Anaerobic treatment of blended sugar industry and ethanol distillery wastewater through biphasic high rate reactor

This study aimed to investigate the physicochemical properties of sugar industry and ethanol distillery wastewater and the treatment of the blended wastewater through a two-stage anaerobic reactor. For this treatment, different initial chemical oxygen demand (COD) concentrations (5–20 g/L) and hydraulic retention times (HRTs) (2–10 days) were applied. The sugar industry effluent characteristics obtained in terms of organic matter (mg/L) were as follows: 5 days biochemical oxygen demand (BOD5): 654.5–1,968; COD: 1,100–2,148.9; total solids (TS): 2,467–4,012 mg/L; and pH: 6.93–8.43. The ethanol distillery spent wash strengths obtained were: BOD5: 27,600–42,921 mg/L; COD: 126,000–167,534 mg/L; TS: 140,160–170,000 mg/L; and pH: 3.9–4.2. Maximum COD removal of 65% was obtained at optimum condition (initial COD concentration of 10 g/L and HRT of 10 days), and maximum color removal of 79% was recorded under similar treatment conditions. Hence, the performance of the two-stage anaerobic reactor for simultaneous removal of COD and color from high-strength blended wastewater is promising for scaling up in order to mitigate environmental problems of untreated effluent discharge.