Research On The Removal Of Estrogenic-like Overall Effect In A Sewage Treatment Plant

Background and Objective: Environmental Endocrine Disrupting Chemicals(EEDCs) could disrupt normal physiological activities of the human and the aquatic biological, destroy the homeostasis of the internal environment. It has been another global environmental problem which followed ozone depletion and greenhouse effects. The research showed that the major reason for the concentration of EEDCs increased in watery environment was the drainage of industrial wastewater and sanitary sewage. Although the concentration of the EEDCs was extremely low, but it caused the potential hazards to human and animal could not be ignored. The sewage treatment plants have played a critical role in interdicting EEDCs to get into the aquatic environment. In this respect our country started late and the detection indexes were not perfect enough. The trend of worse EEDCs pollution has not yet been effectively curbed. This experiment would explore the distribution of estrogenicity during the treatment units and the effectiveness on removal of Estrogenic-like overall effect(ELOE) in the sewage treatment plant and evaluate the level of estrogen-like activity in the receiving river. This experiment could provide scientific foundation for transfering of EEDCs and the technical data for the rebuilding of this plant.Methods:1. The method of SPE-YTH was used to evaluate the ELOE of sewage samples in the solid and liquid phases among different treatment processes. Evaluating the distribution and the overall removal effect of EEDCs in sewage treatment system2. The method of SPE-YTH was used to detect the changing trends of EEDCs in different seasons and the removal efficiency of ELOE under different processing conditions. Meanwhile the EEDCs-ELOE of water samples from different control section was detected in order to evaluate the impact on the receiving rive3. The male brocade carp was used as the test animal to construct the animal model of experiment. The double antibodies sandwich was used to detect the vitellogenin(VTG) and the genadosomatic(GSI) index in order to Evaluate the removal of EEDCs- 。ELOE in sewage treatment plantResults1. The detection methods of ELOE which was constructed by the technology of SPE-YTH,E2 and galactosidase had obvious dose-effect relationship and the standard curve had a relatively high sensitivity with EC50 value of 8.79×10-11mol/L. The method had a high goodness-of-fit and reliable results.2. EEDCs was mainly in the form of dissolved state.The secondary biotreatment process played a dominant role in the removal of EEDCs-ELOE. ELOE could be eliminated obviously by the process of A2 O and the combined process of A2O-BMP, the clearance of EEDCs-ELOE were higher than that in one series. The cleanup-rate of EEDCs-ELOE was low and other season removal efficiency was about 88%. The value of ELOE in self-purification section was higher than that in control section.3. All of the samples induced expression of VTG in the body of male brocarded carp and inhibited the development of gonads organs. The level of VTG which was induced in the raw sewage and primary sedimentation had no statistically significant, in 5% exposed group they were higher than secondary sedimentation tank,in 10% exposed group they were lower. The value of GSI of secondary sedimentation tank was lower than the raw sewage and effluent of primary sedimentation.Conclusion1. The quality of sewage met the acceptance request of relevant national standards during the test. It had a bigger contributor to the cleanup-rate of EEDCs-ELOE, the low temperature in winter had a disadvantage for EEDCs removal.2. The secondary biotreatment process played a dominant role in the removal of estrogenicity. The cleanup-rate of the combined process of A2O-BMP was higher than the process of A2 O. Expanding the volume and extending the hydraulic retention time were helpful to clean EEDCs.3. The tail water from the effluent plant increased the pollution load of the river and aggravated the burden of the self-purification. It had a certain potential environment risks.