节能型超低压反渗透膜ESPA~在市政污水回用领域的应用

市政污水的再资源化可缓解城市缺水问题。膜法工艺是再生水回用处理的核心技术。节能型超低压反渗透膜ESPA~具有超低运行压力、高脱盐率等特点,应用于以超/微滤为预处理的大型市政污水回用工程,抗污染性能良好,节能降耗,明显降低运行费用。本文介绍了节能型超低压膜ESPA~的技术特点,以及其在大型市政污水回用领域的应用案例。     

天津开发区"双膜法"污水再生回用工程

介绍了天津开发区污水再生回用工程的工艺流程、特点及运行效果。该工程以污水处理厂二级出水为原水,采用“双膜法”(CMF RO)进行深度脱盐处理,出水水质优于WHO和USEPA的饮用水水质标准,可广泛回用为工业纯水、工业冷却水、园林绿化及市政生活杂用水。     

双膜法技术在钢铁行业废水回用应用中的机会与挑战

本文将以某钢厂废水回用改造工程为案例,详细研究钢铁废水采用双膜法技术进行深度处理回用的工艺设计和实际运行情况。     

双膜法再生水回用工程的控制系统设计

简述了PLC在某双膜法再生水回用工程自动控制中的应用,介绍了控制系统的硬件构成、网路架构、过程分析、软件设计等。4年的运行结果表明:该控制系统自动化程度高、可靠性好,运行维护操作便利,工程出水水质可满足企业的用水需求,达到了节约资源、降低成本的目的,实现了社会和经济的双重效益。     

纪庄子污水回用工程介绍

天津市纪庄子污水回用工程是国家污水回用示范工程之一,工程规模5×104 m3/d,采用分质供水方案,回用工业区再生水采用传统三段工艺,回用居住区采用CMF+O3工艺.在国内第一次将优质中水大规模回用到居住小区,自动化程度高,水泵的合理搭配为运行的节能降耗提供了充分的调整调度空间.     

双膜法脱盐过程中RO浓水再处理工艺研究

以焦化废水经双膜法深度处理之后的高盐度浓水为研究对象,通过"臭氧催化氧化—药剂软化—砂滤"预处理后,采用"超滤—反渗透—电渗析"进行再处理,考察对高含盐RO浓水的处理效果。结果表明,"预处理+二级双膜法+电渗析"组合工艺深度处理RO浓水完全可行,系统能长期、稳定、高效运行,且双膜法工艺段产水与电渗析产水混合后的水质指标均满足《循环冷却水用再生水水质标准》(HG/T 3923—2007)的要求,可作为补充水回用于循环冷却水中。     

双膜法在防伪纸生产废水深度处理与回用中的应用

针对防伪纸厂废水处理站的二沉池出水,采用中试规模的连续膜过滤(CMF)/反渗透(RO)集成工艺进行深度处理,以期能够满足回用的要求.结果表明,超滤膜有较强的抗污染能力,其过滤出水浊度<0.5 NTU,SS值基本为零,SDI值<3,完全能够满足RO的进水要求;RO产水COD平均为1.7 mg/L,电导率为10 μS/cm,满足防伪纸生产工艺回用水质的要求.采用双膜法深度处理防伪纸生产废水并回用具有工程可行性.     

生物氧化塔/过滤/RO工艺处理二级出水并回用

大连北海热电厂以某污水厂二级处理出水为水源,采用生物氧化塔/纤维束和砂滤二级过滤/RO组合工艺,建设了污水深度处理与回用工程(主要用作循环冷却水和锅炉补水处理系统的原水).运行结果表明,采用单膜法进行污水深度处理是可行的,具有处理效果好、运行稳定、工程投资省、运行费用低等优点.     

双膜法用于冶炼企业废水处理及中水回用

采用化学混凝沉淀、石英砂过滤、活性炭过滤、超滤及反渗透的组合工艺(简称双膜法)对冶炼厂污酸站排水及厂区前期雨水进行回用处理,系统经过长时间运行,设备稳定可靠,产品水水质达到循环冷却水系统补充水的回用要求,反渗透浓水各项水质指标能够达到河南省粗铅冶炼行业排放标准。     

长春市再生水回用现状及发展趋势

通过对长春市水资源利用现状及再生水利用现状的调查分析,指出再生水回用作为污水资源化的重要体现形式,是解决长春市水资源短缺,实现水资源可持续开发利用的重要途径。提出长春市再生水回用应加强宣传,政府通过立法鼓励和辅助再生水回用工程,从规划角度为再生水利用打下良好的基础条件,将目前工业企业再生水回用系统的模式逐步过渡到整个城市再生水集中回用模式。     

淹没式固定床/物化/反渗透处理二级出水并回用

北方某大型化工企业以城市污水厂二级出水为原水建设了中水回用工程,采用了淹没式固定床／物化／反渗透深度处理组合工艺,介绍了该工艺的设计特点及参数。运行结果表明,处理系统的出水水质达到了企业对中水回用的水质要求,取得了良好的社会效益和经济效益。     

Investigation on two integrated membrane systems for the reuse of electroplating wastewater

A pilot study was done on a nanofiltration (NF)‐reverse osmosis (RO) and RO‐NF integrated membrane system about the feasibility of membrane for electroplating rinse wastewater treatment in concentrate stage configuration. Nickel sulphate solution was used as a synthetic wastewater. Water recovery, metal rejection and specific entropy production (SEP) were investigated under different operation pressure, feed temperature and feed concentration. The results showed water recovery of RO‐NF system was more than 10% higher than NF‐RO system but the SEP was 14.47% lower than NF‐RO system. The detailed analysis on economic cost and environmental impact of two systems was conducted based on a certain operation condition. Results indicated that the cost of RO‐NF system was 0.46 $/m³, which was lower than NF‐RO system, and the prevention cost of RO‐NF system was 11.46% lower than NF‐RO system. Generally, RO‐NF system was better than NF‐RO system.     

Impact of microfiltration treatment of secondary wastewater effluent on biofouling of reverse osmosis membranes

The effects of microfiltration (MF) as pretreatment for reverse osmosis (RO) on biofouling of RO membranes were analyzed with secondary wastewater effluents. MF pretreatment reduced permeate flux decline two- to three-fold, while increasing salt rejection. Additionally, the oxygen uptake rate (OUR) in the biofouling layer of the RO membrane was higher for an RO system that received pretreated secondary wastewater effluent compared to a control RO system that received untreated secondary effluent, likely due to the removal of inert particulate/colloidal matter during MF. A higher cell viability in the RO biofilm was observed close to the membrane surface irrespective of pretreatment, which is consistent with the biofilm-enhanced concentration polarization effect. Bacterial 16S rRNA gene clone library analysis revealed dominant biofilm communities of Proteobacteria and Bacteroidetes under all conditions. The Cramer-von Mises test statistic showed that MF pretreatment did not significantly change the bacterial community structure of RO membrane biofilms, though it affected bacterial community structure of non-membrane-associated biofilms (collected from the feed tank wall). The finding that the biofilm community developed on the RO membrane was not influenced by MF pretreatment may imply that RO membranes select for a conserved biofilm community.     

Cyclophosphamide removal from water by nanofiltration and reverse osmosis membrane

The rejection of cyclophosphamide (CP) by nanofiltration (NF) and reverse osmosis (RO) membranes from ultrapure (Milli-Q) water and membrane bioreactor (MBR) effluent was investigated. Lyophilization-extraction and detection methods were first developed for CP analysis in different water matrices. Experimental results showed that the RO membrane provided excellent rejection (>90%) under all operating conditions. Conversely, efficiency of CP rejection by NF membrane was poor: in the range of 20-40% from Milli-Q water and around 60% from MBR effluent. Trans-membrane pressure, initial CP concentration and ionic strength of the feed solution had almost no effect on CP retention by NF. On the other hand, the water matrix proved to have a great influence: CP rejection rate by NF was clearly enhanced when MBR effluent was used as the background solution. Membrane fouling and interactions between the CP and water matrix appeared to contribute to the higher rejection of CP.     

南郊水厂超滤膜组合工艺运行情况评价

分析并评价了东营市南郊水厂(10×104m3/d)以超滤为核心的水质改善工程一年来的运行情况.生产实践表明,超滤组合工艺出水水质较工程实施前有很大提升,超滤出水浊度保持在0.02 NTU以下,组合工艺对CODMn、UV254和TOC的平均去除率分别为(44.96±3.69)%、(43.22±2.21)%和(20.10±...     

Viability of a low-pressure nanofilter in treating recycled water for water reuse applications: a pilot-scale study

The purpose of this study was to investigate the potential of a low-pressure nanofiltration (NF) membrane for treating recycled water for indirect potable water reuse applications. In particular, the tradeoffs in choosing low-pressure NF over reverse osmosis (RO) were investigated including whether or not significantly lowering operating pressures/costs would result in diminished permeate water quality. A NF membrane (Dow/Filmtec NF-4040) with high permeate productivity was selected for pilot-scale testing over a period of 1200h at a water reuse facility employing conventional RO membranes for treating tertiary treated wastewater effluent prior to aquifer recharge. The novel application of an NF membrane in treating wastewater effluent for water reuse applications permitted a comprehensive screening of NF permeate water quality and allowed for the investigation of trace organic contaminant rejection on pilot scale with environmentally relevant feed water concentrations. Results from pilot-scale testing highlighted the selectivity of NF membranes in removing organic solutes present in wastewater effluents at the parts-per-trillion level. While operating pressures were by a factor of 2-3 lower than conventional RO membranes, and bulk and trace organic rejection generally exceeded 90 percent, not surprisingly, the rejection of monovalent ions such as nitrate was poor. The poor-to-moderate rejection of monovalent ions, however, resulted in lowered brine stream total dissolved solids concentration and sodium adsorption ratio as compared with the brine stream of conventional RO membranes, which may be beneficial for brine disposal strategies.     

Treatability of organic fractions derived from secondary effluent by reverse osmosis membrane

Dissolved organic matters (DOMs) from two batches of secondary effluent collected from a local water reclamation plant were fractionated using column chromatographic method with non-ionic resins XAD-8, AG MP-50 and IRA-96. Seven isolated fractions were obtained from the fractionation study and these fractions were quantified using DOC, UV(254) and SUVA values. The fractionation study revealed that the secondary effluent samples comprised about 47.3-60.6% of hydrophobic and 39.4-52.7% of hydrophilic solutes. The treatability of each isolated fraction was investigated by subjecting each fraction to reverse osmosis (RO) treatment individually. It was noted that RO process could achieve high DOC rejections for acid and neutral fractions (ranging from 80% to 98% removal) probably due to the negative charge of RO membrane. The results obtained also indicated that hydrophobicity of DOMs is significant in determining treatability of organic species by RO process. The performance of RO in terms of DOC rejection of un-fractionated secondary effluent was also investigated to assess possible effects of interactions among organic fractions on their treatability by RO process. It was noted that DOC rejection associated with the un-fractionated secondary effluent was generally higher (ranging from 2% to 45%) than the corresponding rejection obtained from each individual fraction isolated from the secondary effluent. This finding suggested there is a beneficial interaction among the fractions that in turn has contributed towards a better overall DOC rejection performance by RO treatment.     

Water recovery from treated urban wastewater by ultrafiltration and reverse osmosis for landscape irrigation

Techno-economic feasibility of water recovery from secondary effluents of an urban wastewater treatment plant (WWTP) for landscape irrigation was investigated considering two distinctive strategies: ultrafiltration (UF)/chlorination and UF/reverse osmosis (RO). Experimental performance evaluations were conducted separately for UF membranes and for different RO trans-membrane pressures. The quality of the effluent recovered by the UF/RO system was in accordance with the national and international guidelines. The produced reuse water was first class quality according to the national guideline for all parameters except sodium adsorption ratio (SAR), which can be eliminated readily by direct addition of KCl into the recovered water. Estimated field-scale costs indicated that UF/RO yielded a total cost of US$12,500,000–13,600,000 with annual operating cost being US$482,000–533,000 at 5–20 bar. The economic estimations guaranteed reimbursement with US$7,600,000–7,400,000 net present value, 0.22–0.39 year payback time, US$0.44–0.49/m³ treatment cost, and a benefit/cost ratio of 0.57.     

Evaluation of an MBR-RO system to produce high quality reuse water: microbial control, DBP formation and nitrate

A membrane bioreactor and reverse osmosis (MBR-RO) system was developed to assess potential reuse applications of municipal wastewater. The objective of the study was to examine the water quality throughout the system with a focus on waterborne pathogens, disinfection by-products (DBPs) and nitrate. This paper will discuss the presence of these contaminants in MBR effluent and focus on their subsequent removal by RO. This study has shown that high quality reuse water can be produced from municipal wastewater through the use of an MBR-RO system. The water meets California Title 22 reuse regulations for non-potable applications and US EPA drinking water limits for trihalomethanes (THM) (80 microg/L), haloacetic acids (HAA) (60 microg/L), chlorite (1.0 mg/L), total coliform (not detectable), viruses (not detectable), and nitrate/nitrite (10 mg N/L). However, THM formation (182-689 microg/L) attributed to cleaning of the MBR with chlorine and incomplete removal by subsequent RO treatment resulted in reuse water with THM levels (40.2+/-19.9 microg/L) high enough to present a potential concern when considering drinking water applications. Nitrate levels of up to 3.6 mg N/L, which resulted from incomplete removal by the RO membrane, are also a potential concern. A denitrification step in the MBR should be considered in potable water applications.