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This article in JEQ

  1. Vol. 40 No. 1, p. 224-232
    Received: May 16, 2010

    * Corresponding author(s): karinj@life.ku.dk
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Carbon, Nitrogen, and Phosphorus Distribution in Particle Size–Fractionated Separated Pig and Cattle Slurry

  1. Karin Peters *a,
  2. Maibritt Hjorthb,
  3. Lars Stoumann Jensena and
  4. Jakob Magida
  1. a Dep. of Agric. and Ecology, Faculty of Life Sci., Univ. of Copenhagen, Denmark
    b M. Hjorth, Dep. of Biosystems Engineering, Faculty of Agric. Sci., Univ. of Aarhus, Denmark. Assigned to Associate Editor Tsutomu Ohno.


Solid liquid separation of animal slurry is a method to reduce the excess nutrient loads from intensive livestock production. Five different separation technologies (sedimentation, centrifugation, pressurized filtration, polymer flocculation and drainage, and iron chloride addition + polymer flocculation and drainage) were applied to pig and cattle slurry in a laboratory study. Separation efficiencies of mass, dry matter (DM), N, and P were measured. Particle size fractionation of the solid fractions was performed by subjecting them to wet fractionation and C, organic N (Norg), and P contents were subsequently measured. Chemical pretreatment with polymer before gravity drainage separated DM, total N, and P from raw pig and cattle slurry with the highest efficiencies. Sedimentation and centrifugation separated P from pig and cattle slurries with higher simple separation efficiencies (0.77 and 0.70, respectively) compared with pressurized filtration (0.15 and 0.37). Pressurized filtration transferred the lowest masses (14 and 18%) to the solid fractions. Solid fractions from pig slurry generally contained higher concentrations of P and C compared with cattle slurry solid fractions. The majority of C in solid fractions was present in particles >25 μm, whereas N and P were present in larger proportions in particles <25 μm. Chemical pretreatment increased the capture of smaller Norg- and P-rich particles into larger particles between 25 and 1000 μm.

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