Assessment of biomass in drinking water biofilters by adenosine triphosphate

Biofilters have gained in popularity for drinking water treatment for reasons that include reducing disinfectant demand, disinfection by‐product formation, and regrowth in distribution systems. Adenosine triphosphate (ATP) detection is being used more frequently as an easy and rapid method to quantify viable biomass in biofilters; however, there is little information on the relationship of ATP levels to biofiltration parameters and performance. In this study, a comprehensive comparison of published ATP data was conducted, which found that concentrations at the top of active, acclimated biofilters typically were in the range of 10 2 to 10 3 ng ATP/cm 3 media. The effect of various biofilter parameters (source water characteristics and quality, pretreatment, hydraulic loading rate, temperature, and sampling depth) on ATP levels is discussed and evaluated using published ATP data. The authors also assess the relationship between ATP and biofilter performance in terms of carbon removal and identify a need for further research in this area.