Effects Of Copper Oxide Nanoparticles On Wastewater Biological Nutrient Removal And Bacterial Community In SBR

With the rapid development of nanotechnology, nanomaterial products have been widely applied in many areas of people’s lives and production. In the process of production and waste of nano-products, nanomaterials can be released into environment, for example, nano-materials will flow into the sewage treatment system, influencing the performance of the sewage treatment process in a certain degree. This paper studied the influence of short-term and long-term exposure of the copper oxide nanopartic les (CuO NPs) on the removal of nitrogen and phosphorus and the variation of microbial community in SBRs.This study investigated the effect of the short-term exposure to different concentrations of CuO NPs on the wastewater treatment efficiency of SBR. After Id of CuO NPs short-term exposure, the results in one cycle showed that there were no acute adverse effects on the removal of COD, NH4+-N and TP, which were highly consistent with that of the control group. After20days of CuO NPs short-term exposure, the reactor effluent of the SBR1(lmg·L-1) and SBR2(10mg·L-1) were not affected. The further activated sludge respiration inhibition test showed that when the CuO NPs was500mg·L-1, the sludge respiration inhibition rate was less than15%, and a low concentration of CuO NPs did not inhibit the activity of activated sludge significantly.In this study the long-term effects of CuO NPs (1mg·L-1and10mg·L-1) on wastewater treatment in SBRs were investigated.The results showed that after exposure to1mg·L-1and10mg·L-1CuO NPs for180d, the effluent COD, NH4+-N and NO2--N of SBR1and SBR2did not show significant difference when compared with the control SBRO. However, the average concentration of effluent NO3--N of SBR1and SBR2were3.86mg·L-1and3.01mg·L-1, respectively, which were lower than SBRO with5.86mg·L-1. The concentrations of the effluent TP of SBR1(1.07mg·L-1) and SBR2(1.65mg·L-1)were higher than that of SBRO (0.30mg·L-1). By measuring the period showed that COD, NH4+-N and NO2--N trends of the experimental group reactors were highly consistent with the control group,but phosphorus and nitrate cycle curve of the experimental group changed, phosphorus release and absorption was reduced, and the rate of formation of nitrate was reduced. Moreover, the effects were more serious as the increasing of the concentrations of CuO NPs.Community analysis showed that the nitrogen and phosphorus removal related bacteria of the experimental group changed. The abundance of poly-phosphate bacteria such as Actinobaculum and Zoogloea genus (Zoogloea) were reduced. The abundance of Zoogloea in the control group SBRO, the experimental group SBR1and SBR2was12%,2%and1%, respectively. The abundance of denitrifying bacteria in experimental group, such as the abundance of Gemmata and Pirellula, were higher than the control group. In addition, the abundance of Nitrospira in the three reactors was0.3%,0.5%and0.7%, respectively.