Exploring the complex role of pre-treatments in anaerobic digestion: from batch to continuous mode

The economic viability of waste anaerobic conversion is largely dependent on feedstock type, pre-treatment and operating scale. Aim of this study was to evaluate pre-treatment potential on performance and stability of. sewage sludge and food waste anaerobic digestion over long-term periods, scaling up from BMP (BioMethane Potential) tests to digesters operated at semi-continuous conditions. A detailed investigation of physical, mechanical and thermal pre-treatment effect on chemical composition (in particular lignocellulosic matrix in food waste) was reported. The impact of readily biodegradable organic compounds on intermediate accumulation, methane conversion rate as well as digestate quality should be taken into account when feedstock pretreatments are selected and optimized, otherwise the strategy can be detrimental rather than beneficial.