Effects of pretreatments on thickened waste activated sludge and rice straw co-digestion: Experimental and modeling study.
In order to maximize the biogas production from thickened waste activated sludge (TWAS), co-digestion of TWAS and rice straw (RS) was studied and the application of thermal/thermo-alkaline and NaOH/H2O2 to TWAS and RS, respectively, was evaluated. The batch experiments were conducted at three different TWAS/RS (volume basis) ratios of 1:3, 1:1 and 3:1, respectively. Furthermore, the modified Gompertz model was introduced to predict the biogas yield and evaluate the kinetic parameters. The highest biogas production (409.2 L/kg VSadded) was achieved from co-digestion of TWASthermo-alkaline and RSNaOH at mixing ratio of 1:1, which is greater by 42.2% and 5.9% than that of digesting TWASthermo-alkaline, and RSNaOH alone, respectively. The highest VS removal rate was obtained from the co-digestion of TWASthermo-alkaline and RSNaOH at mixing ratio of 1:3, which is greater by 55.8% and 14.0% than those of mono-digestion. The modified Gompertz model (R(2): 0.993-0.998 and 0.993-0.999 for mono- and co-digestions, respectively) showed a good fit to the experimental results and the estimated parameters indicating that the pretreatments and co-digestion of substrates markedly improved the biogas production rate.
School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China; Al-Mustansiryiah University, College of Engineering, Baghdad, Iraq.
Zaidun Naji
ZN
Abudi
School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China. Electronic address: huzq@hust.edu.cn.
Zhiquan
Z
Hu
School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China.
Bo
B
Xiao
ThiQar University, Nasiriyah, Iraq.
Alkhafaji R
AR
Abood
School of Civil Engineering and Mechanics, Huazhong University of Science and Technology, Wuhan, 430074, PR China; Al-Mustansiryiah University, College of Engineering, Baghdad, Iraq.
Nagham
N
Rajaa
School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China; Department of Energy and Environment, Faculty of Agricultural Engineering, Sindh Agriculture University, Tandojam, 70060, Sindh, Pakistan.
Mahmood
M
Laghari
D000693:Anaerobiosis; D056804:Biofuels / Q000032:analysis; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D006861:Hydrogen Peroxide; D008962:Models, Theoretical; D012275:Oryza; D012722:Sewage; D012972:Sodium Hydroxide; D018505:Waste Management / Q000379:methods*
D056804:Biofuels; D012722:Sewage; D012972:Sodium Hydroxide; D006861:Hydrogen Peroxide
Anaerobic co-digestion; NaOH/H(2)O(2) pretreatment; Rice straw; Thermal/thermo-alkaline pretreatment; Thickened waste activated sludge