COMPOSTING SOLID SWINE MANURE AND LIGNITE MIXTURES WITH SELECTED PLANT RESIDUES

A study was undertaken to investigate the composting of mechanically s eparated solid swine manure and ground lignite residues mixtures enric hed with rice seed peels and ginned cotton residues. A set of odor-fre e compost piles, due to lignite addition, was installed, on site, at A FI KARAPATIS SA organic fertilizer factory at Zeli in central Greece. The findings of this study indicated that co-composting of solid swine manure and ground lignite (mixed at a ratio of I:I by volume) togethe r with ginned cotton residues and rice seed peels resulted in improved composting and chemical composition characteristics compared to the m ixture of solid swine manure and ground lignite alone or enriched with either ginned cotton residues or rice seed peels. Ground lignite, due to its excellent odor- and moisture-absorbing capacities allowed for the successful incorporation of the wet and malodorous swine manure in to the compost process. Ginned cotton residues (at a I:I mixing ratio by volume) proved to be a bulking agent with excellent 'insulating beh avior' but with lower composting rates and increased EC and Na values in the final product. Rice seed peels, as C/N amendment, speeded up th e compost process and improved the quality characteristics of the fina l product but showed a very poor 'insulation behavior'. When both ginn ed cotton residues and rice seed peels were added to a pile, all adver se effects were removed and best results were obtained (maximum temper ature range between 45-55 degrees C for about 20 days and overall comp ost process of about 85 days with ambient air values below 10 degrees C). Copyright (C) 1996 Elsevier Science Ltd.