Anaerobic treatment of slaughterhouse wastewater in an Expanded Granular Sludge Bed (EGSB) reactor

The performance of an Expanded Granular Sludge Bed (EGSB) reactor for treat ing slaughterhouse wastewater under mesophilic conditions (35 degrees C), w as investigated. The reactor was inoculated with granular sludge from an an aerobic reactor of a brewery factory. The averaged COD removal percentages were 67% for total organic loading rates (B-V.TCOD) UP to 15 kg COD m(-3) d (-1) and a hydraulic retention time (HRT) of 5 h. Total suspended solids (T SS) were 90% removed for total solids loads of 6 kg TSS m(-3) d(-1). Fats w ere 85% removed and no accumulation of fats on the sludge was observed. The specific methanogenic activity of the sludge, after 140 days, was about th ree times higher than the sludge inoculated into the reactor. The sludge ac tivity did not significantly change after one year of work. These findings indicate that the anaerobic treatment of slaughterhouse wastewater in an EG SB system appears to be a feasible option. (C) 1999 IAWQ Published by Elsev ier Science Ltd. All rights reserved.