Progress of Researches on Nitrogen and Phosphorus Removal by Periphytic Biofilm From Non-Point Source Wastewater

In many regions non-point source pollution has been the primary contributor to surface water pollution. Thereby, how to effectively reduce the nitrogen and phosphorus discharge from non-point source has become one of the important scientific issues. Periphytic biofilm (also known as periphyton) is a kind of microbial aggregates growing on the surfaces of submerged solids and being intertwined with surrounding abiotic matters. Periphytic biofilm is common at the soil and water interface, with strong adaptability to the abiotic environment and capability of removing pollutants from water. In recent years, periphytic biofilm has gained wide attentions in wastewater treatment and remediation of natural water bodies. In this paper, the nitrogen and phosphorus removal mechanisms, such as denitrification, ammonia volatilization and stripping, assimilation, adsorption and precipitation of phosphorus, as well as the latent factors driving these processes are summarized. Besides, the recent advances in nitrogen and phosphorus removal by coupling periphytic biofilm with new functional materials are also summarized. Finally, the applications of periphytic biofilm combined with ecological engineering to large-scale non-point source wastewater treatment and ecological restoration are proposed. This study will provide a theoretical reference for the wastewater purification by periphytic biofilm and similar microbial aggregates, as well as for the regulation of periphytic community structure and its functions.