Experimental Study on the Treatment of H2S and NH3 in Hospital Sewage Based on Composite Biological Filter Tower

Abstract

In the study, the H₂S and NH₃ of common foul gases in hospital sewage were treated by the combination of the bio-trickling filter and the biofilter. The results showed that when the temperature was 25℃, air input was 1.0m³/h, aerated concentration of H₂S was 10~50mg/m³ and NH₃ was 10~20mg/m³, spray amount of nutrient solution was 5L/h, pH was 6.0~7.0, the residence time was 60s, the removal rate of H₂S and NH₃ reached optimum and the removal rate was 98.1% and 97.8% respectively. The composite biological filter tower was restarted 30 days later and the fourth day's removal rate reached more than 80%, which showed that the resistance to shock loads was stronger. The research also showed that as a result of the microbial growth environment was different, the microbial species in bio-trickling filter and the biofilter were also different. The separation of bacteria and fungi was more beneficial to the growth and reproduction of microorganism, which was also better for the purification of foul gas