【作者】 韩芸；

【导师】 彭党聪；

【作者基本信息】 西安建筑科技大学 ， 环境工程， 2009， 博士

【摘要】 近些年来采用拦河闸（坝）等形式在河流断面处拦截河水,建造城市河道人工水面,改善区域水环境,在我国北方许多城市较为流行。城市河道人工水面属于缓流、浅水型的城市景观水体,水位受人工调节,水质受来水水源、外来污染源、河道自身环境和条件变化、以及换水周期等因素的影响,使得水面内的流速场及污染物变化规律不同于传统意义上的河流或者城市湖泊。因此,有针对性的进行城市河道人工水面的水质污染及控制研究,对保障人工水面的水域功能和城市水生态系统环境建设具有十分重要的意义。本论文以宝鸡市金渭湖为研究对象,对雨水径流、合流制管道溢流及水体自身等污染特征进行分析,以探明其对金渭湖水质变化的影响;通过对金渭湖水质长期监测,利用单指数评价法和综合水质指数法对水质现状进行评价;建立主要污染指标的水质模型,以实现对特定时段金渭湖水质的预测,从而为污染源的控制提供依据;针对主要污染源（雨水径流和部分合流制管道溢流）进行污染控制研究,建成了以沙渗滤为主的“岸边渗滤系统”,为城市河道人工水面水质保障提供了示范和参考依据。主要结论如下:1、通过现场取样分析,探明了宝鸡市区雨水径流和合流制管道溢流水质的变化规律为:在降雨径流过程中,典型污染物的浓度迅速增加然后逐渐降低,并趋于稳定,直至径流结束。雨水径流中的SS、COD、NH₃-N和TP浓度变化范围分别为989-126mg/L、854-100mg/L、3.89-0.63mg/L和0.96-0.37mg/L;水中溶解态有机物占总有机物的比例较小,悬浮物是引起COD较高的主要原因。不经任何处理的雨水径流的直接排入是造成金渭湖水质下降的主要原因,应针对城市雨水径流水质的特征,提出合理的污染源控制对策。合流制管道溢流中SS、COD、NH₃-N和TP的浓度变化范围分别为1352-154.5mg/L、1930-210 mg/L、57.6-9.4 mg/L和8.66-1.7 mg/L;COD和SS之间存在较好的线性关系,相关系数r=0.8791;NH₃-N和TP主要来源于合流制管道中城市污水的污染,雨水径流对氨氮和磷的贡献不显著。2、针对金渭湖水绵连年爆发的现象,进行了底泥和水体氮磷污染特征的分析,探讨了水绵过度生长的成因。结果表明,底泥中TP和TN含量分别为0.35-0.78mg/g和0.11-1.17mg/g,主要来源于水体中营养物质的沉积,为水绵的生长繁殖提供了条件,水体中氮、磷含量的变化与水绵的生长呈现高度的吻合。研究探明了金渭湖中的磷营养物质在“水体→水绵→底泥→水体”的闭路循环中不断迁移转化是湖内水绵复发的根本原因,同时,充足的光照、适宜的温度及适中的水位也是导致水绵过度繁殖的重要因素。3、以《地表水环境质量标准（GB3838-2002）》中的Ⅳ类标准值作为评价标准,选取pH值、DO、高锰酸盐指数、NH₃-N、TP、TN作为评价因子,分别利用单指数评价法和综合水质指数法进行现状评价,结果表明各监测断面的水质在Ⅳ类到劣Ⅴ类之间变化,影响水质类别的主要污染指标为氨氮及总氮。4、根据金渭湖属河道型水体的特点,建立了高锰酸盐指数、氨氮和总磷的水质模型分别为:C=C₀ exp（-0.0086·t）、N=N₀ exp（-0.0067·t）和P=P₀ exp（-0.0269·t）。模型可较为准确地对金渭湖水质进行预测,高锰酸盐指数和氨氮的预测误差在15%以内,符合模型模拟的精度要求,可用于实际水质模拟与预测。雨水径流对金渭湖水质影响预测结果表明,当雨水径流水质指标中COD浓度低于50mg/L、氨氮浓度低于2 mg/L时,可保证金渭湖主要功能区水质达标。5、结合当地降雨量和雨水泵站的实际运行状况,提出雨水集蓄和处理系统联动的运行模式,当累计降雨量超过30mm时,雨水泵站集蓄了雨水径流和部分合流制管道溢流污水,经渗滤池处理后排入金渭湖。试验结果表明,以沙渗滤为主的“岸边渗滤系统”可有效去除水中的有机污染物和悬浮物,出水SS和COD浓度均小于50mg/L,去除率达80%。渗滤池对有机物、氮和磷的去除与水中污染物的构成特征有关。因此,把雨水排水系统、集蓄系统及渗滤处理系统连为有机整体,是解决城市雨水径流对人工水面水质污染的有效途径。更多还原

【Abstract】 The man-made lake is structured through building the dam across the river in the city and is widely used to improve the water ecological system in urban area in northern China.However,the water level of the man-made lake is related to the function of the lake in particular season while the water quality of the lake is affected by the water quality of the up-stream,the in-stream pollutants,the point and non-point sources,the environmental condition in the lake and water exchanging cycle of the lake.The resultant hydraulic condition,such as the velocity field,and the characteristics of water pollution in the man-made lake across the river in the urban area is significantly different from that of the typical rivers and lakes.Therefore,it is necessary to carry out the related study on water pollution and control for the man-made lake across a river. This is crucial to improve the water quality of the man-made lake and ensure its funcation in improving the aquatic ecological system.In this study,the characteristics of water quality of the runoff,the combined sewer overflows（CSOs） and the in-stream pollution were investigated in Jinwei Lake,which is the typical man-made lake in Baoji city,to figure out the factors affecting on the water quality of the lake.The water quality of the lake is assessed using the single pollution index method and the comprehensive pollution index method using the water quality monitoring data that obtained in this study.The water quality models were set up and used to estimate the water quality in the particular duration.The results that obtained from the water quality models could be used in water pollution control in the lake.The sand filtration system was also structured for runoff water treatment on the base of water pollution characterization.The filtration system can potentially be used for water quality control in the man-made lake.The related results and conclusions are as following: 1、The water quality of the runoff and CSOs in Baoji city was investigated.The results showed that the concentration of the typical pollutants were significantly increased and followed by a decreasing stage and a stable stage in the rainfall process.The results showed that the concentration of the suspended solids（SS）,chemical oxygen demand（COD）,NH₃-N and total phosphorus（TP） in runoff were ranged from 989 to 126mg/L,854 to 100mg/L,3.89 to 0.63mg/L and 0.96 to 0.37mg/L,respectively. The SS is the dominating material that related to the COD in the runoff water and the CSOs while the dissolved organic matter contributed insignificant amount of COD.The untreated runoff water that discharge into the lake is the dominating pollution source for Jinwei Lake and results in the decrease in water quality of the lake.Therefore,it is necessary to figure out the pollution control methods according the characteristics of the runoff water in urban area.The results showed that concentration of SS,COD,NH₃-N and TP of the CSOs in Baoji city were ranged from 1352 to 154.5 mg/L、1930 to 210 mg/L、57.6 to 9.4 mg/L and 8.66 to 1.7 mg/L,respectively.The COD and SS followed the linear relationship with correlation coefficient r=0.8791.The municipal wastewater was the dominating source of COD and SS while the runoff water contributed insignificant amount of COD and SS in the CSOs.2、Aiming at the phenomenon of excessive growth of the Spirogyra in recent early summer in Jinwei Lake,characteristics of nitrogen and phosphorus pollution of the sediment and the water in lake were investigated and the reasons of the Spirogyra growth were explored.The results showed that the concentration of the total nitrogen （TN） and TP were ranged from 0.35 to 0.78mg/g and 0.11 to 1.17mg/g,respectively. Resuspending and releasing of sediment would lead to eutrophication in lake and promote Spirogyra growth.The concentration of TN and TP of sediment and that of water had showed correlation with the Spirogyra growth status.The results proved that the most essential reason of the Spirogyra recurrence was nitrogen and phosphorus circulation in the Jinwei Lake.Meanwhile,the other important reasons of the Spirogyra overgrowth were include lighting,temperature and water level in the lake.3、The water quality of the Jinwei Lake was assessed using pH,DO,oxygen demand,NH₃-N,TP and TN according to the Environmental Quality Standards for Surface Water（GB3838-2002）.The results obtained by using the single pollution index method and the comprehensive pollution index method showed that the water quality of the lake was ranged from typeⅣto the level worse than typeⅤwhile the NH₃-N and TN were shown to be the dominating pollutant affecting the water quality of the lake. 4、Based on hydraulic characteristics and water pollution characteristic of Jinwei Lake,the water quality models of oxygen demand,NH₃-N and TP were established as C=C₀ exp（-0.0086·t）、N=N₀ exp（-0.0067·t） and P=P₀ exp（-0.0269·t）, respectively.The models were verified using the monitored data while the average error of oxygen demand and NH₃-N were less than 15%.The results showed that the models were reliable and can be used in the water quality management.According to the predicting results,it is need to decrease the concentration of COD and NH₃-N in the runoff water in the level of less than 50mg/L and 2mg/L,respectively,to ensure the water quality of Jinwei Lake.5、The operation methods of the rainfall storage system and the runoff water treatment system were figured out according to the characteristics of rainfalls and the practically running condition of the rainfall pumping station in Baoji city.The runoff water and the CSOs should be treated using the sand filtration system before any discharge in the case that the rainfall is higher than 30mm.The results showed that the concentration of COD and SS in the effluent was less than 50mg/L while the COD and SS removal efficiency could reach up to 80%.Therefore,it is necessary to link the discharge system,runoff water storage tank and filtration treatment system to reduce the effect of runoff water on the water quality of man-made lake in the urban area.更多还原