ARS | Publication request: NUTRIENT AND SOLIDS SEPARATION OF DAIRY AND SWINE MANURE USING A SCREW PRESS SEPARATOR

Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: July 21, 1999
Publication Date: N/A

Interpretive Summary: More than half of the rations fed to farm animals remain undigested and show up in the animal manure. Cycling of these nutrients in ways that are both economically and environmentally sound and hence sustainable are of increasing concern. Separation of the manure into a low volume-concentrated fraction and a high volume-low nutrient fraction makes possible the option of applying the former at points distant from their origin where they can potentially have the greatest agronomic benefit and minimize any negative environmental effects. A commercially available screw press was used to separate manure slurry from cattle and swine respectively into a high fiber fraction and a high liquid fraction. In general, more than, 90% of the nitrogen, phosphorus, and potassium where found to be in the liquid fraction. In work reported elsewhere, as much as 80% of the nutrients in the liquid were attached to fine particles. The potential exists to concentrate and remove a large fraction of the nutrients by sedimenting or precipitating the fine particles. The resulting high nutrient sludge could be economically transported to locations where the nutrients would be used to maximum advantage. Adoption of this practice would reduce the amount of chemical fertilizer needed and would prevent the build-up of excess nutrients in the vicinity of animal production facilities making these operations more profitable and sustainable.

Technical Abstract: A KP-10 Vincent Screw Press Separator was evaluated for nutrient and solids separation of dairy and swine manure. For dairy manure the fiber output ranged from 26 to 34% solids with a separator efficiency ranging from 16 to 69% depending on method used. TP in the fiber portion as percent of influent concentration ranged from 8 to 29%. For swine manure the separator refficiency ranged from 15 to 30% with less than 5% of the TP in the fiber stream.