Additive effect 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 effect 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 Cs 1 (control): only MSW, Cs 2 : MSW + cellulolytic bacterial inoculum @ 5 ml (2 × 10 9 CFU ml −1); Cs 3-MSW + cow dung slurry @ 1 kg (1:100 based on wet weight) and Cs 4-MSW + cellulolytic bacterial inoculum @ 5 ml (2 × 10 9 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 effective microorganisms and cow dung slurry projected highest humification degree at 82.4% (P < 0.01). Highest temperature (63 °C) was recorded in the treatment Cs 4 during composting. The data corresponded to an increase in H/C ratio (0.9%) with a decrease in C/N (14.8%) and O/C ratio (0.5%). In addition, most stabilized values for E 4 /E 6 ratio (4.1) and E 2 /E 3 ratio (2.1) were observed in Cs 4. The humification indices manifest positive regression values (F (4, 1) = 0.007; P < 0.01) and 99% significant model. Conclusion In the study, bio-augmentation (bacterial consortia and cow dung slurry) to MSW composting facilitates early maturity compared to other inoculated/uninoculated treatments. The result substantiates the effect of temperature on the humification rate of composting.

Unveiling the Efficiency of Psychrophillic Aporrectodea caliginosa in Deciphering the Nutrients from Dalweed and Cow Manure with Bio-Optimization of Coprolites

“…The increase in both HR and HI in the vermicastings is due to the combined action of earthworm-microbes and is also based on the initial chemical composition of different mixture substrates. A recent study also confirmed the positive influence of vemicomposting on humification of cow and pig manure blended with paper wastes [64,65], and other scientific reports projected the highest humification degree in recycling of municipal solid waste blended with cow dung [66]. The high HI during the vermicomposting could also have contributed to the improvement in mineralization and dissolution of organic matter which reflected an increased percentage of humic acid (Pha) in the coprolites.…”

Microbes as vital additives for solid waste composting

“…Subsequently various undesirable compounds (such as odors and salts) unfavorable for plant development are released (Mohee et al, 2015;Onwosi et al, 2017). A general trend was observed with declined C/N ratio throughout the process attributed to a higher waste degradation (carbon) to mineralization (nitrogen) ratio (Yang et al, 2015;Rastogi et al, 2019a). Hence, to optimize C/N within composting, wide variety of bulking agents are recommended as additives to waste (e.g.…”

“…Hachicha et al (2012), observed similar results with fungus, Trametes versicolor as an inoculate to the lignocellulosic waste. An investigation on MSW composting by Rastogi et al (2019a), stated the effect of cellulolytic bacterial additives on humic characteristics of waste. The study revealed an early maturity in the inoculated compost, owing to a good humification degree.…”

Effect of particle size on rotary drum composting of garden waste and their ranking using analytical hierarchy process

“…Cow dung is a rich source of micro ora and very effective in organic waste degradation (Randhawa and Kullar, 2011;Rastogi et al, 2019). Singh and Kalamdhad, (2013) in his composting study used a rotary drum for a mixture of saw dust, vegetable waste, and cow-dung in composting.…”

“…The heat microbes produce causes the compost temperature to rise rapidly. Microbes release hydrolytic enzymes which breaks complicated structured molecules promoting faster degradation (Rastogi et al, 2019).…”