The importance of soluble microbial products (SMPs) in biological drinkingwater treatment

The formation of soluble microbial products (SMPs) during a drinking water ozone-biofiltration process was estimated using two approaches. First, a mo del was developed that related the assimilation of biodegradable organic ma tter (BOM) to the accumulation of biomass on filter media. The model was ca librated with data from a regularly backwashed, pilot scale biofilter that approximated a steady-state plug flow reactor. The second approach was a di rect measurement of SMP concentrations, accomplished by applying a syntheti c water comprised of known compounds to a bio-acclimated filter. The SMP co ncentration was estimated by determining the difference between known-compo und removal (on a carbon basis) and dissolved organic carbon (DOC) removal, Comparable results were obtained from both approaches. SMPs were found to be important relative to the carbon removal that is typically measured (DOC ), indicating that this measurement can significantly underestimate the act ual BOM removal (17-33% in this research). The concentration of SMPs was ne gligible relative to the filter effluent DOC pool. (C) 2000 Elsevier Scienc e Ltd. All rights reserved.