Anaerobic Removal of Disinfection By-product Using Trickle bed Biofiltration

摘要

Disinfectants in the chlorination process which are used in water treatment systems may react with natural organic matters and produce a range of DBPs including trihalomethanes (THMs) haloaceticacids (HAA5). They exist in most drinking water supplies that are subject to disinfection by chlorine or chloramines. THMs, haloacetonitriles, halonitromethanes (HNMs) are found to be toxic. They are carcinogenic to the liver, kidney and/or large intestine and can cause adverse reproductive or developmental effects. The maximum allowable contaminant level in drinking water for total THMs is 0.08 ppm and HAA5 0.1 ppm. Chloroform is a volatile THMs, that is commonly found in swimming pools at high concentrations, and it can be transferred from contaminated waters to the gaseous phase by air stripping. Removing chloroform by physical and chemical methods is expensive and could generate secondary pollutants . Enhanced coagulation, alternative disinfectants and carbon filters are used at present to control DBPs The utilization of biofiltration as a treatment technique for VOC removal has been shown to be cost effective, safe and eco-friendly . Biofilters are considered as one of the most promising biological treatment methods for the removal of VOCs . By using biofilters phenol, styrene, ethylene chloride and methanol , and H_2S were successfully removed. However, little work was done in the biological treatment of chlorinated compounds except for mono-chlorobenzene, chlorobenzene, trichloroethylene and 1,1,1-trichloroethane and tetrachloroethylene . This study was proposed to investigate the effectiveness of gas stripping of DBP in tandem with degrading them using biofiltration technology under oxygen deficient conditions by using chloroform (CHCl3) as a model for DBP compounds. The performance of BTF was evaluated under different operating conditions and different inlet concentrations of a co-metabolite, inlet concentration of chloroform in the anaerobic environment.