with UF was less than coagulation and bacteria were almost all removed by membrane. The membrane-fouling was mitigated by pre-treatment processes at different degrees, TMP of UF coupled with RPAS process was relatively stable in 15 d of run, the adsorption of PAC and large number of Al(OH)₃ complexes and precipitates for the foulant molecules might be an important mechanism.     

Direct drinking water treatment by spiral-wound ultrafiltration membranes

This paper presents the results of a research on direct drinking water treatment through an ultrafiltration pilot plant unit using spiral-wound membranes (3500 MWCO). The source of water is the Guarapiranga Reservoir, an eutrophicated water body located in the metropolitan region of São Paulo, Brazil. The data were collected during a period of almost 3400 h, from August 2005 to January 2006. The main objective of the study was to evaluate the membrane production capacity and contaminant removal efficiency. It was verified that the system was able to produce a high quality permeate with a flow close to the specified by the membrane manufacturer. The average permeate flow was 19.7 L.h⁻¹.m⁻², at 467 kPa and 25°C, with a global water recovery of almost 85%. The removal efficiencies for TOC, UV light absorption, and turbidity were 85%, 56%, and 95%, respectively. The results provide substantial evidence of the technical feasibility of spiral-wound UF membranes for direct drinking water treatment from euthrophicated sources, as an alternative for conventional drinking water treatment systems.     

PAC与铁盐对污泥深度脱水性能的对比研究

在工业废水和生活污水的处理过程中,会产生大量的污泥。污泥中水分含量达到95%~99%,只要将其中的水分去除.就会大大缩小污泥的体积,以便于进一步处理。文章还通过试验从污泥比阻和泥饼含水率两个方面比较四种加药方案(PAC、PFC、FC和PFS)的脱水效果,四种加药方案各有优点。FC、PFC的脱水效果最佳,在投药量为干污泥的21%以上时,泥饼含水率可降至60%以下;PFS和PAC的效果次之。     

脱硫灰调理对污泥脱水性能的影响

利用脱硫灰调理生活污水剩余污泥并探讨了其作用机理,结果显示,脱硫灰可明显改善污泥脱水性能,单独用脱硫灰调理污泥,投加量为3 g·L^-1时,污泥沉降体积最大为519.5 ml,比阻有效降幅达47.56%;脱硫灰使污泥中胞外聚合物(EPS)脱离并释放出结合水,脱硫灰与聚丙烯酰胺(PAM)联用处理污泥可得到比单独投加PAM更好的脱水效果;通过对比脱硫灰处理前后污泥的粒径分布和扫描电镜照片(SEM)发现,经过脱硫灰处理后,污泥絮体粒径较原泥明显减小,污泥絮体细孔的骨架结构被改变,形成更结实致密而具有较大孔径的絮体,使污泥中的水分更容易脱除,PAM有较好的吸附桥连作用,使已脱稳的污泥絮体迅速形成更大的絮体,更易固液分离,从而提高污泥脱水性能。     

电渗透-过硫酸铵协同污泥脱水过程中胞外聚合物的变化

为了研究电渗透-过硫酸盐协同污泥深度脱水的机制,利用自制装置对市政污水处理厂的污泥进行了脱水研究,系统研究了在过硫酸铵投加量、电压梯度、污泥厚度和机械压力的操作条件下,污泥中胞外聚合物的组分（蛋白质和多糖）变化情况及对污泥脱水效果的影响。结果表明,在过硫酸铵投加量为30mg/gDS、电压为25V/cm、污泥厚度为2.0cm、机械压力为23.1kPa条件下,污泥含水率可以降低至57.4%。不同脱水条件均会造成胞外聚合物组分变化,其中过硫酸铵加量和电压是影响胞外聚合物组分以及污泥脱水效果的主要因素。     

Study of drinking water treatment by ultrafiltration of surface water and its application to China

In China, many water supplies depend on conventional water treatment. Due to unfit soil and water conservationin some regions of China, conventional water treatment has showed some defects for the poor quality of water resource. In addition, advances in membrane technology and increasing requirements on water quality have stimulated ultrafiltration (UF) for water treatment. In this research, OF test apparatus was set up to produce drinking water from raw water of the Binxian Reservoir (China). The performance of UF membranes was investigated. There was a linear relationship between membrane resistance and accumulated permeate water. Using coagulation before OF increased permeate flux and retarded membrane flux decline. Surprisingly, membrane permeate flux in a coagulation/UF process was higher than that in coagulation-sand filtration-UF process with raw water of medium turbidity. OF treatment provided effective turbidity removal. Iron, manganese and aluminum were removed completely. The UF membrane also perfectly removed all coliform bacteria. The reduction of total organic carbon was satisfactory. The treated water quality complied with China's drinking water guidelines. The Ames test showed that the mutagenic activities of membrane permeate water was negative.     

污水处理厂污泥深度脱水系统设计及调试运行

辽宁省阜新市某污水处理厂原污泥处理系统采用带式脱水机机械脱水,脱水后污泥含水率为80%左右,无法满足《城镇污水处理厂污泥处置混合填埋用泥质》(GB/T 23485—2009)的要求。为使污泥含水率达标需对原有污泥处理系统进行提标改造,改造工程中采用重力浓缩/化学调理/高压隔膜压滤机进行污泥深度处理。经调试运行,脱水后污泥含水率可达到60%以下的设计要求。该文对工程设计及运行过程进行了详细介绍,可为同类工程设计提供经验参考。     

Fouling characteristics of an ultrafiltration membrane used in drinking water treatment

The fouling characteristics of ultrafiltration membranes used in drinking water were investigated when used alone and when used in an integrated biofilter-membrane system to treat a humic-acid laden solution. Membrane strands from sacrificial modules operating in parallel with bench-scale modules were analysed from both systems (with and without pretreatment). Chemical and microbiological analyses were performed on these strands together with different process streams along the treatment train. Microscopic observations performed on the sacrificial membrane strands revealed that most of the fouling material was organic in nature with high numbers of viable microorganisms. When comparing their fouling characteristics, a positive effect from the biofilter was observed on the performance of the membrane with pretreatment, decreasing in general the amount of material deposited and reducing the fouling rate. Membranes were tested at two different permeate fluxes; this variable did not have an effect on the overall amount of material deposited, but it significantly impacted the membrane fouling rate.     

城市污水处理厂污泥脱水药剂选型研究

针对某城市污水处理厂的污泥脱水处理,进行了一系列污泥脱水药剂的烧杯倾倒实验、CST实验、污泥比阻实验。实验结果表明：在阳离子、阴离子、非离子PAM中,阳离子PAM污泥脱水效果最优;所实验药剂都有一个最佳投加量,处于4.14～5.52 kg/t绝干污泥之间;在所实验药剂中,分子量对于污泥脱水性能的影响不明显,离子度影响较大,最优离子度为50%。     

污泥脱水预处理技术综述

随着城市化进程的不断加快,城市污水处理的规模和质量不断提高,所产生的剩余污泥作为固体废弃物的处理与处置也越来越成为制约污水处理效果的关键问题。由于污泥混合体的架构复杂且含有微生物组成的细胞和胞外聚合物(EPS)等亲水性物质,污泥脱水困难。污泥预处理作为强化污泥脱水和后续稳定化处理的关键技术能够有效改变污泥组成形态、促进污泥中细胞水和结合水向自由水的转变,是提高污泥脱水效率的主要方法。当前,主要的污泥脱水预处理主要包括:物理法、化学法和上述两种方法的组合等方式。文中主要讨论了不同预处理方法对污泥脱水性能的影响。     

污泥脱水设备在污水处理厂中的应用

污泥脱水是减小污泥体积的关键工艺技术,而枵泥脱水设备的选型对污泥脱水效率的高低和脱水工艺的正常运行最为重要。文章以广州某水厂为例,在介绍常见污泥脱水设备的基础上,选择了合适的污泥脱水设备,在污泥脱水工艺流程中发挥了稳定的脱水效果,该厂的污泥脱水问题也得到了有效的解决。     

Application of HACCP principles in drinking water treatment

One of the most important tasks at any water treatment plant is safeguarding the quality of drinking water. Worldwide, the drinking-water sector is increasingly aware of the limitations of end-product testing for ensuring safety. One limitation is the steady increase in the number of potentially occurring pathogens and chemicals that need to be monitored. A further limitation is the delayed availability of results in relation to the timing of interventions needed to maintain the safety of a supply. Ensuring the safety of a supply requires monitoring not only of the finished drinking-water, but particularly of parameters which indicate whether the key control measures in a given process are functioning correctly. Preventative measures have therefore become very important. The Hazard Analysis Critical Control Points system (HACCP) is a food safety management system which uses the approach of controlling critical points in food and drink production, and the framework of its concept consists of 7 principles. According to the Council Directive 93/43/EEC and the recent Regulation (EC) No 852/2004 on the hygiene of foodstuffs, the application of HACCP in food production is obligatory. In the present work, the HACCP principles were applied to the Aspropyrgos Water Treatment Plant. The critical control points identified include filtration and chemical disinfection.     

超临界水氧化对含油污泥无害化处理效能研究

在间歇反应釜中进行了含油污泥超临界水氧化实验,反应压力为25 MPa,反应温度为390~450℃,反应时间为1~10 min,研究了超临界水氧化后流出液的COD去除效果和可生化降解性以及气体产物组成的变化规律,并对剩余残渣进行了分析。结果表明,随着氧化温度升高,COD去除效果提高,处理后流出液可生化降解性得到明显改善,CO和CO2分别是反应的中间产物和最终产物。在450℃下氧化反应10 min后,COD去除率达到92%,尾气除含有2.64%的CO外不含其它有害气体成分。处理后的固体残渣中基本不含有机物质,主要为无机矿物成分,达到无害化处理要求。     

石油化工污泥调质深度脱水工艺应用研究

以某石油化工企业的污泥为研究对象,对污泥调质深度脱水技术的主要影响因素进行了一系列小试研究。实验结果表明,该技术能够有效降低化工污泥的含水率,实现污泥的减量化。通过单因素试验确定各影响因素对污泥深度脱水的影响。研究得出最佳工艺:在化工污泥中加入12%生石灰和2%ME调理剂后,混合10 min,抽滤15 min,污泥最终含水率降低到50.6%,达到污泥混合填埋对污泥含水率的要求。最佳条件下脱水污泥浸出液重金属浓度比原始污泥有所降低,调理剂不增加脱水污泥的重金属含量。     

污泥生物炭基催化剂在高级氧化水处理的应用

污泥作为污水处理过程的残留物,含有多种重金属、有机物以及微生物等污染物,严重危害环境和人体健康.污泥衍生的生物炭基材料具有优良的孔隙结构、表面电荷分布以及含氧基团,在高级氧化水处理领域显示出极大潜力.目前,多种污泥生物炭基催化剂成功应用于光催化、过硫酸盐活化以及芬顿等氧化体系,显示出较高催化活性.系统地总结了污泥生物炭...     

高盐高有机制药废水污泥电渗透高干脱水

为研究高盐高有机制药废水污泥的电渗透脱水效果,深入认识化学污泥的电脱水过程,本文采用电渗透高干脱水技术对经抽滤脱水的高盐高有机制药废水化学污泥进行深度脱水,考察了泥饼初始pH的改变对污泥电渗透高干脱水过程中阴阳极污泥的含水率、电流、电导率、pH、zeta电位与能耗的影响,验证了对高盐高有机制药废水污泥实行电渗透高干脱水的可行性,解析了化学污泥电渗透脱水过程的机制。结果表明,泥饼pH为2、3、4时,zeta电位为正值,电渗流反向流动,无法脱水;pH增至5时,zeta电位为负值,电渗流从阴极脱除,污泥含水率从53.2%降至44.8%,脱水效果最好;但pH增至6时,脱水量有所降低。污泥电导率随pH的增加而降低。pH为5时初始电流最大。脱水15min时,即污泥含水率降至45.5%时,能源利用率最高。     

城市污水污泥脱水的最新研究进展

随着"十一五"污水处理厂建设数量的大幅增加,我国污泥产量也随之急剧增长,污泥的处理处置已成为制约社会经济发展的重要问题。综述了近十年国内外有关污水污泥脱水的最新研究进展,提出了存在的问题,并对未来研究方向进行了展望。     

污泥低温真空脱水干化成套技术的设计探讨

随着我国经济技术不断发展,污泥处置将从传统的卫生填埋向污泥干化焚烧或资源化利用方向发展。低温真空脱水干化成套设备采用低温真空干化原理,可以一次性将污泥的含水率从98%左右脱水干化至30%~40%,为后续的焚烧或资源化利用创造了条件。池州市前江工业园污水处理厂通过引进该项技术,实现了在一套设备内干化污泥的目的,出泥含水率小于40%。