Anaerobic biodegradation of chlorinated aliphatic compounds using packed bed reactors.

The feasibility of anaerobic packed bed reactors with tezontle (volcanic stone widely available in Mexico) and mineral granular activated carbon (GAC) was explored for the degradation of the main chlorinated aliphatic compounds present in the effluent from chemical industry for ethylene and polyvinyl chloride production. The biofilm on the support materials was developed using as inoculums anaerobic sludge. The biodegradation of the halogenated aliphatic compounds (1,2-dichloroethane; 1, 1, 1 -trichloroethane; trichloroethylene and carbon tetrachloride) was possible without addition of external electron donors. High COD removal was obtained in the reactors with both materials. The use of GAC as a biomass support allows a complete biodegradation of the chlorinated aliphatic compounds at organic loads up to 1.24 kgCOD.m(-3).d(-1), with 94% of COD removal and with a biodegradation rate of 2.062 gCOD.kgGAC(-1).d(-1). The reactor with tezontle also had high biodegradation capacity, but the biodegradation of the 1, 1 -dichloroethene, which appeared as intermediate product, was not reached at the required level in the studied range of organic loads.