Reverse osmosis and ultrafiltration of stillage solubles from dry-milled corn fractions

Grits, flour, degerminated meal and hominy feed from corn were fermented to make ethyl alcohol. The stillage, remaining after distillation of alcohol, was separated by screening and centrifuging into insoluble and soluble fractions. The stillage solubles contained 0.036 to 0.080% nitrogen and 1.4 to 7.2% total solids. Ultrafiltration (UF) membranes separated stillage solubles into permeate and concentrate fractions. Permeates from stillage solubles accounted for 85 to 95% of the original volume, 44 to 67% of the total solids and 40 to 75% of the total nitrogen. Reverse osmosis (RO) membranes separated the UF permeate into RO permeate and RO concentrate fractions. The RO permeate accounted for 70 to 92% of the original volume, 5 to 15% of the total solids and 5 to 21% of the total nitrogen in the UF permeate. Conductivity of some RO permeate fractions was lower than that of tap water. The combination of UF and RO processing of stillage solubles from corn dry-milled fractions appears to be an attractive method to recover most of the solids and nitrogen in small volumes of concentrate, and produces a final permeate with a low concentration of solids and nitrogen. The RO permeate may be reused as water, treated further or discharged. Presented at the AOCS Annual Meeting, May 1984, Dallas, Texas. Deceased.     

Nanofiltration and reverse osmosis of model process waters fromthe dairy industry to produce water for reuse

In dairy plants the process waters generated during the starting, equilibrating, interrupting and rinsing steps contribute to the production of effluents. They correspond to milk products (milk, whey, cream) diluted with water without chemicals. The treatment of these dairy process waters by nanofiltration (NF) or reverse osmosis (RO) operations was proposed to concentrate dairy matter and to produce purified water for reuse in the dairy plant. The study reports one-stage and two-stage (NF + RO and RO + RO) spiral-wound membrane treatments with five model process waters representative of the main composition variations observed in dairies. Performances (permeate flux, milk components rejection, purified water characteristics) of the different operations were compared. Discussion was focused on the comparison between quality of produced waters and vapour condensates (from product drying and evaporation processes) reused in dairy plants. Accordingly, both total organic carbon (TOC) and conductivity of water treated by a single RO or NF + RO operations were convenient for reuse as heating, cooling, cleaning and boiler feed water. With the two-stage RO + RO process, a more purified water complying with the TOC drinking water limit was achieved.     

Comparison of the Efficiency of Five Different Drying Carriers on the Spray Drying of Persimmon Pulp Powders

The aim of this work was to compare the efficiency of different carrier agents (maltodextrin, gum arabic, starch sodium octenyl succinate, whey protein concentrate, and egg albumin) on the powder recovery and physicochemical properties of persimmon powders produced by spray drying. Moisture content, water activity, hygroscopicity, solubility index, total phenol retention, color parameters, particle size, morphology, crystalline state, and sorption isotherms of persimmon powders were determined. No powder was recovered when the persimmon pulp was spray dried alone. The amount of maltodextrin, gum arabic, starch sodium octenyl succinate, whey protein concentrate, and egg albumin needed to obtain a powder recovery of 70% was 45, 30, 30, 25, and 10%, respectively. The use of maltodextrin, gum arabic, and starch sodium octenyl succinate resulted in higher total polyphenol retention and better reconstitution properties, but the powders were paler than those with whey protein concentrate and egg albumin. All carriers could aid the formation of persimmon irregular spherical microcapsules. However, powders produced with maltodextrin and gum arabic had a smoother surface and a more spherical shape than powders produced with other carriers. In addition, powders produced with starch sodium octenyl succinate, whey protein concentrate, and egg albumin were more agglomerated and shriveled compared to those produced with maltodextrin and gum arabic. All experimental data of water adsorption were well fitted to the Guggenheim-Anderson-de Boer (GAB) model.     

超滤和反渗透联用处理玉米浸渍水

对玉米浸渍水的膜分离过程进行了研究，开发出超滤和反渗透联用的分离方法。反渗透浓缩液中蛋白质的截留率为99．77％，反渗透透过液中COD值降到1000左右，可用作工艺回用水，反渗透浓缩液中可提取乳酸等有用物质，超滤浓缩液可浓缩成玉米浆。     

煤化工反渗透浓水的高效降解菌株筛选、鉴定及应用研究

一般煤化工废水经过多级氧化处理后,反渗透淡水回用、浓水经蒸发产生难处理的“危废”,有机物的存在对“危废”循环利用有显著制约作用。以煤化工反渗透浓水为底物（TOC为233.4 mg/L,TDS为50.9 g/L,BOD₅/COD仅为0.05）,从不同菌源中筛选得到9株高效耐盐菌,经16S rDNA测序表明,这些菌株属于假单胞菌属、芽孢杆菌属及嗜盐单胞菌属。将9株耐盐菌配制成复合耐盐菌剂连续式运行处理实际废水,有机物去除率可达30%,为进一步提高去除率,经臭氧氧化预处理,有机物去除率可提高至40%,达到国内外较先进水平。根据气质联用分析,臭氧氧化预处理会破坏废水中环状物质的结构,提高复合耐盐菌剂对难降解有机物的去除效果。本研究为煤化工反渗透浓水中有机物的生物降解提供了可行性方案。     

Membrane application for recovery and reuse of water from treated tannery wastewater

Secondary treated tannery wastewater contains high concentrations of Total Dissolved Solids (TDS) and other residual organic impurities, which cannot be removed by conventional treatment method. A pilot plant membrane system with a designed processing capacity of 1 m³/h, comprising of nano and reverse osmosis (RO) membrane units, accompanied by several pre-treatment operations, was evaluated in order to further treat and reuse the tannery wastewater. The maximum TD S removal efficiency of the polyamide RO membrane was more than 98%. The permeate recovery of about 78% was achieved. The water recovered from the membrane system, which had very low TDS concentration, was reused for wet finishing process in the tanneries. The reject concentrate obtained from the operation was sent to solar evaporation pans. It was evident from the study that the membrane system can successfully be applied for recovery of water from secondary treated tannery effluent, provided a suitable and effective pretreatment system prior to membrane system is employed. Combining nano and RO membranes improved the life of the membranes and permeate recovery rate.     

Wind-Aided Intensified eVaporation (WAIV) and Membrane Crystallizer (MCr) integrated brackish water desalination process: Advantages and drawbacks

Due to the increasing of water shortage problems, the need for inland brackish water RO will continue to increase in future. However, the primary limitations to further application of RO inland are the cost and technical feasibility of concentrate disposal. In this work, Membrane Crystallizer (MCr) and Wind-Aided Intensified eVaporation (WAIV) technologies have been applied in order to mitigate the impact of concentrates on the environment. In particular, the research activity has been carried out on a desalination system in which brackish water was first pre-treated, then desalinated through reverse osmosis (RO) operation. Finally, RO concentrates were further treated in WAIV and MCr units. The effect of the presence of organic contaminants and antiscalants were studied by analysing RO operations working at different recovery factors and with different pre-treatments. In the absence of an antiscalant, RO operates at 75% recovery factor and at a pH low enough to ensure no calcium carbonate precipitation. In the presence of an antiscalant, RO process might work until a recovery factor of 88%. The analysed integrated RO + WAIV + MCr system allowed to reach recovery factors as high as 76.6–88.9% and limit brine discharge to less than 0.75–0.27% of the raw water fed to the system.     

The preparation of soy products with different levels of native phytate for zinc bioavailability studies

Soy products with low, intermediate and normal phytate levels were prepared in the pilot plant for subsequent rat-feeding experiments to evaluate zinc bioavailability. The low level (0.29%) phytate product was made by precipitation of the protein curd at pH 5.5, whereas the normal level (1.05%) phytate product was produced by a similar process except that the phytate previously isolated from the whey fraction was added back to the original curd as native phytate. The intermediate level (0.73%) phytate product was also produced by acid precipitation, but at pH 4.5. The pH 5.5 precipitation process yielded a large quantity of whey in which the ratio of water content to phytate was over 1,000 parts to 1. However, ca. 75% of the water was subsequently removed by reverse osmosis (RO), which increased the concentration of phytate in the whey fraction and facilitated its isolation. Protein was first removed from the whey by precipitation with trichloracetic acid, then phytate was precipitated in the supernatant with ferric chloride. Another series of experiments was run to find optimal conditions to convert ferric phytate to the more soluble sodium phytate form, using a minimal amount of sodium hydroxide so that the phytate could be recycled back to the curd without causing a large increase in sodium content of the product. There were only minor differences in the protein, lipid and mineral contents of the three products.     

膜分离技术处理大豆乳清废水

对用膜分离技术处理大豆乳清废水处理进行了研究,结果表明：废水经截留分子量为8000的超滤膜,可回收几乎所有的蛋白质,对美国Desal公司生产的三种纳滤膜进行了评价,选择了一种可部分脱除蔗糖和单糖的纳滤地超滤透过液进行了浓缩,大豆低聚糖中功能性成分水苏糖和棉子糖的回收率超过90％,纳滤透过液经反渗透处理,可回收大量纯水,采用本工艺处理大豆乳清废水,可大大降低排放量,且可获得较大的经济效益。     

Economical treatment of reverse osmosis reject of textile industry effluent by electrodialysis–evaporation integrated process

Membrane separation methods such as electrodialysis (ED) can reduce the volume load on evaporators by facilitating further concentration of rejects from reverse osmosis (RO) plants. ED studies were carried out on a bench-scale system using five membrane cell pairs to obtain a textile effluent concentrate containing approximately 6 times the quantity of salts present in the RO reject. The limiting current densities were determined to be in the range 2.15–3.35 amp/m² for feed flow rates varying from 18 to 108 L/h. Apart from feed rate, the influence of volume of concentrate and current on membrane performance was evaluated to optimize current utilization. An estimation of energy requirement of an integrated process constituting ED and evaporation for concentration of inorganics present in textile effluent from 4.35% to 24% was made and found to be approximately one eighth of the operating cost incurred by evaporation alone. Detailed design of a commercial ED system revealed that a membrane area of 13.1 m² was required to treat a feed rate of 1500 L/h. The payback period to recover capital investment was found to be 110 days.     

超滤-反渗透集成工艺处理玉米酒糟废水

研究了玉米酒精生产过程中产生的玉米酒糟废水的膜分离过程,开发了处理玉米酒糟废水的超滤-反渗透集成工艺。超滤选用截留相对分子质量为6 000的GR81PP膜平板分离器,入口压力控制为0.6 MPa,操作温度为50℃;反渗透选用标准脱盐率为90%的ESNAI-4040卷式膜分离器,入口压力控制为2.2 MPa,操作温度为40℃。反渗透透过液中蛋白质的平均截留率为94.70%,甘油的平均截留率为65.15%,COD值降到1 000 mg/L左右,可作为工艺回用水,而且反渗透浓缩液中可回收甘油等有用物质,超滤浓缩液可浓缩成饲料,节能效果显著。     

Impact of Protein Removal by an Upstream Ultrafiltration on the Reverse Osmosis of Skim Milk and Sweet Whey

Concentration of milk and whey by ultrafiltration and reverse osmosis (RO) in cascade mode is an amendment of evaporation for high volume reduction ratios (VRR) prior to drying. This study investigated the impact of a prior protein removal and the transmembrane pressure (TMP) on the RO stage, compared to skim milk and sweet whey. It could be found that removal of the protein fraction of both skim milk and sweet whey improved the efficiency of the RO. An upstream ultrafiltration resulted in higher VRR as well as an increased permeate flux.     

Treatment of Fumaric Acid Wastewater Using Integrated Process of Hollow-Fiber Supported Liquid Membrane-Strip Dispersion with Reverse Osmosis

In this paper, the integrated process of series connected hollow-fiber supported liquid membrane-strip dispersion (HFSLM-SD) with reverse osmosis (RO) was designed and used to recover fumaric acid (FA) from waste effluents and treat FA wastewater. The results showed that FA could be almost completely recovered by this integrated process, and TOC of wastewater finally decreased to the environment acceptable level. In addition, the continuous operation of wastewater treatment was implemented by the integrated process. After FA wastewater was extracted by six series connected HFSLM-SD modules, its TOC decreased from 35625 mg/L to 1000 mg/L, and the TOC removal rate reached 97.17%. Then the effluent from HFSLM-SD was further treated by RO, and TOC of permeate in RO was below 100 mg/L. The total TOC removal rate of the integrated process was as high as 99.7%. Furthermore, the effect of the osmotic pressure of RO process on TOC in the feed was obtained. The investigation of RO membrane fouling revealed that washing process was necessary because of the serious fouling in RO system.     

Pilot studies on high recovery BWRO-EDR for near zero liquid discharge approach

A hybrid process combining reverse osmosis and electrodialysis has been shown to be effective in recovering 97-98% of brackish water as product water with chloride levels of 200 mg/L or less. Potential for scaling on the brine side of the electrodialysis unit was prevented by acidification, operating the electrodialysis in a reversal mode (EDR), and a side loop crystallizer which prevented buildup of scaling components. Settlers, inline microfiltration, and side-loop ultrafiltration kept suspended solids from returning to the EDR unit. This process was demonstrated in a series of more than eighty batch experiments of 1.5 to 1.8 m³ of RO concentrate of raw brackish groundwater from the Negev Highland, Israel. Each batch could be processed within a single day. The feed-water was concentrated from 0.3% to over 10% TDS super-concentrate while producing the water that could be recycled to the RO permeate. This super-concentrate from the EDR unit was further concentrated in a wind powered WAIV unit that brought final brine TDS to > 30%, and showed promise as a method to recover mineral byproducts such as magnesium salt. Initial economic estimates show that this hybrid process is competitive with conventional RO and other enhanced recovery processes for inland desalination requiring use of evaporation ponds.     

Production of whey protein concentrates with high solids content

Ultrafiltration is very useful in production of whey protein powders. However, the protein concentrates obtained by this process seldom have a solid content higher than about 20%, and it is very difficult, to evaporate, especially concentrates with relatively high protein contents. This means that a large part of the whey protein concentrates produced today is spray dried directly which in turn is costly and may give troubles with e.g. light and bulky powders.At experiments on a DDS 20 cm lab-module it was possible to concentrate whey protein concentrates with app. 80% protein in solids to more than 35% total solids. A number of hyper filtration and ultrafiltration membranes were tested at temperatures up to 50°C and varyinq pressures. Using ultrafiltration membranes further gave an increase in the relative protein content or the concentrate.Results obtained on the lab-module were later confirmed on a DDS/ Pasilac pilot plant with a 7m² 30 cm module equipment with GR 81P membranes. The pilot plant was operated both in batch and in continous mode. The final concentrates could be “pasteurized” at 66°C 15 seconds but blocked the pasteurizer at 69°C. Spray drying of the product using a nozzle atomizer was uncomplicated and gave a relatively high bulk density of the resulting powders.     

Accelerated desupersaturation of reverse osmosis concentrate by chemically-enhanced seeded precipitation

A two-step chemically-enhanced seeded precipitation (CESP) process was demonstrated for accelerated desupersaturation of antiscalant-containing, gypsum-supersaturated model solutions, which mimicked reverse osmosis (RO) concentrate from RO desalting of agricultural drainage water of high mineral scaling propensity. In the CESP process, CaCO₃ precipitation is first induced via lime dosing for antiscalant scavenging, followed by subsequent CaSO₄ precipitation via gypsum seeding for concentrate desupersaturation. It was demonstrated that lime-precipitated CaCO₃ particles were able to scavenge generic and commercial polycarboxylic-acid antiscalants, thereby facilitating subsequent CaSO₄ precipitation to progress with minimal retardation. The study demonstrated via a series of batch CESP cycles that gypsum particle recycling can sustain CaSO₄ precipitation, suggesting that a continuous CESP process could be feasible. Process analysis suggests that CESP can be significantly less chemical-intensive than conventional precipitation softening and, with its integration as an intermediate RO concentrate demineralization process, can enable desalination water recovery enhancement via secondary RO desalting. For the present case of gypsum-saturated RO feed water, enhancement of overall water recovery from 63% up to 87% or higher appears to be feasible. The study suggests that there is merit for developing a continuous CESP process for high recovery RO desalting of brackish water of high gypsum scaling propensity.     

Mixture Design Approach in Wall Material Selection and Evaluation of Ultrasonic Emulsification in Flaxseed Oil Microencapsulation

Flaxseed oil, sensitive to oxidation, was systematically microencapsulated with six triple wall materials combinations [carbohydrate (maltodextrine and two different modified starches (N-Lok® and HiCap® 100)); protein (sodium caseinate, whey protein concentrate); and Arabic gum] for the highest microencapsulation efficiency and oxidation stability. Proportions of the triple wall materials were optimized in mixture design using the quadratic model. Effects of Ultra-Turrax and ultrasonic emulsifications on microencapsulation efficiencies were additionally characterized in the optimized wall material combinations. The microcapsules produced were investigated for particle size distribution, moisture content, water activity, bulk density, and oxidative stability. Results showed that the combination of modified starch (Hi-Cap® 100)/Arabic gum/whey protein concentrate (4/0/1, w/w/w) provided the highest efficiency in flaxseed oil microencapsulation. However, the only successful combination in preventing flaxseed oil oxidation was maltodextrine/Arabic gum/whey protein concentrate (4/0/1, w/w/w). The microcapsules produced by ultrasonic emulsification had higher microencapsulation efficiency than that of Ultra-Turrax emulsification.     

Ternary Biopolymer Based on Wheat Gluten,Whey Protein Concentrate and Montmorillonite

The aim of the research was to obtain biopolymers based on wheat gluten, whey protein concentrate (WPC) and montmorillonite (MON). Ternary biopolymers were formed as heat-induced gels and they were hardened by water evaporation. Adding 7 % of MON and 5 % WPC to gluten caused ca. four times higher values of storage modulus. Increased moduli values with adding MON and WPC to gluten were probably caused by reinforcing effect of MON, which decreased mobility of gluten chains and possible interactions between gluten and whey proteins by disulphide interchange. Increase in gluten protein concentration and addition of WPC and MON caused increase in viscosity measured by dissipation of ultrasound vibrations. Evaporation of water from the gels formed very hard material with high puncture force values. Obtained gels were very plastic and it was easy to form any type of shapes. They could be used to produce biodegradable pottery (e.g. flowerpots) with the mechanical properties similar to non-degradable clay products.     

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。     

Non-conventional treatment of treated municipal wastewater for reverse osmosis

High-quality potable water can be produced at a reasonable cost if reverse osmosis (RO) technology is applied to renovate secondary/tertiary urban wastewater effluent. Such implementation would yield many advantages to Kuwait, namely: satisfying the increasing agricultural, industrial and domestic demands for good quality water that is free from viruses and bacteria and other microbials present preserving the natural strategic water resources; reducing the environmental pollution resulting from the direct discharge of secondary/tertiary municipal effluents to the sea; and meeting unexpected emergency cases of shortages in freshwater produced from the desalination of seawater for certain domestic applications. The main aims of this work are to assess the technical viability and the economic feasibility of implementing RO technology to renovate Kuwaiti wastewater treated effluent. The paper describes the design of pretreatment, experimental set-up, results, and data analysis of desalinating municipal wastewater by RO. The results indicate that wastewater can be treated to produce an excellent permeate quality almost devoid from salts and pollutants.