【作者】 李建华；

【导师】 王玮；

【作者基本信息】 长安大学 ， 水利工程（专业学位）， 2023， 硕士

【摘要】 水是维持生命的必需品,是人类社会生产和生活的基础,而地下水是最重要的水资源之一。地下水不仅是饮用水和灌溉用水的主要来源,还是保持生态系统循环健康的重要因素。但是随着经济的发展,人类活动对地下水环境产生的影响越来越大,尤其是工业生产对地下水产生的污染具有难以发现、溯源困难和治理成本高等特点。因此,本文使用地下水数值模拟手段对某化工园区地下水污染进行了溯源和污染物迁移预测的工作。在传统的基于MODFLOW和MT3DMS建模方法的基础上,本文利用基于Python语言的地下水模拟包FloPy,结合贝叶斯优化方法、增强型精英保留遗传算法（SEGA）和第三代非劣分层多目标遗传算法（NSGA-Ⅲ）搭建用于地下水污染溯源的模拟-优化模型,对研究区内无法确定位置的污染源进行溯源。本文主要取得了以下结果:（1）通过对研究区41口监测井的水化学检测结果统计可知,所有检测样本中,平均浓度最高的是氯化物,单样本浓度最大的是苯。与《地下水质量标准》中Ⅲ类水指标相比较,平均浓度超标最严重的是氨氮,超标140.8倍;单样本浓度超标最严重的也是氨氮,超标4823.1倍。按照水质标准分级统计结果显示,所有样本中,污染最严重的是锰。（2）通过调整数值模型中污染源的释放时间、浓度和位置,拟合浓度监测点处的污染物实测值,从而确认污染源的位置。拟合结果显示,无论是在时间上还是空间上,这种方法都取得了较好的拟合效果。目前研究区地下水污染还处于污染早期阶段,污染范围较小,污染浓度高,Mn²⁺最大浓度在160 mg/L左右;（3）建立遗传算法与溶质运移模型耦合的模拟-优化模型,成功反演出了无法确定位置的污染源,反演的污染源模拟的污染历史在时空上与大部分实测值拟合较好;并根据溯源结果查明了子研究区1中污染源的污染来源和污染历史;（4）未来污染物迁移趋势预测的结果显示,在近5年内,污染晕的最大浓度衰减较快,到第5年衰减至36 mg/L左右。5年后衰减速度变得缓慢,到第20年,最大浓度还有10 mg/L左右。短时间内污染范围集中在化工园区内,20年后污染晕迁移至化工园区下游荒地之中,基本脱离园区范围。虽然20年后不会对下游居民地产生影响,但是在更长时间下,极有可能会迁移至居民地,因此采取治理措施是十分有必要的。本文的研究结果可以为预防地下水环境恶化、制定地下水污染治理方案、判断地下水污染肇事责任提供参考,本文的研究方法有利于促进复杂的地下水溯源理论向实际生产活动中推广应用。更多还原

【Abstract】 Water is an essential resource for sustaining life and is the foundation of human society’s production and daily life.Groundwater is one of the most important water resources,serving as a primary source for drinking water and irrigation,as well as playing a crucial role in maintaining healthy ecosystems.However,with economic development,human activities are increasingly impacting the groundwater environment,particularly with regard to the pollution generated by industrial production,which is difficult to detect,trace,and expensive to manage.Therefore,this paper uses numerical simulation methods to trace and predict the migration of pollutants in groundwater in a chemical industrial park.Building on traditional modeling methods based on MODFLOW and MT3 DMS,this study uses the Python-based groundwater simulation package FloPy,along with Bayesian optimization methods,Strengthen Elitist Genetic Algorithm(SEGA),and non-dominated sorting genetic algorithm-Ⅲ(NSGA-Ⅲ),to construct a simulation-optimization model for groundwater pollution tracing,targeting the sources of pollution with an unknown location.This study mainly achieved the following results:(1)According to the statistical analysis of the water chemistry test results of monitoring well 41 in the research area,it can be seen that among all the samples,chloride has the highest average concentration,and benzene has the highest concentration in a single sample.Compared with the Class III water quality standards,the most serious average concentration exceeding the standard is ammonia nitrogen,which exceeds the standard by 140.8 times;and the most serious single sample concentration exceeding the standard is also ammonia nitrogen,which exceeds the standard by 4823.1 times.According to the classification of water quality standards,manganese is the most severely polluted among all samples.;(2)By adjusting the release time,concentration,and location of the pollution sources in the numerical model,the measured values of pollutants at the concentration monitoring points were fitted to confirm the location of the pollution sources.The fitting results showed that this method achieved good fitting effects both in time and space.Currently,the groundwater pollution in the study area is still in the early stage,with a small pollution range and high pollution concentration.The maximum concentration of Mn2+ is around 160 mg/L.;(3)A simulation-optimization model coupling genetic algorithm and solute transport model was established,which successfully inverted the location of an unknown pollution source.The simulated pollution history of the inverted source matched well with most of the measured values in time and space.Based on the tracing results,the pollution source and its history in sub-study area 1 were identified.;(4)The results of the prediction of future pollution migration trends show that in the past5 years,the maximum concentration of pollution has decreased rapidly,and by the 5th year,it has decreased to around 36 mg/L.The rate of decline slows down after 5 years,and by the 20 th year,the maximum concentration is still around 10 mg/L.In the short term,the pollution is concentrated within the chemical park,but after 20 years,the pollution plume will migrate to the downstream wasteland outside the park,basically leaving the park area.Although it will not affect downstream residential areas after 20 years,it is highly likely to migrate to residential areas in the longer term,so it is necessary to take remedial measures.The research results of this paper provide references for preventing groundwater environmental degradation,formulating groundwater pollution control plans,and determining liability for groundwater pollution incidents.The research method presented in this paper promotes the application of complex groundwater tracing theory to practical production activities.更多还原