BIOFILTRATION PERFORMANCE .1. RELATIONSHIP TO BIOMASS

A phospholipid analytical technique was used to measure the amount of biomass attached to the surfaces of drinking water filter media. The m ethod was reproducible and able to detect significant differences in b iomass concentrations in different filters and at various depths withi n filters. The amount of attached biomass decreased as filter depth in creased, suggesting that most removal of natural organic matter occurr ed at the top of the biofilters. The results show that granular activa ted carbon media were able to hold more biomass than were anthracite a nd sand media and that concentrations of biomass in anthracite-sand fi lters were lower with chlorine in the backwash water.