Numerical Modeling On Groundwater Contamination By Petroleum Around Dalian Petrochemical Company

As a kind of important natural resource, groundwater is the basic and the main water resource of industry, agriculture and human living in many places. However, the rapid development of petrochemical industry in recent years has caused many negative effects to underground water resource. The petroleum-contaminant cannot be ignored any more. Some of the toxic compounds in oil have high potential to cause cancer, teratogenesis and mutation, which would finally do harm to human health by entering into food chain through water circulation system. In this paper, we took Dalian Petrochemical Company of Petrol China as the case study. Through collecting data of the current hydrogeological condition of the studied site and carrying out pumping test to get the permeability coefficient K, the conceptual model and numerical model were constructed. Visual MODFLOW was applied to solve the model. After identification and verification, the constructed model could veritably reflect the characteristics of ground water flow of the studied site. After model construction, three different scenarios were assumed to forecast the petroleum contaminant of the site, the prevention and control measures were developed then.The forecasting results show as follows:(1) In early stage of pollution, the petroleum contamination of studied sites is mainly accumulated on the surface of unconfined aquifer of the pollution source;(2) Under normal conditions, there is less underground water pollution caused by waste dripping and leakage, which can be treated though adsorption and natural micro-biological degradation;(3) Large sudden leak accident would lead to severe underground water pollution with high concentration, large scale and long lasting time. After adding the reaction terms, the pollution plume area of200mg/L reduced by35.85%, and the contaminant concentration dropped by9.05%.The forecasting results of three programs proved that, the underground water of the studied site might well be polluted, and it primarily happened in the water table. The pollution might be aggravated if no treated in time and it could also cause pollution to the marine environment through transporting into the sea. Therefore, it is very necessary to take prevention and treatment measures. Pump-and-Treat technique was chosen to treat the pollution. The modeling results showed that the treatment efficiency could be higher than90%and the site will be generally clean10years later.