Anaerobic co-digestion of sewage sludge with shredded grass from public green spaces

► Adding greenery from public spaces to co-digestion with sewage sludge was evaluated. ► The grass species in this study was not managed, and just shredded and not ensiled. ► The grass shredded by a commercially available shredder was 20 mm or less in length. ► The batch experiment showed a methane production of around 0.2 NL/gVS-grass. ► An average methane production was 0.09 NL/gVS-grass in the continuous experiment.