Moving municipal WWTP towards circular economy: Cellulose recovery from primary sludge with ionic liquid

Tetrakis (hydroxymethyl) phosponium chloride ionic liquid was evaluated to recover carbohydrates, especially cellulose, from municipal wastewater treatment plant (WWTP) primary sludge (96 % water content). Different process operative conditions were evaluated: temperature (35, 60 and 80 ℃), time (6, 13 and 20 h) and sludge weight:ionic liquid volume ratio (1 g TS of SLUDGE: 7, 12 and 17 mL). A three levels, three factors central design was...