THE EFFECT OF HYDRAULIC RETENTION TIME ON THE HYBRID ANAEROBIC BAFFLED REACTOR PERFORMANCE AT CONSTANT LOADING

An experimental study was undertaken to determine the effect of hydraulic retention time (HRT) on a 1501 hybrid anaerobic baffled reactor (HABR) at constant organic loading 10 kg m-3 d-1. When the HRT was gradually changed from 1 day to 6 days, i.e. the feed concentration changed from 10 g l-1 to 60 g l-1, the COD reduction dropped from 75% to about 40%, the gas production rate decreased from 5.2 m3 m-3 d-1 to 3.4 m3 m-3 d-1, and the effluent volatile fatty acids (VFA) concentration increased from 430 mg l-1 to about 16,000 mg l-1. Thus methanogenic inhibition occurred at longer HRTs. The experimental results strongly suggested that the HRT is a significant factor for HABR performance.