Study On Culture Of Nonylphenol Ethoxylates Degradation Flora Based On A/o Process

Nonylphenol ethoxylates is a kind of nonionic surfactant that'is steady and widely used in the world. After its access to water, its main degradation products are NP and short-chain NPnEO which are refractory and hydrophobic and have characters of bioaccumulation. They show estrogenic activities to the organism and they have been proved Endocrine Disrupting Chemicals(EDCs).Domestic and foreign scholars have done a great deal of study on innocent treatment of environmental hormones. They have developed several effective methods. Mainly, they are interested in two methods which are micro-biological degradation and physicochemical treatment. However, all physicochemical treatments have weaknesses of consumption of energy and resources. So the current researches still focus on micro-biological degradation that has advantage of lower energy consumption. Experts and scholars have done much more study on micro-biological initial degradation of NP10EO compared with study on ultimate micro-biological degradation. Although much literature believe that ultimate micro-biological degradation can not happen, there are also documents approving that ultimate micro-biological degradation may occur.In the experiment, A/O process is considered. It works under optimal conditions. And micro-biological degradation of NP10EO by A/O process is evaluated. In the same time, NP10EO degradation flora is cultured and analysed. The experimental results show that the state of activated sludge will be affected with increase of NP10EO in raw water. But with the adaption of activated sludge, the state will gradually be improved and indicators of the state of activated sludge will be more stable. When the density of NP10EO becomes higher, various indicators of water quality will also be impacted. Removal rate of COD and TN will drop. With the concentration of NP10EO being stable, removal rate of COD will rebound and removal rate of TN will also be stable. Removal of NP10EO by A/O process is obvious after a short-term acclimation. But change of concentration of NP10EO will lead to substantial change of removal rate. During the course, ultimate micro-biological degradation of NP10EO will happen and the structure of benzene ring will be destroyed. Both ultimate micro-biological degradation and adsorption of activated sludge lead to satisfying removal rate.In this study, modern molecular biology techniques are used such as PCR and DGGE to analysis structural changes of microbial flora in the process. It is found that with concentration changes of NP10EO in raw water structure of microbial flora will change too. The number of bands in DGGE will decrease. Dice coefficient of both of the two pools will be smaller. However, with the stability of concentration of NP10EO, dice coefficient of the two pools will increase. The structure of microbial flora will be relatively stable. And ultimately we get the microbial flora that adapt for degradation of NP10EO and its intermediate products.