冶金工业废水深度处理循环利用研究

首先介绍了采用超滤加反渗透的双膜过程深度处理冶金工业废水的工艺流程,并进行了系统经济分析.超滤加反渗透双膜法处理冶金工业废水并进行循环利用,不但在技术上和经济上都是可行的,而且经济效益和环境效益都非常显著.     

抗污染超滤—反渗透膜在电厂中水回用中的应用

以某钢铁厂废水处理车间出水为回用水源,采用双介质过滤器、超滤和反渗透工艺进行深度处理,其中的膜系统采用抗污染膜元件,对运行中膜污染情况和产水压力过高问题进行了分析。通过系统的长时间运行效果可以看出,超滤出水浊度小于0.1NTU,反渗透脱盐率大于98.5%,回收率维持在72%~75%,系统出水电导率维持在11μS/cm左右,COD、总铁、油均未检出,出水水质可达到回用要求,超滤、反渗透均未发生膜污染情况,系统每年可回用1 360万m3中水,节约厂区淡水资源。     

热电厂脱硫废水近零排放改造技术

西北地区某热电厂脱硫废水近零排放系统采用预处理+软化+超滤+反渗透+MVR结晶工艺.单位水处理成本约为55.21元/m3.系统处理效果稳定、技术先进,实现了超过80％的废水回用.该工艺实现浓水减量,降低了投资及运行成本.     

超滤-反渗透工艺在处理循环水排污水中的应用

本文结合超滤-反渗透工艺处理循环水排污水的工程实例,对其系统调试、运行过程中出现的问题进行了静态和动态的实验分析,并提出了相应的处理建议,以推广超滤-反渗透水处理工艺在循环水排污水中的应用.     

全膜分离法脱盐水处理系统设计

全膜法制水系统即超滤加两级反渗透工艺,已广泛应用于钢铁企业脱盐水的制取,以某冷轧厂脱盐水处理设计为例,介绍了超滤、两级反渗透法制取脱盐水系统的特点、工艺流程、主要设备、产水能力及出水水质;并通过对该工程实际调试运行过程中问题的总结,提出了对全膜分离法脱盐水处理工程设计的几点建议。     

超滤—反渗透深度处理玉米深加工废水最佳运行参数研究

采用超滤(UF)—反渗透(RO)组合工艺深度处理玉米深加工废水。通过批次试验,优化出超滤-反渗透工艺的最佳运行参数。试验结果表明,超滤最佳运行参数是操作压力为0.1 MPa,反洗周期为30min,反洗时间为60s;反渗透最佳运行参数是操作压力为0.7 MPa,回收率为10%。在此工艺参数下,系统对总溶解固体、COD、氨氮、硝态氮、溶解磷的平均去除率分别为96.4%、99.9%、97.6%、96.9%、99.4%,出水水质可达到《循环冷却水用再生水水质标准》(HG/T3923—2007)。     

三沙市永兴岛海水淡化厂工程设计

为满足三沙市永兴岛上的居民生活用水需求,根据海岛特点,在岛上新建海水淡化厂,利用海水作为水源直接供应清水。水厂设计规模1 000 m~3/d,采用斜管沉淀-超滤-反渗透-再矿化的净水处理工艺。其中沉淀表面负荷为1.46 m~3/(m~2·h);超滤设计通量为30 L/(m~2·h),回收率90%;采用二级反渗透,其中一级反渗透设计产水通量0.60 m~3/(h·支),最大压力6.5 MPa,二级反渗透设计产水通量0.90 m~3/(h·支),最大压力12.5 MPa;反渗透产水采用投加CaCl_2和NaHCO_3进行再矿化。建成后运行产水水质满足国标要求,饮用口感良好,电耗约3.5 kW·h/m~3。     

反渗透处理高含盐废水的实验研究与膜污染分析

试验以经过混凝-超滤预处理后的高含盐废水为研究对象,考察了一级两段反渗透处理工艺对CODcr、TDS等的去除效果以及操作压力、温度、pH等因素对反渗透去除效果的影响。研究表明:在最佳工艺条件下,CODcr的去除率大于90%,TDS的去除率大于99%。反渗透处理后出水达到工业循环冷却水水质要求(GB50330-2002)。膜受污染后采用化学清洗和水力清洗相结合的方法可使膜的透水量恢复97.53%。     

全膜法在电厂锅炉补给水处理系统中的应用与分析

某热电厂采用超滤(UF)—反渗透(RO)—电去离子(EDI)工艺处理地下深井水作为锅炉补给水。重点介绍EDI的工艺特点及运行情况,并就进水水质、浓水流量、电导率以及操作电流对系统的影响进行了详细讨论。工程实践表明,采用UF—RO—EDI工艺出水水质完全符合锅炉补给水水质标准,EDI系统运行稳定可靠。     

印染废水处理与回用的工艺设计与应用

采用固定化生物滤池+连续微滤膜(CMF)+反渗透(RO)系统工艺对印染废水进行处理与回用,将反渗透浓水通过高级氧化技术进行处理。介绍了系统的设计、调试运行情况及主要经济指标。运行结果表明:该工艺运行稳定,处理效果较好,出水水质能够作为企业生产循环水与补充水回用;反渗透浓水经深度处理后,水质可达到《纺织染整工业水污染物排放标准》(GB 4287-2012)企业直接排放要求。     

组合膜分离技术资源化处理印染废水工艺的研究

为解决印染废水的资源化处理问题,针对实际印染废水研究了以超滤和纳滤膜分离技术为核心的印染废水处理及回用工艺在工程上的可行性。实验结果表明:还原染料废水采用超滤系统处理,膜出水水质即能够满足印染厂内回用水质要求;活性染料废水通过纳滤浓缩能够获得较好的染料回收效果。采用双膜膜分离系统(UF+NF)能够使两种染料废水的污染物均得到明显去除,还原性染料废水的总悬浮物、COD、浊度和色度的去除率达到了100%、95.21%、92.86%和100%;活性染料废水上述各项指标去除率达到100%、82.85%、98.46%和99.43%。双膜膜分离系统适用于工业印染废水处理及染料回收,是资源化处理印染废水的发展方向。     

Tertiary treatment of biologically treated piggery wastewater using vibratory shear-enhanced RO membrane.

This study presents a good example for the tertiary treatment of biologically treated piggery wastewater using vibratory shear enhanced RO membrane (VSEP RO). Through a simple process combination, utilizing Bioceramic SBR(BCS) and VSEP RO, at Gimhae plant livestock wastewater is treated excellently to meet the strict effluent standards. Application of RO membrane directly to the biologically treated effluent has been successful without any pretreatment to reduce high suspended solids. The combination of VESP UF followed by RO filtration processes produced a higher recovery rate in the 3-week pilot test.     

Membrane filtration and sonication for industrial wastewater reuse

This paper presents an experimental study aimed at estimating the efficiency of the innovative process of ultrafiltration (UF) combined with sonication (Son.) for the refinement of treated effluent to be reused in wet textile processes. Such a novel approach, which has not yet been employed on a full industrial scale, has been experienced at pilot scale on the secondary effluent of the Baciacavallo wastewater treatment plant (WWTP), which treats part of the effluent from one of the largest textile industry districts in Italy. The combined treatment efficiency was assessed both on ozonated and non-ozonated Baciacavallo secondary effluent. The membrane filtration process was optimized in terms of running time, backwash, chemical addition and cleaning procedures. The sonication treatment was optimized on laboratory-scale with synthetic solutions (demineralized water added with dyestuffs) in terms of hydroxyl radicals formation rate, frequency, acoustic power, hydrogen peroxide addition, contact time and pH. The optimal conditions have been applied on the pilot-scale sonicator which was used in combination with the UF treatment. According to the experimental results, the best configuration within the Baciacavallo WWTP was the sonication of non-ozonated wastewater followed by the UF. The combined treatment guaranteed the compliance with the target values for wastewater reuse in wet textile industries. This study is part of the Research Project PURIFAST (Purification of industrial and mixed wastewater by combined membrane filtration and sonochemical technologies) LIFE + ENV/IT/000439.     

Combined membrane bioreactor (MBR) and reverse osmosis (RO) system for thin-film transistor-liquid crystal display TFT-LCD, industrial wastewater recycling.

In TFT-LCD industry, water plays a variety of roles as a cleaning agent and reaction solvent. As good quality water is increasingly a scarce resource and wastewater treatment costs rises, the once-through use of industrial water is becoming uneconomical and environmentally unacceptable. Instead, recycling of TFT-LCD industrial wastewater is become more attractive from both an economic and environmental perspective. This research is mainly to explore the capacity of TFT-LCD industrial wastewater recycling by the process combined with membrane bioreactor and reverse osmosis processes. Over the whole experimental period, the MBR process achieved a satisfactory organic removal. The COD could be removed with an average of over 97.3%. For TOC and BOD5 items, the average removal efficiencies were 97.8 and 99.4% respectively. The stable effluent quality and satisfactory removal performance were ensured by the efficient interception performance of the UF membrane device incorporated with biological reactor. Moreover, the MBR effluent did not contain any suspended solids and the SDI value was under 3. After treatment of RO, excellent water quality of permeate were under 5 mg/l, 2.5 mg/l and 150 micros/cm for COD, TOC and conductivity respectively. The treated water can be recycled for the cooling tower make-up water or other purposes.     

UF-RO组合工艺处理循环冷却排污水的研究

在电力循环冷却排污水回用系统中,采用UF-RO组合工艺对循环排污水进行去浊除盐.通过现场试验,考察了超滤在循环冷却排污水回用中作为反渗透预处理的可行性;在工程实践中确定了系统实际运行工艺参数并对运行成本进行了分析.该工艺为循环冷却排污水的再利用开辟了一条新途径,既节约了水资源,又减少了环境污染.     

Design considerations for wastewater treatment by reverse osmosis.

Reverse Osmosis is finding increasing use for the treatment of municipal and industrial wastewaters due to the growing demand for high quality water in large urban areas. The growing success of membranes in this application is related to improved process designs and improved membrane products. Key factors which have been determined to result in successful operation of large-scale plants will be discussed. Factors which play a key role in the use of RO membranes include ultra or microfiltration pretreatment, low fouling membranes, flux rate, recovery and control of fouling and scaling. In particular, high flux rates can be used when UF or MF pretreatment is used. These technologies remove most of the suspended particles that would normally cause heavy fouling of lead elements. Typically, fluxes in the range of 17-21 lmh lead to cleaning frequencies in the range of 3-4 months. By combining the use of membrane pretreatment and chloramination of the feed water through chlorine addition, two of the primary sources of RO membrane fouling can be controlled. The use of chloramine has become a proven means to control biofouling in a membrane for wastewater applications. The other significant problems for RO membranes result from organics fouling by dissolved organics and scaling due to saturation of marginally soluble salts. The former can be a significant problem for membranes, due to the strong attraction forces. To some extent, these can be mitigated by making the membrane surface more hydrophilic or changing the charge of the membrane surface. To minimize fouling, many plants are turning to low fouling membranes. Extensive studies have demonstrated that the membrane surface is hydrophilic, neutrally charged over a broad pH range, and more resistant to organic adsorption. Also, an analysis of the potential scaling issues will be reviewed. In particular, calcium phosphate has been found to be one of the key scalants that will limit RO system recovery rate. Calcium phosphate concentrations can reach high values in many wastewaters, and scaling of this compound is not often modeled in most RO projection software. Various process options will be presented to evaluate the most economic means of avoiding phosphate scaling. Finally, data from major RO wastewater treatment plants will be presented to show how the RO membranes operate under actual conditions, utilizing many of these design features. Long-term data from the 2.6 mgd Bedok demonstration Plant demonstrate that the RO membranes operate consistently on wastewater. Experiences from the 8.5 mgd (32,000 m3/day) Bedok and 10.5 mgd (40,000 m3/day) Kranji plants will also be presented. These large plants started operation in the fall of 2002 and have demonstrated an effective means to reclaim high quality water from difficult source waters, such as municipal wastewaters.     

Efficiency of membrane processes for taste and odor removal.

The occurrence of tastes and odors (T&O) in drinking water is considered as one of the main problems by the drinking water companies. Thus, several treatment processes were developed over the years to control T&O including air stripping, activated carbon and oxidation using ozone. However, little information is available in the literature on the use of membranes for T&O removal. Therefore, the objectives of this paper are to present potential of membrane processes for removal of taste and odor causing compounds. Several membranes were tested including ultrafiltration (UF), UF combined with powdered activated carbon (PAC), nanofiltration (NF) and low pressure reverse osmosis (LP RO) membranes. The results of this study indicate that the combination of UF with PAC is effective for T&O control whereas the benefit of NF and LP RO remains unclear for T&O control.     

Reuse potential analysis on WWTP effluent of industrial parks in Taiwan.

This study examined the reuse potential of the effluents discharged from several unified wastewater treatment plants (WWTPs) of industrial parks in Taiwan, with designed capacity exceeding 10,000 CMD. Parameters were selected based on the relevant reuse purposes. The "potential recycling percentage", R of the WWTP effluent was defined as the maximal percentage of pure water extractable by the "ideal reverse osmosis module" while the RO retentate still met local effluent standards and required no treatment. The analytical results demonstrated that the WWTP effluents had potential for recycling. A pilot plant was installed in one of the WWTPs. The treatment process included a sand filter, an ultrafiltration unit (UF) and a reverse osmosis module (RO). Results of this study demonstrated that the production quantity and quality are stable and appropriate for various purposes, including both industrial and domestic applications.     

Application of immersed MF (IMF) followed by reverse osmosis (RO) membrane for wastewater reclamation: A case study in Malaysia.

A pilot scale membrane plant was constructed and monitored in Shah Alam, Malaysia for municipal wastewater reclamation for industrial application purposes. The aim of this study was to verify its suitability under the local conditions and environmental constraints for secondary wastewater reclamation. Immersed-type crossflow microfiltration (IMF) was selected as the pretreatment step before reverse osmosis filtration. Secondary wastewater after chlorine contact tank was selected as feed water. The results indicated that the membrane system is capable of producing a filtrate meeting the requirements of both WHO drinking water standards and Malaysian Effluent Standard A. With the application of an automatic backwash process, IMF performed well in hydraulic performance with low fouling rate being achieved. The investigations showed also that chemical cleaning is still needed because of some irreversible fouling by microorganisms always remains. RO treatment with IMF pretreatment process was significantly applicable for wastewater reuse purposes and promised good hydraulic performance.     

Technical and economical evaluation of water recycling in the carwash industry with membrane processes.

In the carwash industry, water recycling is necessary to be in accordance with present and upcoming environmental laws. As this is not possible with traditional techniques, membrane processes (like ultrafiltration (UF) and nanofiltration (NF)) are technically and economically evaluated in this study. Concerning the technical part, there needs to be a compromise between a high permeate permeability on the one hand and a high permeate purity on the other hand. Depending on the use of the purified wastewater, ultrafiltration (to recycle wastewater in the main wash cycle) or nanofiltration (to recycle wastewater in the rinsing step) would be the optimal choice. Concerning the financial part, the implementation of membrane processes in the wastewater purification installation is economically feasible, especially when expensive tap water is used as pure water. These positive evaluations imply that membrane processes can be useful to recycle wastewater in the carwash industry, on condition that the right membrane type (with the least membrane fouling) and the right process format (e.g., hybrid process of UF and/or NF with a biological treatment) is selected.