Application of solar drying as a pre-treatment method for storing wet feedstocks prior to use in anaerobic digesters: Effect on methane production and digestate composition

•Solar drying process had small effect on pH, TOC, TKN and vS of the initial materials.•The addition of solar dried feedstocks increased the biogas production by 1.7 times.•In all cases, the estimated biodegradability of mixtures was over 50%•vS removal was 23% for the maximum biogas production.