Cost effective dry anaerobic digestion in textile bioreactors: Experimental and economic evaluation

- Dry anaerobic digestion of solid wastes using textile reactor is a novel technology.
- Methane yield using acclimated bacteria was 290 NmlCH4/gVS of manure and straw.
- Digestate was affirmed suitable as supplement for soil deficient of major nutrients.
- Industrial concept for dry anaerobic digestion using textile reactor was proposed.
- Economic analysis shows dry-AD using textile bioreactor is a cost effective solution.

The aim of this work was to study dry anaerobic digestion (dry-AD) of manure bedded with straw using textile-based bioreactor in repeated batches. The 90-L reactor filled with the feedstocks (22-30% total solid) and inoculum without any further treatment, while the biogas produced were collected and analyzed. The digestate residue was also analyzed to check its suitability as bio-fertilizer. Methane yield after acclimatization increased from 183 to 290 NmlCH4/gVS, degradation time decreased from 136 to 92 days and the digestate composition point to suitable bio-fertilizer. The results then used to carry out economical evaluation, which shows dry-AD in textile bioreactors is a profitable method of handling the waste with maximum payback period of 5 years, net present value from $7,000 to $9,800,000 (small to large bioreactors) with internal rate of return from 56.6 to 19.3%.