| dc.description.abstract | A pilot scale Hybrid Vertical Anaerobic Biofilm (HyVABr) reactor was applied to the treatment of waste oil refinery wastewater. The reactor comprised a bottom anaerobic digestion stage operated as an Up-flow Anaerobic Sludge Blanket (UASB) and a moving bed biofilm stage (during washing mode) on top operated as a Continuous Flow Intermittent Cleaning (CFICr).
The reactor was operated continuously for 90 days, with Organic Loading Rate (OLR) increasing from the lowest 3 kg COD/m3.d to the highest 33.1 kg COD/m3.d. Oil wastewater was heated to 35_C before pumping through the bottom of the reactor. Average Chemical Oxygen Demand (COD) concentration of the feed was 10 g/L.
The results showed that the HyVABr reactor had good performance in terms of COD removal and biogas generation. Highest sCOD removal e_ciency of 98.5% and tCOD removal e_ciency of 95.4% was achieved at 12 hours Hydraulic Retention Time (HRT) in AD, and highest OLR of 18.7 kg COD/m3.d. Most of the COD removal took place in AD stage. Around 86% COD in oil wastewater was transformed into biogas in which methane content was 80-90%. Biogas formed was collected at anaerobic and aerobic interface via a three phase separator.
Volatile Fatty Acid (VFA) accumulation was observed during the initial and later operation stage a_ecting COD removal, biogas production and total suspended solids in e_uent. Suspended solid production measured in the e_uent was approximately 0.16 kg VSS/kg COD removed. Meanwhile, sludge loading rate (SLR) increased from 0.1 kg COD/kg VS.d at the initial phase to 0.55 kg COD/kg VS.d at 71st day. Also, specific methanogenic activity (SMA) increased from 0.074 kg COD-CH4/ kg VS.d to 0.428 kg COD-CH4/ kg VS.d at 71st day.
On the whole, the compact HyVABr exhibited good stability in terms of acidity and alkalinity. Replacing CFICr with HyVABr can save significant amount of money on aeration up to $ 5.35 per day per m3 of treated wastewater. HyVABr reactor can be an attractive alternative while treating high strength wastewater at relatively lower operational cost. | nb_NO |
