南淝河示范段内源污染特征及原位控制研究

发布时间：2018-02-24 00:20

  本文关键词： 南淝河 沉积物 营养物 释放 原位控制　出处：《合肥工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：南淝河沉积物记录着水体污染历史、人类影响和环境变迁,沉积物与水体有着紧密的相互作用,研究南淝河沉积物的污染现状及其动态变化,对控制南淝河水体内源负荷和生态系统状况有着重要的理论和实际意义。本研究在国家水体污染控制与治理科技重大专项(2011ZX07303-002)的依托下,通过室内实验分析,对南淝河疏浚工程示范段沉积物中营养物和重金属的污染特征、环境风险的评价,沉积物—上覆水界面营养物的释放规律,以及原位控制技术对南淝河沉积物营养物释放的影响效果进行了系统的研究,主要研究成果如下：(1)南淝河疏浚工程示范段十个代表性采样点沉积物检测结果表明：沉积物中氮、磷、有机质的含量范围分别为253.83mg/kg-1235.73mg/kg、 131.34mg/kg-1068.75mg/kg和1.49%-6.83%,其中表层沉积物中氮磷的含量较高。根据有机氮和有机指数评价结果发现,示范段存在一定程度的氮污染和有机污染。示范段表层沉积物中重金属P、 Zn、 Cr的含量范围为21.6-152.9mg/kg、 36.7-1529mg/kg和33.6-132.6mg/kg。根据地累积指数法和潜在生态危害系数法评价结果发现,沉积物重金属元素污染程度排序为Zn Pb Cr;各采样点的Zn含量都已超过安全值,其中P8、P9、P10采样点的Zn污染较为严重；Pb污染主要集中在下游地区；Cr污染程度较轻,主要分布在P9和P10采样点。(2)沉积物—上覆水界面营养物释放规律试验结果表明：a.水体的环境温度越高,对沉积物—上覆水界面营养物的释放影响就越大。温度由5℃升至25℃时,上覆水总磷浓度呈现先升高后缓慢下降的趋势,总氮浓度由慢到快的增长,COD浓度增加了1.64倍；b.水体的环境pH值为7时,沉积物—上覆水界面氮磷和COD释放量最小,降低或升高pH值均使沉积物营养物的释放量增加；C.扰动对沉积物—上覆水界面营养物的释放影响较大,当有足够的扰动强度时,沉积物会发生再悬浮,导致上覆水氮磷和COD浓度的升高。(3)投加某物化凝聚剂原位控制沉积物营养物释放的影响效果试验结果表明：凝聚剂的投加量为800mg/L(“L”为沉积物体积)时,对沉积物营养物释放的控制效果最好。
[Abstract]:The sediment of Nanfeihe River records the history of water pollution, human influence and environmental change, and there is a close interaction between sediment and water body. The present situation and dynamic change of sediment pollution in Nanfeihe River are studied. It is of great theoretical and practical significance to control the internal load of water body and the condition of ecosystem in Nanfeihe River. This study is based on the important scientific and technological project of water pollution control and treatment in China (2011ZX07303-002). The pollution characteristics of nutrients and heavy metals in sediment, environmental risk assessment and nutrient release from sediment to overlying water interface in the demonstration section of dredging project of Nanfeihe River were studied. And the effect of in-situ control technology on nutrient release from sediment of Nanfeihe River was systematically studied. The main results are as follows: 1) the results of sediment detection at ten representative sampling sites in the dredging project of Nanfeihe River show that: nitrogen in sediment, The contents of phosphorus and organic matter were 253.83 mg / kg 1235.73 mg / kg, 131.34 mg / kg 1068.75 mg / kg and 1.49 ~ 6.83 mg / kg, respectively. The contents of heavy metals P, Zn, Cr in the surface sediments of the demonstration section were 21.6-152.9 mg / kg, 36.7-1529 mg / kg and 33.6-132.6 mg / kg respectively. The pollution degree of heavy metal elements in sediments is in the order of Zn Pb Cr.The Zn content in each sampling site has exceeded the safe value, among which Zn pollution in P8 P9 P10 sampling site is more serious and Pb pollution is mainly concentrated in the lower reaches of the area. The results showed that the higher the ambient temperature of the water was, the higher the environmental temperature was, the higher the environment temperature was, the higher the nutrient release rate was at the interface between sediment and overlying water, which was mainly distributed in the sampling sites of P9 and P10. When the temperature increased from 5 鈩，

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