Effect of Organic Load on the Performance and Methane Production of an AnSBBR Treating Effluent from Biodiesel Production

Abstract

Currently, there is an increasing demand for the production of biodiesel and, consequently, there will be an increasing need to treat wastewaters resulting from the production process of this biofuel. The main objective of this work was, therefore, to investigate the effect of applied volumetric organic load (AVOL) on the efficiency, stability, and methane production of an anaerobic sequencing batch biofilm reactor applied to the treatment of effluent from biodiesel production. As inert support, polyurethane foam cubes were used in the reactor and mixing was accomplished by recirculating the liquid phase. Increase in AVOL resulted in a drop in organic matter removal efficiency and increase in total volatile acids in the effluent. AVOLs of 1.5, 3.0, 4.5 and 6.0 g COD L(-1) day(-1) resulted in removal efficiencies of 92%, 81%, 67%, and 50%, for effluent filtered samples, and 91%, 80%, 63%, and 47%, for non-filtered samples, respectively, whereas total volatile acids concentrations in the effluent amounted to 42, 145, 386 and 729 mg HAc L(-1), respectively. Moreover, on increasing AVOL from 1.5 to 4.5 g COD L(-1) day(-1) methane production increased from 29.5 to 55.5 N mL CH(4) g COD(-1). However, this production dropped to 36.0 N mL CH(4) g COD(-1) when AVOL was increased to 6.0 g COD L(-1) day(-1), likely due to the higher concentration of volatile acids in the reactor. Despite the higher concentration of volatile acids at the highest AVOL, alkalinity supplementation to the influent, in the form of sodium bicarbonate, at a ratio of 0.5-1.3 g NaHCO(3) g COD (fed) (-1) , was sufficient to maintain the pH near neutral and guarantee process stability during reactor operation.

AnSBBR applied to biomethane production for vinasse treatment: effects of organic loading, feed strategy and temperature

“…The last condition was performed in batch mode with an influent concentration of 10000 mgCOD.L -1 , with the temperature increased from 30°C (from the other conditions) to 45°C, while maintaining the operation in batch mode (Condition C10). In all experimental conditions, the cycle time length was 8 hours, and the stirring was 300 rpm (Bezerra et al, 2011;Lovato et al, 2012;Selma et al, 2010;Silva et al, 2013).…”

“…Finally, some papers related to AnSBBR and methane production regarding feed strategy and organic load improvement: Lovato et al (2012) studied the effects of feed strategy treating the effluent from biodiesel production; Bezerra et al (2011) treated the same effluent to test the effect of the organic load; and Lullio et al (2014) aimed at integrating hydrogen and methane production treating the effluent of hydrogen production to produce methane. Only a few studies involved the use of an AnSBBR to produce methane, and there are no papers in the published literature regarding the use of vinasse as a substrate.…”

Conversion of residues and by-products from the biodiesel industry into value-added products

“…Similar to coagulation, anaerobic digestion needs to pretreat BWW to reduce G&O and COD (Bezerra et al 2011). Pretreatment processes allowed efficient COD and G&O reduction using anaerobic treatment; nevertheless, high concentrations of some chemicals from the pretreatment can be harmful for the anaerobic process (Siles et al 2011).…”

“…Pretreatment processes allowed efficient COD and G&O reduction using anaerobic treatment; nevertheless, high concentrations of some chemicals from the pretreatment can be harmful for the anaerobic process (Siles et al 2011). In addition to COD and G&O removal, anaerobic process produces considerable amount of methane, with removals around 278-305 mL CH 4 /g COD removed, which is about 88 % of the possible methane yield from COD (Siles et al 2011;Bezerra et al 2011). (Pitakpoolsil and Hunsom 2014) In the last few years, BWW has been treated using adsorption and membrane technology to reduce the COD and G&O concentrations.…”

“…The duration of the process is variable; anaerobic treatment is a slow process which takes 30-40 days (Bezerra et al 2011); however, coagulation takes only 20 min to 1 h (Ngamlerdpokin et al 2011). Anaerobic process and membrane technologies have a reduced cost compared with coagulation; the first ones do not have any additional price and anaerobic digestion has the advantage of producing energy from methane which could be sold or utilized in the biodiesel plant.…”