Experimental comparative study of the secondary micro-flocculation and routine flocculation

以石家庄某水库低温低浊水为研究对象,采用有机物表观相对分子质量分级和有机物化学极性分级技术从分子水平的变化对原水溶解性有机物进行分析,并测定了其各组分质量分数与三卤甲烷生成势的相关性,获得了原水中溶解性有机物dOM去除率较低的原因,同时进行了二次微絮凝和常规絮凝的混凝试验,考察了水体浊度、zETA电位、抽滤时间、颗粒数和有机物等各指标的变化情况。结果表明,二次微絮凝比常规絮凝有更强的混凝去除效果,当聚合氯化铝PAC总投加量为13 Mg/l、絮凝时间为3 MIn时,滤后水浊度可达到0.1 nTu以下。二次微絮凝不但改变了胶体的zETA电位,增加了絮凝效果,而且提高了对有机物和颗粒数的去除率,抽滤时间也相应缩短。The present paper attempts to introduce its study on the low temperature and low turbidity water originally taken from a reservoir of Shijiazhuang as a research subject for our research topic on the secondary micro-flocculation and conventional flocculation.For the said purpose of our research,we have analyzed the dissolved natural organic matter in the untreated sewage for the molecular change and the correlation between the content and the disinfected by-product-formation potential(DBPFP) of its components.While applying the technology of the organic apparent molecular weight classification and the organic chemical polarity classification,we have done some research on the effect of processing a kind of typical southern water suitable for the technology of the secondary micro-flocculation.As we know,great changes have taken place with the quality of water from Hebei.Whether the technology can be used for treating the water of low temperature and low turbidity in the north of China remains to be carefully tested.We have also tested the secondary micro-flocculation and conventional flocculation and determined some factors that have been detected,such as the turbidity,Zeta,filtration time,the number of granules and organic pollutants.The results of our experiments show that the secondary micro-flocculation has a higher removal efficiency than the conventional flocculation in the coagulation process.When the total dosage of the polyaluminium chloride PAC is 13 mg/L and the flocculation time is 3 min,the flocculation of the ideal Zeta potential should be kept within ± 5 mV,and the water turbidity can be kept lower than 0.1 NTU after filtration.What is more,the secondary micro-flocculation can not only change Zeta and enhance flocculation effect,but also can improve the removal rate of organic pollutant and the number of granules,and helps to shorten the filtration time,too.Particularly speaking,the secondary micro-flocculation can also help to enhance the removal ability of TOC and UV254.Thus,it can be seen that the present study has provided a theoretical basis for the sewage-processing plants to improve their purifying process.国家重点基础研究发展计划(973计划)项目(2010CB428805

泊江海子流域土壤有机质、全氮空间分布特征

以鄂尔多斯国家级遗鸥自然保护区所在的泊江海子流域为研究对象,根据采集的土样中有机质、全氮含量的数据,利用ArcGIS进行地理信息系统分析和并绘制了含量分布图,分析了整个流域土壤中有机质、全氮含量的水平、垂直分布特征及与土壤覆盖类型、pH值之间的相关性。结果表明:泊江海子流域表层土壤有机质含量均值为6.67 g/kg,全氮含量均值为0.36 g/kg,二者含量均偏低且存在显著正相关性(

马海盆地近40年以来气温、降水演变规律分析

为研究在全球气温变暖条件下以马海盆地为代表的青藏高原北缘地区的气候变化特征,运用累积距平法、M ann2Kendall检验法、小波分析法对马海盆地的年降水量和年平均气温时间序列变化进行了多周期分析。研究表明,1970年-2010年马海盆地年降水量基本处于稳定状态,而年均气温有升高的趋势;在2001年之前,马海盆地降水呈减少的趋势,之后降水有增多的趋势,而年均气温在1995年之前呈现下降的趋势,之后开始回升;这一地区降水量变化震荡周期主要为15 a、30 a,气温变化则以26 a为主周期;研究区降水和气温在不同的时间尺度上经历了不同的多2少及冷2暖的循环变化过程。对于不同的尺度周期,同一时段的降水量、气温变化会有所不同,时间尺度越小,气温、降水变化位相差异越小

泊江海子流域土壤重金属分布与生态风险探讨

以泊江海子流域的土壤为对象,采集表层土样54份,对7种重金属(Cu、Zn、Pb、Cr、Ni、Hg、As)含量进行了分析,利用Arc GIS 10.1获取各重金属在该流域空间分布特征,运用单因子法、综合污染指数法及Hakanson潜在生态危害指数法对研究区的土壤质量及重金属潜在生态危害程度进行评价。结果表明,土样中7种重金属含量平均值从高到低依次为Zn(79.60 mg/kg)、Cr(56.40 mg/kg)、Ni(12.89 mg/kg)、As(12.48 mg/kg)、Cu(8.34 mg/kg)、Pb(6.60 mg/kg)、Hg(0.03 mg/kg),均达到了国家土壤环境质量标准(GB15618-1995)一级标准,其中Zn、Cr、Pb含量均值高于内蒙古土壤背景值,Ni、As、Cu含量低于内蒙古土壤背景值;7种重金属空间变异系数均达到中等变异程度;土壤各重金属元素的单因子指数均值从大到小依次为As、Zn、Cr、Ni、Cu、Hg、Pb,综合污染指数平均值为0.95,说明整个研究区土壤为尚清洁状态;相对于标准,约1/3土壤存在轻微以上污染,Zn含量的高低是影响土壤环境质量的主导因素;Hg、As为综合潜在生态风险主要贡献元素,综合潜在生态风险指数RI均值为85.98,该流域处于轻微生态危害等级