Kinetics of inoculation composting of some biowastes

Abstract EN

A method was used to improve the composting efficiency by seeding with inoculum (a blend of Bacillus magisterium, Bacillus lichenformis, Trichoderma harzianum and Streptomyces cellulosae).

In this study, blends of tree trimmings and sawdust, in ratio 2.

6 : 1, were treated with the inoculum or were not treated.

The effect of inoculation was evaluated in terms of time required to obtain a stable product and product quality based on physicochemical variables of temperature, water retention capacity (WRC), organic carbon and microbial concentration were investigated to study the efficiencies of inoculation composting.

In order to understand the mechanisms of inoculation composting process, two stages kinetics equations were developed from the viewpoint of microbial kinetics.

The inoculated composting process didn't only reach a relatively high temperature (62°C) but also maintained the high temperature for long time (15 days).

The highest value of WRC was obtained with inoculated composting process (2.54 g g"1).

The high values of THB, the rmophilic bacteria, total fungi and total actinomycetes were recorded with inoculated composting process (12, 8, 7 and 8.5 logio CFU g"1 dry wt, respectively).

The equations of two- stage composting showed that microbial concentration, in the first stage, was the main limiting factor of the degradation rate.

The degradation rates in inoculated and inoculated were 21.93 and 32.15 g kg ~l d, respectively.

In second stage, the degradation rate was mainly affected the half velocity coefficient Km and in turn stabilize the composting products efficiently.

Therefore, inoculation could improve the efficiency of the composting process.