The effect of electron acceptors on biogas production from tannery sludge of a Mexican wastewater plant

Abstract

Effluents from the leather processing generally are discharged into rivers or are used to irrigate farmland. The biogas production from the digestion of sludge produced could be used as alternative sources for energy and power generation. A study was carried out to examine the effects of various electron acceptor amendments on biogas production from Mexican tannery sludge. Two bench scale experiments were performed: The first experiment used different electron acceptors (nitrate, iron and sulfate) and three different levels for each variable (4.5, 9.0 and 13.5 mg/mL); in the second only urea was used as a nitrogen source with three carbon/nitrogen ratios (6.0, 8.0 and 11). It was found that the reactors with nitrate as electron acceptor (4.5 mg/mL) generated the most biogas (200 mL of biogas accumulated in 25 days). Similarly, the reactors with the lower ratio of carbon/nitrogen (6.0) produced larger biogas production (131.50 ± 19.1 mL of biogas) in a shorter period of time (9 days). The results also showed that the addition of glucose did not significantly influence the production of biogas.

Modeling the Disintegration Process in Anaerobic Digestion of Tannery Sludge and Fleshing

“…In developing countries, where tanning industry plays a prominent role within the local economy, AD turns very attractive to handle the massive waste production due to the relevant reduction of solids to be disposed and possible pay-back in terms of energy/heat production. Some of the reported studies on AD of tannery wastes refer to industrial districts in Asia (Vasudevan and Ravindran, 2007;Thangamani et al, 2010;Sri Bala Kameswari et al, 2014), Latin America (López et al, 2015;Ruiz-Aguilar et al, 2015;Priebe et al, 2016) and Northern Africa (Zerdani et al, 2004). The majority of this works were oriented toward codigestion of untanned solid wastes with other organic substrates in order to face/prevent possible problems of unbalanced C/N ratio as well as inhibitory conditions from ammonia, long chain fatty acids and sulfide accumulation (Dhayalan et al, 2007;Shanmugam and Horan, 2009;Zupancic and Jemec, 2010;Giaccherini et al, 2016).…”