Abstract:

Treatment of anaerobic effluent from Hengfan wastewater treatment plant in Lin'an with bamboo fiber biofilm carrier contact oxidation reactor was carried out. Effects of hydraulic retention time (HRT) and gas-water ratio on removal efficiencies in terms of chemical oxygen demand (COD_Cr), ammonium nitrogen (NH₄⁺-N), total nitrogen (TN) and total phosphorus (TP) were investigated. Results showed that the biofilm formation and startup of the reactor were finished in 12 days. When the HRT was between 8 h and 15 h, removal efficiency of COD_Cr increased with HRT. However, there were no significant variations in removal of NH₄⁺-N, TN and TP. Gas-water ratio did little effect on COD_Cr removal. The removal efficiencies of NH₄⁺-N and TN decreased from 91.46% and 46.12% to 69.21% and 36.43%, respectively, while that of TP increased from 29.18% to 36.40% with the increase of gas-water ratio. Comparison results of bamboo fiber biofilm carrier contact oxidation reactor and activated sludge aeration pond on COD_Cr removal indicated that the reactor was more efficient in removing COD_Cr and had better shock load tolerance. Thus, it is feasible to innovate the activated sludge aeration pond using the bamboo fiber biofilm contact oxidation reactor.

Key words: bamboo fiber, biofilm carrier, contact oxidation, mixed wastewater, removal efficiency