基于数学规划法的工业园区间接循环水网络优化

为解决工业园区水资源消耗高和水污染排放强度大等问题,整体优化园区水资源网络,实现水资源的高效利用是非常必要的。基于数学规划法,以园区企业间水耗、排水量和水质的差异为基础,兼顾经济和环境要素,构建了包括水源、处理单元以及水阱的水网络优化模型,形成适用于工业园区水资源间接循环利用的优化方法。以典型工业园区为研究对象,基于水网络优化模型,在园区最小新鲜水需求量目标下,比较了不同情景的新鲜水需求量、废水排放量和总费用。结果表明：采用间接循环水网络优化方案可使园区总新鲜水需求量减少24.7%,废水排放量减少40.5%,废水重复利用率提升40.5%,总费用比较适中,为486.09万元/a,具有较高的环境效益,该优化模型能够显著提升工业园区水资源利用效率。

     

焦化废水处理工程运行能耗的单元解析模型——以OHO流化床工艺为例

焦化废水产生于煤炭的不完全气化过程,其水质成分复杂,处理工艺技术单元多、水力停留时间长且存在多指标目标,处理过程需消耗大量能量,从若干工程实践中发现,影响焦化废水处理工程运行能耗的因素主要包括水质特性、工艺流程、运行时间、设备状况等,系统分析这些因素对运行能耗的贡献,了解耗能规律并模型化,可为焦化废水处理工程设计提供节能依据.本研究以好氧/水解/好氧(OHO)流化床工艺为核心的实际焦化废水处理工程为案例,根据耗能设备、处理目标和单元功能不同将整个处理工程分解为气浮、废水输送、泥渣输送、鼓风曝气、混合、脱水、加药、公用的8个耗能系统,分别分析各系统的耗能因子,建立模型,加权得到总能耗模型;然后分别用HRT(停留时间)法和24 h法计算能耗值,与实际24 h读表电耗值相比较评价模型的准确性.分析结果表明,焦化废水处理工程总运行能耗与进水水量、污泥量、溶解氧、硝化液回流比、进水COD、进水总氮浓度的相关性强;HRT法与24 h法得到的能耗值与实际24 h读表能耗值呈显著线性关系,R2分别为0.93和0.97,相对误差分别为4.28%~19.18%和3.45%~8.94%,模型分析值与工程实测值吻合度比较好,表明模型准确可靠.因此认为,基于耗能单元系统建立的工程系统总能耗模型可以用于预测因水质特性、工艺流程、设备条件等变化的实际工程运行总能耗,得到了建立焦化废水处理工程单元解析模型的系统性新方法.     

废纸再生造纸废水处理工程应用

废纸再生造纸废水处理工艺在广东东莞东江造纸厂应用3个月,吨成品纸耗用废纸量下降20%,成纸裂断长增加20%～30%,成纸的环压强度提高20%～30%,纸机的有效生产时间和毛布的使用寿命提高。提供了既降低生产成本又提高生产力的有效途径。     

某麦芽生产厂废水管理与处理实践研究

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。     

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.     

Eco-efficiency trends of the Flemish industry: decoupling of environmental impact from economic growth

A methodology for eco-efficiency reporting is proposed with eco-efficiency indicators for climate change, acidification, photo-oxidant formation, human toxicity, freshwater aquatic ecotoxicity, eutrophication, energy consumption and waste generation. The method is applied to emission, consumption and production data of the Flemish industry provided by the Flemish environmental agency for the period 1995–2006. For climate change, acidification, photo-oxidant formation, human toxicity, freshwater aquatic ecotoxicity and eutrophication, the eco-efficiency improved by 39, 55, 41, 58, 72 and 53%, respectively. For each of these impact categories, the total environmental impact decreased despite an increase in production, indicating absolute decoupling of environmental impact from economic growth. The eco-efficiency indicator for energy consumption and waste generation improved by 16 and 14%, respectively. However, due to the increase in production, the total energy consumption and the amount of waste generated increased: for these two environmental themes decoupling from economic growth was relative. Despite the improved eco-efficiency, industry remains one of the main polluters in Flanders. The application of the method to emission, energy consumption and production data of the Flemish industry resulted in a comprehensive and correct source of information for the general public and the government. Moreover, it can serve as a basis for economically and environmentally sound decisions and for the evaluation of the impact of former decisions.     

Cleaner production for continuous digester processes based on hybrid Pareto genetic altorithm

Pulping production process produces a large amount of wastewater and pollutant emitted ,which has become one of the main pollution sources in pulp and paper industry.To solve this problem,it is necessary to implement cleaner production by using modeling and optimization technology.This paper studies the modeling and multi-objective genetic algorithms for continuous digester process.First,model is established, in which environmental pollution and saving energy factors are considered.Then hybrid genetic algorithm based on Pareto stratum-niche count is designed for finding near-Pareto or Pareto optimal solutions in the problem and a new genetic evaluation and selection mechanism is proposed.Finally using the real data from a pulp mill shows the results of computer simulation.Through comparing with the practical curve of digester, this method can reduce the pollutant effectively and increase the profit while keeping the pulp quality unchanged.     

Cleaner production for continuous digester processes based on hybrid Pareto genetic algorithm

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草甘膦生产工艺水资源代谢分析与优化建议

以某农药集团草甘膦生产工艺为例,运用工业代谢分析方法对其水资源代谢过程进行量化分析,建立了水代谢平衡账户并绘制了水代谢图,在此基础上,识别和筛选出草甘膦生产过程中的主要用水单元及废水排放单元,并据此提出优化建议. 结果表明,草甘膦生产过程中的主要用水类别为蒸汽,其蒸汽消耗单元多且用汽量大,而换热网络单一,冷凝水浪费较严重,系统中水资源重复利用水平较差.针对该问题,从系统优化和节水管理等方面提出了工艺废水的重复利用及主要用汽单元之间的换热网络优化等建议,以期提高生产过程中的水资源利用效率.      

滨海化工区水污染物排放现状与减排潜力分析

化工产业是天津滨海新区重要的支柱产业,该行业废水因污染种类复杂,具有高盐、高毒、难降解等特点,是滨海新区污染物控源减排的主要威胁。通过对滨海化工区水污染物排放现状与减排潜力进行分析研究,得知化学原料及化学制品制造业在石化行业中耗水量最大,占石化行业总新鲜水消耗量的70.3%～80%;其废水、COD和氨氮的排放量最高;除橡胶和塑料制品业外,其他3个行业废水排放量逐年减少;滨海新区化工行业万元工业增加值水耗与全国及天津市相比存在一定差距,有较大的减排潜力;从其未来发展趋势来看,近期仍将是以污染末端治理为主要途径。但从远景来看,在生产环节减少外排污水量,大力推广清洁生产机制,建立企业间废水的循环利用模式才是其必然归宿。     

A process integration approach to industrial water conservation: a case study for an Indian starch industry

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.     

Improving eco-efficiency in the steel industry: The ArcelorMittal Gent case

In addition to CO₂ released by the combustion of fossil fuel and leading to climate change, large steelworks emit pollutants that have other environmental impacts. ArcelorMittal Gent, an integrated steelwork producing ca. 5 × 10⁶ tons of steel per year, not only decreased its specific energy consumption and CO₂-emissions, but also reduced the environmental impact of its other emissions. This is illustrated by means of the evolution of 6 partial eco-efficiency indicators for the impact categories acidification, photo-oxidant formation, human toxicity, freshwater aquatic ecotoxicity, eutrophication and water use. The partial eco-efficiency indicators are eco-intensities, defined as the environmental impact in the respective impact category, divided by the amount of liquid steel produced. In the period 1995 – 2005 these indicators decreased by 45, 4, 52, 9, 11 and 33% respectively, whereas the steel production increased by 17%. The net impact of discharges of wastewater is negligible for human toxicity and is negative (concentrations lower than in the canal water used) for freshwater aquatic toxicity and eutrophication. For acidification, human toxicity (only emissions to air) and water use, the decoupling between environmental impact and production was absolute; for photo-oxidant formation, freshwater aquatic ecotoxicity (only emissions to air) and eutrophication, it was relative.     

基于过程改变法的铁厂节水调控优化研究

将过程改变法应用到铁厂用水系统改造中,对其用水网络进行调优,实现废水排放量最小化。在厂区用水情况调查基础上,确定用水系统范围及限制杂质;并计算所确定用水系统的最小新鲜水用量和最小废水排放量;最后对其用水网络进行优化设计。改造后的铁厂用水网络新鲜水用量节约57.7%,废水排放量减少75.9%。     

废水产氢产酸／同型产乙酸耦合产酸条件优化

为了更好地发挥产氢产酸／同型产乙酸耦合系统在废水厌氧发酵生产乙酸方面的优势,有必要寻找一种简单有效的方法以获得该系统产酸的优化条件。利用经过加热处理并活化的厌氧污泥作种泥,以模拟废水中的葡萄糖为底物,针对发酵时间、底物浓度、种泥浓度、初始pH进行4因素10水平均匀设计实验,得到了乙酸生产指标与产酸条件之间关系的回归方程;也得到了以高乙酸产量为主要目标导向同时兼顾高乙酸产率和高乙酸生产强度目标的优化条件;优化条件实验乙酸浓度比均匀设计中最高乙酸浓度提高20％左右。研究表明,将均匀设计应用于废水产氢产酸／同型产乙酸耦合产酸条件优化,可以避免盲目性,迅速获得满意结果。     

Water and wastewater eco-efficiency indicators for the sugar cane industry

The consumption of large volumes of water and the generation of organic compounds as liquid effluents are major environmental problems in sugar cane processing industry. The volume of freshwater required by this industry can be significantly reduced by recovering the intrinsic water present in sugar cane. This amount of freshwater will depend on the process technology. Three new indices for sugar cane plants are introduced in this work: WIN, which indicates the efficiency of water use, and EIN1 and EIN2, which quantify Chemical Oxygen Demand of wastewater. Selected case studies illustrate the advantages of employing these indices as guides for the selection among process design alternatives that account for environmental performance.     

锐态型纳米TiO_2光催化处理含镉废水的研究

采用溶胶-凝胶法制备锐态型纳米TiO2,用XRD、SEM对粉体进行表征。在紫外光的作用下将自制纳米TiO2光催化处理废水中的Cd2+。考察反应时间、pH值、废水负荷、催化剂用量等因素对去除率的影响。实验结果表明:纳米TiO2光催化处理含镉废水的去除率高,含镉废水pH值、废水负荷、纳米二氧化钛浓度以及反应时间等因素影响含镉废水去除率。在优化的处理条件中:废水镉浓度为30mg/L,纳米TiO2投加量为3mg/L,含镉废水的pH为10,反应时间为2.5h,废水中镉的去除率可达99.52%。     

Wastewater and stormwater minimisation in a coal mine

This paper presents a case study on the application of cleaner production principles in the mining industry. The water balance prepared for the case study showed that less than 20% of the wastewater generated by the colliery is discharged off-site. The remaining 80% of the wastewater is recycled back into the colliery. Modeling of the stormwater system showed that 75% of the clean runoff becomes contaminated through poor management practices. It was also found that the present system of stormwater management causes the process wastewater management system to fail in wet weather. Improved process and stormwater management systems are proposed. Relatively simple alterations to the operation of the coal wash filtration dams are expected to reduce the periods of inefficient operation of these dams by 95% and the pumping cost by 30%. The use of stormwater diversion channels and retention basins reduces the overflow volumes of the process wastewater treatment dams in 5 year average recurrence interval (ARI) storms by 100%. The paper also includes several recommendations for reducing the production of process wastewater at source and off-site disposal of wastewater.     

浓缩果汁生产中的节水减污分析

浓缩果汁生产过程中消耗大量新鲜水,排放废水COD含量高,水质、水量波动大,传统的好氧处理方法难以取得理想效果。通过对几个典型浓缩果汁企业用水的调查和在线监测,从水量控制、废水减排、废水处理工艺等方面提出节水减污建议,实行清洁生产措施后,该企业耗水量减少了31.68%,排入污水站COD总量减少约20%。     

基于结构分解法的长江经济带产业排水量驱动因素评估

为分析长江经济带产业排水量变化的驱动因素,以2002年、2007年和2012年长江经济带11省市投入产出表、排水估计量为基础,利用基于投入产出的结构分解法对各省市数据进行比较静态分析,对驱动产业排水量变化的因素进行分解及定量评估,包括节水减排效应、投入结构效应、需求结构效应及规模效应.结果表明:①长江经济带产业排水量由增长趋势变为下降趋势,2002—2007年排水量增长了16.9%,2007—2012年排水量降低了0.4%,2002年、2007年、2012年产业平均耗水率为46%,上海市、江苏省等省市产业排水量下降趋势明显.②规模效应是驱动各省市产业排水增加的主要因素,其在2002—2007年、2007—2012年带动排水量分别增长了67%和61%;规模效应影响逐渐分化,上海市、江苏省、浙江省规模效应带动产业排水量增幅逐渐减弱.③节水减排效应是驱动排水量减少的最主要因素,其在2002—2007年、2007—2012年带动排水量分别减少了35%和60%,节水减排效应影响逐渐增强,各省市排水强度明显降低.④长江经济带大部分省市的需求结构效应驱动产业排水量不断减少,其驱动力的绝对值呈增长趋势;投入结构效应对产业排水量的驱动力较弱且变化规律性不明显.建议长江经济带通过技术进步、应用创新等提高清洁生产能力,通过需求及投入结构优化带动产业结构调整,对进一步降低产业排水量具有一定价值.      

上海市电镀废水及其重金属污泥处置现状

对上海５００多个电镀厂（点）两次调查结果表明，１９９０年与１９８５－１９８６年相比，虽然电镀生产增长约２．１倍，金属总耗量仅增加５．２％，其中毒性最大的铬耗量从占金属总耗量约１０．２％下降到７．６％；工艺用水采用全封闭或半封闭循环的厂（点）增至４９．０％，电镀废水排放量减少２２．９％；化学法处理废水的厂（点）从５５．２％增至６６．１％离子交换和电解法分别从３０．７％、７．８％降至２２．０％、３．８