Costs of Advanced Treatment in Water Reclamation

The additional removal of trace organic contaminants (TOrCs) provided by advanced water and wastewater treatment inevitably requires additional financial costs, which must be estimated to support utility planning and compare alternatives. This study presents conceptual-level (Class 4) capital and annual operations and maintenance (O&M) cost curve equations to aid evaluations of advanced treatment trains for water reuse. The cost curve equations are broadly applicable to the water reuse community, particularly those interested in ozone-based treatment trains. Unit processes include microfiltration or ultrafiltration membranes (MF/UF), nanofiltration or reverse osmosis membranes (NF/RO), ozone (with or without hydrogen peroxide, H₂O₂), ultraviolet (UV) treatment with H₂O₂ (UV/H₂O₂), and biological activated carbon (BAC); all cost curves are for a unit process and can be added together to obtain costs for a combined treatment train. The cost curves indicate that at all plant capacities (1 to 500 MGD), membrane treatment (e.g., MF or RO) represents the highest cost unit process, ozone the least, and BAC or UV/H₂O₂ fall in between. Additionally, the relationship between ozone dose and TOrC removal is discussed with a demonstration of how costs change with increasing ozone dose to achieve desired TOrC destruction.     

反渗透技术用于高矿化度矿井水处理的研究

采用反渗透技术对高矿化度矿井水进行处理,考察了CPA(芳香族聚酰胺)膜对矿井水中各种离子的去除效果.试验结果表明:系统运行24 d,对矿井水的处理效果显著,Ca2+、Cl-、SO2-4、Mg2+各离子的平均去除率可分别达到98%、94%、98%、95%以上,系统出水水质稳定,出水达到国家饮用水标准;并根据静态清洗反渗透(RO)污染膜的分析结果,总结出反渗透膜的污染特征,最终优选出先碱洗后酸洗的膜清洗方案.     

Grey water treatment and simultaneous surfactant recovery using UF and RO process

The membrane-based grey water treatment for grey water reuse and surfactant recovery is presented in this research paper. Grey water from washing machine discharges having turbidity and used surfactant was processed through the polymeric ultrafiltration (UF) membrane to remove the turbidity. The UF treated grey water is further purified by reverse osmosis (RO) membrane for surfactant recovery and water reuse. The surfactant trapped inside the RO spiral wound membrane module is recovered through various membrane physical regeneration techniques such as backwashing, simultaneous backwash–back-flush and ozone back-flush. Among this, backwash–back-flush is found to be effective process for surfactant recovery. The methodology for optimising surfactant recovery is captured by studying effect of various operating parameters such as feed detergent concentration, backwash pressure, backwash temperature and back-flush flow rate. By implementing optimal process conditions, the integrated UF and RO membrane process is able to produce 300 L of reusable pure water and 80 L of concentrated detergent solution and 20 L of turbid water while treating 400 L of grey water discharges. Maximum surfactant recovery of 82% is obtained while treating grey water which consists of 720 ppm of total dissolved solids (detergent) and 45 ppm of surfactant. The extent of UF and RO membrane fouling is determined by measuring the pure water flux before and after the grey water treatment. The membrane performance is found to be stable when membrane is regenerated by backwash–back-flush technique for RO and gravity backwash for UF membrane.     

An advanced treatment of high-strength opium alkaloid processing industry wastewaters with membrane technology: pretreatment, fouling and retention characteristics of membranes

This paper presents the results of the laboratory and pilot-scale membrane experiments of opium alkaloid processing industry effluents. Different types of ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes were evaluated for membrane fouling, permeate flux and their suitability in separating COD, color and conductivity. Experiments demonstrated that membrane treatment is a very promising advanced treatment option for pollution control for opium alkaloid processing industry effluents. Almost complete color removal was achieved with NF and RO membranes. COD and conductivity removals were also greater than 95% and met the current local standards. Nevertheless, pretreatment was an important factor for the NF and RO membrane applications. Membrane fouling occurred with direct NF membrane applications without UF pretreatment. The total estimated cost of the UF and NF treatment system was calculated as $0.96/m³, excluding the concentrate disposal cost.     

脱盐水超滤膜反渗透膜的运行管理

超滤作为反渗透预处理,截留了大部分的悬浮物、胶体、有机物等,保证了反渗透装置正常运转。但超滤、反渗透存在膜易污染,易阻塞、氧化等问题,日常运行中加强对超滤反渗透的管理,即可延长膜使用寿命,也可减少污水排放。     

电解铝厂多功能天车调度管理系统

针对目前电解铝厂使用的多功能天车的现状以及所存在的问题,介绍了NKMNoell中国服务中心开发的电解铝厂多功能天车调度管理系统的硬件、网络构成,软件功能特点。     

膜分离技术处理放射性废水

介绍了膜技术在中、低浓度放射性废水处理中的研究和应用进展.膜组合技术处理放射性废水净化率可达98%～99.9%、净化因子可达100～1000.指出反渗透、纳滤、超滤、微滤和电渗析是目前应用的主流膜技术,并对其工艺特点作了评述.今后膜技术在核工业放射性废水处理中将获得更广泛的应用.     

Digital textile printing (DTP) wastewater treatment using ozone and membrane filtration

Digital textile printing (DTP) is considered as an environmentally benign process because its wastewater production is relatively small compared with the conventional textile printing system. DTP is usually practiced at building office in an urban area rather than in a textile industrial complex, so that process development for on-site treatment of the DTP wastewater is currently needed. The aim of this study was to propose a DTP wastewater treatment system suitable for operation in building and to verify if the proposed system has a rationale treatment system should be compact and reliable because it should be installed near the DTP system. Thus, a hybrid system consisting of ozone, ultrafiltration (UF) and reverse osmosis (RO) was proposed for treatment of DTP wastewater. Prior to UF and RO, ozone was introduced to the DTP wastewater to reduce organic loadings to membrane filtration as well as to treat the concentrates recycled from UF and RO. When ozone was injected with C-T value of 255 g·s/L, the removal efficiency of COD and color was 63 and 81%, respectively. Ozonation of the DTP wastewater led to aggregation of colloidal particles, so that the cake resistance (R_c) calculated after ozone and UF was lower than that of the control (= without ozonation), suggesting that pre-ozonation is beneficial to not only flux enhancement but also to good permeate water quality. Further treatment of UF permeates using RO was carried out since the UF permeates was not enough for direct discharge or reuse. Final effluents through the whole process of ozonation, UF and RO met the criteria of direct discharge and reuse, suggesting that the proposed hybrid system could be used for DTP wastewater treatment satisfactorily.     

Organic fouling of RO membranes: Investigating the correlation of RO and UF fouling resistances for predictive purposes

This study examines the characteristics of deposits from dead-end UF and cross-flow RO filtration of dilute mixtures of sodium alginate (SA) and humic acids (HA), which are representative of common foulants in RO and NF feed waters. The data are interpreted in terms of specific cake resistance, α. The presence of alginates in the mixed fouling layers, even in relatively small percentage, imparts characteristic properties to these deposits; i.e. a gel-like structure which is associated with reduced compressibility and permeability. With SA/HA mixtures, high rejection of organic species and high deposition factors are obtained in UF and RO tests, respectively. The specific resistance of mixed SA and HA deposits tends to increase with increasing SA concentration in solution. The resistances α exhibit fairly strong (power law) dependence on the pressure difference across the cake, ΔΡ_c, for both RO and UF tests. The fairly satisfactory correlation of resistance α versus ΔΡ_c data, obtained from both types of tests (for the mixtures of organic species tested at small salinity) is a significant result of this work. Based on this correlation, an approach is suggested for estimating fouling index I and initial membrane fouling rate of a specific RO process, relying on limited UF tests.     

双膜法在瑞源水厂处理氟化物和硫酸盐中的应用

武城县瑞源水厂以南水北调东段末端调蓄水库大屯水库为水源,原水中氟化物和硫酸盐超标,采用常规处理+臭氧-活性炭工艺并不能去除氟化物和硫酸盐,此次水厂升级改造采用超滤-反渗透双膜法对活性炭滤池出水进行深度处理。膜车间出水与活性炭池出水以1∶2勾兑后,氟化物浓度≤1 mg/L,硫酸盐浓度≤250 mg/L,水质达标,运行稳定。通过对工艺设计参数及运行效果现状分析,总结了双膜法在工艺设计及水厂运行方面的经验,建议工程设计处理氟化物和硫酸盐时采用双膜法,运行时加强数据监控,及时进行清洗护理工作,以延长膜组件使用寿命,降低水厂运行成本。     

Removal of fluoride from electronic industrial effluentby RO membrane separation

The electronics industry generates large amounts of fluoride-containing effluents. The objective of this studyis to study the feasibility of applying reverse osmosis (RO) membrane separation to reduce fluoride load to less than 1 kg/d. The effect of transmembrane pressure on the removal of fluoride ion has been investigated in detail, and the design parameters of a small RO separation unit were estimated. The present study indicated that the rejection of fluoride ion is typically higher than 98%, considering that the RO membrane was fully regenerated after each set of experiments. The effect of upstream concentration on the required mechanical pressure was determined by estimating the theoretical osmotic pressure of the feed solution. For industrial effluents, the process developed in this work allows us to reduce the treated volume from 6 m³/d to 0.36 m³/d without any pretreatment or adding additional compounds. The cost of the designed RO separation plant (€76,000) is much less than that of the conventional treatment (€533/m³) that deals mainly with volumes rather than specific     

生物炭对几类常见新兴污染物去除的研究进展

近年来药物和个人洗护用品（PPCPs）以及内分泌干扰物（EDCs）等新兴污染物频频检出,引起人们高度关注。众多研究表明,这些新兴污染物已经广泛分布在河流、湖泊、海洋、土壤、沉积物和地下水等环境介质中,而这些物质具有不易降解特性,加之不断排入水体环境,在水体环境中呈现“假持续存在”状态,对生态环境和人体健康造成诸多的不良影响。本文首先简述了以PPCPs和EDCs为代表的新兴污染物在环境中的来源、传播、分布和去除技术,并以表格形式综述了PPCPs和EDCs在各地区的污染现状。最后介绍了生物炭在去除PPCPs和EDCs上的研究现状和进展,分别通过生物炭制备原料、热解温度、改性或活化方式、溶液pH、离子强度和干扰物等因素综述了其对生物炭吸附PPCPs和EDCs的影响,并在最后做出总结和展望,以期能给今后生物炭在去除PPCPs和EDCs等新兴污染物上的相关研究和实际应用提供更多思路。     

Feasibility study for reclamation of a secondary treated sewage effluent mainly from industrial sources using a dual membrane process

A feasibility study for reclamation of a secondary treated sewage effluent mainly from industrial sources (60%) in Singapore has been conducted using a dual membrane UF-RO process. The pilot system had a treatment capacity of 2 m³/h. The UF unit and RO unit were operated at 70–80% and 40% water recovery, respectively. Six-month run for the pilot was carried out to study the stability and fouling tendency of membranes.

The characteristics of the raw feed indicated that ammonia-N was consistently high at 30–50 mg/L. Very high fluctuations in iron (0.3–3.7 mg/L), turbidity (1–27.1 NTU) and TOC (3.2–56.7 mg/L) were observed. Nitrate was low at <0.2 mg/L. The results of the study showed that dosage of alum in the UF process significantly reduced organic foulants and phosphate scalants. The polymeric RO membrane could tolerate organics from industrial wastewater and performed >96% salt rejection at the end of the study after 6 months. The study concluded the dual membrane process was capable of reclaiming the sewage effluent mainly from industrial sources for industrial use.     

Membrane processes for water reuse from the effluent of industrial park wastewater treatment plant: a study on flux and fouling of membrane

Both the relationship between the flux and the fouling mechanism of ultrafiltration (UF) membrane and the effects of pretreatment before reverse osmosis (RO) process on the treatment of the effluent of industrial park wastewater treatment plant (IPWTP) were investigated to examine the application of membrane processes on the water reuse treatment. For the former, the flux data was first fitted to the Hermia model to give the implication of the fouling mechanism. Then, the fouling mechanism was further identified with the aid of the SEM morphology of membrane surfaces. For the latter, the changes of both water characteristics (turbidity, TOC, conductivity, particle size distribution, and organic solute molecular weight) and membrane properties (surface zeta potential and surface morphology) before and after the treatment of membrane processes were measured. It was found that the major blocking mechanisms of UF membrane process at initial and final stage were standard blocking of pore (causing from colloid materials) and cake blocking of pore (causing from suspended particles), respectively. On the other hand, it was concluded that the permeate from 1 μm/UF/RO process was suitable for the reuse of cooling water and low pressure boiler water.     

微细通道内CO2沸腾换热与干涸特性

CO₂作为一种天然制冷剂在微通道内应用具有很大的换热优势,然而由于微尺度效应及其物性,在低干度区容易发生干涸,严重影响换热效果。为研究微细通道内CO₂流动沸腾换热与干涸特性,搭建了相应实验装置,对内径分别为1mm、2mm、3mm以及内表面粗糙度为16μm的不锈钢管,在CO₂制冷剂热流密度2~34kW/m²、质量流率50~1350kg/(m²·s)、饱和温度-10~15℃下进行换热性能与干涸实验对比研究。结果表明:常规管径换热特性在微细通道内不再适用;热流密度的增加对于强化核态沸腾换热具有显著影响,高于临界热流密度(critical heat flux,CHF)则发生干涸;质量流率对于核态沸腾区换热系数的影响则较小;不同饱和温度时换热特性有所不同,高饱和温度下换热系数随其升高而提高,低饱和温度下则相反;干涸过程对总换热系数的影响占34%。研究结论为CO₂微通道换热器的研究开发提供理论依据。     

纳滤膜特性及对水中微污染物的控制

随着膜技术的发展与应用,20世纪80年代出现的纳滤膜充分弥补了反渗透与超滤之间的空白。介绍了纳滤膜的特性及其独特分离特点,阐述了纳滤膜在处理饮用水中有机污染物的必要性和合理性。最后指出了它的应用前景。     

膜分离技术在垃圾渗滤液处理中的应用

垃圾渗滤液是一种重污染的有毒有机废水,对生态环境造成了严重的威胁。本文综述了垃圾渗滤液现有的膜处理技术,与传统处理工艺相比,膜技术具有低能高效等优点,是未来渗滤液处理技术的重要发展方向。由于垃圾渗滤液组成的复杂性,根据不同处理目的,微滤膜(MF)、超滤膜(UF)、纳滤膜(NF)和反渗透膜(RO)4种膜在垃圾渗滤液处理中都得到了一定的应用。总结发现,其中MF和UF对渗滤液的处理效果较差,一般作为渗滤液的预处理技术;NF和RO对渗滤液的处理效果较好,主要作为其深度处理技术。然而,膜污染阻碍了膜技术在渗滤液处理方面的发展与应用,为此可通过研究开发新型膜材料、有效的预处理技术和膜分离工艺优化等方面来防止膜污染的发生,以便膜技术在渗滤液及其他水处理方面得到更加广泛的应用。     

Evaluation and Comparison of Conventional and Advanced Oxidation Processes for the Removal of PPCPs and EDCs and Their Effect on THM-Formation Potentials

Pharmaceuticals and personal care products (PPCPs), endocrine disrupting compounds (EDCs) and disinfection by-products are suspected to have potential adverse impact on humans and hence their elimination during drinking water treatment is often desired or regulated. Based on pilot-plant experiments with three raw water sources, conventional treatment poorly removed the selected PPCPs and EDCs, while ozone/H₂O₂ and UV/H₂O₂ (both) with conventional treatment effectively removed PPCPs and EDCs. In most of the experiments, ozone/H₂O₂ + conventional treatment additionally removed THM formation potentials (THM-FPs) compared to those of conventional treatment. However, UV/H₂O₂ treatment was found to increase THM-FPs compared to conventionally treated water.     

A two stage membrane treatment of secondary effluent for unrestricted reuse and sustainable agricultural production

Field experiments are in progress for secondary wastewater upgrading for unrestricted use for irrigation and sustainable agricultural production. The integrative treatment system for the secondary effluent polishing is based on implementing in series of two main treatment stages: ultrafiltration (UF) and reverse osmosis (RO) membrane treatment. The pilot system has the capacity of around 8 m³/h. The UF effluent is used to feed the RO membrane stage. Different mixtures of UF and RO permeates are subsequently applied for drip irrigation of various agriculture crops. The field results indicate the importance of the UF component in the removal of the organic matter and the pathogens that are still contained in the secondary effluent (the secondary effluent is obtained from a waste stabilization pond treatment system). Under specific conditions, when the dissolved solids content is relatively low, the UF effluent can be applied directly for unrestricted irrigation. In the successive RO stage most nutrients are removed, allowing applying the effluent without jeopardizing the soil fertility and the aquifers. Preliminary economic assessment indicates that the extra cost for effluent polishing via the UF stage only is in the range of 8–12 US cents/m³. The extra cost for the RO stage is as well assessed at 8–12 US cents/m³. The additional treatment expenses depend to a large extent on the quality of the incoming raw secondary effluent and local requirements at the command agricultural production sites.