Removal Efficiency Of Chlorpyrifos, BPA And4-NP In Subsurface Flow Constructed Wetland

Chlorpyrifos and some chemical products based on BPA and4-NP has brought great economic benefit to human life, but these chemicals have come into natural environment inevitably including the water resource、atmosphere as well as the soil. Nowadays more and more researches find that those micropollutants have severely contaminated the natural water including surface water and underground water. However, the efficiency of recent water treatment technology in the sewage treatment plant and waterworks is very limited. Those micropollutants are considered to be a threat to the quality of the water resource. Our research disposed of sewage with subsurface flow constructed wetland. SPE-HPLC was used to detect Chlorpyrifos, BPA and4-NP in water. We also did researches on the removal efficiency of different wetland plants and the mechanism of degradation. This will offer theoretical support for the promotion of constructed wetlands in water micropollution.1、 The research used SPE-HPLC to pretreat and detect the Chlorpyrifos, BPA and4-NP in natural water.2、Building8sets subsurface flow constructed wetland small pilot plant to study aquatic plants effects on removal rate. Four plant species include reed, Typha latifolia, Typha latifolia ’Variegata’ and Typha minima. The result showed that four plant species all have high removal rates for Chlorpyrifos, Typha latifolia has the highest removal rate (89.24%), but there were no significant difference between the four plant species. The removal efficiency was a little lower for4-NP generally, Typha latifolia reached the highest removal rate (84.36%), and Typha minima got the lowest (76.80%), still there were no significant difference. While for BPA, Typha latifolia had a significant higher removal rate for about82.66%(P<0.05), and Typha latifolia ’Variegata’(69.32%) and Typha minima (69.63%) both were significantly higher than the reed (62.96%, P<0.1)3、Five tanks were modified as constructed wetlands, named as M1～M5, M1was only filled with artifical wastewater. Typha latifolia was chosen as wetland plant according to the previous research, and M2-M5were set as the blank group, control group and experimental group by adding Ampicillin to inhibit microbes, thus the removal efficiency of wetland plant、ceramsite and microbes were analysed. The result showed that in natural water bodies, Chlorpyrifos, BPA, and4-NP degradation rate were significantly lower than that of artificial wetland simulation system. The adsorption of ceramsite to Chlorpyrifos, BPA, and4-NP was significant; Typha latifolia can also improve the removal rates of those micro pollutants; In the presence of Typha latifolia, microbes shows significant effects on the degradation of pollutants comparing with the control group, but it shows little effects on the degradation of chlorpyrifos and4-nonylphenol regardless of wetland plant.4、Under the static condition, the degradation equation of Chlorpyrifos, BPA and4-NP in SFCW all followed first-order kinetics:c=124.63exp(-t/25.393)+3.7618①, c=316.61exp(-t/34.955)+0.56475②,c=168.91exp(-t/17.061)+12.133③(c, residue concentration, μg L-1; t, retention time, h),and the half-life were approximately18h、21h and11h respectively.