The anaerobic digestion of biologically and physicochemically pretreated oily wastewater.
To enhance the degradation of oily wastewater and its biogas production, a biological-physicochemical pretreatment was introduced prior to the anaerobic digestion system. The digestion thereafter proceeded more efficiently due to the inoculation by oil degrading bacteria (Bacillus). A 2-stage pre-mixing is more effective than directly mixing. The effects on the methane production were also investigated by pre-treatment with ultrasonic (US) treatment, combined with citric acid (CA) addition. US pre-treatment was found to improve the initial methane production, and CA pre-treatment could maintain this improvement during the whole digestion stage. Pre-mixing Bacillus at 9 wt.% inoculation, combined with US for 10 min and a CA concentration of 500 mg/L provided the optimum conditions. The most effective enhancement of methane yield was 1100.46 ml/g VS, exceeding that of the control by 280%. The change of coenobium shape and fatty acid content further proved that such pretreatment of oily wastewater can facilitate digestion.
Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing 100029, PR China.
Liyu
L
Peng
Meidan
M
Bao
Qingfeng
Q
Wang
Fangchao
F
Wang
Haijia
H
Su
D000693:Anaerobiosis / Q000187:drug effects; D061249:Batch Cell Culture Techniques; D001673:Biodegradation, Environmental / Q000187:drug effects; D056804:Biofuels; D055598:Chemical Phenomena; D019343:Citric Acid / Q000494:pharmacology; D008697:Methane / Q000096:biosynthesis; D009821:Oils / Q000737:chemistry*; D013997:Time Factors; D014465:Ultrasonics; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D056804:Biofuels; D019343:Citric Acid; D008697:Methane; D009821:Oils; D062065:Wastewater
Anaerobic digestion; Methane yield; Oil-degrading bacteria; Oily wastewater; Physicochemical pretreatment