Biogas Production in Dairy Cattle Systems, Using Batch Digesters With and Without Solids Separation in the Substrates

Abstract

This research aimed to evaluate the biogas production during the anaerobic biodigestion process of dairy cattle manure, with and without solids separation. Sixteen biodigesters of the batch type were used, each one with 2L of capacity, supplied with manure in four different conditions: (1) pure manure, after washing the floors of the free stall system; (2) manure after the solids separator; (3) manure after the solids separator and sand decanter and (4) manure with the solid retained in separator solids, dissolved in water. The hydraulic retention time was of 196 days. The highest reductions of volatile solids (VS) were obtained for the biodigesters supplied with manure that went through some process of solids separation. The highest potential of methane production(CH4) obtained was of 0.2686 m³ CH4 kg -1 of added VS, supplied to digesters with manure after solids separator. The best potential for biogas and methane production was observed when there was a reduction of the solids concentration in the manure and, in this case, the hydraulic retention time can be reduced, which reduces the volume of the biodigester and the cost of implementation and maintenance, but the highest biogas production occurred in the biodigesters without solids separation.

Dairy cattle manure utilization by smallholder dairy farmers in West Java, Indonesia

“…In addition to fresh milk and other products, dairy farms produce waste such as manure. Manure can have economic value if processed and utilized appropriately, such as for biogas [2][3][4][5][6][7][8] and fertilizer [9][10][11]. However, most dairy farmers in this region discharge it into their surroundings [12][13][14].…”

Biodigester with mixing by hydraulic recirculation of the wastewater on biogas production: Fundamentals in the design and scaling by a dimensional analysis

“…Biogas generation by anaerobic digestion from high charges of total solids (>10%) has been demonstrated to be more suitable in biodigesters operated by batch and has been conducted at the laboratory scale (0.25 to 40 L) (Zhang et al, 2008;Guendouz et al, 2010;Anjos et al, 2017;Lee et al, 2019) and pilot plant scale (60 to 280 L) (Anozie et al, 2005;Di Maria et al, 2013;Onofre et al, 2015). The development of this technology has been focused principally on two aspects: firstly, in the feasibility of biogas generation, depending on the kind of waste substrate present in the wastewater (Mata-Alvarez et al, 2000;Zhu et al, 2011;Teniza-García et al, 2015); and secondly, in the design and operational conditions of the biodigesters (Zupancic et al, 2008;Kaparaju et al, 2009;Nkemka et al, 2010;Liu et al, 2012).…”