Anaerobic co-digestion of solid slaughterhouse wastes with agro-residues: Synergistic and antagonistic interactions determined in batch digestion assays

Abstract

Please cite this article as: J.P. Díaz, I.P. Reyes, M.J. Taherzadeh, I.S. Horváth, M. Lundin, Anaerobic co-digestion of solid slaughterhouse wastes with agro-residues: Synergistic and antagonistic interactions determined in batch digestion assays, Chemical Engineering Journal (2014), doi: http://dx.doi.org/10. 1016/j.cej.2014.02.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractDifferent mixture ratios of solid cattle slaughterhouse wastes (SB), manure (M), various crops (VC), and municipal solid wastes (MSW) were investigated for biogas production. The objective was to explore possible significant synergistic effects obtained from the combination of these different substrates. The performance of the process was assessed in thermophilic anaerobic batch co-digestion assays, using a four factor mixture design and methane yield (Y CH4 ) and specific methane production rate (r sCH4 ) as response variables.The highest methane yield, 655 NmL CH 4 /g VS was obtained when equal parts (ww) of SB, M, VC, and MSW were combined, while the combination of SB, M, and MSW resulted in the highest specific methane production rate (43 NmL CH 4 /g VS/d). A mixture design model was fitted to data in order to appraise synergistic and antagonistic interactions. Mixing all four substrates resulted in a 31% increase of the expected yield which was calculated from the methane potential of the individual fractions, clearly demonstrating a synergistic effect due to more balanced nutrient composition enhancing the anaerobic digestion process. However, no significant antagonistic effects were observed. In order to maximize both response variables simultaneously, a response surface method was employed to establish the optimal combination of substrate mixtures. The statistical results and analysis of the biological process gave a coherent picture of the results.

Methane and hydrogen sulfide production during co-digestion of forage radish and dairy manure

“…A synergistic effect results in increased CH 4 production from the substrates beyond what is achieved from digestion of each individual component [5,9]. A synergistic effect was observed when co-digesting equal mass fractions of municipal solid waste, slaughterhouse waste, manure, and various crops.…”

Bioconversion of Egypt's Agricultural Wastes into Biogas and Compost

“…Experimentally, co-digestion of a mixture of cow manure and fruit and vegetable waste (50:50 by weight) produced 450 m 3 ton -1 VS at 35 ±0.5ºC [61], whereas a mixture of buffalo manure and maize silage (70:30 by VS content) at 35 ±1ºC produced 358.23 ±44.15 m 3 [62]. It has also been shown that meadow grass with its biochemical methane potential value of 388 ±30 mL g -1 VS has a yield increase of 114% when codigested with manure in a continuous stirred tank reactor [63], and when a mixture of solid cattle slaughterhouse waste, manure, various crops, and municipal solid wastes are batch-digested in thermophilic process, a methane yield of 655 mL g -1 VS was obtained [64]. The approximate biogas yield estimated in Denmark by co-digestion for harvest residues including straw, stems, sugar beet toppings, and fibrous mater is 375 m 3 ton -1 , and animal manure (dough) was 200-500 m 3 ton -1 ; food industry waste, confectionary waste, and whey was 400-600 m 3 ton -1 ; slaughterhouse waste flotation sludge, animal fat, stomach and gut contents and blood was 550-1,000 m 3 ton -1 ; waste from paper industry was 400-800; sludge from gelatin and starch production was 700-900 m 3 ton -1 ; source-separated bio-wastes were 400-500 m 3 ton -1 ; and market waste was 500-600 m 3 ton -1 [65].…”

Mesophilic anaerobic co-digestion of aloe peel waste with dairy manure in the batch digester: Focusing on mixing ratios and digestate stability

“…Furthermore, all of the co-digestion experiments clearly demonstrated a synergistic effect and strengthened the process stability of AD. Pagés-Díaz et al (2014) also pointed out that a mixture of different substrates with various characteristics could provide balanced nutrients and trace elements for anaerobic bacteria, and the diversity in the substrate composition would in turn promote more microorganism growth and accelerate the degradation of organic matter. Based on the above-mentioned analysis and discussion, it can be concluded that co-digestion is an excellent way to treat biomass wastes.…”