Behaviour of acidity, Total nitrogen and total phosphorus in fermented solid organic waste from pig-rearing complex

Abstract

The research aim was to establish the mathematical dependencies between the acidity, total nitrogen content, and total phosphorus content in the starting mixture and resulting organic fertiliser and the fermentation time of the organic waste from the pig-rearing complex. The starting mixture consisted of the solid fraction of pig slurry coming from the screw separator, the solid fraction of pig slurry coming from the decanter centrifuge and the grain mechanical cleaning waste. The fermentation of the mixture into an organic fertiliser lasted for seven days. The fermenter operating mode included the aeration time of 5 min•h -1 , air supply rate of 10 m•s -1 , and the drum rotation interval -every 12 hours. The samples of the processed mixture were taken every day to determine the acidity, total nitrogen and total phosphorus content. The average pH of the processed mixture during the experiment increased by 5 % -from 8.8 to 9.2, uniformly by 1 % per day average. The total phosphorus content in the resulting organic fertiliser was 11 % higher than that in the starting mixture -3863.3 mg•kg -1 against 3506.3 mg•kg -1 . During fermentation, the total phosphorus content in the processed mixture increased uniformly, in proportion to the mixture mass and moisture content decrease. The average total nitrogen content in the resulting organic fertiliser was 28 % higher than that in the starting mixture -7840.7 mg•kg -1 against 6128 mg•kg -1 . During fermentation, the total nitrogen content in the processed mixture increased uniformly by 4 % per day average. Thus, the solid organic fertiliser with higher nutrient content against the starting mixture was produced in seven days. The general conclusion is that the established mathematical dependencies allow forecasting and controlling the fermentation process aimed to obtain products with tailored properties.

Trends in the development of technical means for recycling organic waste from agricultural production

“…In the production of livestock products abroad, special attention is paid to reducing emissions of ammonia and other gases into the atmosphere. In the Netherlands, pollution abatement is being tested in small pilot farms [7]. Similar experiments are being carried out in Denmark, where systems for evaluating the use of protein in cattle feed and their influence on the release of ammonia are additionally investigated [8].…”

Pig Manure Management: A Methodology for Environmentally Friendly Decision-Making

“…The subject of another separate experimental study was the fermentation of the solid fraction of pig manure in a laboratory drum fermenter with the solid organic fertiliser as the end-product [52,53].…”