Efficient biogas production from the liquid fraction of dairy manure

Abstract

Abstract. A farm integrated process for small scale biogas production from manure is designed. The anaerobic digestion (AD) process is tested on diary manure and consists of a manure storage tank, a separation unit to remove coarse solids, and an AD reactor for biogas production using the resulting manure liquid fraction as substrate. The performance of the 220 L pilot AD reactor, run at 8.8 days hydraulic retention time depended on the raw manure storage time. The biogas production was 0.7-1.5 g COD L -1 reactor d -1, and the maximum biogas methane yield was 0.19 g COD g -1 feed COD. The overall AD process gained 29 % of the total methane potential of the raw dairy manure. High manure alkalinity (8-9 g CaCO 3 L -1 ) ensures stable pH (7.8-8.0) at high load. The results imply that diary manure can be treated more sustainable by AD at even higher loadings.

Microbial community dynamics and biogas production from manure fractions in sludge bed anaerobic digestion

“…Dairy manure handling is described in Bergland et al . () while the influent properties are in Table . The other four reactors (PA1, PA2, PB1 and PB2) were fed pig manure slurry supernatant (named pig manure for short hereafter) for 106 days.…”

“…The HRT of the CA reactors was decreased towards the end of the experiment while the CB reactors were kept at constant HRT. Dairy manure handling is described in Bergland et al (2014) while the influent properties are in Table 1. The other four reactors (PA1, PA2, PB1 and PB2) were fed pig manure slurry supernatant (named pig manure for short hereafter) for 106 days.…”

Granular Sludge Bed Processes in Anaerobic Digestion of Particle-Rich Substrates

“…Difficulties experienced with the treatment of high particulate substrates, such as manure, that contains straws and other long fibers are mainly mechanical as it often leads to pipe blockage and channeling. During storage, however, such fibers tend to float if the substrate is left undisturbed for a day or more [18,19] and a supernatant can be withdrawn and used as UASB substrate. Even at suspended solids concentrations above what is considered appropriate for UASB, high conversion rates and yields, and substantial conversion of the particulates at low HRT is achieved [11].…”

Temperature Effects in Anaerobic Digestion Modeling

“…The cattle were fed grass and clover ensilage and 25 % "dairy concentrate" (19 % protein). The manure was flushed into an indoor temporarily storage tank, diluting the manure with flush water by 14 % on average (Bergland et al, 2014). The manure was stored for 1-6 weeks in the storage tank before treated in a rotating vacuum drum filter (mesh light opening of 1.4 mm) to remove the coarse solids.…”