Biodegradation of high strength phenolic wastewater in a modified external loop inversed fluidized bed airlift bioreactor (EIFBAB)

An EIFBAB was modified with a mixed-tank reactor placed in series to extend the phenol treatability range. Phenol degradation at high concentrations was investigated at recycle rates from the mixed-tank reactor from 0 to 15 L/h under batch operation. With a total working volume of 10 L, the new setup could handle 3000 mg/L phenol at a comparable volumetric biodegradation rate of 9 mg/L(.)h at optimized operation of 5 L/h recycle rate, as the 11 mg/L(.)h in the original EIFBAB. While the original EIFBAB could not handle phenol concentrations exceeding 3000 mg/L, continuous operation was ascertained in the modified EIFBAB for phenol degradation of up to 5000 mg/L phenol and feed flow rates up to 160 mL/h. The recoverability of the system under shock loading of phenol up to 5000 mg/L was also assessed.