To obtain an efficient composting process, the influencing factors must be controlled and optimized.
The remaining solid material after protease extraction could be easily stabilized to obtain a final good quality compost-like material as the final dynamic respiration index was lower than 1 g O2 kg−1 OM h−1.
Moreover, an optimized ratio MSW/LTR of 1/1 (w/w), moisture content in the range of 40 55% and moderate to low aeration rate (0.05 0.175 Lair kg−1 mis−1) is recommended to maximise degradation and to obtain a stable product during co-composting of MSW and LTR.
Therefore, in order to obtain faecal compost that is safe for agricultural use, the pathogenic organisms must be eliminated (Agyekum 2015).
The composting reactors were mixed manually by wearing sterile gloves for obtaining a homogen mass before taking the samples.
Municipal waste compost (MWC) was obtained from Isfahan Compost Company, air dried, and passed through a 2-mm sieve.
Chattopadhyay et al. (1992) indicated that organic acids and mineral phosphorous obtained from compost decomposition can simultaneously increase phosphorous availability in soil.
A compost inoculum was obtained on August 6, 2007 from a Grover Soil Solutions compost facility located in Zamora, CA. This facility composts green waste and agricultural wastes (e.g. prunings from perennial crops and hulls from nut and rice processing) in turned and watered windrows.
The favorable yields obtained with OMF compost used in the current study were at a rate of 20 or 30 ton h−1 combined with 50% of the recommended dose of the NPK fertilizers.
All of them were highly similar and belonged to the genus Mycobacterium, one of which (C1) was obtained from the compost sample, while the others (UC 2, 7, 8) were obtained from the soil-compost mixture (Additional file 2: Table S1).
