Effect of temperature on haloacetic acid degradation by biologically active carbon

Haloacetic acids (HAAs), as ubiquitous disinfection byproducts in drinking water using chlorination and chloramination and with high hydrophilicity and carcinogenicity, have been regulated to ensure water quality and human health all over the world. The removal of nine HAAs by biologically active carbon (BAC) was investigated. The effect of temperature on HAA biodegradablities and HAA removal mechanism, reaction kinetics and thermodynamics were also discussed in this study. It demonstrated that BAC could availably remove mono-and di-HAAs but was hard to degrade tri-HAAs. When the water temperature ranged from 5 to 15℃, the concentration of HAAs was almost constant, but in warmer water between 25 and 35℃, HAA was prone to degradation by BAC. Under various temperatures, the HAA biodegradation conformed to first order reaction kinetics with rate constants from 0.01 to 0.40 min^-1. The HAA removal mechanism was not halogen sequentially replaced by hydrogen but all halogens of HAAs removed simultaneously. The activation energy of HAA biodegradations ranged from 63.5 to 89.2 kJ/mol.