Rapidly Start-up and performance of the EGSB Reactor Treating Actual Coking Wastewater when seeded with Digestion Sludge

To accomplish rapidly the granulation process of digestion sludge for the treatment of actual coking wastewater and meanwhile achieve high COD, phenol, SCN- and CN- removal, the EGSB reactor was employed with two operation stages. Stage I: Granular sludge was formed from digestion sludge using brewery wastewater as substrate in the anaerobic way (meanwhile adding little granules, which were 1/7 of the total biomass). Stage II: Granular sludge was acclimatized with the actual coking wastewater through continuous micro-oxygenation way. The experimental results showed that the granular sludge could quickly form in 10d in the EGSB reactor seeded with digestion sludge and little loose granules. It took only about 6 months for the successful micro-aerobic acclimating of the granular sludge by the actual coking wastewater. The removal efficiencies of COD, phenol, SCN- and CN- were 72.9, 99.5, 95.7 and 97.5%, respectively, at 12.1h hydraulic retention time (HRT) and for 631-922, 12.8-37.7, 66.7-232.7 and 0.3-57.8mg.L-1 influent COD, phenol, SCN- and CN- concentration.