Effect of additives on process stability of mesophilic anaerobic monodigestion of pig slaughterhouse waste.
The effect of two additives on anaerobic monodigestion of pig slaughterhouse waste was studied in three laboratory scale continuously stirred tank reactors (CSTRs) operated for 242-284 days at 35°C. A higher organic loading rate (OLR), namely 2.25 kg volatile solids (VS)/m(3)d with a hydraulic retention time (HRT) of 30 d was feasible with an additive containing Fe, HCl and trace elements while an OLR of 1.5 kg VS/m(3)d (HRT 30 d) led to instabilities in CSTR with an additive consisting of Fe and HCl and in CSTR without additives. Methane yields of ca. 700 dm(3) CH(4)/kg VS(fed) were obtained in all reactors under stable conditions. Both additives decreased H(2)S concentration of the biogas below detection limit 0.5 ppm while in a control reactor H(2)S concentration was up to 1900 ppm. In conclusion, the results suggest the possibility that additives may facilitate higher OLRs in monodigestion of pig slaughterhouse waste.
University of Jyväskylä, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland. suvi.bayr@jyu.fi
Suvi
S
Bayr
Outi
O
Pakarinen
Aki
A
Korppoo
Saku
S
Liuksia
Ari
A
Väisänen
Prasad
P
Kaparaju
Jukka
J
Rintala
D000003:Abattoirs; D000693:Anaerobiosis / Q000187:drug effects; D000818:Animals; D001673:Biodegradation, Environmental / Q000187:drug effects; D056804:Biofuels / Q000032:analysis; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology / Q000379:methods*; D005232:Fatty Acids, Volatile / Q000032:analysis; D006851:Hydrochloric Acid / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007501:Iron / Q000494:pharmacology*; D008697:Methane / Q000096:biosynthesis; D034421:Sus scrofa; D013696:Temperature; D014866:Waste Products / Q000032:analysis*
D056804:Biofuels; D005232:Fatty Acids, Volatile; D014866:Waste Products; D007501:Iron; D008697:Methane; D006851:Hydrochloric Acid