Effect of pre-treatments on hydrolysis and methane production potentials of by-products from meat-processing industry.
In this study, the effect of five pre-treatments (thermal, ultrasound, acid, base and bacterial product) on hydrolysis and methane production potentials of four by-products from meat-processing industry was studied. The bacterial product Liquid Certizyme 5 increased soluble chemical oxygen demand (CODsol) of digestive tract content and drumsieve waste the most as compared to untreated material (62 and 96%, respectively), while ultrasound was the most effective to increase CODsol with dissolved air flotation (DAF) sludge (88%) and grease trap sludge (188%). In batch experiments, thermal treatment increased methane production potential of drumsieve waste, acid of grease trap sludge and all pre-treatments of DAF sludge. However, with all other pre-treatments, methane production potential was decreased compared to untreated materials, apparently due to inhibition by hydrolysis products and/or possible re-crystallization of some compounds. Methane production potentials from the untreated materials were as follows: digestive tract content 400+/-50m(3)CH(4)/t volatile solids (VS)(added), drumsieve waste 230+/-20m(3)CH(4)/tVS(added), DAF sludge 340+/-17m(3)CH(4)/tVS(added) and grease trap sludge 900+/-44m(3)CH(4)/tVS(added).
Luste
Sami
S
University of Kuopio, Laboratory of Applied Environmental Chemistry, Patteristonkatu 1, FI-50100 Mikkeli, Finland. sami.luste@uku.fi
Luostarinen
Sari
S
Sillanpää
Mika
M
D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D005525:Food-Processing Industry; D006868:Hydrolysis; D007220:Industrial Waste; D008460:Meat; D008697:Methane / Q000096:biosynthesis*; D012037:Refuse Disposal / Q000379:methods*; D013696:Temperature
D007220:Industrial Waste; D008697:Methane