PERFORMANCE OF UPFLOW ANAEROBIC BIOFILTER PROCESS IN PHARMACEUTICAL WASTE-WATER TREATMENT

Anaerobic processes have become increasingly important in the treatmen t of complex industrial wastewaters, which may not only have high conc entrations of organics but may contain toxic, persistent/recalcitrant substances. The present paper reports an investigation into the start- up characteristics, feasibility and performance of the Upflow Anaerobi c Biofilter Process (UABP) for treating a pharmaceutical effluent, whi ch would be typical of such wastewaters, with an organic concentration of 20,000 mg L-1 COD and two branched-chain fatty acids believed to b e persistent/recalcitrant, pivalic acid (PA) and 2-ethylhexanoic acid (2-EHA). In addition to these, there is a readily degradable component , acetic acid. The data from the start-up process beginning with bioma ss seeding to stable operation showed that the UABP could be satisfact orily started up in two months by using a multiple seeding protocol. H ydraulic Retention Time (HRT) was found to be an important key paramet er which can improve the removal rates of all targeted substances. Tra cking results derived over a year indicated that the process was able to achieve stable performance at 15 days HRT. Increasing the HRT to 20 days substantially improved removal rates of COD and 2-EHA to 93% and 100%, respectively. This longer HRT particularly improved the removal of pivalic acid from 15% to 90%. The biofilter was then able to maint ain this good performance when HRT was subsequently decreased in steps to 1.2 days HRT which brought it towards failure. This investigation demonstrated that the UABP could treat pharmaceutical wastewater conta ining persistent organics effectively.