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。     

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。     

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.     

A Laboratory Decanting Procedure to Simulate Whole Stillage Separation in Dry-Grind Corn Ethanol Process

In the dry-grind corn ethanol industry, horizontal decanter centrifuges are used to separate the whole stillage into wet grains and thin stillage. The wet grains mixed with condensed thin stillage are dried to form dried distiller’s grains with solubles (DDGS). In order to investigate the effect of different corn breaking treatments on increasing oil partitioning in thin stillage, a laboratory method is needed to simulate industrial decanting where a typical thin stillage is produced. The thin stillage obtained using a conventional laboratory centrifuge had much lower solids content and less than one-half of the dry-matter yield compared to the industry counterpart because the conventional laboratory centrifuge and industry decanter centrifuge have different separation mechanisms. By evaluating the properties of industrial thin stillage and the mechanism of industrial decanter centrifugation, a laboratory decanting device was designed and a decanting procedure, the multiple-wash centrifugal filtration (MWCF) method, was developed. This method involves multiple steps of filtration under centrifugal force after washing the solids with the liquid generated from the same mash. Four cycles of MWCF produced a thin stillage with similar solids content (7.3 vs. 7.2%), dry-matter yield (54.2 vs. 54.7%), and wet yield (83.3 vs. 80.6%) compared to industrial thin stillage. The presence of ethanol did not influence the laboratory decanting results, which indicates the application robustness of this laboratory thin stillage preparation method.     

Whey fractionation through the membrane separation process

The aim of this work is to improve the utilisation of fractions of whey through membrane separation processes. From a solution of whey treated by ultrafiltration (UF) associated with diafiltration (DF), two streams were obtained: a concentrate and a permeate. In this process, a purified protein concentrate with about 70% of protein was obtained. Permeate was treated by electrodialysis (ED) to obtain a fraction rich in lactose (90%). The final effluent was treated by reverse osmosis (RO) in order to recover water free of salts. RO made it possible to recover 50% water and retain 85% of the salts.     

Electrodialysis Application of the Ultrafiltration Permeate of Milk Before and After Reverse Osmosis

Ultrafiltered (UF) milk permeate was concentrated by reverse osmosis (RO). UF and UF + RO samples were then desalted by electrodialysis (ED) to three levels of desalination: 1, 2.5, and 4 % of ash in the dry matter. Ions were analyzed by a new high‐performance liquid chromatography method, which enables simultaneous estimation of cations and anions. ED of UF permeate has some advantages over that of UF + RO samples, including a shorter ED time and a higher average salt flow rate, but RO treatment of UF permeate before ED enables the processing of larger volumes of UF permeate. Therefore, ED of milk permeate, particularly after RO, improves the handling characteristics and may offer advantages for further processing of secondary dairy products.     

组合膜-表面活性剂法处理垃圾渗滤液中的氨氮

氨氮是《生活垃圾填埋污染控制标准》(GB 16889-1997)严格控制的、也是传统工艺难处理的一项指标。文中以北京市北神树垃圾填埋场渗滤液为研究对象,采用组合膜-表面活性剂法对其氨氮进行了处理。水样依次通过OSMONICS微滤EW膜和超滤GE膜后,调节膜出水pH值为6.5,加入质量分数0.02%的十二烷基苯磺酸钠(SD-BS),通过静电引力与NH4+形成大分子的复合态铵,然后经反渗透SE膜进一步处理。处理后的水样清澈透明,无异味,水质达到了GB 16889-1997的一级排放标准,氨氮去除率为99.4%。另外还探讨了水样的pH值、SDBS投加量等因素对氨氮去除率的影响。     

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。     

Changes in Lipid Composition During Dry Grind Ethanol Processing of Corn

During the dry grind ethanol process, ground corn is fermented and the major co-product is a feed called distillers dried grains with solubles (DDGS). This study investigated the changes that occur in the composition of corn oil that can be extracted from various process fractions during the dry grind ethanol process. In the first part of this study, samples of distillers dried grains, thin stillage, condensed distillers solubles (also known as syrup), and DDGS were obtained from 7 dry grind ethanol plants. The levels of deleterious free fatty acids were high (>7%) and those of valuable total phytosterols were also high in all fractions (>2%). In the second part of this study, changes in the content and composition of the fatty acids, phytosterols, tocopherols and tocotrienols were quantitatively analyzed in crude oil samples extracted from nine dry grind process fractions from three commercial ethanol plants. Fatty acid and phytosterol composition remained nearly constant in all nine fractions, although some significant variations in phytosterol composition existed among the fractions. Examination of the tocopherols and tocotrienols revealed that γ-tocopherol was the most abundant tocol in ground corn but an unknown tocol became the predominant tocol after fermentation and persisted in the remaining processing fractions and in the final DDGS product. Overall, the remaining majority of tocols remained relatively unchanged.     

Comparative analysis of the processes of collagen concentration by ultrafiltration using different types of membranes

Tangential flow filtration of the collagen protein solutions with a molecular weight 12, 14, and 24 kDa is investigated using flat sheet membranes. The effects of tangential ultrafiltration (UF) on the permeate properties using two regenerated celluloses (RCs) and two polyethersulfone (PES) membranes with molecular weight cut-off (MWCO) of 5 and 10 kDa are reported. The permeate and concentrate obtained in the UF experiments are characterized from a physical–chemical point of view by determining the temperature, pH, electrical conductivity, nitrogen content, and protein concentration. In addition, the experimental data are modeled using Hermia's model. The UF experiments demonstrated that permeate flux declined with increasing molecular weight of collagen at constant concentration (1%). Regardless of the molecular weight of collagen, the rejections decrease in the following order: PES 5 kDa > RC5kDa > RC10kDa > PES10kDa. In case of membrane with higher MWCO, the clogging phenomenon is mainly due to the blockage of the internal pores of the membrane than the formation of a polarization layer. Morphologies and characteristics of the membranes are characterized using scanning electron microscopy.     

Application of full permeate recycling to very high gravity ethanol fermentation from corn

A ceramic membrane with pore size of 0.2 μm was used to percolate grain stillage of very high gravity (VHG) ethanol fermentation from corn, and the micro-filtration permeate was completely recycled for the cooking step in the next fermentation process. The concentrations of solids, sugars, total nitrogen and Na⁺ in the grain stillage and permeate reached a relative steady state after two or three batches of filtration and recycling process. There are no negative effects of by-products on VHG ethanol fermentation, and the final ethanol yield was above 15% (v/v). The conditions of filtration were examined to determine the optimum conditions for the process and included an initial flux of clean water above 550 L·m⁻²·h⁻¹ (0.1 MPa), an operating differential pressure of 0.15 MPa, an operating temperature above 70 °C, and a permeation flux greater than 136 L·m⁻²·h⁻¹. It could be concluded that full permeate recycling during ethanol production was an efficient process that resulted in less pollution and less energy consumption. Zhongyang Ding and Liang Zhang made equal contribution to this research.     

Processing of black liquors by UF/NF ceramic membranes

This study deals with the treatment of black liquor from wood pulping by means of membranes. UF/NFmembranes with a skin layer of TiO₂ and ZrO₂ have been applied to recover water and to concentrate the residual effluent. Three different membranes with molecular weight cut-off of 1, 5 and 15 kDa have been checked. The membranes have been tested either in single stage operation or in cascade. Total dissolved solids, organic matter, organic to mineral matter ratio and ash have been determined. In addition, chemical oxygen demand (COD) retention was calculated by measuring in the feed solution as well as in the permeate and in the concentrated solution. During the concentration step the steady state was reached after a few minutes running. There was not significant change in the permeate flow until the volume was reduced at half. Only the 15,000 Da membrane showed continuous permeate flow declining. Regardless the membrane used, dry matter, organic matter and COD analyses showed that the retention of organic substances fell in the range of 60-70%, depending on the conditions selected.     

Utilization of zearalenone- contaminated corn for ethanol production

Two lots of yellow corn, severely damaged byFusarium fungi and contaminated with 8.0 and 33.5 ppm zearalenone, respectively, were used for ethanol fermentations. Substrate corn (5-kg samples) was processed in a laboratory procedure similar to that used by the fermentation industry. Stillages obtained were 7.0 to 9.0% ethanol. Ethanol was recovered by distillation, residual grain solids by filtration, and solubles by concentration. No zearalenone could be detected in the ethanol fraction. Zearalenone in the original corn was concentrated in the residual solids and solubles, which are generally used for animal feed. Treatment with formaldehyde significantly reduced the level of zearalenone in fermentation solids. Ammonium hydroxide was a much less effective agent for toxin degradation. Presented at ISF/AOCS World Congress, New York,NY,April 27-May 1, 1980     

Thermoplastic polymers as modifiers for urea‐formaldehyde (UF) wood adhesives. I. Procedures for the preparation and characterization of thermoplastic‐modified UF suspensions

Acrylic thermoplastic copolymers with different degrees of hydrophilicity were prepared and introduced into a commercial aqueous urea‐formaldehyde (UF) suspension at 5–10% w/v. The most hydrophilic acrylic thermoplastic was introduced into the UF suspension as an aqueous solution, whereas the most hydrophobic acrylic was introduced as a surfactant‐stabilized suspension. Acrylics with intermediate hydrophilicity were introduced into the UF suspension as a self‐dispersed aqueous suspension. The thermoplastic‐modified UF suspensions with 5% thermoplastic (58% solids) had a viscosity at 30°C of ～ 114 cP, compared with a viscosity of ～112 cP for the original UF suspension (60% UF solids). At 10% thermoplastic (63% solids), all the thermoplastic‐modified UF suspensions exceeded 200 cP. The viscosity of the UF suspension modified with self‐dispersed thermoplastic was reduced by ～ 50% by reducing the thermoplastic molecular weight. SEM micrographs of cured thermoplastic‐modified UF showed phase‐separated thermoplastic domains in a continuous UF phase for the UF modified with self‐dispersed and surfactant‐stabilized thermoplastic, but UF modified with the water‐soluble thermoplastic showed a single phase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 890–897, 2003     

Influence of filtration conditions on the performance of nanofiltration and reverse osmosis membranes in dairy wastewater treatment

Filtration performance and fouling of nanofiltration (NF) and reverse osmosis (RO) membranes in the treatment of dairy industry wastewater were investigated. Two series of experiments were performed. The first one involved a NF membrane (TFC-S) for treating the chemical-biological treatment plant effluents. The second one used a RO membrane (TFC-HR) for treating the original effluents from the dairy industry. The permeate flux was higher at higher transmembrane pressures and higher feed flowrates. The curves of permeate flux exhibited a slower increase while the feed flowrate decreased and the pressure increased. Membrane fouling resulted in permeate flux decline with increasing the feed COD concentration. Furthermore, the flux decline due to the COD increase was found higher at higher pressures for both NF and RO membranes.     

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.     

Water Quality Improvement by Combined UF,RO, and Ozone/Hydrogen Peroxide System (HiPOx) in the Water Reclamation Process

Conventional water reclamation processes, such as membrane bioreactors, are not always effective in removal of pharmaceuticals and personal care products (PPCPs), endocrine disrupting chemicals (EDCs) and/or N-nitrosodimethylamine (NDMA), even with the reverse osmosis (RO) membrane process. A study was conducted, at a NEWater factory in Singapore, to compare a conventional ultrafiltration (UF) membrane /RO treatment process with a treatment train having the HiPOx unit, an advanced oxidation process (AOP), which was installed between the UF and the RO unit operations. By incorporating the HiPOx into the UF/RO treatment process, following results were observed; 1) increased removal of PPCPs, EDCs and NDMA, 2) improvement in ultraviolet transmission (UVT) of the RO permeate, 3) enhanced removal of TOC and color, and increased UVT of the RO brine, 4) suppression of the increase in the RO transmembrane pressure by organic fouling.     

Membrane processing of crude vegetable oils: Pilot plant scale remoyal of solvent from oil miscellas

The recovery of solvents used in the extraction step of edible oil processing is required for economical, environmental, and safety considerations. The miscella (mixture of extracted oil and solvent) exits the extractor at 70 to 75 wt% solvent content. Currently, the solvent is recovered by distillation. This paper reports the results of a study on separation of vegetable oils from commercial extraction solvents using various types of Reverse Osmosis (RO) and Ultrafiltration (UF) membranes. Solvent permeation rates and separation performances of various RO and UF membranes were determined by using ethanol, isopropyl alcohol and hexane as the solvents. One membrane exhibited a flux of 200 GFD (ethanol) with 1% oil remaining in the permeate. However, hexane rapidly deteriorated all but one of the membranes tested. The membrane that was compatible with hexane had a low flux and unacceptably low oil retention. Industrial-scale membranes were also evaluated in pilot plant trials. A hexane separation was attempted with a hollow-fiber membrane unit, and it was noted that the pores of the fibers swelled almost closed. Some of the commercially available membranes selectively removed solvent (ethanol or isopropanol) from the edible oil miscellas with reasonable flow rates. The research reported has shown that membranes manufactured from polyamide were the least affected by hexane. Fluxes achieved during solvent-oil separations were increased by increases in either temperature or pressure and decreased by increases in oil concentration in the feed. The processing temperature affected the percentage of oil in solution in either ethanol or isopropanol as well as the viscosity of the feed. Both of these factors in turn influenced the flux achieved. Approximately 2 trillion Btu/yr could be saved using a hybrid membrane system to recover solvents used in the extraction step of crude oil production. Studies to date report marginal success. The development of hexane-resistant membranes may make this application viable.     

Optimization of PACl dose to reduce RO cleaning in an IMS

In order to ensure stable treated water quality and to reduce chemical costs in any treatment plant it is necessary to study and optimize the coagulant dosing control (CDC). This research focused on the affects of coagulant in the integrated membrane (UF & RO) system employed for industrial water production. The dose of coagulant (PACl) might be associated (partly) with the frequency of cleaning in the RO units, and a value of 20 abs/m in the UF permeate is the control of the dosage process. This could suggest that organic fouling is directly and indirectly (inducing biofouling as well) the cause of fouling of the RO membranes. Nevertheless, high doses of PACl could produce scaling of aluminium and, in this work minimizing PACl to prevent operational problems in RO membranes was focused.

The approach involved the study of the treatment processes, determination of the optimum dose of coagulant, evaluation of the removal efficiency of UV and DOC by coagulation. The available data, which comprised monthly/weekly measurements for a period of six years of operation, was studied and analyzed and an attempt was made to draw some conclusions for the plant regarding the coagulant dosage and the link with UV absorbance as control.

The study of the coagulant dosing control revealed that the use of simple and robust online sensors like UV measurement allows an automatic dosing control although this parameter is not found to be sufficient to fully characterize nor predict fouling during membrane operation and there is no link between UV after the UF and the cleaning frequency of the RO. Parameters, as the added value allowed to verify the doses efficiencies in UV and DOC removal. Coagulant dose depends on the level of UV absorbance in the UF permeate and it should never be higher than 20 abs/m to ensure a RO cleaning frequency as long as possible. However, it was found that the target value of 20 abs/m produced substantial over dose of coagulant — 90% of the time – when UV removal is considered only. In the same way, for coagulant doses in excess of 5 mg/L, the additional removal of UV is less than 2.5% per mg coagulant/L, which suggests that the current dose is on the high side.

Furthermore, a coagulant dose in excess of 5 mg/L did not produce significant additional UV removal, and thus a reduction from 14 mg/L (2005 dose) to ca. 7 mg/L could be considered.     

Reaction of coal with quinoline during extraction

Yubari coal vitrite was extracted with quinoline at 420° C for 0–4 h and the products were separated into several fractions. Quinoline solubles (QS) and insolubles (QI) increased with time and the total recovered weight became nearly 200% of the original weight of the coal. A large part of this weight increase was due to the contribution of the formation of biquinoline and to quinoline addition to coal. Depolymerization to smaller molecules and polymerization to QI took place simultaneously via the addition of quinoline and the production of biquinoline.