Characteristics of RO foulants in a brackish water desalination plant

This study identified the membrane fouling of a two-stage RO process of the Bai-sha brackish water desalination plant facing serious fouling problems. Two membrane modules, one from each stage, were autopsied and diagnosed for the cause for the failure of the RO system. Different morphologies were exhibited on the fouled membrane. Results suggested that the fouling on the first-stage membrane tended to be organic and biological, while that on the second-stage membrane appeared to be scaling. Higher than 85% of the foulants on the first stage membrane were organic substances in opposed to the 5 to 8% of those on the second stage membrane. However, the total organic matter on the second stage membrane was more than that on the first stage one. The thick layer of scalants on the surface of the second-stage membrane was identified to be calcium carbonate of which the crystal was clearly seen in the SEM images. The scaling was thickest at the outlet of the membrane. Huge amount of microbes were found on both membranes. The FTIR results also suggested the existence of extracellular polymeric substance (EPS) on the first stage membrane. This study recommended that the recovery rate, pH and the potential for bio-fouling should be defined at the real operation.     

Optimal design of an electrodialysis brackish water desalination plant

This paper considers the optimal design and operation of electrodialysis (ED) desalination plants. In general an ED plant aims to produce potable water from a high salinity source, like brackish water or high salinity water. The system is modelled mathematically as mixed-integer non-linear programming (MINLP) optimization problem, determining the number of desalination stages, the membrane area, the total required energy so as to minimise the total annualised cost of the investment accounting for both infrastructure and operating costs. Two examples from the literature illustrate the applicability of the proposed approach and evaluate the quality of the results obtained.     

RO membrane autopsy of Zarzis brackish water desalination plant

Tunisia, located in a semi-arid zone, has limited water resources. The shortage of good water quality in particular at the south regions required a brackish water desalination to supply these regions with potable water. Zarzis desalination plant, working since 1999, has revealed difficulties related to the loss of membrane performances. In the aim to determine the reason of membrane fouling, foulant layer were analysed. The membrane autopsy has achieved by different methods, such as TOC (total organic carbon) measurement, SEM (scanning electron microscopy), AFM (atomic force microscopy), FTIR (fourier transform infrared spectroscopy) analysis, diffraction by X-ray. Results show that the foulant layer composed mostly of SiO₂, clay, organic matter (polysaccharide, protein), CaSiO₃, Fe₃O₄, AlPO₄, and CaSO₄. The characteristics bonds obtained by IR indicate the presence of polysaccharides and proteins that constitute a source for further microbiological growth; this is the problem of biofouling. The metallic elements results of corroded stainless steel and internal coating of cartridges filter that are damaged by the silica particle rejected by sand filters. The scale of CaSO₄ and CaSiO₃ deposition is owing to the bad antiscaling efficiency. The results are presented and discussed in the light of new trends in material.     

Feasibility of reverse osmosis desalination of brackish agricultural drainage water in the San Joaquin Valley

The technical feasibility of reverse osmosis (RO) desalination of agricultural drainage (AD) water in California's San Joaquin Valley (SJV) was evaluated based on systematic analysis of water quality monitoring data and field water desalting tests in a laboratory plate-and-frame RO (PFRO) system. Thermodynamic solubility analysis and diagnostic PFRO desalting tests served to determine the feasible range of water recovery limits and to assess the mineral scaling potential. Analysis of the recovery limits imposed by scaling due to sparingly soluble salts (e.g. calcite, gypsum, silica) suggested feasible recoveries in the range of 46%-69%. Diagnostic PFRO desalting tests with five representative field water sources from the SJV (having gypsum and calcite saturation indices in the range of 0.12-1.03 and 2.9-9.5, respectively) confirmed the above recovery range. Mineral scale coverage was consistent with the observed flux decline. Deployment of RO technology for treatment of brackish SJV AD water would require site-specific process optimization given the geographic and temporal water quality variabilities. Therefore, RO operation with variable feed water quality (with respect to salinity and scaling propensity) and at sufficiently high recovery would require effective plant control, enabled by real-time mineral scale detection and adaptable process operation to mitigate mineral scaling.     

反渗透技术在化纤厂污水回用项目中的应用

介绍了反渗透技术在浙江某化纤厂污水回用项目中的应用情况。该公司以当地污水厂达标排放的污水为水源,采用反渗透技术作为主要脱盐处理工艺制备工厂所需的工艺用水。运行情况表明,反渗透系统运行良好,运行成本较低,且实现了污水的可持续利用,为推进化纤厂的绿色转型做出了贡献,同时也会带来良好的社会和经济效益。     

矿井水脱盐过程中卷式反渗透膜性能的数值模拟研究

为了更好地研究矿井水中无机盐组分对于反渗透过程产水、结垢及脱盐效果的影响,以内蒙古某煤矿矿井水水质组分作为进水水质条件,采用计算流体力学（CFD）模拟单支商用标准8寸卷式反渗透膜元件（陶氏BW30-400）内部的传质以及局部浓差极化的分布,预测实际运行情况下微溶盐结垢的风险。进水通道采用以阿基米德螺旋曲线为卷制轨迹的几何模型。无机盐的混盐作用通过混盐渗透压模型模拟。从全尺度卷式反渗透膜元件的模拟结果可以看出,卷式反渗透膜内的水流主要以轴向流速为主,沿切向阿基米德螺旋线的流速较低,对整体盐度分布的影响较小（<1%）,可以忽略不计,在后续模拟中采用简化模拟单元或几何模型或网格。在模拟操作条件下,卷式膜元件的浓水网产生的水头损失占整体水头损失约86%,为卷式膜元件中的主要水头损失来源。在没有安装浓水网的进水流道中最高Na₂SO₄浓度位于元件浓水出口处,高达3594 mg/L,约为有浓水网情况下的1.8倍。而且有浓水网的进水流道内,浓差极化现象主要发生在浓水网背水侧局部区域,影响范围较小。该模型模拟得到的产水量与实测产水量做对比,误差小于5%,同时模拟结果也接近ROSA9.1模拟数据（误差<4.4%）,因此可以对卷式反渗透膜的无机盐脱盐过程进行较精确的模拟仿真。与商业设计软件如ROSA（反渗透系统分析）相比,其只提供产水和浓水中的盐浓度信息,本文开发的模型可以提供浓度极化的特征信息,加深了对卷式反渗透膜在不同位置的潜在结垢风险的理解。     

The role of desalination in bridging the water gap in Jordan

The water resources of Jordan have always been scarce. The demand for water in the country exceeds the available resources and the gap between the water supply and demand is continuously increasing. Furthermore, the quality of water resources has dramatically deteriorated in recent years, which prevented the utilization of some resources. To secure the economic sustainability of the country, it is important at this stage to consider non-conventional water resources, such as sea and brackish water desalination. This study examines the water resources of Jordan, projected water demand, and the gap between the demand and supply based on two scenarios. The possibility of closing this gap by water desalination was investigated. Both sea and brackish water desalination were considered. The analysis revealed that seawater desalination process is economically infeasible for domestic water uses at this stage. This is attributed to that Jordan is not an oil producing country and the location of sea shoreline in Aqaba is on the Red Sea, away from the consumption centers. However, seawater desalination may be a viable option for tourist and industrial enterprises that will be established as a result of the new Law of Aqaba Free Zone. The most convenient and realistic option for Jordan in the short term, is the desalination of brackish water by reverse osmosis (RO). The brackish water with total dissolved solids between 2000-10000 mg/l is available from many aquifers and springs of the country. The study concluded that Jordan is facing a severe water crisis. Until recently, the water planners have not given the water desalination the required attention as a potential source of water supply. Taking into account the progress that is being achieved in the field of desalination technology, Jordan has to consider the desalination option more seriously and to start building a national capacity in the field of water desalination. It was emphasized that desalination is not a substitute to traditional water resources, it is rather a supplementary source that can contribute in bridging the water gap of the country.     

超滤、反渗透在循环冷却塔排污水处理中的应用

结合某电厂工程实例,介绍了循环水排污水处理工艺系统"混凝澄清+超滤+反渗透处理",给出了混凝剂和助凝剂加药量的配比参考值,总结了工艺运行过程存在的问题,提出建议,可以为以后的工程设计提供参考。     

HSE管理体系在石化装置的应用

本文对化工厂易发事故进行了分析,并将HSE管理体系应用于管理中,提出了应急预案模式,保证了安全生产。     

在PET装置建设中从事项目管理的体会

介绍了筹建PET装置的思路,着重指出筹建队伍的组建,项目谈判和合同签订的注意事项;在建设过程中,要处理好与工程公司和施工单位之间的关系;妥善解决建设过程中出现的各种矛盾。     

城镇污水处理厂常规水污染物日排放现状评价分析

以北方某城市城镇污水处理厂常规水污染物(以BOD5为例)日排放现状评价为目标,收集了该城市13家城镇污水处理厂3年例行监测数据,基于统计学的方法理论,分析了常规污染物(以BOD5为例)的排放浓度分布特征。借鉴美国水污染物排放限值制定方法,对该城市城镇污水处理厂BOD5日排放现状进行评价分析,并以此为例,探讨了地方城镇污水处理厂常规水污染物日排放评价分析方法。在此基础上,提出了该方法对地方及国家水污染物排放标准制定的借鉴意义,及其他需要进一步探讨的问题。     

合成氨厂循环水水稳剂配方的改型

介绍全有机膦系水稳剂在合成氨厂循环水系统的应用情况,与腐植酸系水稳剂比较,JL全有机膦系水稳剂具有优良的结蚀阻垢杀菌性能。     

选煤厂浓缩机入料管槽的敷设方式

分析了选煤厂浓缩机 U形入料管系统的水力状况 ,介绍了系统设计要点。指出采用该系统可以有效改善浓缩机中心稳料桶处的水力条件 ,提高浓缩机的处理效率 ,改善厂区环境 ,减少建设投资。     

大直径有压给料三产品重介质旋流器在动力煤选煤厂的应用研究

针对淮南矿区顾桥矿选煤厂动力末煤煤质及可选性和已建成的浅槽重介质分选块煤车间的现实情况,开发了3DMC1500/1100AP型大直径有压给料三产品重介质旋流器选煤工艺及设备,投产后的检查结果表明,在不脱泥分选30~0mm、灰分为40.35%的原煤时,单机处理能力达580t/h,分选下限达0.25mm,精煤灰分为16.13%,Ep值在0.025以下,精煤数量效率达99.90%。     

电厂污水回用于循环冷却水系统补充水的研究

以电厂循环冷却水系统补充水水质标准，作为对电厂污水净化处理的要求，在净化处理中引入电厂冲灰水作为助凝剂，提高了处理效果，然后用净化后的污水做阻垢缓蚀试验，筛选出合适的配方，达到污水回用的目的，使电厂污水基本达到零排放。     

复极性三维电极反应器处理焦化废水主要影响因素研究

以经吸附处理的活性炭-涂膜活性炭为填充粒子,对复极性流化床三维电极反应器处理焦化废水进行了静态条件试验研究。主要探讨了通气量、电解时间、涂膜活性炭比、槽电压对COD去除率的影响。结果表明,通气量为1．5L／min,通电时间为60min,涂膜活性炭比为45％,槽电压为6V时,COD去除率最高,达87％。废水主要成分也发生了较大变化。     

无压给料三产品重介质旋流器在郑州矿区选煤厂的应用

郑州煤田赋存的构造贫廋煤粒度偏细,煤质易碎,采用脱泥与无压给料三产品重介质旋流器选煤工艺对50～0.5 mm粒级进行洗选的结果表明,该工艺对煤质适应性强、分选精度高、介耗低,精煤产品满足用户要求,但二段E值较高,需优化旋流器结构参数。     

酒精厂循环冷却水降温系统的制冷改造设计

为保证酒精及其相关产品的产量、质量和收得率,通常采用以开放式冷却塔为降温设备的循环冷却水系统.但冷却塔的降温效果与气象条件密切相关,在高温高湿天气下只能通过补充大量新水来保证冷却水的温度,从而造成水资源的浪费.针对这方面的问题,某酒精厂的冷却水系统在原有冷却塔后增加大型离心式制冷机组,实现冷却水温度的有效降低和控制,收到了明显的改善工艺条件、节约用水和节约运行费用的效果.实践证明制冷降温技术在工业冷却水领域应用具有可行性、合理性和必要性.     

Cementitious properties of metakaolin-normal Portland cement mixture in the presence of petroleum effluent treatment plant sludge

The physicochemical characteristics of cocalcined kaolin and petroleum effluent treatment plant (ETP) sludge and its effect on the technological and hydration characteristics of cement have been presented. Conductivity measurements indicate that both the sludge ash (SA) and cocalcined kaolin-sludge mixtures in aqueous medium are reactive in nature. The rate of hydration was investigated by determining the combined water (CW) and Ca(OH)₂ content in the hydration products. The hydration products were characterized by FTIR spectrophotometric method and XRD analysis technique. The rates of hydration of cement containing cocalcined kaolin-sludge mixtures are comparatively higher than the others. Blended cements with improved technological properties may be prepared by replacing 20% cement with cocalcined kaolin-sludge mixtures containing up to 30% sludge.     

A comparison of the effectiveness of predator odor and plant antifeedant in deterring small mammal feeding damage on lodgepole pine seedlings

The influence of mustelid (weasel) anal-gland compounds (semiochemicals) and a plant antifeedant (pinosylvin) on snowshoe hare (Lepus americanus) and meadow vole (Microtus pennsylvanicus) feeding damage was investigated. This study has shown conclusively that when applied to spring-planted lodgepole pine seedlings, pinosylvin is effective in significantly reducing feeding damage. Seedlings treated with pinosylvin suffered damage levels of 2.3% and 21.2% compared to the controls with damage levels of 24.5% and 41.0%. Weasel scent was found to reduce damage levels, but the reduction was not statistically significant in all blocks.