【作者】 张莹；

【导师】 蒋绍阶；

【作者基本信息】 重庆大学 ， 市政工程， 2019， 博士

【摘要】 进入新世纪以来,中国城市化进程明显加速,大量人口和工业生产向城市聚集,对城市生态环境造成巨大压力,也威胁着我国社会经济可持续发展的能力。目前中国城市面临着诸多生态环境问题,其中水环境恶化问题极为突出。在许多城市,“水质型缺水”特征明显,已成为阻碍经济发展的重要因素。水环境污染每年给我国造成巨大的经济损失。水环境评价与模拟是评估区域水污染现状、解析污染源、预警污染风险的主要技术手段。本文首先对面临严重污染问题的深圳市茅洲河流域水环境现状进行评价,着重分析了严重污染的河道底泥氮磷元素的吸附解吸附特征。MIKE系列软件是目前世界上领先的优秀水质模拟软件。软件的功能涉及整个水文水质循环,从1D到3D,从水动力到水环境和生态系统的模拟,其中MIKE-11模型主要用于河口、河流、灌溉系统和其他内陆水域的水文学、水力学、水质和泥沙传输模拟。本文在流域水环境评价的基础上利用MIKE-11模型开展流域水环境综合研究,模拟了茅洲河流域的水质,并计算了以共和村断面为控制断面,地表水V类水质为标准下的茅洲河流域水环境容量。最后,利用MIKE-11模型计算了流域基于不同补水景下水质达标情况,发现若仅采用河口建闸拦污和污水厂提标改造的方法很难在短时间内改善流域水质,因此需要引外流域客水补充地表径流,并评估了引西江补水对流域水质的改善效果,为流域水环境保护和治理提供决策依据。本文主要结论如下:(1)在详实的调查监测数据的基础上,解析了茅洲河流域的外源污染负荷,2015年COD、氨氮和总磷的入河负荷分别为86201吨/年、8420吨/年和433吨/年,并且发现茅洲河流域各污染来源中,生活源、工业源和径流面源的贡献率依次减小。通过对沿河点源污染排放特征的解析,发现流域中782个排水口有污水排放,每日排放量约为33.44万m~3。流域大部分排污口COD、总磷、氟化物和LAS超标在10倍以下,但氨氮浓度超标集中在10~50倍之间。河流污染负荷通量的计算表明茅洲河支流每日向干流排入COD 42.4t、氨氮6.26t、总磷0.55t、氟化物2.83t以及LAS 0.229t。(2)基于对底泥采样数据的分析评价,发现茅洲河流域表层沉积物中重金属元素Pb、Cd、Cr、Cu、Zn、Ni含量较高。从空间来看,茅洲河主要支流沙井河底泥污染最为严重,其次为茅洲河干流下游,再次是中游。分污染物来看,全河水平上底泥深度为0~2m有机质含量较高;底泥深度0~1m总氮总磷含量最高,随深度含量逐渐降低。茅洲河底泥总氮总磷含量垂向变化存在随深度的增加呈现出下降的趋势;重金属中Cu含量最高,Zn含量次之,Cd含量最低。各个总金属含量排序为Cu>Zn>Cr>Ni>Pb>Cd。(3)通过对茅洲河底泥中氮磷元素的吸附解吸附特征规律和底泥中的氮释放通量的研究,发现氮磷元素的吸附解吸附实验研究发现0~1米深度的底泥平衡浓度最高,其次为1~2米,2~3米深度的底泥平衡浓度最低。上覆水体的氮磷浓度分别小于2mg/L和0.4mg/L时,发生表层底泥的解吸附现象。(4)利用MIKE-11建立的茅洲河水质数学模型具有很好的精度,准确的模拟了茅洲河水质数据,反映了茅洲河水质变化规律。除个别情况外,共和村断面氨氮浓度预测值与实测值的最低氨氮浓度出现的时间差在30分钟之内,同时在该时刻的计算值与实测值十分接近,因此模型能够很好地反应共和村断面的氨氮浓度变化规律;通过对所有数据的统计分析,计算值与实测值的平均相对误差较小,平均为20.68%,因此模型的可靠性较好,该模型能够应用于茅洲河水质数据的模拟预测。(5)通过对四种补水情景的模拟,发现仅利用污水厂出水提标和修建河口挡潮闸的方式虽能显著改善水质,但仍不达标(地表水V类)。在叠加东莞侧和深圳侧引西江水补充径流后,全流域水质达标且有较大的安全冗余。综上所述,本文以茅洲河流域为研究对象,全面评估了茅洲河流域的内外源污染。应用MIKE-11模型开展流域水环境综合研究,系统模拟了流域内水质过程,经模型校准和验证,模拟效果良好。在水质模拟的基础上,计算了流域的水环境容量。并通过设置不同的流域补水情景,利用模型分析了引西江补水措施对流域水环境的改善效果。本研究为我国严重污染的城市流域底泥污染释放特征解析与水环境模拟提供了参考案例,并为流域水环境综合治理方案的推广应用提供了先进思路。更多还原

【Abstract】 Since the beginning of the new century,China’s urbanization process has accelerated obviously.A large number of people and industrial production have centralized in urban areas,which has exerted tremendous pressure on the urban ecological environment and threatened the ability of China’s social and economic sustainable development.At present,Chinese cities are facing many ecological and environmental problems,and the problem of water environment deterioration is extremely prominent.“Water shortage induced by bad water quality”has been outstanding in many cities,and has become an important factor hindering economic development.Water pollution have caused huge economic losses to China every year.Water environment assessment and simulation are the main technical means to assess the status of regional water pollution,analyze pollution sources,warn of pollution risks,and formulate watershed environmental planning and pollution prevention and control programs.This paper firstly evaluates the water environment of the heavily polluted water quality in the Maozhou River Basin in Shenzhen,and analyzes the adsorption and desorption characteristics of nitrogen and phosphorus in the riverbed sediments of the seriously polluted rivers.Based on the MIKE-11 model,a comprehensive study on the water environment of the basin was carried out to simulated the water quality and calculated the water environment capacity of Maozhou River Basin.Finally,the MIKE-11 model is used to calculate the water quality compliance of the basin based on different water replenishment scenarios.It is found that it is difficult to improve the water quality of the basin in a short period of time if only apply the method of building tide gate in the estuary to block the polluted water flow into the river and improve the out flow quality from the sewage plant.Therefore,the basin needs to diverse water from Xijiang River to supplement surface runoff,and then the improvement effect of the water supply on the water quality of the basin is evaluated.Furthermore,this study provides decision-making basis for water environment protection and treatment.The main findings of this paper are as follows:（1）Based on the detailed survey and monitoring data,the point source pollution discharge characteristics of the Maozhou River Basin were analyzed.It was found that782 drainage outlets in the basin had sewage discharge,and the daily discharge was334,400 m³/d.Most of the drainage outlets in the basin have COD,TP,fluoride and LAS exceeding 10 times compared with the standard,but the NH_3.N concentration is over 10 to 50 times compared with the standard.The calculation of river pollution load flux indicates that the tributary of Maozhou River discharges COD 42.4t,NH_3.N 6.26t,TP 0.55t,fluoride 2.83t and LAS 0.229t into the main stream.（2）Based on the analysis and evaluation of the sediment sampling data,it is found that the content of heavy metal elements such as Pb,Cd,Cr,Cu,Zn and Ni in the surface sediments layer of Maozhou River Basin is high.From the spacial perspective,the sediment of the main tributary of Maozhou River（Shajing River）,is the most heavily polluted,followed by the downstream of the main stream of Maozhou River,and then the middle reaches.According to the pollutants,the sediment content depth of the whole river is generally 0²m,and the organic matter content is high.The nitrogen depth is 0¹m in the sediment,and the total nitrogen content is the highest,which decreases with the depth of the sediment.The vertical variation of total nitrogen content of Maozhou River showed a downward trend with the increase of depth.The content of Cu was the highest in heavy metals,followed by Zn and Cd.The total heavy metal content is ranked as Cu>Zn>Cr>Ni>Pb>Cd.（3）Through the study on the characteristics of adsorption and desorption of nitrogen and phosphorus in the sediment of Maozhou River and the release flux of nitrogen in sediment,it is found that the adsorption and desorption of nitrogen and phosphorus elements has found a sediment balance of 0¹ m depth.The highest concentration,followed by 1 to 2 meters,the lowest concentration of sediment at the depth of 2 to 3 meters.When the concentration of nitrogen and phosphorus in the overlying water is less than 2 mg/L and 0.4 mg/L,respectively,the desorption of surface sediment occurs.（4）MIKE-11 performs good precision in modelling the water quality of Maozhou River.The model can accurately simulate and reflects the variations of the water quality.Except for a few cases,the time difference between the predicted ammonia nitrogen concentration in the Gonghe village section and the lowest ammonia nitrogen concentration in the measured value is within 30 minutes,and the calculated value at that time is very close to the measured value,so the model responses well to the variation of ammonia nitrogen concentration in the Gonghe section;through the statistical analysis of all the data,the average relative error between the calculated value and the measured value is small,with an average of 20.68%,so the reliability of the model is good.The model can be applied to simulate and predict the water quality of Maozhou River.（5）Through the simulation of the four water replenishment scenarios,it is found that the method of using only the sewage plant effluent to raise the standard and constructing the estuary tidal gate can significantly improve the water quality,but it still does not meet the water quality standard（surface water V）.After diverse clean water from the Xijiang River to supplement runoff in the upstream of Maozhou River,the water quality of the whole basin improved obviously and meet the standard,furthermore,the water supplement provide greater safety redundancy for the basin.In summary,this paper takes the Maozhou River Basin as research area and comprehensively evaluates the internal and external point pollution of the Basin.The MIKE-11 model was used to model the water quality variation process.The model was calibrated and verified by using the monitored data,and gives good simulation results.Based on the water quality simulation,the water environment capacity of the basin was estimated.And by setting different water replenishment scenarios in the basin,the model is used to analyze the impact of the water supplement measures on the improvement of water environment.This study provides an example for the promotion and application of water environment treatment and water replenishment measures in severely polluted river basins in China.更多还原