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Hydraulic performance issues in drinking-water biofilters have sometimes been associated with phosphorus limitation and increased production of extracellular polymeric substances in previous bench-scale studies. However, field studies utilizing phosphorus supplementation to improve biofilter hydraulic performance have produced mixed results. Here, we determined the ratio of activities for phosphatase to glycosidase (PHO:GLY), which are enzymes involved in acquiring orthophosphate and biodegradable organic carbon from complex organic substrates, to assess phosphorus limitation in 21 pilot-and full-scale biofilters. Supplementation of the pilot-scale biofilter influents with 37 μg/L orthophosphate-P reduced the PHO:GLY from 1.8-40.3 (mean 14.8) to 0.3-15.9 (mean 5.3), demonstrating that increased orthophosphate availability decreases PHO:GLY. In the absence of phosphorus supplementation, the PHO:GLY of the pilot-and full-scale biofilters ranged from 0.3 to 40.3 (mean 10.1), and no hydraulic performance issues were noted. Thus, severe phosphorus limitation appears uncommon in the field, suggesting that phosphorus supplementation is unlikely to improve hydraulic performance in typical drinking water biofilters.

No abstract

The United States (US) Environmental Protection Agency (EPA) included strontium (Sr) in the Contaminant Candidate List 3 as a potential chemical for future regulation. Sr occurrence data at US public...

The water industry is experiencing renewed interest in optimizing manganese (Mn) control. With greater knowledge of Mn in drinking water, water utilities will be better prepared to develop effective management strategies.