Modeling HAA biodegradation in biofilters and distribution systems

摘要

Using a plug-flow reactor model and literature values for haloacetic acid (HAA) biodegradation kinetic parameters, the authors evaluated HAA removal efficiency in biofilters and distribution systems. The simulations performed indicated that HAA removal through bacterial activity is possible both within biofilters and along the pipe walls from the distribution system. Because large numbers of bacteria are needed to be able to reduce HAA levels below US Environmental Protection Agency limits, only the biofilters-where relatively large bacterialrndensities can accumulate on the filter media-proved efficient systems for removing HAAs. Although previous research showed that HAAs could be degraded in biologically active carbon filters and along distribution systems, none of these studies correlated HAA degradation efficiency with physical and biological parameters (e.g., pipe diameter, filter grain diameter, flow velocity, biodegradation kinetic constants). The current research fills in these gaps and demonstrates why a biofilter is more efficient than the distribution system at removing HAAs.