催化湿式氧化处理造纸废水的研究

以过渡金属氧化物CuO为活性组分,采用催化湿式氧化法处理造纸废水,考察Cu负载量、催化剂用量、反应温度对废水COD去除率的影响。结果表明:固定氧气分压在2.5MPa和反应时间3h,催化剂用量为3g,Cu负载量为4%,反应温度为220℃,500mL浓度为3250mg/L造纸废水的COD去除率为90%,色度去除率为89%,pH值由9.6变为7.8。另外,对催化剂进行再生处理和稳定性测试。结果表明:450℃下活化3h,在上述相同反应条件下,对原废水的COD去除率降低为88%,重复使用9次后对废水的COD去除率仍能保持在85%左右。     

High-resolution modeling and evaluation of ozone air quality of Osaka using an MM5-CMAQ system

High-resolution modeling approach is increasingly being considered as a necessary step for improving the monitoring and predictions of regional air quality.This is especially true for highly urbanized region with complex terrain and land-use.This study uses Community Multiscale Air Quality (CMAQ) model coupled with MM5 mesoscale model for a comprehensive analysis to assess the suitability of such high-resolution modeling system in predicting ozone air quality in the complex terrains of Osaka,Japan.The 1-km and 3-km grid domains were nested inside a 9-km domain and the domain with 1-km grid covered the Osaka region.High-resolution Grid Point Value-Mesoscale Model μgPV-MSM) data were used after suitable validation.The simulated ozone concentrations were validated and evaluated using statistical metrics using performance criteria set for ozone.Daily maxima of ozone were found better simulated by the 1-km grid domain than the coarser 9-km and 3-km domains,with the maximum improvement in the mean absolute gross error about 3 ppbv.In addition,1-km grid results fared better than other grids at most of the observation stations that showed noticeable differences in gross error as well as correlation.These results amply justify the use of the integrated high-resolution MM5-CMAQ modeling system in the highly urbanized region,such as the Osaka region,which has complex terrain and land-use.     

珠江广州河段着生藻类的群落结构及其与水质的关系

于2007年6月、7月和9月,采用玻璃挂片法对珠江广州河段9个断面处着生藻类的分布状况进行了调查,同时测定了叶绿素a、总氮、总磷、溶解氧、pH等环境因子.本调查共观察到着生藻类35种,主要以丝状绿藻占据优势,其中毛枝藻是绝对优势种,其最高数量百分比达97.4%;而附着在绿藻藻体的一些硅藻,如异极藻、脆杆藻也是常见优势物种.着生藻类数量丰富,为3.16×104-3.06×106cells·cm-2;种类多样性较低,Shannon-Weaver种类多样性指数为0.15～2.68.从总氮和总磷含量来看,珠江广州河段水质为Ⅲ类至Ⅴ类之间.调查期间,2007年7月12日举行了广州市万人游珠江活动,由于活动期间采取的一些截污治理措施,6月、7月水质特别是广州市区河段水质有所好转;但活动过后,营养盐特别是总磷浓度迅速上升,叶绿素a含量和着生藻类数量急剧增加.研究结果说明,珠江广州河段水质能够得以改善,但需要采取持续而有效的措施防止水质的进一步恶化,才能保证珠江水资源的可持续发展.     

Development and application of a two-dimensional water quality model for theDaqinghe River Mouth of the Dianchi Lake

Water quality models are important tools to support the optimization of aquatic ecosystem rehabilitation programs and assess their efficiency. Basing on the flow conditions of the Daqinghe River Mouth of the Dianchi Lake, China, two-dimensional water quality model was developed in the research. The hydrodynamics module was numerically solved by the alternating direction iteration (ADI) method. The parameters of the water quality module were obtained through the in situ experiments and the lab analyses that were conducted from 2006 to 2007. The model was calibrated and verified by the observation data in 2007. Among the four modelled key variables that were water level, CODcr, NH3-N and PO4-P, the minimum value of the coefficient of determination (CoD) was 0.69, which mean the model performed reasonably well. The developed model was then applied to simulate the water quality changes at the downstream cross-section assuming that the designed restoration programs were implemented. According to the simulated results, the restoration programs could cut down the loads of CODcr and PO4-P about 15%, however, they would have very little effect on the NH3-N removal. Besides, the water quality at the outlet cross-section would be still in class V (3838-02), indicating more measures should be taken to further reduce the loads. The study demonstrated the capability of water quality models to support aquatic ecosystem restorations.     

废黄河水质的多元统计分析

用主成分分析的方法,找出影响废黄河2007年水质的主成分,计算各样本的主成分得分,用聚类分析的方法将样本水质分类,结合分类结果及水质综合评分对各样本水质进行评价。     

滇池大清河河口二维水环境模型研究与应用

以滇池大清河河口为对象,根据其水动力特征,建立了二维水环境模型.其中水动力模块采用交替方向迭代法进行数值求解,水质模块中参数的取值通过2006年和2007年现场原位实验和实验室模拟实验获得,并利用2007年的实际监测数据对模型进行率定和验证.运用率定的模型,模拟了生态修复工程实施后大清河人湖控制断面的水质变化情况,以期为治理方案的优化和效果评价提供参考.     

基于小波神经网络的芦苇潜流人工湿地水质预测

人工湿地系统对污水的处理效果好,工艺简单,投资运行费用低,但影响其出水水质的因素很多,并且往往是非线性的,因此目前很难将这些影响因素模型化并用于水质预测. 已有的预测方法不是过于复杂就是预测精度不高. 神经网络是一种具有较强预测能力的新方法,适用于各种非线性模型的预测. 在小试研究的基础上,使用3种不同的、经过训练的小波神经网络,对芦苇潜流人工湿地沿程各采样口的水温,ρ(DO),pH,Eh和ρ(COD_Cr)等水质指标进行了预测. 结果显示,各指标的平均相对误差分别为:水温≤4.21%,pH≤1.36%,ρ(DO)≤9.77%,Eh≤6.50%,ρ(COD_Cr)≤17.76%,表明小波神经网络模型适用于人工湿地模型的预测.      

沂河4条支流浮游植物多样性季节动态与水质评价

2006年11月—2007年8月对沂河4条支流水体浮游植物展开调查. 结果表明:东汶河、蒙河、涑河和柳青河内检测到的浮游植物分别为75,67,70和80种,浮游植物种类组成和细胞密度季节变化明显. 东汶河、蒙河、涑河和柳青河水体浮游植物Shannon-Wiener指数分别为2.97～3.96,3.05～3.35,2.86～4.02和1.74～2.89;Margalef指数分别为2.92～4.42,2.44～4.03,3.07～5.38和1.23～2.76;Pielou指数分别为0.78～0.92,0.71～0.94,0.73～0.89和0.48～0.90. 4条支流的细胞密度分别为1.54×107～5.69×107,0.28×107～12.64×107,0.97×107～3.19×107和4.17×107～9.96×107 L-1. 综合水质评价结果:东汶河和蒙河为β-中污型—寡污型,涑河为β-中污型—清洁型,柳青河为α-中污型—β-中污型. 水质从优至劣排序为涑河＞东汶河＞蒙河＞柳青河. 东汶河和涑河为温度制约型,蒙河和柳青河为温度和营养盐制约型.      

上海中心城区苏州河沿岸排水系统降雨径流水文水质特性研究

为了解城市合流制管道系统降雨径流的水文水质变化过程与特征,于2007年7～9月对上海中心城区合流制排水系统(CSS)4类强度降雨(小雨、中雨、大雨和暴雨)的降雨量、径流量和污染浓度进行了同步连续监测与分析.结果表明,径流过程线滞后于降雨过程线约15～25 min,形态与降雨过程线相似,波动幅度低于降雨过程线.4类强度降雨的径流系数分别为：0.33、 0.62、 0.67和0.73.CSS基本存在30/30标准的降雨径流初始冲刷现象,污染物浓度过程线滞后于降雨过程线约30～40 min. 4类强度降雨径流的pH值和重金属Cu、Zn、Cr、Cd、Pb、Ni的事件平均浓度(EMC)均符合地表水环境质量标准Ⅴ类水要求,COD、BOD₅、NH⁺₄-N和TP的EMC的变化范围分别为225.0～544.1、 31.5～98.9、 8.9～44.2和1.98～3.52 mg·L^-1,平均分别超过Ⅴ类水标准9.3、 5.6、 11.7和6.1倍,接近国外城市CSS的平均污染水平.SS与COD、BOD₅、NH⁺₄-N和TP在P<0.01水平上均具有一定的正相关性(R为0.359～0.736),颗粒态有机类和营养类污染物的比例平均为70.21%.     

基于遗传集对分析的空气环境质量评价

集对分析是针对确定与不确定问题进行定量分析的一种方法,而表征差异度系数i的取值,一直没有确定的方法,即使在确定了同一度、差异度、对立度之后,整个联系数仍因i的不确定取值而呈现既确定又不确定的特征。文章将遗传算法应用于联系数表达式中i值的优化求解,使得联系数确定化,并结合实例对空气环境质量进行评价,评价结果与用其它方法评价结果比较表明该方法的可行性。