Removal Of Nutrients And Pharmaceuticals And Personal Care Products From Wastewater Using Periphyton Photobioreactors

The rising nutrients concentration in water of nitrogen and phosphorus,which comes from agricultural sewage,industrial wastewater and domestic wastewater,leaded to seriously eutrophication.Currently,many mature and effective technologies of treating nutrients in wastewater are being used,however,these traditional wastewater treatment technologies are meant to remove nutrients,which ignored the new organic pollutants in wastewater.Variously,the kinds of emerging organic pollutants including endocrine disruptors,pharmaceuticals,personal care products,plasticizer,surfactants and so on.According to previous studies,this compounds with different concentration widely existed in water,and may have toxicology effect on aquatic organisms in different extent.Under this circumstance,we’ve done this research which combined photoreactor and periphyton method,built a small periphyton photobioreactors to remove the nutrients and pharmaceutical and personal care products(PPCPs)in the artificial wastewater.We set up four treatments with different hydraulic retention time,light intensity and illumination time,explored the influence of different operation conditions on the nutrients and PPCPs removal efficiency.Combined the results of periphyton characteristics,algae identification and Hiseq sequencing of the 16 S rRNA,we discussed the role of algae and bacteria in the removal of nutrients and PPCPs.The results shown that:(1)Overtime,nitrogen removal rate in four treatments between 39% and 77%,and from the result of one-way analysis of variance(ANOVN),we found that the hydraulic retention time and the illumination time has a significant influence on nitrogen removal(p < 0.05).The removal of phosphorus in the four treatments showed a decreasing trend,ranged from 42% to 68% on day 2 to 15.8% to 44% on day 22,which may be related to a saturation of the adsorption sites in periphyton.(2)Only bisphenol A(BPA)has been effectively removed in four treatments of the 5 selected PPCPs.The highest removal rate of this compound reached 86.4%,the lowest was 72%.This result was likely due to its biodegradability and associated with the experimental conditions in our study.The removal rate of hydrochlorothiazide(HCT)and ibuprofen(IBU)changed between 26.2% and 48.7%.Nevertheless,the lowest removal rate of gemfibrozil(GEM)and carbamazepine(CBZ)was only 6.45% to 20.6%,which mainly caused by their physical and chemical properties and the change of the experimental conditions.(3)Higher nutrients removal rate was observed in treatment and B and C,which may be affected by the higher total microbial activity.Among different treatments,treatment D showed the best removal efficiency for the PPCPs that could be owing to higher relative abundance of Proteobacteria than other treatments.(4)From the results of nutrients and PPCPs removal in different treatments,longer hydraulic retention time was improved the reaction process and led to effective removal of pollutants.But the illumination time on nutrient and PPCPs removal has an opposite impact.