Combined industrial and domestic wastewater treatment by periodic allocating water hybrid hydrolysis acidification reactor followed by SBR

Abstract

A pilot-scale hybrid hydrolysis acidification reactor (HHAR) with periodic water allocation mode operation followed by sequencing batch reactor (SBR) in anoxic and aerobic metabolic function was evaluated for the treatment of low-biodegradable combined industrial and domestic wastewater. The HHAR combines the advantages of both the UASB reactor and AF, omitting the three-phase separator. Furthermore, it has lower average up-flow velocity (0.38–0.92m/h) and higher periodic up-flow velocity (6m/h), which made the reactor keep higher MLSS concentration (more than 10,000mg/L) and sludge-bed is in periodic “expansion-sedimentation-expansion” state. When HRT less than 10h, the B/C variation was positive and reached the maximum value of 0.07 at 8h. SBR with a total cycle period of 4.5h was applied as the post-treatment process to remove residual COD, NH3-N and TN. At steady stage, the pilot-scale SBR effluent COD, NH3-N and TN concentration was 65, 0.75 and 17.71mg/L, corresponding in this case to full-scale SBR plant effluent was 93, 16.4 and 34mg/L. Comparison results indicated that the application of HHAR–SBR system to treat combined industrial and domestic wastewater can improve effluent quality significantly.