废水处理仿真基准模型BSM1简介

文章比较详细地介绍了欧盟科学技术合作组织所研究的项目中，一个关于水处理的仿真基准模型（BSM1）。该模型建立在活性污泥法处理废水的基础之上，所选择的建模对象是一种简单常见的生物反应器和二次沉淀池组成的活性污泥水处理系统，致力于C、N的去除。应用该模型可以很方便地进行水处理控制方案之间的效果比较，对于世界各地的水处理研究机构之间的沟通有很大的帮助。文章结尾部分还对该模型存在的缺陷和今后的发展方向做了分析。     

活性污泥工艺的多目标优化分析

研究了多目标优化方法在活性污泥工艺优化中应用的可行性,以国际水协(IWA)发布的基准仿真模型BSM1的工艺流程为对象,以出水水质、过程能耗和反应池体积的指标为优化目标,以反应池池容(5个)、混合液回流量、污泥回流量、污泥排放量、反应池氧气传质系数(3个)等11个变量为决策变量,构建了基于BSM1的多目标优化模型,并利用MatLab非支配排序遗传算法NSGA-II进行求解,获得了BSM1多目标优化模型的Pareto解.研究结果表明,在Dry进水条件下,通过将体积指标增大4.1%,可以明显改善出水水质指标(降低81.5%),能耗指标也能得到一定改善(降低13.3%);在3种进水条件(Dry,Rain,Storm)下,相对于BSM1工艺参数的缺省值,利用本研究的优化解作为工艺参数,均能不同程度改善出水水质、降低能耗.研究结果显示,在活性污泥过程不同目标之间进行权衡可以通过多目标优化方法来实现.     

基于降维状态观测器的曝气量最优控制仿真研究

为降低污水处理厂曝气过程的能耗,对曝气系统的优化控制进行了研究.首先,建立了基于活性污泥模型ASM1的曝气系统的简化模型;然后,利用降维状态观测器重构在线不可测状态,提出了基于降维状态观测器的曝气量最优控制策略;最后,将该优化控制策略应用于污水处理基准仿真模型BSM1,仿真采用晴天进水数据.结果表明,与溶解氧的PID控制相比,最优控制在保证出水氨氮浓度和化学需氧量等水质的情况下,降低了曝气量和出水总氮浓度,同时曝气能耗相比PID控制可下降5%以上,并且改善了出水指数.     

浅谈A~2O活性污泥系统的模拟和验证

国际水质协会(IAWQ)推出的活性污泥数学模型系列(Activated Sludge Model 1~3),即ASM模型。本文以数学软件Mat Lab作为研究工具,使用国际水协(IWA)公布的活性污泥一号模型(ASM1)对浙江某污水厂的A2O工艺建立数学模型并且加以模拟,并将模拟结果和该厂同期的水质监测结果进行横向比较,发现两者结果基本吻合,偏差在可容忍的范围之内。     

理化性质对土壤吸附-解吸苄嘧磺隆的影响

为探讨土壤理化性质对其吸附-解吸BSM(苄嘧磺隆)的影响,采用批量平衡法研究了采自我国东南沿海和中部14个省区的21个土壤样品对BSM的吸附-解吸行为,以及BSM吸附-解吸行为与土壤pH、w(有机质)、w(TN)、w(黏粒)、CEC(阳离子交换量)等理化性质的关系. 结果表明:BSM在土壤中的等温吸附线可用Freundlich方程进行拟合,不同土壤对BSM的吸附强度差异较大,K_f (Freundlich常数)介于0.52~24.05之间. 土壤pH、w(有机质)是影响BSM吸附的主要因素,二者对K_f的解释率为58.1%;土壤对BSM的吸附还受w(TN)、w(黏粒)等的影响. 土壤对BSM的吸附-解吸存在滞后现象,HI(迟滞系数)与土壤pH呈极显著负相关,与w(黏粒)呈显著正相关,其中土壤pH对HI的解释率为33.0%. 吸附平衡溶液pH与K_d (分配系数)呈极显著负相关,对其进行调节可显著改变土壤对BSM的分配能力.      

A/O法活性污泥系统计算机模拟研究

介绍了以活性污泥 1号模型 (ASM1 )和固体通量沉淀模型为基础 ,结合反应器原理 ,用VB6 .0计算机语言建立A/O法活性污泥模拟器的方法 ,探讨了A/O法活性污泥系统的模拟工艺流程、各组分的物料平衡关系和欧拉法数值积分的步长选取等问题。模拟器的校准结果表明 ,该模拟器建立的思路和方法完全正确 ,可以用于A/O法活性污泥系统的模拟和预测。     

SimuLink模拟活性污泥工艺的研究

以数学软件matlab内嵌的SimuLink工具箱为研究工具,结合国际水协( IWA)提出的活性污泥一号模型(ASM1)对欧盟科学技术合作计划(COST)提供的AO标准工艺流程建立数学模型并加以模拟,将模拟结果和COST提供的标准模拟结果进行比较,在各级反应器内的两者结果基本匹配,认为模型的建立、模拟结果合理可靠,基于该工艺模型的拓展模型和变型可进一步为实际工艺的设计与运行提供参考。     

活性污泥对四种非极性有机物的吸附

以苯酚、氯仿、氯苯和萘作为目标有机物,进行了活性污泥吸附非极性有机物的试验研究,根据活性污泥对非极性有机物的吸附由表顽吸附和分配两个部分组成的假说,建立了相应的数学模型q=k1Ce^1/k k2Cr,试验结果与模型比较吻合。     

试论ASM水质特性参数测定方法

综述了活性污泥数学模型的相应理论及发展历程.主要介绍了广泛应用的ASM模型,并详细介绍了模型中的水质特性参数(Ss、S1、Xs、X1)的各种测定方法.     

简化活性污泥数学模型在城市污水厂中的应用

以活性污泥 1号模型 (ASM1 )为开发平台 ,建立了简化的活性污泥数学模型 (ASM CN)。该模型主要描述了碳氧化和硝化过程 ,其中模型组分、反应过程和参数的数量都少于ASM1 ,从而提高了该模型在城市污水厂中的实用性。通过测定模型组分、化学计量系数和动力学参数 ,为模型的应用提供了重要的前提和基础。最后利用ASM CN模型对实际城市污水厂的运行进行了动态模拟 ,模拟结果良好 ,验证了ASM CN模型的实用性和有效性 ,并且也验证了模拟程序的准确性。     

镉和乙草胺、苄嘧磺隆对水稻吸收能力的影响

为探讨镉和两种常用除草剂的复合污染对水稻吸收必需矿质元素影响,采用水培法研究了镉(Cd)、乙草胺(AC)和苄嘧磺隆(BSM)在单一及复合污染条件下处理水稻幼苗72h及解除污染并恢复培养96小时后,水稻基本营养元素含量的变化,并对水稻幼苗根系损伤情况也进行了研究。研究发现:Cd和AC、BSM单一和复合处理降低了水稻根系Mn、Cu、Zn的含量。AC单独处理增加了水稻根系Fe的含量,Cd与AC、BSM联合作用时则降低了水稻根系Fe的含量。AC单一及Cd与AC和BSM的复合作用能增加水稻地上部分Fe的含量,最高可达对照的4.5倍。Cd降低了水稻幼苗对Mg的吸收,而AC和BSM却能促进对Mg的吸收。水稻幼苗经96h的恢复培养后,其根和地上部分叶营养元素含量也发生了一些重要的变化,水稻幼苗地上和地下部分Cd的含量发生了显著性下降。Cd和乙草胺、苄嘧磺隆在单独和联合作用下根系和叶片相对电导率、MDA含量都较对照有所升高,而根系活力下降。     

Study of control strategy and simulation in anoxic-oxic nitrogen removal process

The control strategy and simulation of external carbon addition were specially studied in an anoxic-oxic(A/O) process with low carbon: nitrogen(C/N) domestic wastewater. The control strategy aimed to adjust the flow rate of external carbon dosage to the anoxic zone, thus the concentration of nitrate plus nitrite(NOx^- -N) in the anoxic zone was kept closed to the set point. The relationship was studied between the NOx^- -N concentration in the anoxic zone(SNo) and the dosage of external carbon, and the results showed that the removal efficiency of the total nitrogen(TN) could not be largely improved by double dosage of carbon source when SNO reached about 2 mg/L. Through keeping SNO at the level of about 2 mg/L, the demand of effluent quality could be met and the carbon dosage could be optimized. Based on the Activated Sludge Model No. 1 (ASM No. 1), a simplified mathematical model of external carbon dosage was developed, Simulation results showed that PI controller and feed-forward PI controller both had good dynamic response and steady precision. And feed-forward PI controller had better control effects due to its consideration of influent disturbances.     

Analysis of culturable and unculturable microbial community in bensulfuron-methyl contaminated paddy soils

To investigate the influence of bensulfuron-methyl(BSM)on culturable microbial quantities and unculturable microbial community structures,conventional and molecular biological methods were employed in five BSM treated soils with three replications,respectively. The results obtained with traditional culture-dependent methods showed that a low-level of BSM had slight and transient effects on culturable microorganisms;nevertheless,high concentration of BSM resulted in a dramatic decrease in bacterial colony fo...     

Adsorption characteristic of bensulfuron-methyl at variable added Pb^2＋ concentrations on paddy soils

The combined pollution of heavy metal Pb²⁺ and bensulfuron-methyl (BSM), originating from chemical herbicides, in agroecological environments has become commonplace in southern China. The adsorption of BSM on three paddy soils in the presence of Pb²⁺ was examined using high-performance liquid chromatograph (HPLC). Results indicated that adsorption of BSM could accurately be described by a Freundlich isotherm equation with correlation constant (R) > 0.98, irrespective of the presence of spiked Pb²⁺. Of the various factors influencing BSM sorption, soil pH appeared to be the most influential. The constant K_f of Freundlich isotherm equation tended to increase with increasing Pb²⁺ concentration in soil which indicated that the spiked of Pb²⁺ in paddy soils would promote the sorption of BSM. ΔG^θ of BSM in three paddy soils was less than 40 kJ/mol in all treatments, indicating the adsorption of BSM is mainly physical in nature. The elution of soil dissolved organic matter (DOM) enhanced the adsorption of BSM in paddy soils. The mechanisms involved in the promotion effects of the spiked Pb²⁺ on BSM adsorption might be the modified surface characteristics of paddy soil solids due to the soil acidification and the increase of soil organic matter concentration because of DOM binding.     

Expression of sulfur uptake assimilation-related genes in response to cadmium, bensulfuron-methyl and their co-contamination in rice roots

The responses of sulfur （S） uptake assimilation-related genes＇ expression in roots of two rice cultivars to cadmium （Cd）, bensulfuron-methyl （BSM） and their co-contamination （Cd＋BSM） were investigated by gene-chip microarray analysis and quantitative real-time PCR （QRT-PCR） technology. Treatments of Cd and Cd＋BSM induced expression of sulfate transporter and permease genes, and promoted sulfate uptake in rice roots. Cd＋BSM could alleviate Cd toxicity to cv. Fengmeizhan seedlings, probably due to Cd＋BSM promoting greater S absorption by seedlings. Cd and Cd＋BSM induced expression of sulfate assimilation-related genes, and thus activated the sulfur assimilation pathway. Cd and Cd＋BSM induced expression of phytochelatin synthase and metallothionein genes, and induced expression of glutathione S-transferases （GSTs）, glutathione synthase （GS） and S- containing antioxidation enzyme genes, which detoxified Cd2＋. It is suggested that （to cope with the toxicity of Cd, BSM and their co-contamination） the S uptake and assimilation pathway was activated in rice roots by increased expression of related genes, thus enhancing the supply of organic S for synthesis of Cd or BSM resistance-related substances.     

Adsorption characteristic of bensulfuron-methyl at variable added Pb2+ concentrations on paddy soils

The combined pollution of heavy metal Pb2+ and bensulfuron-methyl (BSM), originating from chemical herbicides, in agro- ecological environments has become commonplace in southern China. The adsorption of BSM on three paddy soils in the presence of Pb2+ was examined using high-performance liquid chromatograph (HPLC). Results indicated that adsorption of BSM could accurately be described by a Freundlich isotherm equation with correlation constant (R) > 0.98, irrespective of the presence of spiked Pb2+. Of the...     

信息约束条件下的流域农业面源污染控制优化

我国广大小流域迫切需要开展农业面源污染控制,但却面临着水质、水文、气象、土地等监测资料不足的信息约束条件。为了应对此问题,本文以具有冻融变化特征的东北地区为例,开发了一套信息约束条件下的流域农业面源污染控制优化系统。首先,提出了农业面源污染负荷的计算方法。其次,分析了流域水质的影响因素。接着,建立了面源污染输入与流域出水口水质之间的响应关系,经验证该系统输出数据与实际污染状况相吻合,能够很好地模拟流域污染状况。最后通过各种削减策略的运用,模拟出农业面源污染削减率和削减后的总氮浓度。通过采用本研究制定的控制优化方案,改变种植类型和面积以及改善施肥配施比,将污染源数据进行量化作为输入数据,经系统输出得到模拟污染输出数据,可得到较好的污染削减效果。研究结果为信息约束条件下治理流域农业面源污染提供了决策支持。     

Energy input during friction stir spot welding

Friction stir spot welding is performed on thin plates of an aluminum alloy. This paper presents the results on how the number of tool rotations affects the quality of the resulting spot weld. Different combinations of rotation rate and dwell time are investigated. A linear relationship was found to exist between the number of tool rotations completed during the spot weld and the resulting tensile shear strength. Spot welds that only completed 10 rotations were 177% stronger than those created at 50 tool rotations. The energy generated during the welding operation was quantified and also found to have a linear relationship with tensile shear strength. A modified open-loop position control system is proposed that monitors and limits the energy generated during friction stir spot welding by adjusting the dwell time.