Biochemical Methane Potential of Beef Feedlot Manure: Impact of Manure Age and Storage

Abstract

Methane capture and use from intensive livestock industries is relatively new, and there is limited chemical and kinetic degradation information available for beef feedlot manure in Australia or internationally. This paper evaluates the biochemical methane (CH) potential, apparent first-order hydrolysis rate coefficient, and losses in organic content of manure as it ages on feedlot pads and in stockpiles. Chemical characterization of fresh, pad, and stockpiled manure is assessed. Biochemical CH potential on volatile solids (VS) almost always decreased significantly from fresh to pad and from pad to stockpile, ranging (in mL CH g VS) from 230 to 360 in fresh manure, from 70 to 280 in pads, and from 60 to 200 in stockpiles. Kinetics of degradation also varied with manure age (fresh: 0.12 ± 0.01 d; pad: 0.06 ± 0.02 d; and stockpiled: 0.05 ± 0.04 d). At least 50%, and up to 80%, of the original biochemical CH potential of the manure (i.e., degradable material) was lost on drying in pads, and the loss after stockpiling was much greater (>85%). The loss of N was 15 to 60% as manure dried on pads and was much greater after stockpiling (40-90%). Phosphorus loss, though lower than nitrogenous losses, was still significant (25-65% on pads and 35-85% in stockpiles). Although digestion of stockpiled manure is still feasible to generate energy, collection of fresh manure is important to maximize outcomes, with a possible order of magnitude increase in CH production achievable.

<b>Enteric and feces methane emissions, fermentative ruminal parameters and feeding behavior of cattle fed cottonseed and vitamin E</b>

“…Volumetric methane yield of 0,13-0,16 L CH 4 /g VS-fed were found in Pratt's et al (2016) study. Other studies have (IPCC, 2006) reported 0,17 L CH 4 /g VS-fed and variation of 0,07-0,28 L CH 4 /g VS-fed (Gopalan et al 2013). Present data are in agreement with those reported; the average volumetric methane yield was 0,16 L CH 4 /g VS-fed.…”

Assessment of the biochemical methane potential of in-house and outdoor stored pig and dairy cow manure by evaluating chemical composition and storage conditions

“…For both manure types there is evidence for a fast decrease in the BMP at the beginning of the storage and declining rates with increasing storage time, agreeing with the rates presented in Table 2 , and with the observations of de Buisonjé & Verheijen, (2014) . Also, Gopalan et al (2013) conducted an analysis of the average BMPs of beef feedlot manure samples. The researchers found that fresh samples (<8 h old) had BMPs of 350 mL CH 4 g VS -1 , pad samples (aged between 3 and 8 weeks) had BMPs of 270 mL CH 4 g VS -1 , and stockpile samples (aged between 8 and 12 months) had BMPs of 140 mL CH 4 g VS -1 .…”

Kinetics of methane production and hydrolysis in anaerobic digestion of corn stover

“…The small and large BMP assays of grass silage were carried out in small serum bottles and 1.5 L reactor, respectively [9]. BMP test was conducted in 240 mL serum bottle with working volume 100 mL using beef feedlot manure as substrate [10]. BMP tests were carried out at different scales (5 L and 0.5 L) for both wet and dried food waste [11].…”