Effect of Cattle Slurry Separation on Greenhouse Gas and Ammonia Emissions during Storage

Abstract

Storage of cattle slurry leads to emissions of methane (CH(4)), nitrous oxide (N(2)O), ammonia (NH(3)), and carbon dioxide (CO(2)). On dairy farms, winter is the most critical period in terms of slurry storage due to cattle housing and slurry field application prohibition. Slurry treatment by separation results in reduced slurry dry matter content and has considerable potential to reduce gaseous emissions. Therefore, the efficiency of slurry separation in reducing gaseous emissions during winter storage was investigated in a laboratory study. Four slurry fractions were obtained: a solid and a liquid fraction by screw press separation (SPS) and a supernatant and a sediment fraction by chemically enhanced settling of the liquid fraction. Untreated slurry and the separated fractions were stored in plastic barrels for 48 d under winter conditions, and gaseous emissions were measured. Screw press separation resulted in an increase of CO(2) (650%) and N(2)O (1240%) emissions due to high releases observed from the solid fraction, but this increase was tempered by using the combined separation process (CSP). The CSP resulted in a reduction of CH(4) emissions ( approximately 50%), even though high emissions of CH(4) (46% of soluble C) were observed from the solid fraction during the first 6 d of storage. Screw press separation increased NH(3) emissions by 35%, but this was reduced to 15% using the CSP. During winter storage greenhouse gas emissions from all treatments were mainly in the form of CH(4) and were reduced by 30 and 40% using SPS and CSP, respectively.

Ammonia losses from the storage and application of raw and chemo-mechanically separated slurry

“…Studies conducted by Amon et al (2006), Dinuccio et al (2008) and Fangueiro et al (2008) found high emission of NH 3 , CO 2 and NO 2 during the storage of the separated raw slurry solid fraction. Moreover, Nyord et al (2008) and Dinuccio et al (2011) claimed that high losses of nitrogen as NH 3 might take place from the liquid fraction of separated slurry, especially during the land application.…”

Nutrient losses from cattle co-digestate slurry during storage

“…Considering the separation efficiency, the liquid fractions account for 66% of total nitrogen loss. As in Fangueiro et al (2008), these results are mainly due to the losses from the liquid fractions, usually characterized by the highest TAN/TKN ratio and lowest TS contents; Vaddella et al (2013) found that the NH3 mass transfer coefficient decreases with increasing TS concentration. These results are in accordance with other studies that report higher emission from the separated fractions during storage (Fangueiro et al, 2008;Dinuccio et al, 2008).…”

“…The volatilisation of NH3, stimulated by the aerobic environment of the storage conditions due to the porosity of SF, may explain this observation. Part of this reduction might be also explained by N immobilisation, because of the high C/N ratio of the solid fraction (Fangueiro et al, 2008). …”

“…Some previous studies (Dinuccio et al, 2008;Fangueiro et al, 2008) have addressed mechanical separation of animal manure but few have studied the application of this technology on digestate from anaerobic digesters. Further, there are few studies that have monitored nutrient losses from manure in completely open field conditions for both winter and summer seasons.…”

Spatial and Temporal Variation in Physicochemical Properties of Dairy Lagoons in South-Central Idaho

“…There is also a potential concern for crop productivity and quality related to salt accumulation on fields where lagoon water is continually applied over time (Segal et al, 2010;Shapiro et al, 2005). The amount of nitrogen (N) and solids (particularly volatile solids, VS) within a lagoon can also influence the amount of ammonia (NH 3 ) and methane (CH 4 ) emissions generated from the lagoon, which is a concern from an air quality and climate change perspective (IPCC, 2007;Huang et al, 2010;Montes et al, 2009;Fangueiro et al, 2008;Ni, 1999). The spatial variability and seasonal dynamics of these lagoon characteristics are important for understanding the potential variation in emissions.…”