Wastewater reclamation and reuse in China: Opportunities and challenges

The growing water stress both in terms of water scarcity and quality deterioration promotes the development of reclaimed water as a new water resource use. This paper reviewed wastewater reuse practices in China, and the opportunities and challenges of expanding reclaimed water use were analyzed. Rapid urbanization with the increasing of water demand and wastewater discharge provides an opportunity for wastewater reuse. The vast amount of wastewater discharge and low reclaimed water production mean that wastewater reuse still has a great potential in China. Many environmental and economic benefits and successful reclamation technologies also provide opportunities for wastewater reuse. In addition, the overall strategy in China is also encouraging for wastewater reuse. In the beginning stage of wastewater reclamation and reuse, there are many significant challenges to expand wastewater reuse in China including slow pace in adopting urban wastewater reuse programs, the establishment of integrated water resources management framework and guidelines for wastewater reuse programs, incoherent water quality requirements, the limited commercial development of reclaimed water and the strengthening of public awareness and cooperation among stakeholders.     

造纸达标废水回用的实验研究

通过实验论证了造纸达标废水回用于生产或农灌的可行性，同时对各种回用方法存在的问题提出了相应的对策和建议，为造纸废水的排放去向提供了新思路。     

Water reuse in tannery beamhouse process

In tanneries, the phases of conditioning and preparing the hide for tanning, as well as the transportation and fixation of tanning substances, are all carried out in aqueous media. Most of the steps of these processes are carried out with fresh water, which is used as a vehicle for the diffusion of chemical products and the extraction of undesirable materials from the hide. The objective of this study is to provide the minimization of water consumption at tanneries by applying the reuse of water at some stages of the process. Alternatives for water reuse were evaluated through analysis of the process wastewater to determine the concentration of some contaminant parameters. In tests with half-hides, the possibility of reusing the liquors from the 2nd bating washing in the 1st bating washing, and of reusing the liquors from the pre-deliming washing in the pre-deliming operation, was verified. In industrial scale the water reuse from a mixture of bating washings in the deliming and deliming bating was tested successfully. The quality of wet-blue leather analyzed in the systems with and without water reuse did not show any considerable differences and satisfies the tannery specifications. Finally, a mathematical program for mass integration was applied to solve the problem of water reuse in the beamhouse steps.     

Initiating automotive component reuse in Malaysia

As the production of local vehicles increases, the impact of end-of-life vehicles (ELVs) wastes to the environment will also increase. ELVs recovery including reuse, remanufacture, and recycle apparently become a strategy in solving this environmental problem. This study identifies the existing conditions of automotive reuse in Malaysia by conducting some interviews in selected local automotive and automotive component manufacturers. Results from the interviews indicated that reuse of automotive components in newly manufactured vehicles has never been practiced by the selected companies. However, there is interest among respondents in developing automotive components for after-market reuse. Some strategies were proposed in this study to initiate automotive components reuse in the local automotive manufacturers including the establishment of the end-of-life directive, enhance research and development on design for reuse and increase reusability and economic benefits of reuse.     

Simulation of irrigation reuse system nitrate losses and potential corn yield reductions

Places, where intensive row crop irrigated farming is practiced, are experiencing nitrate contamination of groundwater. The farmers are increasingly becoming aware of high nitrate concentrations in the groundwater. As a result, farmers have started to test their groundwater for nitrate concentrations and take account of this concentration in their crop nitrogen budget. If a farmer utilizes an unlined reuse pit and groundwater nitrate concentration to base his nitrogen fertilizer budget on, he may underestimate his nitrogen fertilizer requirement for a given yield goal because of nitrate loss out of the reuse pit. The objective of this study was to compute: (1) nitrate loss from the irrigation reuse pit during an irrigation season, 1 July to 31 August; and (2) the potential corn yield reduction for a field receiving irrigation water from the reuse pit. A computer program based on the Green–Ampt equation was written to simulate these losses and yield reductions. Use of the Green–Ampt infiltration equation allows for a two-layer reuse pit, which may have a clay liner on top of the native soil material. To conceptualize the magnitude of water loss volumes and mass of nitrate leached, the reuse pit was assumed to serve a 32.4-hectare field. The results show that lining the pit with clay can significantly reduce nitrate leaching from a reuse pit and cut yield losses. The results also show the importance of a lined reuse pit in sandy sub-soils. Budgeting for crop nitrogen needs assuming irrigation water from the pit with a substantial nitrate concentration could result in crop nitrogen stress. If ponding were also considered in the reuse pit, it would increase the nitrate and yield losses from the reuse pit.     

太原市中水利用现状分析及回供模式研究

通对太原市中水利用情况进行分析,提出城市污水厂中水及建筑中水回用方向,并探讨了适合太原市的中水回用模式。分析表明,太原市中水回用率低,应加快中水工程建设,优先发展污水厂中水回供工业、景观用水的同时进行建筑中水回供。结合地形特点及城市建设时序,针对老城区、新城区、城市边缘地区及工业区采取了不同的回供模式进行相互结合和补充。     

废旧轮胎的热能利用和热分解

对废旧轮胎的热能利用和热分解技术进行了综述。热能利用介绍了作为锅炉燃料和水泥燃料使用;热分解介绍了制备液体燃料和炭黑。     

浅论工业固体废物的资源化和减量化

从工业固体废物所具有的资源性特征出发,简要论述了工业固体废物资源化和减量化的重要意义。通过对资源化前景的分析,提出了发展社会化,专业化资源再利用和加强立法保障的对策建议。通过对国内外废物减量化的一些实例分析,论述了废物减量化的根本途径和今后的发展方向。     

探析清洁生产模式在化工企业的应用与效益

介绍了河南神马尼龙化工公司的生产工艺及存在的主要环境问题,指出进行清洁生产的必要性和可行性,并从生产工艺改进、水再生及回用、设备改造、废物回收利用及清洁生产管理等多个方面介绍了河南神马尼龙化工公司实施清洁生产的具体措施,分析了该企业实施清洁生产后产生的效果,实施后达到了充分优化工艺、回收资源、降低系统能耗、减少污染排放、保护环境并取得了良好经济效益和社会效益的三赢目的,对相关企业起到相应的参考作用,从而可以加快清洁生产在化工企业的应用.     

An effective technique for wastewater minimisation in batch processes

This paper presents a mathematical formulation for freshwater and wastewater minimisation in multipurpose batch plants. The minimisation of wastewater is achieved through the exploitation of recycle and reuse opportunities. A superstructure that entails all possible recycle and reuse possibilities is used as the basis for the formulation. The existence of an optimal production schedule, which provides starting and finishing times for water using operations, is assumed. The paper addresses the specific case where the contaminant concentration in the outlet water stream from each operation is maintained at its maximum. This condition allows the overall model to be cast as a mixed integer linear programming (MILP) problem for which global optimality is guaranteed. The effectiveness of the developed formulation is demonstrated through a published literature example and a practical case study.     

Integrated water resource management model for process industry in Lithuania

Water resource management has become an important operational and environmental issue. The increasing costs of dependable water supplies and wastewater disposal have increased the economic incentive for implementing technologies that are more environmentally friendly, and that can ensure efficient use of natural resources. A structured “integrated water resources management,” (IWRM) model for water management is presented as a useful tool for research into complex water using production systems in industrial companies. The step-by-step procedure and the consistent relationships between the diagram types allow straightforward implementation of water saving projects. By performing various case studies, it became clear that the IWRM model is applicable to various types of water using industrial companies. Therefore, wastewater reclamation and reuse are effective procedures for more sustainable industrial development programs.     

甘肃河西保护地水热资源及其在栽培中的再利用研究

通过试验，用气候学原理，对保护地内水热资源的再利用作了系统分析，定量得出再利用资源值后，将其结果应用到瓜菜生产中，得出当地瓜菜生产的适播期和部分热量指标，为保护地设计提供了理论依据。     

甘肃河西保护地水热资源及其在栽培中的再利用研究

通过试验,用气候学原理,对保护地内水热资源的再利用作了系统分析,定量得出再利用资源值后,将其结果应用到瓜菜生产中,得出当地瓜菜生产的适播期和部分热量指标,为保护地设计提供了理论依据。     

城市废水资源化面临的挑战及其对策

城市废水资源化对于缺水城市或水资源污染严重的城市具有十分重要的意义。本文论述了当前城市废水资源化实践中面临的发展战略、立法、评价体系、水质标准、处理技术、设施建设、管理水平、公众态度等方面的障碍和挑战，提出了加强制定有关城市废水资源化的法规和政策、制定合理的回用水水质标准和规范、加强宣传教育、发展运行稳定且高效低耗的废水处理工艺以及将废水资源纳入整体的水资源管理体系等对策和建议。     

镁砂企业发展循环经济探析——以中兴矿业为例

镁砂生产是污染大、高耗能行业,生产过程中产生大量粉尘及固体废物。以辽宁中兴矿业集团有限公司为例,介绍镁砂企业如何实施循环经济理念,把经济活动组织成一个“资源-产品-废弃物-再生资源-再生产品”的循环生产新模式,通过“减量化、再利用、再循环”,使所有的物质和能源在这个不断进行的经济循环中得到合理、持久的利用。     

工业用水价格杠杆的有效性——基于联立方程模型

对于工业用水而言,价格杠杆的有效性以及用水价格上涨能否提升工业用水重复利用率,对推进工业节水以及工业转型发展具有重要意义。基于2016年中国地级以上城市的216个数据,利用联立方程处理内生性问题,其三阶段回归结果估计所得工业用水价格弹性为-3.423,即价格每上涨1%,工业用水需求量将减少3.42%,这一结果高于农业、居民生活用水价格弹性。另外,进一步从工业用水特征出发,研究讨论价格杠杆能否提高工业用水重复利用率。分别运用普通最小二乘法和加权最小二乘法探讨水价对工业用水重复利用率的影响,结果表明：水价与工业用水重复利用率显著正相关。因此,提高工业水价能促进工业循环用水,进而实现节约用水。     

甲醛生产装置的节能改造

甲醛生产过程中需要并产生大量的热能,在清洁生产思想指导下对原生产工艺进行改造,将急冷器改为甲醛余热炉,新增尾气炉将原对空排放的尾气燃烧,并利用两炉产生的热能生产蒸汽供生产中使用,新增的玻璃钢冷却塔使部分水循环利用。     

Optimization of water networks in industrial processes

Industry is responsible for high water consumption and it has become one of the main sources of water resource deterioration. However, industries are seeking alternatives that minimize the impact of using these natural resources. Some of the alternatives for reducing water consumption involve the reuse and/or recycling of wastewater. This study aims to seek alternatives to optimize water networks, minimize freshwater consumption and/or reduce costs. A non-linear program (NLP) model targeting the minimization of freshwater consumption and/or operating costs was developed. The model is based on the conservation equations of chemical species (contaminants) and mass (water). Options to reduce the cost and consumption of networks with and without regeneration processes are presented. The solutions are identified using a two-step procedure in which cost is optimized while the previously obtained minimum freshwater consumption remains fixed. The results showed excellent agreement with results reported by other authors.     

小麦燃料乙醇循环产业生态足迹分析

为提高循环产业研究结果的可比性,以小麦燃料乙醇生产为例,采用生态足迹方法对各子系统的生态占用、资源循环利用和污染排放等进行分析.小麦燃料乙醇循环产业包括农业生产、乙醇生产、循环生产和废物处理4个子系统.结果表明:小麦燃料乙醇循环产业链的延长将增加生态足迹,其中农业生产子系统生态足迹占系统生态足迹的比例最大,主要是因为该子系统中耕地占用较大;生态足迹的经济效益随产业链的延长而增加,说明延长产业链可以提高资源利用效率;循环生产和废物处理子系统解决了乙醇生产过程中环境污染问题;系统的能源足迹和水足迹占用比例较大,应考虑降低能耗和水耗.结果也表明,生态足迹评价方法能够全面反映循环产业各子系统资源利用和环境污染状况,是评价循环产业系统的有效手段.      

水厂排泥水的处理技术：分离水回用 泥饼综合利用及铝盐回收

介绍了水厂排泥水处理后,分离水的水质和回用、泥饼制砖和污泥用作水泥掺合料的方法和试验结果,以及铝盐回收的工艺。