Fe-doped hydrochar facilitating simultaneous methane production and pharmaceutical and personal care products (PPCPs) degradation in co-anaerobic digestion of municipal sludge and food waste

•Porous and electrochemically active Fe-doped hydrochar (Fe-HC) was prepared.•Fe-HC improved anerobic co-digestion (co-AD) performance of food and sludge wastes.•Pharmaceutical/personal care products removal was enhanced in Fe-HC treated co-AD.•Fe-HC facilitates hydrolysis, acidogenesis, acetogenesis and methanogenesis.•Syntrophism of Syntrophaceticus and Methanoculleus in co-AD was enhanced by Fe-HC.