共查询到20条相似文献,搜索用时 31 毫秒
1.
Development of maximum water recovery (MWR) networks for continuous processes based on Pinch Analysis has been rather well established. In contrast, less work has been done on the water minimisation problem for batch process systems. This work presents a two-stage procedure for the synthesis of an MWR network for a batch process system, covering both mass transfer-based and non-mass transfer-based water-using processes. The first stage of the synthesis task is to locate the various network targets, which include the overall and interval-based minimum utility targets (fresh water and wastewater flows) as well as storage capacity target using the newly developed time-dependent water cascade analysis (WCA) technique. In the second stage, a new tool called the time-water network is introduced to help in the development of the MWR network to achieve the established utility targets. This new network representation has an advantage of clearly depicting the time-dependent nature of a batch water network. 相似文献
2.
A case study for water using network of a Starch industry in the state of Gujarat, India, is undertaken with an aim to reduce demineralised water and freshwater flow rates and consequently the wastewater flow rate. The problem was identified as a multi contaminant, reuse and recycle problem. The freshwater consumption and demineralised water consumption were 100 t/h and 51 t/h respectively before modification and the network was dealing with three major contaminants such as total organic content, total dissolved solids and total suspended solids. A program was developed in MATLAB for analysis using Water Pinch. The improved water using network designed for the present work consumed less demineralised and freshwater. The reductions are of the tune of 28% and 64.38% for demineralised and fresh water respectively. Due to alteration in piping, there will be a saving of 406 026 INR per year, which will be utilized for development of efficient environment policy for the company. The entire concept had been implemented on plant level on 1st February-2009 and the reductions are of the tune of 25% and 60% for demineralised and fresh water respectively. 相似文献
3.
MBR因其显著的优势成为市政污水深度处理领域最有效的技术之一,但高昂的运行成本限制了MBR的推广应用。以北方某再生水厂大型MBR污水处理工程为例,探究所采用的新型膜装置以及合理的工艺设计对膜污染及运行能耗的控制效果。实际运行数据分析得出以下结论:1)进水污染物浓度虽然有较大波动,但其出水水质稳定,各项指标优于排放标准(DB 11/890—2012《城镇污水处理厂水污染物排放标准》)中B标准的要求。2)MBR系统采用PVDF材质,TIPS工艺制造的膜产品,膜丝强度大,组器填充密度高达895 m2/m3。3)MBR工艺采用先进的预处理系统和高强度脉冲曝气系统有效缓解膜污染,节省曝气量约25%。 相似文献
4.
神经网络模型用于数值水质模型逼近的适用性及非敏感参数的欺骗效应 总被引:7,自引:2,他引:5
水质模型被广泛应用于水环境管理和决策,但却面临着计算时间和模型应用效率等多方面的问题;利用函数映射和逼近等方法来建立水质模型的输入-输出响应关系,可有效减少计算成本并显著改善模型效率.水质模型的输入-输出响应函数关系有多种形式,本文以其中的2种为例,并分别基于2个水质模型(零维总磷模型、WASP/EUTRO5)的案例,分析和验证了神经网络模型在响应关系逼近中的适用性.案例的结果表明:神经网络函数可以有效地用于水质模型输入-输出响应关系的逼近;当网络规模超出阈值大小时,神经网络函数逼近的准确度和泛化度对网络规模不敏感.在案例研究的基础上,推导和讨论了在神经网络模型函数映射过程中所可能出现的非敏感参数的欺骗效应,以及可能由此导致的过度预测或过低预测问题;并建议在神经网络函数逼近中,应只包含水质模型的敏感参数,以防止降低神经网络模型的准确度. 相似文献
5.
Débora Campos de Faria Antônio Augusto Ulson de Souza Selene Maria de Arruda Guelli Ulson de Souza 《Journal of Cleaner Production》2009,17(9):857-862
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. 相似文献
6.
麦芽生产过程包括清选、浸麦、发芽、烘干以及除根等工序,废水主要来自于浸麦、发芽等工序。某麦芽生产厂根据麦芽过程用水和废水产生的特点,采用设备改进、加强工艺管理、用水管理、废水回用、提高员工技能等措施,通过源头削减和生产全过程控制,合理调节生产用水,降低生产用水量和废水产生量,麦芽生产水耗指标为2.4 m3水/吨麦芽。麦芽废水采用SBR工艺进行处理,出水水质满足排放标准要求。该麦芽企业废水管理和处理经验为同行业提供了较好的案例。 相似文献
7.
Optimal retrofit of water conservation networks 总被引:1,自引:0,他引:1
César Sotelo-PichardoJosé María Ponce-Ortega Mahmoud M. El-HalwagiSergio Frausto-Hernández 《Journal of Cleaner Production》2011,19(14):1560-1581
This paper presents a new general mathematical programming model for the optimal retrofit of material conservation networks considering recycle, reuse and regeneration schemes (notice that most of the previously reported methods only have considered the synthesis case, and nowadays it is very important to have strategies for the retrofit of water networks because several existing water network are functioned under suboptimal conditions because these were synthesized using inefficient approaches or because the process and environmental constraints have changed). The model considers the reconfiguration of existing networks to satisfy stricter process and environmental constraints considering the repiping for the network, the reuse of the existing treatment units, the modification for the capacity and performance of the existing units and the installation of new treatment units to reduce the overall operating cost through the reduction of the use of fresh sources. The objective function accounts for the minimization of the total annual cost associated to the retrofit process. This retrofit process involves simultaneously economic (because the reduction of the fresh sources costs) and environmental (because the reduction of the waste streams discharged to the environment and with a better quality) improvements. The applicability of the proposed model is proved through a set of example problems addressed, where no numerical complications were observed. In addition, the proposed approach is general and it can be applied to any specific case with the information required. 相似文献
8.
关于钢铁企业全膜法制取脱盐水工艺原水选择的探讨 总被引:1,自引:0,他引:1
全膜法制水系统,即超滤加二级反渗透工艺,已广泛应用于钢铁企业脱盐水的制取。为实现节能减排,越来越多的钢铁企业追求将工业污水收集后处理制成脱盐水和回用水用于生产。从全厂水量平衡、水质平衡的角度,对分别采用工业新水和工业污水作为制取脱盐水原水的工艺进行了分析比较,论证了采用工业污水作为制取脱盐水的原水是否可以真正的实现节能减排,可作为实际工程的参考。 相似文献
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10.
Chao HE Zhaolin GU Shucheng YANG Jidong LIANG Weina DAI Yanling HE 《Frontiers of Environmental Science & Engineering in China》2010,4(4):466-474
China’s paper production reached 79.8 × 106 t in 2008 and ranked number one in the world. Because of its high consumption of water, energy and materials and its serious
pollution, the present processes are not likely to be sustainable. An alternative, the closed Water Loop-Papermaking Integration
(WLPI) method, is put forward in this paper. The WLPI method can be realized in a recycled paper mill by adding technologies
and using recycled water. Many industrial case studies have shown that a large quantity of water, energy and materials can
be saved, and the quantity of waste sludge and wastewater discharge was minimized by using the WLPI method. The design of
the water reuse system, control of calcium hardness, water recycling and minimal waste sludge are discussed. Anaerobic technology
plays an important role in the WLPI method to lower cost, energy use and waste. In the brown paper and coated white board
production, zero-effluent discharge can be realized. Fresh water consumption is only 1–2m3·t−1. For the paper mills with deinking and bleaching processes, about 10 m3·t−1 of fresh water and a similar amount of effluent discharge are needed. Power saving using anaerobic technology is 70% when
recycled water is used in comparison with the conventional activated sludge process.Waste sludge can be decreased to about
5% of the initial process due to reuse of the waste sludge and the lower bio-sludge production of the anaerobic process. 相似文献
11.
Jiyong Kim Jinkyung Kim Junghwan Kim ChangKyu Yoo Il Moon 《Journal of Cleaner Production》2009,17(2):162-171
A new systematic methodology for designing wastewater and heat exchange networks for process industries involving effluent streams containing multiple contaminants is proposed. A simultaneous optimization approach mathematically combines the problems of wastewater and heat exchanger network optimization into a single step. This process includes two global iterations of a similar two-stage approach and optimizes networks for water and heat exchange simultaneously based on cost estimation. The objective function is to minimize the total annual cost of the wastewater and heat exchange network design which is subject to the mass and energy balance constraints on all the pertinent flows and to constraints related to the concentrations of contaminants. The proposed method employs a strategy to address a mixed integer non-linear programming (MINLP) formulation. Cost estimates for optimized wastewater and heat exchange networks for an oil refinery process are generated, illustrating the effectiveness of the proposed methodology. 相似文献
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以某高海拔地区污水处理厂的二级生化处理水为研究对象,通过对人工湿地进出水中COD、NH+4-N、TP浓度的变化,研究了水力负荷、气水比两个参数对人工湿地净水效果的影响。结果表明:人工湿地去除生活污水中COD、NH4+-N、TP的最佳水力负荷为0.33 m3/(m2·d)、气水比为3:1,在此最佳试验条件下,COD、NH4+-N、TP的去除率分别可达84%、69%、68%,出水水质满足《地表水环境质量标准》Ⅲ类水质标准。 相似文献
14.
印染废水处理回用工艺现状研究 总被引:1,自引:0,他引:1
印染废水产生量大、有机物含量高、具有一定的毒害性,因此印染废水的回用是降低印染废水污染和印染用水消耗的重要途径,印染废水回用包括原废水和二级生化出水的处理回用。印染废水主要回用于印染生产过程,在以印染原废水处理回用时,典型工艺是生化处理+膜分离组合工艺;在以印染废水处理后的二级生化出水进行处理回用时,其典型工艺分别是超滤+反渗透组合工艺,工艺出水可回用于印染漂洗、染色等生产过程,实现废水厂内循环利用。 相似文献
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16.
水质交易是美国提升和保持水质的创新性政策工具。美国水质交易政策完善,实施时间长、范围广,其中不乏成功案例。太湖流域化学需氧量排放交易已在浙江省的杭州、嘉兴正式开展,江苏省太湖流域化学需氧量排放交易项目正处于积极准备中。太湖流域水污染排放交易应该借鉴水质交易的经验,妥善解决交易基准、交易方资格、排放权价格、交易区域和交易比率等关键问题。 相似文献
17.
Computing payment for ecosystem services in watersheds: An analysis of the Middle Route Project of South-to-North Water Diversion in China 总被引:1,自引:0,他引:1
Zhengju Dong Yan Yan Jing Duan Xiao Fu Qingrong Zhou Xiang Huang Xiangen Zhu Jingzhu Zhao 《环境科学学报(英文版)》2011,23(12):2005-2012
An improved watershed criteria model was developed in light of research on payment for ecosystem services outflows theory. 相似文献
18.
造纸废水高效生化处理情况 总被引:2,自引:0,他引:2
阐述了某大型造纸厂的废水处理工艺及运行情况。结果表明:生物酸化单元能够降低废水的COD、SS指标、提高废水的可生化性,还能通过较长的水力停留时间有效地调节水量与水质,从而保证了二级生物氧化的稳定与高效运行。在二极生化之后,增设水葫芦吸附墉COD、SS与色度、更好地保护了天然水本的环境质量,且为实现废水的深度处理与回用建立了良好的条件。 相似文献
19.
Naoko NAKAGAWA Masahiro OTAKI Shinji MIURA Hironobu HAMASUNA Katsuyoshi ISHIZAKI 《环境科学学报(英文版)》2006,18(6):1088-1093
Sustainable sanitation is an approach for more ecological and sustainable water resources management. In this paper, we proposed one of the new integrated waste treatment systems: an "sustainable sanitation system" that includes separation of the black water from water system by a non-flushing toilet (bio-toilet), and a gray water treatment based on a biological and ecological concept. Sustainable sanitation system also converts the domestic waste to soil conditioners and fertilizers, for farmland use. As one of the case studies, Environmentally Symbiotic Housing in which people actually live using the bio-toilet for the black water treatment and the household wastewater treatment facility for the gray water was introduced. The availability of this system was investigated by analyzing the sawdust used in the bio-toilet and the quality of the effluent in the household wastewater treatment facility. As the result, the water content of the sawdust did not exceed 60% in any of the sampling points and the BOD and COD of the effluent of the household wastewater treatment facility were below 10 and 20 mg/L respectively, due to the low loading. Compared to the pollution load on the water environment created by the conventional system, it was found that the effluent of the house has a lower load than the tertiary treatment and the volume of the water consumption is 75% of the conventional system. 相似文献
20.
水资源供需矛盾与对策 总被引:1,自引:0,他引:1
一、水资源的有限性 根据自然资源的不同特点,人们通常将自然资源划分为三大类,即生物资源(可更新资源)、矿物资源(不可更新资源)和生态资源(恒定资源)。太阳辐射、热量、水分、风能、海潮等属于生态资源,这类资源具有显著的区域性特点,合理开发它们,发挥各地所长,可以永恒使用,即人们常说的是“取之不尽、用之不竭”的资源。 水资源作为恒定资源之一,是由于水资源被开发利用后,并不导致它们在地球上的总储量减少。应该指出,对水资源来说,总储量的不变,只能是从全球的宏观角度出发,这里所说的水资源是广义的概念。广义地来说,海洋、地下水、冰川、湖泊、土壤水、河川径流、沼 相似文献