反硝化作用下苯胺降解的实验研究

Experimental Study on Aniline Degradation Under Denitrification Conditions

采用室内土柱动态模拟实验来模拟渭河渗滤系统,研究了反硝化作用下,苯胺在该系统中的环境行为及净化机制。结果表明,河流渗滤系统中苯胺的环境行为主要为吸附作用和生物降解作用。且400mg·L-1苯胺在反硝化条件下能够100%降解,其净化率达到100%,说明反硝化作用下河流渗滤系统对苯胺有很大的去除作用,同时渗滤的结果容易产生其他环境效应,例如系统pH的变化、渗透性能的变化等。

Aniline is a deadly organic substance, and harmful to humans. Much aniline-wastewater from many industries has been released into the environment, and has been detected in surface water including river water. For many cities in north China such as Xi＇ an, Lanzhou and so on, the drinking water is produced from groundwater recharged by river water through riverbank filtration（RBF）, so it is important to study the degradation of aniline in the RBF to protect water and soil from aniline pollution. The degradation characteristic of aniline in the RBF process under denitrification conditions was studied in Weihe riverbed sediments, situated in Shaanxi province and close to Xi＇an of China by using soil columns containing sediment and aquifer media collected from the Weihe riverbed and its bank. The concentrations of aniline, NO3^-, NH4^＋, Ca^2＋ and pH were monitored. The results indicate that the purification mechanism of aniline is mainly through adorption and biodegradation and all aniline could be degraded by habituated indigenous microorganisms. During the experiments with nitrate as electron acceptor, the concentration of aniline and NO3^- were decreased simultaneously, therefore, aniline degraded by the denitrifers. The aniline has the potential to be biodegraded in the RBF under denitrification conditions, and the potential lasts for long time, and this has not been monitored in the groundwater along the polluted river. Duing the 153 d testing process, the concentration of NO3^--N was about 80.0 mg·L^-1, and the aniline concentration was 40, 80 and 400 mg·L^-1 at 0-74 d, 75-104 d and 105-153 d respectively in infiltrated water. Indigenous microorganisms grow on aniline as the source of carbon in the RBF under denitrification condition. Aniline concentration in leachate is lower than the detected limits, with removal rate 100%, and the nitrate removal rate is 100% for 40, 80 and 400 mg ＂L-1 aniline concentrations respectively.