Rheological properties and dewaterability of anaerobic co-digestion with sewage sludge and food waste: effect of thermal hydrolysis pretreatment and mixing ratios
Anaerobic co-digestion (co-AD) of sewage sludge (SS) and food waste (FW) converts municipal organic waste into renewable energy, which plays an important role in achieving carbon emissions reduction. The existing anaerobic digestion (AD) treatment projects often have problems such as low organic con...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
IWA Publishing
2023-05-01
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| Series: | Water Science and Technology |
| Subjects: | |
| Online Access: | http://wst.iwaponline.com/content/87/10/2441 |
| Summary: | Anaerobic co-digestion (co-AD) of sewage sludge (SS) and food waste (FW) converts municipal organic waste into renewable energy, which plays an important role in achieving carbon emissions reduction. The existing anaerobic digestion (AD) treatment projects often have problems such as low organic conversion and unstable performance. SS and FW were used as raw materials to explore the effects of thermal hydrolysis pretreatment (THP) and mixing ratios on the dewaterability and rheological properties of the digestate. The results showed that co-digestion of FW and SS in a ratio of 1:1 obtained the highest biogas production (255.14 mL/g VS), which was 1.53 times and 14.5 times higher than that of mono-digestion of FW and thermal hydrolysis pretreatment sewage sludge (THSS), respectively. However, the dewaterability of this ratio deteriorated sharply after co-digestion, with a decrease of 54.92%. The groups containing a higher proportion of THSS had improved dewaterability after AD. The apparent viscosity and shear stress were reduced by co-digestion compared with mono-digestion of THSS and FW, indicating a higher flow property of the co-digestion matrix. After the Herschel–Bulkley model fitting, there were linear correlations between rheological indices and soluble chemical oxygen demand (SCOD), and digestate dewaterability.
HIGHLIGHTS
THP could promote the dissolution of OM and the digestate dewaterability.;
The highest biogas production and the worst dewaterability were achieved by the 1:1 mixing ratio of SS and FW.;
Co-AD of SS and FW reduced the apparent viscosity and shear stress of the digestate compared with mono-digestion of THSS and FW.;
There were linear correlations between rheological indices and SCOD, and digestate dewaterability.; |
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| ISSN: | 0273-1223 1996-9732 |