The disintegration of municipal waste activated sludge (MWAS) by energy-intensive physical pretreatments is considered expensive. In the present study, an effort was undertaken to disintegrate the sludge by microwave assisted pretreatment (MAP) in an energy-efficient and economical way by combining the microwave with oxidant potassium persulphate. Besides, the sulphate radicals generated through activated persulfate can efficiently disintegrate and solubilize sludge. In this context, microwave pretreatment was combined with potassium persulfate to activate the generation of sulphate radicals for economically enhanced sludge solubilization. MAP was done by varying the microwave power levels (10 to 50 %) and pretreatment time (0 to 30 min). Microwave assisted potassium persulphate pretreatment (MAPPP) was done by varying the potassium per sulphate dosage (0.005 to 0.04 g/g Total solids (TS) and pretreatment time (0 to 14 min). Combining microwave with potassium persulfate brings about a synergistic effect, generating sulphate and hydroxyl radicals that can effectively disintegrate and solubilize biopolymers of sludge. A higher sludge lysis rate of 37.25 % was achieved by this microwave assisted potassium persulfate pretreatment (MAPPP) when compared to microwave assisted pretreatment (MAP) alone (26.27 % after thickening). A higher methane yield of 219.14 mL/g Volatile solids (VS) was obtained through MAPPP compared to MAP (154.22 mL/g VS). The detailed mass, energy, and economic assessment at a large-scale level for MAP and MAPPP revealed that MAPPP was energetically and economically feasible with an energy ratio of 1.22 and net profit of 42.03 USD/Ton compared to MAP. Thus, it can be confirmed that MAPPP was economically viable to implement on a large scale.
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