Microbial degradation of EDTA in an industrial wastewater treatment plant

For the first time it is shown that EDTA is ultimately biodegraded under practical industrial wastewater treatment conditions, involving a Finnish plant dedicated to treat the effluent from a paper mill. Monitoring measurements on the influent and the treated effluent showed an EDTA elimination of about 80%. The mean EDTA concentration in the influent was 23.8 mg l−1 and in the corresponding effluent 5.8 mg l−1. The biodegradability of EDTA was verified in the laboratory with activated sludge from the treatment plant. Using a combined CO2/DOC method the total mineralization of EDTA was indicated by >80% CO2 formation and ≥99% DOC removal.