水处理集成微藻生物柴油生命周期系统环境影响评价

采用生活废水的二级出水培养微藻可有效提高微藻生物柴油生产过程的环境效益，降低其环境影响。本文基于生命周期分析原理，针对结合了废水培养微藻的两种微藻生物柴油生产技术路线，即传统路线和热解酯化路线，建立了环境影响评价模型；提出了水处理集成微藻生物柴油生命周期系统评价的水处理过程替代效应的概念及其环境效益定量评价方法；通过计算对比了基于新鲜水培养微藻的两种技术路线的总环境影响指数和废水培养微藻的两种技术路线的环境效益，表明热解酯化工艺结合废水培养微藻路线相较其他工艺路线具有最小的环境影响，表明水处理过程替代效应在水处理集成微藻生物柴油生命周期系统评价中的有效性和必要性。     

Evaluating and improving environmental performance of HC's recovery system: A case study of distillation unit

Waste solvents/valuable products in the effluent stream are one of the major environmental problems in the chemical industry if not properly controlled. Separation processes are vital for the recovery of waste solvent/valuable product from the effluent stream to reduce the pollution along with improvement in economic performance. Among the various separation processes, distillation is most widely used. A number of environmental indicators, each satisfying researchers own need, and methodologies such as life cycle assessment (LCA), minimum environmental impact assessment (MEIM), waste reduction algorithm (WAR) and environmental fate and risk assessment (EFRAT) are available for evaluation of environmental performance of chemical processes. In this article, a systematic procedure, introducing an environmental performance index (EPI) based on potential environmental impact (computed from waste reduction algorithm (WAR)), energy consumption, resource conservation and fugitive emission, for evaluating environmental performance is presented. Analytical hierarchy process (AHP) is used at two levels for the determination of weighting of individual categories. The procedure is applied for the study of environmental performance of distillation column (steam stripping column) from a real chemical plant for the recovery of acetone and HC's from the off gases of the distillation fraction (DF) plant. Alternatives are compared using environmental performance index and best alternative is selected.     

Cellular-automata and individual-based approaches for the modeling of biofilm structures: Pros and cons

Fresh water shortage is one of the greatest problems of modern society; as a result, water desalination, particularly with membrane processes, is becoming increasingly important, since it makes possible the use of brackish water for potable water, or the reuse of lower-quality water for industrial, irrigation, or other uses. Membrane processes used in water desalination and wastewater treatment are often affected by the degradation of biofouling, in which biofilms play a critical role, thus making biofilm simulation models very relevant. Biofilms are highly complex and heterogeneous systems, containing cells distributed in a non-uniform manner in polymers. Two classes of models, the cellular-automata and the individual-based models, which are used to simulate the growth and development of biofilm structures as a result of microbial growth in different environmental conditions, are presented. After a short review of models presented in the last decade, we identify similarities and differences and present the environmental conditions that can be best simulated with each model type.     

Membrane bioreactor technology for wastewater treatment and reuse

Treatment technology for water recycling encompasses a vast number of options. Membrane processes are regarded as key elements of advanced wastewater reclamation and reuse schemes and are included in a number of prominent schemes world-wide, e.g. for artificial groundwater recharge, indirect potable reuse as well as for industrial process water production. Membrane bioreactors (MBRs) are a promising process combination of activated sludge treatment and membrane filtration for biomass retention. This paper will provide an overview of the status of membrane bioreactor applications in municipal wastewater reclamation and reuse in Europe and will depict their potential role in promoting more sustainable water use patterns. Particular attention will be paid to the impact of MBR technology on emerging pollutants. A case study will be presented on a full-scale MBR plant for municipal wastewater which is operated by Aquafin in Belgium.     

Evaluation of technologies for a desalination operation and disposal in the Tularosa Basin, New Mexico

According to the United Nations Environment Programme, one-third of the world's population lives in a situation of water stress. In the case of New Mexico, about 90% of the 1.8 million inhabitants depend on ground brackish water as their only source of potable water in many areas of the state. This report presents a technically-supported, economically-feasible and environmentally friendly proposal to desalinate brackish water to supply potable water to inland, isolated communities in southwest New Mexico. Several existing technologies were reviewed to identify opportunities for optimization by combining them to provide potable water and reduce the waste stream. Alternatives were studied and experimentation was conducted for some of them. The alternatives proposed were the use of natural coagulants for pretreatment, various solar collectors' arrangements for energy supply, reverse osmosis (RO), low temperature multi-effect distillation (LT-MED), multi-stage flash distillation (MSF), solar distillation (SD), and electrodialysis for desalination process; Spirulina cultivation and SD for waste treatment, and deep well injection (DWI) for waste disposal. Some alternatives were eliminated because they are either technologically or economically not feasible for this case and present high environmental impact. Three plant configurations were analyzed. Option A involves using the linear Fresnel systems (LFS) to produce steam for the first effect of a nine-effect evaporation plant. The number of effects was determined to achieve the optimal relation between equipment investment costs and steam production cost. This plant operates 8 h per day with solar energy and the rest of the 24 hour operating time is provided with fossil fuels. The waste produced will be further evaporated with SD to minimize its flow and the concentrated brine will be injected into a deep well. Option B has the same elements as option A, except that it does not consider the SD, but direct brine injection into a deep well. Option C considers the use of SD as the only process for distillation with DWI as the waste disposal method. The selection criteria for the best configuration were optimal use of solar energy resources, minimization of fossil fuel consumption and waste stream generation and disposal. Operation requirements and economic analysis were considered to select a proposal easy to implement and operate in rural isolated communities. For the following reasons option A is the best configuration to cover the necessity of potable water in New Mexico: (A) the plant is easy to construct and operate. In addition, it can handle different ranges of brackish water flow. (B) The 76% water recovery of the system almost matches the recovery achieved in a RO plant (80%), with the advantage that maintenance costs are reduced and treatment flowrates cannot be matched by the RO plant. (C) Use of the LFS reduces the emission of combustion gases to the atmosphere by 33%. This manifests as a positive point in a LCA evaluation. (D) The minimum environmental impact of the process facilitates the public involvement plan (PIP) because it gives the plant an environmentally responsible image in terms of avoiding greenhouse gases emissions. (E) The return on investment (ROI) is 10.2% at a price of $5.00/m³ of desalinated water, which is superior to the estimated minimum attractive rate of return (MARR) used for LT-MED plants as 9.5% annually.     

Environmental assessment of flue gas cleaning processes of municipal solid waste incinerators by means of the life cycle assessment approach

Life cycle assessment (LCA) is an environmental assessment tool generally applied to products but also to processes. Features of the LCA of processes are presented in this paper. This approach was used to compare two flue gas cleaning processes: the typical wet-type process and the new transported droplets column process. The LCA result shows that the global environmental burden is similar between the two processes, which confirms the viability of the transported droplets column. The distribution of the environmental burden, however, is different between the two processes. The weak points of the transported droplets column are the pollution transfer from air to water and a larger volume to stabilize. Its strong point: it is more efficient in capturing dust particles and toxic pollutants. This process could be improved from an environmental standpoint by adding an electrostatic filter upstream of the transported droplets column to capture the particles. The laboratory results of the transported droplets column need, however, to be confirmed at a larger scale.     

Development of an experimental system for greywater reuse

Greywater reuse promotes a significant reduction in potable water consumption and sewage production, once the water is used a second time for non potable purposes prior of being discharged to the sewer system. However, its quality must assure the user's safety and thus a treatment system is necessary.The present article presents a study on a low cost and easy maintenance experimental system for greywater reuse with a collection tank and a treatment system composed of a pump, filter and UV disinfection. The objectives of this study include analysis of the treatment efficiency and assessment of the quality potential of treated greywater. For this study, raw greywater was collected from washing basins of public and exclusive access toilets as well as from showers of a changing room.The experimental treatment system showed potential for greywater recovery, because of the simple, low-cost and easy maintenance features, and also because it provides high reduction of SS, COD and BOD. More significantly, no total or fecal coliforms were detected in all treated greywater samples. However, concentrations of SS and BOD after treatment were not low enough to reach the limits presented in legal and reference documents, hence further improvement procedures are suggested.     

废旧动力电池回收的环境影响评价研究

产业化制备镍钴锰酸锂有4种工艺,包括定向循环、传统湿法回收、传统火法回收和原矿冶炼。为了寻找环境影响程度最小的生产工艺,采用Eco?鄄indicator 99评价体系对4种工艺进行生命周期评价。结果表明,生产 1 000 kg镍钴锰酸锂,定向循环、传统湿法回收、传统火法回收和原矿冶炼环境指标分数分别为-11 883、-1 552、57、25 896,回收废旧电池社会意义显著。因此,从环境影响的角度选择镍钴锰酸锂三元材料的生产工艺应优先采用定向循环工艺,原矿冶炼工艺因其环境损害最大,不提倡使用。     

Klimaschonung durch Membrananwendung – Membrandestillation zur Erzeugung von pharmazeutischem Reinstwasser

Water is the most important medium in the pharmaceutical industry. The required water quality depends on the intended purpose and this in turn influences the effort involved in water treatment. Today, the production of pure water for use in the pharmaceutical industry is mainly based on multistage distillation and membrane processes, especially the combination of reverse osmosis, electrodeionization and ultrafiltration. Membrane distillation (MD) as a relatively new method is an alternative to these classic methods of pure and ultrapure water production. The treatment of pharmaceutical water from drinking water with the help of MD is presented. More specifically, the focus is on the suitability for pharmaceutical water treatment, the effect of different process parameters on the performance, and the possibility to reduce the specific energy demand.     

甲基丙烯酸甲酯-甲醇-水共沸体系萃取分离工艺模拟

针对甲基丙烯酸甲酯?甲醇?水共沸体系,分别选择水、正己烷和水?正己烷双溶剂为萃取剂建立分离流程进行模拟, 建立单溶剂、双溶剂萃取工艺过程进行全流程模拟,采用灵敏度分析优化工艺过程的溶剂比和操作温度. 结果表明,双溶剂萃取工艺比水、正己烷单溶剂萃取工艺能耗分别降低15.1%和34.9%. 采用绿色度评价方法量化3种分离工艺对环境的影响,水、正己烷、水?正己烷双溶剂萃取工艺的绿色度分别为–7.25, –21.3和–6.75 gd.     

Implementation of sustainability drivers in the design of industrial chemical processes

A methodology based on key performance indicators was developed and applied to the design of sustainable industrial processes. The methodology provides a procedure for the definition of a dynamic set of quantitative key performance indicators suitable to capture the environmental, economic and societal impacts of process options, thus, tracing the sustainability footprint of alternatives. The preliminary design of a production plant for cyclohexanone is presented as the leading case in the discussion. The influence of design choices on environmental impact profiles, economic efficiency and inherent safety performance was pointed out. The application evidenced that the definition of appropriate indicators may have an important added value in supporting design activities, both for the correct assessment of alternative options and for the proactive identification of design improvements. © 2011 American Institute of Chemical Engineers AIChE J, 2011     

Ozone Treatment of Secondary Effluent at U.S. Municipal Wastewater Treatment Plants

Ozone is a strong oxidant used to treat a variety of constituents in potable water, wastewater, water reuse, and industrial water treatment applications. Ozone is effective at oxidizing a wide range of organic and inorganic compounds and disinfection. Well-known in potable water treatment, with about 400 US installations and 3,000 world-wide, ozone has limited application at wastewater treatments, with less than 10 operating facilities in the US. The ability of ozone to significantly reduce low level concentrations of trace organic compounds, including endocrine disrupting chemicals (EDCs), pharmaceuticals and personal care products (PPCPs), and other emerging contaminants have increased interest in applying ozone in potable water and wastewater treatment. Treating at the point source discharge rather than the water supply intake may be more effective. A recent American Water Works Research Foundation (AwwaRF) report indicated high removals of many EDCs and PPCPs at typical disinfection doses. Several wastewater utilities have installed or are in the process of installing ozone to treat secondary effluent. These utilities are using ozone in a variety of ways: as a primary disinfectant, for treatment of microconstituents, and in combination with other processes (e.g. membranes and UV) to produce high-quality water for indirect potable reuse (IPR). The different applications, treatment goals and basis of process selection are compared and contrasted. Secondary benefits of ozone treatment of secondary effluent, including the use of off-gas in biological treatment is also discussed.     

Life Cycle Optimization for Synthetic Rubber Glove Manufacturing

Production of synthetic gloves may cause adverse environmental impacts, including global warming, carbon footprint, acidification, photochemical ozone formation, eutrophication, human toxicity, and water footprint. Thus, life cycle assessment is applied as an environmental management tool to evaluate its environmental impacts. Life cycle optimization is implemented to minimize energy consumption and emission of greenhouse gases by proposing five alternative process improvement scenarios. Using electricity generated from biodiesel shows the least environmental impacts as compared to the other alternatives for the production of synthetic gloves. Future economic analysis is needed to evaluate the cost feasibility of these alternatives.     

Feed water pretreatment in RO systems: unit processes in the middle east

The paper deals with the conventional physical, chemical and biological unit processes that are widely applied in the Middle East for treating feedwater to reverse osmosis (RO) systems which produce potable water from brackish groundwater and saline seawater. Depending on the quality of intake water, membrane process, posttreatment and desired quality of product water, a pretreatment system was designed. Such a system usually comprises a train of unit processes based on technical and cost considerations. Proper decision for selecting unit processes involves a thorough evaluation of available alternatives. Results of previous experiences and present guidelines and schemes that are developed combining unit processes for pretreatment of RO feed are reviewed. Through the process, the combination of pretreatment units is made in such a way so that the quality of feedwater is improved at a minimal cost for pretreatment and with minimal adverse effects on succeeding processes: membranes, storage and supply systems. Conceptual layouts of several such systems of alternatives are presented along with comparative data on expected system performance and cost.     

Efficient technologies for worldwide clean water supply

An overview of the problems associated with worldwide water shortage problem and of the increasing public participation and awareness to this problem is presented in this work. The existing water treatment processes and their importance in terms of amount, quality and cost of water produced as well as their environmental impact are illustrated. That includes a survey of the current desalination techniques in use and an overview of possible future technologies, aiming at solving different water issues.The technological developments and challenges together with new possible production modes for the future urban water planning are also presented. Finally, routes towards a modern and advanced city planning in a cheaper and more sustainable way based on a more rational use of water, by supplying water of different quality to the final users according to their requirements, as well as the employment of process intensification principles are discussed.     

Sustainability analysis and benchmarking of olive mill wastewater treatment methods

A large number of publications are available in the literature regarding olive mill wastewater treatment methods. However, none of the proposed methods can be considered as a best available method in terms of its effectiveness, and its environmental and economic impact. Using a literature survey, data were collected and evaluated in order for a sustainability and benchmarking analysis to be developed. Physicochemical, biological and advanced oxidation methods were evaluated and judged in terms of their effectiveness, environmental impact and cost. Effectiveness of each method was estimated in terms of COD and phenolic compounds reduction, environmental impact in terms of CO₂ production, while for the economic impact the operational costs were taken into account. Finally, a procedure is suggested for selection of the most appropriate method based on user preferences (in terms of effectiveness, environmental impact and cost). The present analysis showed that the most effective processes in terms of organics reduction are membrane filtration, electrolysis, supercritical water oxidation and photo‐Fenton. Lower environmental impact was found with anaerobic digestion, coagulation and lime processes, while the lowest cost category involves biocomposting and membrane filtration, thanks to the exploitation of byproducts (biocompost and phenolic compounds, respectively). © 2013 Society of Chemical Industry     

Computer-aided process engineering for environmental efficiency: Industrial drying of biomass

The idea of taking into account environmental impact criteria in the process design becomes a necessity for both the industry and governments, due to increased binding regulations. Moreover, to address the issue of integrating sustainable processes, environmental impact must be weighed and balanced against other concerns, such as economic performance, product quality, and long-term sustainability. Therefore, this study introduces a methodology for environmental impact minimization and optimization of multiple conflicting criteria. A general eco-design method for biomass drying process is proposed. The main target is to develop an assessment computer-aided process engineering tool that compares environmental impacts of different operating conditions and fuel types to support decision-makers for an improved compliance to environmental criterion and sustainability.     

Economic value and environmental impact (EVEI) analysis of biorefinery systems

The selection of product portfolios, processing routes and the combination of technologies to obtain a sustainable biorefinery design according to economic and environmental criteria represents a challenge to process engineering. The aim of this research is to generate a robust methodology that assists process engineers to conceptually optimise the environmental and economic performances of biorefinery systems. A novel economic value and environmental impact (EVEI) analysis methodology is presented in this paper. The EVEI analysis is a tool that emerges from the combination of the value analysis method for the evaluation of economic potential with environmental footprinting for impact analysis. The methodology has been effectively demonstrated by providing insights into the performance of a bioethanol plant as a case study. The systematisation of the methodology allowed its implementation and integration into a computer-aided process engineering (CAPE) tool in the spreadsheet environment.     

Economic evaluation of desalination by small-scale autonomous solar-powered membrane distillation units

Solar-powered desalination is an attractive and viable method for the production of fresh water in remote arid areas. One of the most important factors determining desalination decisions is economics. This paper presents an economic assessment performed to estimate the expected water cost, which is the ultimate measure of the feasibility of the stand-alone system. Based on the calculations, the estimated cost of potable water produced by the compact unit is $15/m³, and $18/m³ for water produced by the large unit. Membrane lifetime and plant lifetime are key factors in determining the water production cost. The cost decreases with increasing the membrane and/or the plant lifetime.     

Overview of seawater concentrate disposal alternatives

This article discusses the available alternatives for ocean concentrate disposal, site specific factors involved in the selection of the most viable alternative for a given project, and the environmental permitting requirements and studies associated with their implementation. The article focuses on the three most widely used alternatives for ocean discharge of concentrate: direct discharge through new outfall; discharge through existing wastewater treatment plant outfall; and co-disposal with the cooling water of existing coastal power plant. Key advantages, disadvantages, environmental impact issues and possible solutions are presented for each discharge alternative. Results from recent salinity tolerance and toxicity study completed at the Carlsbad, California seawater desalination demonstration plant for a variety of sensitive marine organisms are presented. The practical implementation of this study along with other methods for analysis of the environmental impact of ocean discharges from large seawater reverse osmosis plants is illustrated with case study examples.