Synergetic effect of combined pretreatment for energy efficient biogas generation

- Combined TCO3 pretreatment improves disintegration of WAB effectually.
- This novel method aid solubilization at lesser specific energy of 141.02 kJ/kg TS.
- COD solubilization of about 30.4% was achieved in 0.0012 mg O3/mg VS ozone dosage.
- Highest methane yield of 0.32 g COD/g COD was observed in TCO3 pretreated biosolids.
- Combinative pretreatment offers a net profit of about 35.49 $/ton of WAB.

Physiochemical disintegration of waste activated biosolids (WAB) through thermochemical (TC) pretreatment requires high energy and cost for efficient energy generation. Therefore in the present study, an attempt has been made to enhance the biodegrdability and to minimize the operational cost of TC pretreatment by combining it with ozonation. A higher solubilization of about 30.4% was achieved at lesser energy input of about 141.02 kJ/kg TS and a ozone dosage of about 0.0012 mg O3/mg SS through this combined thermo chemo ozone (TCO3) pretreatment. The methane production potential (0.32 g COD/g COD) of TCO3 pretreatment was comparatively higher than the (0.19 g COD/g COD) TC pretreatment. The energetic analysis and economic assessment of the proposed method of pretreatment can possibly reduces the energy requirement of TC pretreatment with a positive net profit of about 35.49 $/ton of biosolids.

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