Additive efect of cow dung slurry and cellulolytic bacterial inoculation on humic fractions during composting of municipal solid waste

Abstract

Purpose The work aimed to investigate the efect of cow dung and cellulolytic bacteria on humic characteristics during municipal solid waste composting. Four Bacillus isolates (B. subtilis, B. tequilensis, B. venezuelans and B. amyloliquefaciens) sourced from dumpsite soil were formulated as consortium for the study. Methods Four treatments were considered with addition of bulking agents (ratio 1:7:6) to 15 kg MSW. Treatment Cs1 (control): only MSW, Cs2: MSW+cellulolytic bacterial inoculum @ 5 ml (2×109 CFU ml−1); Cs3—MSW+cow dung slurry @ 1 kg (1:100 based on wet weight) and Cs4—MSW+cellulolytic bacterial inoculum @ 5 ml (2×109 CFU ml−1)+cow dung slurry @ 1 kg (diluted 1:100 based on wet weight). The analyses of humic acids were done by elemental analyzer, UV and Fourier transform infrared spectroscopy during 90 days of composting. Results MSW amended with consortia of efective microorganisms and cow dung slurry projected highest humifcation degree at 82.4% (P