REMOVAL OF ENVIRONMENTALLY RELEVANT CONCENTRATIONS OF THE PESTICIDE METALDEHYDE FROM WATER IN BIOAUGMENTED PILOT-SCALE SLOW SAND FILTERS

A metaldehyde-degrading bacterial library was screened using batch assays to identify the best strains for removal of the compound at micropollutant concentrations from water. A. calcoaceticus E1 and Sphingobium CMET-H were used for bioaugmentation of pilot-scale slow sand filters. The former was not able to achieve metaldehyde-compliant water even though a remarkably high population was present in the sand. In contrast, the latter could swiftly bring metaldehyde concentrations to compliant levels that persisted for 14 d until reactor shutdown, even though its population in the top layer of the sand filters was relatively low.