title: Co-digestion of sewage sludge and sterilized solid slaughterhouse waste: methane production efficiency and process limitations.
abstract: The rendering product of Category 2 and 3 Animal By-Products is known as sterilized mass (SM) and it is mainly composed of fat and proteins, making it interesting substrate for anaerobic digestion. Batch and semi-continuous laboratory experiments were carried out to investigate the effect of SM addition in co-digestion with sewage sludge on methane production and possible process limitations. Results showed that SM addition in the feed mixture up to 5% (w/w), corresponding to 68.1% of the organic loading, increased methane production 5.7 times, without any indication of process inhibition. Further increase of SM addition at 7.5% (w/w) caused methane production decrease and volatile solids removal reduction, that was mainly related to remarkably increased free ammonia concentration in the digester of 596.5±68.6 gNH3 L(-1). Sterilized mass addition of 10% (w/w) caused intensive foaming, LCFA accumulation of 9172±701.2 mgCOD-LCFA g(-1) sample and termination of the experiment.
authors.affiliation: Department of Chemistry, Tallinn University of Technology, 12618 Tallinn, Harjumaa, Estonia. peeppitk@gmail.com
authors.forename: Peep
authors.initials: P
authors.lastname: Pitk
authors.forename: Prasad
authors.initials: P
authors.lastname: Kaparaju
authors.forename: Jordi
authors.initials: J
authors.lastname: Palatsi
authors.forename: Rim
authors.initials: R
authors.lastname: Affes
authors.forename: Raivo
authors.initials: R
authors.lastname: Vilu
mesh_terms: D000003:Abattoirs; D000818:Animals; D061249:Batch Cell Culture Techniques; D001673:Biodegradation, Environmental; D019149:Bioreactors; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005232:Fatty Acids, Volatile / Q000032:analysis; D008697:Methane / Q000096:biosynthesis*; D009930:Organic Chemicals / Q000302:isolation & purification; D010100:Oxygen / Q000032:analysis; D012722:Sewage / Q000032:analysis*; D062611:Solid Waste / Q000032:analysis*; D013242:Sterilization
chemical_list: D005232:Fatty Acids, Volatile; D009930:Organic Chemicals; D012722:Sewage; D062611:Solid Waste; D008697:Methane; D010100:Oxygen