Anaerobic co-digestion of meat-processing by-products and sewage sludge - effect of hygienization and organic loading rate.
Anaerobic co-digestion of a mixture of animal by-products (ABP) from meat-processing industry and of sewage sludge was studied at 35 degrees Celsius for co-digesting such by-products in digesters at wastewater treatment plants. The three reactors were fed with ABP mixture and sewage sludge (1) in a ratio of 1:7 (v/v), (2) in the same ratio but with hygienization (70 degrees Celsius, 60 min) and (3) in a ratio of 1:3 (v/v). Hydraulic retention time (HRT) was decreased from 25 to 20 days and finally to 14 days, while organic loading rates (OLR) ranged from 1.8 to 4.0 kg VS/m(3) day. The highest specific methane yields were achieved with 20-days-HRT (1) 400 + or - 30, (2) 430 + or - 40, (3) 410 + or - 30 m(3) CH(4)/t VS. Hygienization improved methane production to a level above the highest OLR applied (feed ratio 1:3 (3)), while the quality of the digestate remained similar to the other reactors.
Luste
Sami
S
University of Kuopio, Department of Environmental Science, Yliopistonranta I E, FI-70211 Kuopio, Finland. sami.luste@uku.fi
Luostarinen
Sari
S
D001421:Bacteria, Anaerobic / Q000378:metabolism*; D019149:Bioreactors; D005387:Finland; D005525:Food-Processing Industry; D008460:Meat / Q000382:microbiology*; D008697:Methane / Q000378:metabolism; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage / Q000382:microbiology*
D012722:Sewage; D008697:Methane