Comparison of two thermal methods of chicken manure treatment

Abstract

© 2019, International Multidisciplinary Scientific Geoconference. All rights received. Chicken meat is easy to produce, and as a result, it is a cheap and massively used source of animal protein in food. However, poultry farms produce more than 200 thousand tons of chicken manure per year, which must be treated. In the large scale farms biological treatment requires huge facilities and investments, therefore other methods are required. Among them, high-temperature drying and pyrolysis. The goal of this work was to compare the products of chicken manure treatment by means of two thermal methods-high-temperature drying technology (250 ° C, 30 s) with subsequent granulation (IG) and slow pyrolysis (400 ° C, 2h) with subsequent granulation (BG)-according to a number of parameters: the effect on plant growth, reduction of toxicity after treatment (eluate test using Paramecium caudatum and Cereodaphnia affinis), the content of biogenic elements (C, N) in different forms, the presence of pathogens such as Listeria monocytogenes, E. coli, Salmonella spp, Mycobacterium paratuberculosis, Enterococcus spp, Campylobacter jejuni, Clostridium perfringens, Yersinia enterocolitica, Bacillus anthracis, Bacillus thuringiensis, Bacillus cereus, Streptococcus dysgalactiae and the presence of antibiotic-resistant genes. The results obtained were compared with the data received for unprocessed chicken manure (ChM). In all the three variants (soil treated by IG, BG or ChM), the plant chlorophyll content increased by 30–36% as compared with control soil, plant biomass increased by 30–46% as compared with control, the stem and root length did not differ from those of control. During thermal treatment, ecotoxicity decreased in both cases-on average, by 1.1-1.5 for IG and by 2.3-3.3 for BG. High-temperature drying did not lead to significant changes in the pathogenic microorganisms counts estimated by real time PCR with specific primers as compared with initial ChM, while pyrolysis allowed to get rid of all the pathogens. Thus, from the point of view of final product characteristics, slow pyrolysis is a preferable method to thermally treat chicken manures.