title: Techno-economic evaluation of ultrasound and thermal pretreatments for enhanced anaerobic digestion of municipal waste activated sludge.
abstract: To enhance the anaerobic digestion of municipal waste-activated sludge (WAS), ultrasound, thermal, and ultrasound+thermal (combined) pretreatments were conducted using three ultrasound specific energy inputs (1000, 5000, and 10,000 kJ/kg TSS) and three thermal pretreatment temperatures (50, 70 and 90°C). Prior to anaerobic digestion, combined pretreatments significantly improved volatile suspended solid (VSS) reduction by 29-38%. The largest increase in methane production (30%) was observed after 30 min of 90°C pretreatment followed by 10,000 kJ/kg TSS ultrasound pretreatment. Combined pretreatments improved the dimethyl sulfide (DMS) removal efficiency by 42-72% but did not show any further improvement in hydrogen sulfide (H(2)S) removal when compared with ultrasound and thermal pretreatments alone. Economic analysis showed that combined pretreatments with 1000 kJ/kg TSS specific energy and differing thermal pretreatments (50-90°C) can reduce operating costs by $44-66/ton dry solid when compared to conventional anaerobic digestion without pretreatments.
authors.affiliation: Department of Chemical and Biochemical Engineering, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Bipro Ranjan
authors.initials: BR
authors.lastname: Dhar
authors.forename: George
authors.initials: G
authors.lastname: Nakhla
authors.forename: Madhumita B
authors.initials: MB
authors.lastname: Ray
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels / Q000032:analysis*; D057919:Biological Oxygen Demand Analysis; D002241:Carbohydrates / Q000032:analysis; D005232:Fatty Acids, Volatile / Q000032:analysis; D006358:Hot Temperature; D006862:Hydrogen Sulfide / Q000032:analysis; D008697:Methane / Q000096:biosynthesis; D011506:Proteins / Q000032:analysis; D012722:Sewage; D013016:Sound; D013440:Sulfides / Q000032:analysis; D013457:Sulfur Compounds / Q000032:analysis; D018505:Waste Management / Q000191:economics / Q000379:methods*
chemical_list: D056804:Biofuels; D002241:Carbohydrates; D005232:Fatty Acids, Volatile; D011506:Proteins; D012722:Sewage; D013440:Sulfides; D013457:Sulfur Compounds; D008697:Methane; C004784:dimethyl sulfide; D006862:Hydrogen Sulfide