A biofilter based on light expanded clay aggregate (LECA) and cells of the obligate ethylenediamine tetraacetate (EDTA) destructor Chelativorans oligotrophicus LPM-4 has been developed. The culture steadily maintained a high level of EDTA monooxygenase activity of 180–200 nmol/min/mg of protein during three months. EDTA was converted completely or by 80% at initial concentrations of 0.5–0.7 or 2.0 g/l, respectively, in a 2-dm2 biofilter at a flow rate of 20 ml/h.