Thermophilic aeration of cattle slurry with whey and/or jam wastes.
Thermophilic aeration of cattle slurry and food industrial by-products was studied with the aim to improve hygienic qualities of the slurry so that it could be used as a safe fertiliser for berries to be eaten raw. We also wanted to study if the process would be energetically favourable in an arctic climate. Cattle slurry alone or with whey and/or jam waste was treated. The tests were done in a well heat-insulated reactor with a 10 m(3) volume. Temperature increases up to over 70 degrees C could be recorded in 19 days even though some processes were carried out in winter time when the ambient air temperature was less than 0 degrees C. The heat energy formed was higher than the electrical energy needed to carry out the aeration. The hygienic qualities of the aerated product were good with only minor nitrogen losses. The end product could be useful as a fertiliser and soil improving compound to increase the organic matter content of agricultural soil. Cattle slurry alone was well suited as the raw material if attaining a high temperature was the main goal. A part of slurry could be replaced with food-industrial side products. Whey waste suited better for co-composting than jam waste but the mixture of whey, jam waste, and slurry was optimal for composting.
Heinonen-Tanski
Helvi
H
Department of Environmental Sciences, University of Kuopio, P.O. Box 1627, FIN 70211 Kuopio, Finland. helvi.heinonentanski@uku.fi
Kiuru
Tapio
T
Ruuskanen
Juhani
J
Korhonen
Kari
K
Koivunen
Jari
J
Ruokojärvi
Arja
A
D000388:Air; D000818:Animals; D002417:Cattle; D005285:Fermentation; D005525:Food-Processing Industry / Q000379:methods*; D006358:Hot Temperature; D007220:Industrial Waste; D008372:Manure / Q000382:microbiology; D010100:Oxygen / Q000378:metabolism; D010865:Pilot Projects; D018505:Waste Management / Q000379:methods*
D007220:Industrial Waste; D008372:Manure; D010100:Oxygen