Comparative study of the bio-remediation of eutrophic river water, using two biofilm processes

Abstract

Filamentous bamboo and plastic filling were used as biofilm carriers for the bio-remediation of nitrogenous compounds from eutrophic river water. Two corresponding biofilm reactors were developed: a filamentous bamboo reactor (FBR) and a plastic filling reactor (PFR). Experimental results indicated that the average removal rates of total nitrogen (TN), ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃⁻-N), nitrite nitrogen (NO₂⁻-N), chemical oxygen demand using KMnO₄ as oxidizer (COD_Mn) and chlorophyll A were 63.86%, 47.80%, 64.75%, 20.00%, 63.50% and 58.36% for FBR, and 11.29%, 18.24%, 43.90%, −165%, 9.56% and 15.25% for PFR, respectively. Statistically significant differences between FBR and PFR (p < 0.05) were noted in TN, NH₄⁺-N, NO₃⁻-N, NO₂⁻-N and COD_Mn. The results showed that NO₂⁻-N was associated with accumulation phenomena in the PFR. It was also noted that the observed diversity of microorganisms (Protozoa and Metazoa) and the biomass of nitrifying bacteria and denitrifying bacteria were higher on the filamentous bamboo than that on the plastic filling (p < 0.05). These results suggest that filamentous bamboo may be a potential carbon source that could be used for glucose-replacement during de-nitrification.