THE EFFICACY OF GRAVEL-BED HYDROPONIC SYSTEM IN THE REMOVAL OF DDT RESIDUES FROM SEWAGE EFFLUENT

A high performance liquid chromatography method was employed to monito r DDT and some of its metabolites in sewage effluent which had undergo ne primary treatment. A gravel bed hydroponic (GBH) system was designe d to treat the effluent in order to reuse it in agricultural purposes. The system was made of six channels covered with common reeds (Phragm itis australis). High concentrations of DDT-type residues were detecte d in the effluent. Results indicated the ability of GBH system to remo ve more than 80% effluent-borne DDT residues.