The Behavior of Organic Phosphorus under Non-Point Source Wastewater in the Presence of Phototrophic Periphyton

To understand the role of ubiquitous phototrophic periphyton in aquatic ecosystem on the biogeochemical cycling of organic phosphorus, the conversion and removal kinetic characteristics of organic phosphorus (Porg) such as adenosine triphosphate (ATP) were investigated in the presence of the periphyton cultured in artificial non-point source wastewater. The preliminary results showed that the periphyton was very powerful in converting P-org evidenced by the fact that inorganic phosphorus (P-inorg) content in solution increased from about 0.7 to 14.3 mg P L-1 in 48 hours in the presence of 0.6 g L-1 periphyton. This was because the periphyton could produce abundant phosphatases that benefited the conversion of P-org to P-inrog. Moreover, this conversion process was described more suitable by the pseudo-first-order kinetic model. The periphyton was also effective in removing P-org, which showed that the P-org can be completely removed even when the initial P-org concentration was as high as 13 mg P L-1 in 48 hours in the presence of 1.6 g L-1 periphyton. Furthermore, it was found that biosorption dominated the P-org removal process and exhibited the characteristics of physical adsorption. However, this biosorption process by the periphyton was significantly influenced by biomass (absorbent dosage) and temperature. This work provides insights into P-org biogeochemical circulation of aquatic ecosystem that contained the periphyton or similar microbial aggregates.