Biomethane production from vinasse in upflow anaerobic sludge blanket reactors inoculated with granular sludge

Abstract

The main objective of this study was to evaluate the anaerobic conversion of vinasse into biomethane with gradual increase in organic loading rate (OLR) in two upflow anaerobic sludge blanket (UASB) reactors, R1 and R2, with volumes of 40.5 and 21.5 L in the mesophilic temperature range. The UASB reactors were operated for 230 days with a hydraulic detection time (HDT) of 2.8 d (R1) and 2.8–1.8 d (R2). The OLR values applied in the reactors were 0.2–7.5 g totalCOD (L d)−1 in R1 and 0.2–11.5 g totalCOD (L d)−1 in R2. The average total chemical oxygen demand (totalCOD) removal efficiencies ranged from 49% to 82% and the average conversion efficiencies of the removed totalCOD into methane were 48–58% in R1 and 39–65% in R2. The effluent recirculation was used for an OLR above 6 g totalCOD (L d)−1 in R1 and 8 g totalCOD (L d)−1 in R2 and was able to maintain the pH of the influent in R1 and R2 in the range from 6.5 to 6.8. However, this caused a decrease for 53–39% in the conversion efficiency of the removed totalCOD into methane in R2 because of the increase in the recalcitrant COD in the influent. The largest methane yield values were 0.181 and 0.185 (L) CH4 (g totalCOD removed)−1 in R1 and R2, respectively. These values were attained after 140 days of operation with an OLR of 5.0–7.5 g totalCOD (L d)−1 and totalCOD removal efficiencies around 70 and 80%.

Combination of chemical coagulation, photo-Fenton oxidation and biodegradation for the treatment of vinasse from sugar cane ethanol distillery

“…This is a very critical issue because part of the biodigested vinasse is recirculated back into the anaerobic reactor. The advantage of recirculating the treated vinasse is to reduce the consumption of chemicals for neutralization of the stream fed to the anaerobic digester, taking advantage of the alkalinity of the biodigested vinasse (Barros et al, 2016;Guerreiro et al, 2016).…”

Treatment of sugarcane vinasse by combination of coagulation/flocculation and Fenton’s oxidation

“…However, despite the high reduction of COD and BOD, the final effluent resulting from this process still contains recalcitrant compounds and inhibitors of the biological activity (Santos et al, 2005), which is very undesirable because part of the biodigested vinasse is recirculated back into the anaerobic reactor. The main goal of such strategy is to take advantage of the alkalinity of recirculated vinasse, therefore reducing the consumption of chemicals (NaOH) for neutralisation (Barros et al, 2016), as schematised in Fig. 1.…”

CFD simulation and PIV validation of the gas/liquid behavior in an UASB reactor

“…the use of recycle streams, series reactors, changes in the hydraulic retention time (HRT) (EL-SHEIKH et al, 2011;INTANOO et al, 2014;RIZVI et al, 2015;FERRAZ JUNIOR et al, 2016). Changes on the biomass source and the supplementation of the process aiming higher biogas production are also under study by some authors (JANKE et al, 2016;BARROS;DUDA;OLIVEIRA, 2016).…”