Definitions and abbreviations

Life Cycle Assessment of Slurry Management Technologies

Ash. Ash is the remains after heating the dry matter (DM, see below) at 550^oC for one hour. Typically, 20% of the dry matter is ash.

DM - Dry matter. DM is the fraction of the manure that is left after water has been evaporated due to heating at 80^oC to constant weight for typically 24 hours. It typically constitutes 1 – 10% of the manure by mass (Sommer et al., 2008). In Danish: Tørstof (TS).

LCA - Life Cycle Assessment. LCA is the assessment of the environmental impact of a product (or service) throughout its lifespan, i.e. “from cradle to grave”. The environmental impacts are followed through the whole product chain, typically from raw material extraction, through production and use, to final disposal or recycling.

TAN - Total Available Nitrogen: TAN is the sum of NH₃-N + NH₄⁺-N. At pH 7.8 almost all the TAN is NH₄⁺(only around 1% is NH₃). TAN is often used as synonym for NH₄⁺ (assuming that the amount of NH₃ is insignificant), e.g. by Hansen et al. (2008) and by the Danish Norm Data (Poulsen et al. (2001), DJF (2008) and DJF (2008)), which use “NH₄⁺” and “TAN” for the same numbers (for example “NH₄⁺” in the heading of at table or in the text combined with “TAN” in the table and vise versa). Strictly speaking, it does not totally cover the same – however, for practice use, they are used as synonyms – also in this study.

VS - Volatile solids. VS is the fraction of DM that volatilize when heating the DM at 550^oC for one hour. Typically, 80% of DM is VS. This is the fraction lost during incineration. (Sommer et al., 2008). The content of volatile solids is equal to the difference between the dry matter and ashes (VS = DM – ash). In Danish: Askefrit tørstof eller glødetab.

VS – easily and heavily degradable. The share of easily degradable VS and heavy degradable VS for pig slurry is based on Sommer et al. (2001, Appendix 5). According to this, the VS in slurry can be divided into an easily degradable fraction and a heavyly degradable fraction. The easily degradable fraction is defined as the organic material that is converted to biogas (CO₂ and CH₄) during 14 days in a thermophile reactor and 3 weeks in a mesophile reactor. The content will depend on the pre-treatment of the slurry. The part of VS in slurry that is not degradable in a biogas plant is defined as heavily degradable (1-VS easily degradable).

Slurry:A mixture of all the faeces, urine and some bedding materials (straw, etc.) which is traditionally collected from the pit below the slatted floors. The dry matter content of slurry is typically 1-10% which is lower than for other types of manure, due to addition of washing water and little use of bedding materials.

Slurry “ex animal”: Slurry directly after its excretion from the animals (ex-excretion) and before undergoing any further transformation (i.e. losses or addition). See figure 3.2.

Slurry “ex housing”: Slurry leaving the slurry pits in the housing system. See figure 3.2.

Slurry “ex storage”: Slurry after a long time of outdoor storage. See figure 3.2.