Microbial diversity during Rotary Drum and Windrow Pile composting

Abstract

This study investigates the prevailing microbial communities during the composting of vegetable waste, cattle manure and saw dust, in a household (250 l) batch scale Rotary Drum composter and Windrow Pile. Physico-chemical parameters were analyzed to study the organic matter transformations. Total organic matter reduced from 63.8% to 36.2% in rotary drum and 39.6% in windrow pile composting. The C/N ratio decreased from 26.52 to 8.89 and 14.33 in rotary drum and windrow pile composting. The indigenous population of total heterotrophic bacteria decreased in rotary drum and windrow pile composting after 20 days. However, total fungal load initially increased within initial 4 days, then subsequently reduced in final composts. The average number of fecal coliforms and fecal Streptococci showed decrement with time, in both composting systems. Escherichia coli and Salmonella species number deduced during the study. Composting cycle started with Gram positive rods but ended up with the dominance of Gram negative bacilli shaped bacteria. Transformation of organic compounds during the biodegradation of organic waste, difference in the utilization of nutrients (organic matter) by the different group of microbes and high temperature could be cited as a possible reason of the above changes. Scanning electron microscopy has been used to obtain the surface structures of the cultured mycoflora. Results of the study revealed that higher diversity of microbes prevailed in rotary drum as compared to windrow pile, yielding more stable and pathogenic free compost in lesser period of composting.

Microbial population, stability and maturity analysis of rotary drum composting of water hyacinth

“…This was the highest reduction among all other trials. However, it has also been reported that fungal count had reduced completely in vegetable waste composting (Bhatia et al 2012). During municipal solid waste composting fungal count decreased from 4.5 × 10 6 CFU/g to 6.3 × 10 3 CFU/g in the 3…”

“…The microbial communities in whole composting period keep on changing (Hassen et al 2001;Bhatia et al 2012). Bacteria, actinomycetes, streptomycetes and fungi are the major contributors of biodegradation.…”

“…Partanen et al (2010) studied bacterial diversity of over 2,000 different phylotypes in municipal organic waste composting. Bhatia et al (2012) studied that a majority of bacterial species isolated from compost included Bacillus spp., Pseudomonas spp. and Entrobacter spp., whereas Aspergillus and Rhizopus species were the fungal communities in windrow and rotary drum composting of vegetable waste.…”

Evolution of chemical and biological characterization during thermophilic composting of vegetable waste using rotary drum composter

“…The final residual organic matter consisted of humic-like substances which are highly non-biodegradable and also the most stable fraction of mature compost (Chefetz et al 1996). In composting, the organic matter degradation is carried out by different diversity of microorganisms including mesophilic bacteria, spore-forming bacteria, fungi and actinomycetes to transform them into stable humic components (Garcia et al 1992;Bhatia et al 2012). However, the degradation pattern and humification during composting is considered to follow different pattern depending on the raw materials used for composting (Huang et al 2006).…”

“…And moreover, the final compost had been completely stabilized with lower carbon dioxide (CO 2 ) evolution and oxygen uptake rate (OUR). Organic fractions of MSW, vegetable waste, water hyacinth and many other wastes had been successfully composted using rotary drum composter (Tolvanen et al 2005;Bhatia et al 2012;Singh and Kalamdhad 2013). In addition, Gajalakshmi and Abbasi (2008) have also reported the possible advantages of composting and the use of rotary drum for effective degradation process.…”