Combined anaerobic-aerobic and UV/H₂O₂ processes for the treatment of synthetic slaughterhouse wastewater

Abstract

The biological treatment of a synthetic slaughterhouse wastewater (SSWW) is studied using an anaerobic baffled bioreactor (ABR) and an aerobic activated sludge (AS) at a laboratory scale in continuous mode. The total organic carbon (TOC) loading rate, the total nitrogen (TN) loading rate, and the flow rate are 0.03–1.01 g/(L.day), 0.01–0.19 g/(L.day), and 2.93–11.70 mL/min, respectively. The results reveal that combined anaerobic-aerobic processes had higher efficiency to treat SSWW than a single process. Up to 96.36% TOC, 80.53% TN, and 99.38% 5-day carbonaceous biochemical oxygen demand (CBOD₅) removal from an influent concentration of 1,009 mgTOC/L, 420 mgTN/L, and 640 mgCBOD₅/L at the hydraulic retention time (HRT) of 6.24 days and a flow rate of 3.75 mL/min are achieved. The UV/H₂O₂ process is studied to treat a secondary effluent of SSWW with TOC loadings of 65–350 mg/L. Up to 75.22% TOC and 84.38% CBOD₅ removal are obtained at the HRT of 3 h with H₂O₂ concentration of 900 mg/L. Optimum molar ratios of 13.87 mgH₂O₂/mgTOC_in and 4.62 mgH₂O₂/mgTOC_in.h are also obtained. Combined anaerobic-aerobic and UV/H₂O₂ processes enhanced the biodegradability of the TOC, TN, and CBOD₅ present in the SSWW. Up to 99.98% TOC, 82.84% TN, and 99.69% CBOD₅ overall removals are obtained for an influent concentration of 1,005 mgTOC/L, 200 mgTN/L, and 640 mgCBOD₅/L at the HRT of 4 days and a flow-rate of 5.90 mL/min.

Keywords:

• Synthetic slaughterhouse wastewater (SSWW)
• anaerobic baffled bioreactor (ABR)
• aerobic activated sludge (AS)
• advanced oxidation processes (AOPs)
• UV/H₂O₂
• combined processes