Performance Study of the Single and Double Stages Anaerobic Biological Filters in Treating Domestic Greywater


AbstractIn this paper, a laboratory plant was constructed and operated in order to assess the effect of stages; detention times and depth of filter on the performance of the upflow anaerobic biological filter that treating domestic grey water. The experimental plant was consisted of two upflow anaerobic filters; the first one operates with a single stage, while the second one was with two stages. Crushed gravels were used as a medium for growing the biological organisms. The two filters were worked simultaneously in continuous flow regime at hydraulic detention times of 12, 18 and 24 hours using greywater samples with COD concentration between 190-350 mg/l. The results showed that the two stages filter was more efficient than the single stage filter. The COD and BOD removals were (55.5, 62.7, 75.3)% and (57.2, 67.4, 78.2)% for the detention times of (12, 18 and 24) hours respectively. While the COD and BOD removals were (67.7, 54.8, 39.1)% and (73.2, 60.5, 44.8)% for the first filter and at the same detention times respectively. The two filters were also efficient in removing the suspended solids. Increasing depth of filter has a little influence on the performance efficiency. Depth of (0.3) m was considered the most effective height by which the quickest COD removal is performed.