Enhancing methane production from dewatered waste activated sludge through alkaline and photocatalytic pretreatment

[Display omitted] •Alkaline, photocatalytic and combined pretreatment of dewatered sludge was studied.•Individually, alkaline pretreatment disintegrated the sludge more than photocatalysis.•Alkaline and combined pretreatment resulted in 11 and 37% disintegration degree.•Methane yield enhanced by 50...

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Bibliographic Details
Published in:Bioresource technology 2021-04, Vol.325, p.124677, Article 124677
Main Authors: Maryam, Ayesha, Zeshan, Badshah, Malik, Sabeeh, Mariam, Khan, Sher Jamal
Format: Article
Language:English
Subjects:
Alkaline-photocatalytic pretreatment
Anaerobic digestion
Anaerobiosis
Dewatered waste activated sludge
Kinetic model fitting
Methane
Sewage
Sludge solubilization
Sodium Hydroxide
Waste Disposal, Fluid
Water Purification
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Summary:[Display omitted] •Alkaline, photocatalytic and combined pretreatment of dewatered sludge was studied.•Individually, alkaline pretreatment disintegrated the sludge more than photocatalysis.•Alkaline and combined pretreatment resulted in 11 and 37% disintegration degree.•Methane yield enhanced by 50 and 71% due to alkaline and combined pretreatment. Waste activated sludge generated from wastewater treatment plants makes an abundant source of biomass. Its effective utilization through anaerobic digestion (AD) requires pretreatment to disintegrate the sludge matrix and increase organic matter availability. In this study, dewatered waste activated sludge (DWAS) was subjected to alkaline, photocatalytic, and alkaline-photocatalytic pretreatment for its disintegration and subsequent methane production using different concentrations of sodium hydroxide and titania nanoparticles. Individual pretreatment resulted in maximum disintegration degree (DDsCOD) of 11.3 and 5.2% at 0.8% NaOH and 0.6 gTiO2/L, respectively. Alkaline-photocatalytic pretreatment yielded 37% DDsCOD at 0.8% NaOH–0.4 g/L TiO2. As compared to control, AD at 0.4% NaOH and 0.5 g/L TiO2 pretreatments yielded maximum methane, which was 50.4 and 32.6% higher. Similarly, alkaline-photocatalytic pretreatment at 0.4% NaOH-0.5 g/L TiO2 yielded methane as 462 N mL/g VS, which was 71.1% higher. Modified Gompertz model fitted the methane yield data well.
ISSN:0960-8524
1873-2976
DOI:10.1016/j.biortech.2021.124677