Identification of synergistic impacts during anaerobic co-digestion of organic wastes

Abstract

Anaerobic co-digestion has been widely investigated, but there is limited analysis of interaction between substrates. The objective of this work was to assess the role of carbohydrates, protein and lipids in co-digestion behaviour separately, and together. Two sets of batch tests were done, each set consisting of the mono-digestion of three substrates, and the co-digestion of seven mixtures. The first was done with pure substrates--cellulose, casein and olive oil--while in the second slaughterhouse waste--paunch, blood and fat--were used as carbohydrate, protein and lipid sources, respectively. Synergistic effects were mainly improvement of process kinetics without a significant change in biodegradability. Kinetics improvement was linked to the mitigation of inhibitory compounds, particularly fats dilution. The exception was co-digestion of paunch with lipids, which resulted in an improved final yield with model based analysis indicating the presence of paunch improved degradability of the fatty feed.

Anaerobic membrane bioreactors enable high rate treatment of slaughterhouse wastewater

“…Biomethane potential tests ( Figure 3 previously been reported in the range of 1-1.5 g.L -1 [5], this is similar to the initial FOG concentrations in the slaughterhouse wastewater in this study and suggests that the minor inhibition was the result of LCFA accumulation. In this case the inhibition appeared to be minor, and relatively quickly overcome and was likely more related to acclimatization or biostatic inhibition than to the loss of metabolic function or cell death [33].…”

“…Daily biogas production from anaerobic lagoons may vary by an order of magnitude depending on temperature or plant operational factors [4]. While the organic solids in slaughterhouse wastewater is highly degradable [3,5] reducing sludge accumulation and expensive desludging events, there are increased risks of scum formation [4] which can reduce methane recovery and damage lagoon covers. Therefore, even in warmer climates, there is an emerging and strong case for reactor based technologies.…”

Anaerobic co-digestion of animal manure at different waste cooking oil concentrations

“…Decrease in biogas yield is related to the metabolism of lipids since they are hydrolyzed into LCFA and glycerol (SILVESTRE et al, 2011) and later processed into biogas, which causes toxicity to the system because LCFA are adsorbed onto microbial cell membranes and affect their functionality (ASTALS et al, 2014;MATA-ALVAREZ et al, 2014). In contrast, FIERRO et al (2014) reported no effect of toxicity when assessing the co-digestion of swine manure and lipid-rich residues since they worked with low inclusions (maximum of 25g waste cooking oil.kg manure -1 ).…”

A new organic matter fractionation methodology for organic wastes: Bioaccessibility and complexity characterization for treatment optimization

“…through pretreatments (Aquino et al 2008;Bougrier et al, 2006;Cesaro and Belgiorno, 2014;Costa et al, 2013;Donoso-Bravo et al, 2011), by process control (García-Diéguez et al, 2011;HolmNielsen and Oleskowicz-Popiel, 2013;Madsen et al, 2011) or by co-digestion (Abouelenien et al, 2014;Astals et al, 2014;Bouallagui et al, 2009). When considering the valorization of organic wastes through land spreading (with or without previous biological treatments), some other issues were considered too.…”