Migration process simulation of ammonia nitrogen in contaminated site
DU Qing-qing1, YIN Zhi-hua1, ZUO Rui1, WANG Jin-sheng1, YANG Jie1, TENG Yan-guo1, ZHAI Yuan-zheng1,2
1. Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing 100875, China; 2. Institute of Karst Geology, Chinese Academy of Geological Sciences, Karst Dynamics Laboratory, Ministry of Land and Resources and Guangxi Zhuang Autonomous Region, Guilin 541004, China
Abstract：In order to identify and predict the impact on soil and groundwater quantitatively due to ammonia nitrogen wastewater discharge, the soil water migration and solute transport model was built by using HYDRUS-1D software to simulate the process of migration and attenuation of ammonia nitrogen in the unsaturated-saturated zone of wastewater discharge area in this paper. The results showed that the adsorption-desorption phenomenon existed in the process of ammonia nitrogen wastewater vertical infiltration. Besides, the concentration of ammonia nitrogen showed a gradual wave-like decline vertically with attenuation of ammonia nitrogen. The wastewater discharge had a significant impact on the soil and groundwater of the site. The concentration of ammonia nitrogen in the groundwater table was raised to 867mg/L, which was 8178 times higher than the local groundwater background value (0.106mg/L) and 4334 times than Ⅲ grade groundwater quality standard (GB/T 14848-93)(0.2mg/L). The groundwater function was damaged. However, due to the timely cut off the pollution source and the termination of the discharge behaviour, concentration of ammonia in the soil was close to 0after 330 days suspension period and groundwater ammonia concentration was less than 2mg/L.
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