Optimization of "Serpa" cheese whey nanofiltration for effluent minimization and by-products recovery

Second cheese whey (SCW) is a by-product of cheese and curd cheese production that is usually not recovered and therefore substantially contributes to the negative environmental impact of the cheese manufacture plants. Membrane technology, namely nanofiltration (NF), is used in this work for the recovery of SCW organic nutrients, resulting from "Serpa" cheese and curd production. The SCW is processed by NF to recover a rich lactose fraction in the concentrate and a process water with a high salt content in the permeate. The permeation experiments were carried out in a plate & frame NF unit, where two NF membranes (NFT50 and HR-95-PP) were characterized and tested. The NF permeation experiments were performed accordingly with two different operation modes: total recirculation and concentration. In order to select the best membrane and operating pressure for the SCW fractionation, total recirculation experiments were carried out. The NF modeling was also performed, in terms of permeate fluxes and rejection coefficients using the resistances-in-series model and the solution-diffusion model, respectively. After the membrane selection, the concentration experiments showed that the selected membrane (NFT50) at 3.0MPa allows a water recovery of approximately 80%, concentrating the SCW nutrients approximately 5 times. Therefore, the NF operation can successfully reduce the wastewater organic load and simultaneously contributes to the valorization of the cheese and curd cheese manufacture by-products.     

纳滤膜去除内分泌干扰物/医药化合物研究进展

如何有效去除水中内分泌干扰物、医药活性化合物等有机微污染物的研究逐渐增加,其中,纳滤膜由于其较高的去除率得到了广泛关注。但由于纳滤膜去除这些物质的分离机理较为复杂,有时并不明确,给实验带来较大困难。文章总结了纳滤膜去除水中内分泌干扰物/医药活性化合物的典型应用及其三种分离机理——筛分作用、电荷作用、吸附作用,并对去除过程中所产生的问题和解决方案加以总结。为今后纳滤膜去除内分泌干扰物/医药活性化合物的研究提供参考依据。     

聚酰胺复合纳滤膜的制备及除盐研究

以聚砜超滤膜为支撑膜,分别采用1,6-己二胺、邻苯二胺和哌嗪为水相功能单体,均苯三甲酰氯（TMC）为油相功能单体,通过界面聚合法制备了纳滤膜。通过过膜试验,比较了三种配方制得纳滤膜的水通量和脱盐效率;并对纳滤膜功能层聚哌嗪均苯三甲酰胺进行深入研究,探讨了哌嗪与TMC界面聚合反应的最佳胺氯比。实验结果表明,哌嗪与TMC界面聚合反应制得的纳滤膜性能优于其他两种配方,并且当两者的胺氯比约为10∶1时,所制得的复合膜具有最佳脱盐效果。     

Adoption of European Union's IPPC Directive to a textile mill: Analysis of water and energy consumption

The present study was undertaken as part of the first application and evaluation of the BREF (Best Available Techniques; BAT Reference Document) Textile Document within the context of the European Union's Integrated Pollution Prevention and Control (IPPC) Directive to a large scale textile mill in Turkey. The BAT requirements for the denim manufacturing textile mill were selected in cooperation with the factory management. Detailed mass balance calculations were conducted to evaluate the overall effect of the selected BAT options. The initial findings indicated that the adoption of the selected BAT options resulted in considerable savings in water and energy consumption in the mill. Besides the installation of flow meters and use of semi-counter current rinsing in the most water-intensive processes, minimization of wash waters in the water softening plant, reuse of the concentrate stream from the reverse osmosis plant and compressor cooling waters provided a 29.5% reduction in the total specific water consumption of the mill, reaching the lower limits suggested by the BREF Textile Document. In terms of energy consumption, use of waste heat from finishing wastewater streams in heating up the wash waters, heat insulation and maintenance applications in addition to BAT measures taken for water minimization reduced specific energy consumption by 9% achieving the limits set by the BREF Textile Document.     

Treatment of Landfill Leachate Wastewater by Nanofiltration Membrane

Abstract

Nanofiltration (NF) membrane is an alternative lower energy membrane type compared to reverse osmosis membrane. NF is suitable for rejection of ions and molecules with molecular weight greater than 200 Da. In this study leachate wastewater from a sanitary landfill site in Malaysia was filtered through a NF membrane in order to determine the rejection capability of the membrane towards pollutants such as chemical oxygen demand (COD), conductivity, nitrate, ammonia-nitrogen, and heavy metals such as Pb, Cd, Cu, Zn, Fe. The NF membrane used was HL membrane, which under the atomic force microscope (AFM) imaging, showed visible discrete pores. The overall rejections of the pollutants were more than 85% except for nitrate and ammonia nitrogen. NF can be considered an alternative for advanced filtration especially within a hybrid treatment system combining biological–physical treatment and membrane filtration.     

Process analysis and economics of drinking water production from coastal aquifers containing chromophoric dissolved organic matter and bromide using nanofiltration and ozonation

In regions characterized by water scarcity, such as coastal Southern California, groundwater containing chromophoric dissolved organic matter is a viable source of water supply. In the coastal aquifer of Orange County in California, seawater intrusion driven by coastal groundwater pumping increased the concentration of bromide in extracted groundwater from 0.4 mg l?1 in 2000 to over 0.8 mg l?1 in 2004. Bromide, a precursor to bromate formation is regulated by USEPA and the California Department of Health as a potential carcinogen and therefore must be reduced to a level below 10 μg l?1. This paper compares two processes for treatment of highly coloured groundwater: nanofiltration and ozone injection coupled with biologically activated carbon. The requirement for bromate removal decreased the water production in the ozonation process to compensate for increased maintenance requirements, and required the adoption of catalytic carbon with associated increase in capital and operating costs per unit volume. However, due to the absence of oxidant addition in nanofiltration processes, this process is not affected by bromide. We performed a process analysis and a comparative economic analysis of capital and operating costs for both technologies. Our results show that for the case studied in coastal Southern California, nanofiltration has higher throughput and lower specific capital and operating cost, when compared to ozone injection with biologically activate carbon. Ozone injection with biologically activated carbon, compared to nanofiltration, has 14% higher capital cost and 12% higher operating costs per unit water produced while operating at the initial throughput. Due to reduced ozone concentration required to accommodate for bromate reduction, the ozonation process throughput is reduced and the actual cost increase (per unit water produced) is 68% higher for capital cost and 30% higher for operations.     

A review of textile industry: Wet processing,environmental impacts,and effluent treatment methods

The word “textile” means to weave and was taken from the Latin word “texere.” Nowadays, textiles not only fulfill humankind's basic necessity for clothing, they also allow individuals to make fashion statements. As one of the oldest industries, the textile industry occupies a unique place in India. It is responsible for 14% of the total industrial manufacture in India. However, the textile industry is also considered to be one of the biggest threats to the environment. Pretreatment, dyeing, printing, and finishing operations are among the various stages of the industrial textile manufacturing process. These fabrication operations not only utilize huge quantities of power and water, they also generate considerable amounts of waste. The textile industry utilizes a number of dyes, chemicals, and other materials to impart the required qualities to the fabrics. These operations produce a significant amount of effluents. The quality of effluents is such that they cannot be put to other uses, and they can create environmental problems if they are disposed of without appropriate treatment. This review discusses different textile processing stages, pollution problems associated with these stages, and their eco‐friendly alternatives. Textile wet processing is described in detail, as it is the key process in the industry and it also generates the greatest amount of pollutants in textile processing. The environmental impact of textile effluents is discussed, as textile effluents not only impose negative effects on the quality of water and soil, they also imperil plant and animal health. In this paper, various methods for treating textile effluents are described. Discussion of physical, chemical, biological, and advanced treatment technologies of effluent treatment are included in this paper.     

Preliminary estimations of energy and cost for CO2 recovery by a membrane flash process utilizing waste thermal energy

The membrane flash process utilizing waste thermal energy was developed to achieve an energy-saving technology and to substitute it for a conventional regenerator. The operating conditions of the membrane flash at high temperature were studied. The petroleum refining process and iron manufacturing process were proposed for candidate processes that actually had waste energy sources. The DEA concentration and the flashing pressure had optimum values to improve the performance and reduce the energy consumption for CO₂ recovery. Energy consumptions and costs for CO₂ recovery in the membrane flash and chemical absorption were estimated by a process simulator and discussed under the same conditions. The membrane flash can achieve lower energy capture than the chemical absorption for the above industrial processes. The membrane flash is suitable for the CO₂ emission sources that had high CO₂ concentration independently of the plant scale. The chemical absorption can be applied if the plant scale is large and also the CO₂ concentration is low.     

Air‐Water Temperature Relationships in the Trout Streams of Southeastern Minnesota's Carbonate‐Sandstone Landscape

Carbonate‐sandstone geology in southeastern Minnesota creates a heterogeneous landscape of springs, seeps, and sinkholes that supply groundwater into streams. Air temperatures are effective predictors of water temperature in surface‐water dominated streams. However, no published work investigates the relationship between air and water temperatures in groundwater‐fed streams (GWFS) across watersheds. We used simple linear regressions to examine weekly air‐water temperature relationships for 40 GWFS in southeastern Minnesota. A 40‐stream, composite linear regression model has a slope of 0.38, an intercept of 6.63, and R² of 0.83. The regression models for GWFS have lower slopes and higher intercepts in comparison to surface‐water dominated streams. Regression models for streams with high R² values offer promise for use as predictive tools for future climate conditions. Climate change is expected to alter the thermal regime of groundwater‐fed systems, but will do so at a slower rate than surface‐water dominated systems. A regression model of intercept vs. slope can be used to identify streams for which water temperatures are more meteorologically than groundwater controlled, and thus more vulnerable to climate change. Such relationships can be used to guide restoration vs. management strategies to protect trout streams.     

纳滤膜分离技术在安全饮用水保障中的应用

纳滤膜分离技术在饮用水制备方面具有独特的作用,是保障安全饮用水生产的有效方法。本文详细综述了国内外纳滤膜技术在饮用水生产中应用研究的最新进展,以及纳滤膜对地表水或地下水中存在的各种无机、有机污染物的分离特性。     

不同操作条件对纳滤膜去除水中五价砷的研究

采用纳滤膜（NF90）过滤自配含砷水,研究在不同操作条件下纳滤膜对水中砷去除效果的影响。本实验探讨膜进水浓度、水的pH值、膜进水温度、操作压力、水中天然有机物浓度等对膜除砷效率的影响。结果表明：纳滤膜对水中五价砷（As（Ⅴ））的去除率很高,最高去除率能达到99%,在实验的前2.5个小时内,砷的去除率均在90%以上。但是,纳滤膜除砷效率随着时间变化,去除率会降低。不同的操作条件对纳滤膜除砷的影响很大,研究不同条件的影响对应用很有意义。     

Resource conservation and environmental control

The article examines the quantity and nature of resource savings that may arise through the operation of pollution control, particularly in the textile dyeing and finishing and non- ferrous metals industries. It is found that certain organizational, economic and product specific factors are associated with the extent of recycling, while the marginal cost of this is shown to be a sharply rising function.     

膜分离技术在电镀废水处理中的应用现状

膜分离技术作为一种新型分离技术,具有分离效率高、过程能耗低等特点,被广泛应用于废水处理领域。由于电镀废水污染物种．是多样,纳滤、反渗透、聚合物强化超滤、电渗析等膜分离过程作为电镀废水的处理与资源化技术被深入研究,纳滤、反渗透及其组合工艺等被应用于电镀废水的处理及其资源化,有着良好的应用前景。     

Investment Evaluation of an Integrated Steel Mill using Multiple Criteria

A conventional steel manufacturing process generates considerable amounts of reject streams and secondary raw material. These streams are either recycled back to the process or treated as waste. Recycling affects negatively on the production yield and on the controllability of unit operations. Waste represents considerable cost unless utilized in another production process as raw material. In these streams, there exists a potential to use the chemical elements more effectively. Therefore, it might be interesting to find an economical technical solution to collect the streams and increase steel production.

Investments on process equipment are typically evaluated using conventional economic figures, like payback time, Net Present Value (NPV) etc. The problem with these practices is, that they consider only numerical aspects. Non-numerical and non-economical criteria are hard to cater to the evaluation. Still, they may affect on the investment profitability in the long run. Such criteria include environmental friendliness or the aspects of process integration.

The article presents a comparison of a conventional steel manufacturing process with one reject stream processing alternative. A target in the process modification is to optimize the use of material and energy within the site. The comparison is based on a balanced set of criteria that affect on the efficiency of an investment. The use of these criteria is a part of the new methodology that has been developed to evaluate investments on integrated process sites. In addition to the criteria, the complete methodology includes: 1) connection of company’s strategic issues into technical design and decision making, 2) optimization of the process and calculation of process potentials (differences in the performance values between the existing process and the modified process) through the use of process integration methodologies and 3) use of decision-making aids. The research is a part of Finnish National Technology Program, “Process-Integration 2000–2004”.     

Desorption of CO2 from activated carbon fibre–phenolic resin composite by electrothermal effect

CO₂ capture by electrothermal swing adsorption is considered superior over conventional adsorption approaches: temperature swing adsorption and pressure swing adsorption. In this work, the effects of electricity, preheating and flow rate were studied. An increase in energy input by electricity has been found able to improve desorption performance more significantly than an increase in current level. However, higher current level is recommended because it can minimise energy loss while passing electricity. Higher flow rate can also be beneficial due to the improved desorption rate and reduced desorption time. However, there is a drop in CO₂ concentration in the effluent gas. When desorption takes place at a high current level, preheating is not required as it extends desorption duration with no obvious improvement in desorption rate. CO₂ capture by electrothermal swing adsorption has also been tested with different concentrations of CO₂. It is found that electrothermal swing adsorption can be more energy efficient while dealing with higher concentration CO₂.     

Groundwater purification by membrane technology

Hyperfiltration and nanofiltration membranes were tested with different water matrices for the removal of excess fluoride from underground water. Initially, the experiments were done with synthetic samples prepared by adding known amounts of sodium fluoride and calcium chloride in distilled water. The effect of feed water composition, pH, temperature of feed water, operating pressure, and feed water flow rate on separation efficiency of both types of membrane was studied by varying one parameter at a time and keeping all other parameters constant. Thus, the optimum operating conditions for the process were determined and after that ground water samples collected from three villages of district Gurgaon, Haryana, India (Farukhnagar, Wazirpur, and Mevka) were treated under optimum operational conditions. The mass transfer coefficient and membrane parameters were estimated for each data point using two-parameter model (Film theory and Solution-diffusion model) to study the concentration polarization on membrane surface. The nanofiltration membrane showed high percentage rejection of bivalent ions when compared to monovalent ions in a binary system. But in multicomponent system, when fluoride and calcium coexisted, the removal of fluoride was comparable to calcium removal because of the low solubility product of calcium fluoride. The results with RO membrane revealed that it removes practically all the ions present in water at high pressure, which need to be passed through a lime column to remineralize the water, to make it suitable for drinking purposes, whereas by running the system at low pressure which will further reduce the cost of operation, rejection percentage goes down to get permeate of required quality.     

Modeled Sources,Transport, and Accumulation of Dissolved Solids in Water Resources of the Southwestern United States1

Anning, David W., 2011. Modeled Sources, Transport, and Accumulation of Dissolved Solids in Water Resources of the Southwestern United States. Journal of the American Water Resources Association (JAWRA) 47(5):1087‐1109. DOI: 10.1111/j.1752‐1688.2011.00579.x Abstract: Information on important source areas for dissolved solids in streams of the southwestern United States, the relative share of deliveries of dissolved solids to streams from natural and human sources, and the potential for salt accumulation in soil or groundwater was developed using a SPAtially Referenced Regressions On Watershed attributes model. Predicted area‐normalized reach‐catchment delivery rates of dissolved solids to streams ranged from <10 (kg/year)/km² for catchments with little or no natural or human‐related solute sources in them to 563,000 (kg/year)/km² for catchments that were almost entirely cultivated land. For the region as a whole, geologic units contributed 44% of the dissolved‐solids deliveries to streams and the remaining 56% of the deliveries came from the release of solutes through irrigation of cultivated and pasture lands, which comprise only 2.5% of the land area. Dissolved‐solids accumulation is manifested as precipitated salts in the soil or underlying sediments, and (or) dissolved salts in soil‐pore or sediment‐pore water, or groundwater, and therefore represents a potential for aquifer contamination. Accumulation rates were <10,000 (kg/year)/km² for many hydrologic accounting units (large river basins), but were more than 40,000 (kg/year)/km² for the Middle Gila, Lower Gila‐Agua Fria, Lower Gila, Lower Bear, Great Salt Lake accounting units, and 247,000 (kg/year)/km² for the Salton Sea accounting unit.     

Separation and recovery of carbon dioxide by a membrane flash process

A novel process for carbon dioxide (CO₂) separation, which was named a membrane flash process, was developed to realize an energy-saving technology and to substitute it for a conventional regenerator. The electric energy for CO₂ recovery in a membrane flash process using aluminum oxide and diethanolamine was lower than the thermal energy of the conventional chemical absorption process. Flashing at elevated temperature by the low temperature energy significantly reduced the electric energy and required much less membrane area. This process has potentiality of low cost capture of CO₂ when the low temperature energy, which is not available for other purposes, can be utilized to elevate flashing temperature.     

Oxygen supply for oxyfuel CO2 capture

This paper presents the results of a study to develop Air Products’ air separation unit (ASU) offerings for oxyfuel coal CO₂ capture projects. A scalable “reference plant” concept is described to match particular sizes of power generation equipment, taking into account factors such as safety, reliability, operating flexibility, efficiency, and low capital cost. We describe the selection of a process cycle to exploit the low purity requirements, as well as the options for compression machinery and drivers as the scale of the plant increases and the sizes of referenced equipment limit the possibilities. We also explore integration with other elements of the system, such as preheating condensate or heating and expanding pressurised nitrogen. In addition, we consider how the ASU affects the flexibility of the oxyfuel system and discuss how its power consumption can be reduced during periods of high power demand. Finally, the advantages and disadvantages of different execution strategies for air separation unit projects are discussed, as well as alternative commercial models for the supply of oxygen.     

Energy sub-modules applied in life-cycle inventory of processes

The heating and cooling of unit processes (utilities) are often the most significant energy fraction of a gate-to-gate life-cycle inventory (LCI) for individual chemicals. Electricity usage is typically a smaller factor. An LCI of a manufacturing process for a specific chemical has been used to identify the heating and cooling requirements. This paper demonstrates the sub-modules used to convert these utilities into actual energy-related emissions for use in the LCI of a specific chemical. Assumptions and results of the unit operation inventory data and of the potential life-cycle burdens are clearly stated, to foster the objective of transparency. A user may substitute another energy grid, fuel sources, or efficiencies based on some site-specific data. The sub-modules utilize a design basis for calculating the utility emissions. Results may be used in LCI studies in the chemical, biochemical, and pharmaceutical industries.