呼和浩特市再生水综合利用模式及风险评估研究

发布时间：2018-05-25 18:18

  本文选题：再生水 + 灌溉　； 参考：《内蒙古农业大学》2017年硕士论文

【摘要】：水资源供需矛盾成为当前我国北方干旱区城市面临的凸出问题之一,合理利用再生水成为缓解甚至实现可持续发展的重要途径之一。本研究以呼和浩特市现已投入使用的章盖营污水处理厂为例,开展了呼和浩特市再生水综合利用模式。分别通过室内试验研究再生水灌溉对绿地植物-黑麦草生长及土壤理化性质的影响、野外长期定点定期取小黑河水样研究再生水补给城市天然水体对其水质的影响、对土默川平原污灌区进行野外调查取样分析短期、中期、长期污灌年限条件下玉米品质及土壤理化性质的变化规律,结合科学的评价方法,对再生水使用存在的潜在生态风险进行了评价,本研究得出的主要结论如下几方面:1.再生水灌溉草坪草方面:建筑回填土下使用再生水灌溉对草坪草的生长速率有很明显的促进作用。再生水灌溉增加了土壤盐分,但并未对草坪草生长构成威胁。再生水灌溉下的土壤中重金属As、Hg、Pb、Cd、Cr富集量均远远小于《土壤环境质量标准》(GB15618-1995)二级标准限值。黑麦草对不同重金属的富集系数由高到低依次为:Cd、Cr、Hg、Pb、As。通过内梅罗综合污染指数法和潜在生态危害指数法等4种方法评价Pb和Hg是对土壤生态环境构成威胁的主要因素。2.再生水补给小黑河方面:时间尺度上,TN、NH4+-N和TP平均质量浓度均高于规定的V类水最小允许值,并且主要集中在冬季和春季,叶绿素a平均质量浓度也处于富营养化水平,主要集中在夏季和秋季。2016年水体污染程度低于2015年。利用对数型幂函数普适指数公式对小黑河富营养化的评价结果表明,小黑河研究河段EI值在时间尺度和空间尺度上均高于分级标准的最高上限,水体富营养化状况不容乐观。单因子水质标识指数(Pt)和综合水质标识指数(WQⅡ)结果表明,小黑河无论是在时间尺度上还是空间尺度上均处于"劣V且黑臭"的水平,且TN和TP是引起小黑河水质处于"劣V且黑臭"水平的主要贡献因子。3.再生水回用于灌溉玉米方面:随着灌溉年限的增加,土壤中全盐量也有不同程度的增加,具有20年以上污灌历史的土壤盐分的累积已出现轻度盐渍化污染,并且主要累积在土壤耕作层。污灌区土壤中重金属Cd、Cr、Cu、Pb、Zn和Hg含量随着污灌年限的增长而产生累积。具有10年和20年以上污灌历史的玉米籽粒中Cr、Pb含量已较国家食品安全限量值高出100%和26%以上,不同污灌年限均增加了玉米籽粒中粗蛋白、粗淀粉和粗纤维的含量,而抑制了粗脂肪的形成。通过内梅罗综合污染指数法、地积累指数法、污染负荷指数法和潜在生态危害指数法4种评价Cd是引起当地农田环境生态风险最主要的因素。
[Abstract]:The contradiction between supply and demand of water resources has become one of the prominent problems faced by cities in arid areas of northern China. Rational utilization of recycled water has become one of the important ways to alleviate and even realize sustainable development. Taking Zhanggaiying sewage treatment plant which has been put into use in Hohhot as an example, the comprehensive utilization mode of reclaimed water in Hohhot was carried out. The effects of reclaimed water irrigation on the growth of green plant-ryegrass and physical and chemical properties of soil were studied in laboratory, and the effect of reclaimed water supply on the water quality of urban natural water was studied. Field investigation and sampling analysis of corn quality and soil physical and chemical properties under the condition of short, medium and long term sewage irrigation in Tumechuan Plain, combined with scientific evaluation method, were carried out in this paper. The potential ecological risk of reclaimed water use was evaluated. The main conclusions of this study are as follows: 1. In the aspect of irrigating lawn grass with reclaimed water, the utilization of recycled water irrigation under the building backfill can obviously promote the growth rate of turfgrass. Reclaimed water irrigation increased soil salinity, but did not pose a threat to lawn grass growth. The enrichment of heavy metal As-HgPbPbCdcr in soil irrigated with reclaimed water was much lower than that of the second grade standard (GB15618-1995). The enrichment coefficient of different heavy metals in ryegrass from high to low is 1: CdCrCrHgPbAs. The main factors that threaten the soil ecological environment are Pb and Hg, which are evaluated by Nemero comprehensive pollution index method and potential ecological hazard index method. Recharge of reclaimed water to small Heihe River: the mean mass concentrations of TNNH4-N and TP were higher than the minimum allowable value of V water in time scale, and were mainly concentrated in winter and spring, and the mean mass concentration of chlorophyll a was also in eutrophication level. Water pollution in 2016 was lower than that in 2015. The evaluation results of eutrophication of Xiaohei River by using the universal exponent formula of logarithmic power function show that the ei value of Xiaohehe study reach is higher than the maximum upper limit of classification standard in time scale and space scale, and the eutrophication condition of water body is not optimistic. The results of single factor water quality identification index (Pt) and synthetic water quality identification index (WQ 鈪，

本文编号：1934194