Improvement of Waste Dehydrated Sludge for Anaerobic Digestion through High-Temperature and High-Pressure Solubilization

Biochemical methane potential tests and lab-scale continuous experiments were conducted to improve the yield and energy efficiency of anaerobic digestion through thermal hydrolysis pre-treatment. Methane generation, yield, and solubilization efficiency were evaluated through lab-scale tests. The pre...

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Bibliographic Details
Published in:Energies (Basel) 2020-01, Vol.13 (1), p.88
Main Authors: Hong, Eui-Hwan, Park, Jun-Gyu, Lee, Beom, Shi, Wei-Qi, Jun, Hang-Bae
Format: Article
Language:English
Subjects:
Ammonia
Anaerobic digestion
Biodegradability
Biodegradation
Biogas
Chemical oxygen demand
Chromium
Collectors
Dehydration
Efficiency
Energy efficiency
Experiments
Heat
Heat treatment
high pressure
High temperature
Hydrolysis
Methane
Methane generation
Nitrogen
Organic matter
Polymers
Pressure gauges
Pretreatment
Proteins
Retention
Sludge
Sludge digestion
Solubilization
waste dehydrated sludge
Yield
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Summary:Biochemical methane potential tests and lab-scale continuous experiments were conducted to improve the yield and energy efficiency of anaerobic digestion through thermal hydrolysis pre-treatment. Methane generation, yield, and solubilization efficiency were evaluated through lab-scale tests. The pre-treated samples presented 50% biodegradability at 140 °C and 61.5% biodegradability at 165 °C. The increase in biodegradability was insignificant at 165 °C or higher temperature, and it was confirmed that the optimum conditions were achieved at 165 °C and 20 min of solubilization. The lab-scale continuous experiments confirmed that polymers were decomposed into low-molecular-weight compounds due to thermal hydrolysis, and pH decreased. NH4HCO3 produced by thermal hydrolysis acted as an alkali to enable a more stable operation compared to that before thermal hydrolysis. Total chemical oxygen demand as chromium (TCODCr) and soluble chemical oxygen demand as chromium (SCODCr) indicated 35.4% and 23.1% removal efficiency in terms of organic matter removal, respectively. Methane yield was approximately 0.35 kg m−3 at 2.0–4.0 kg (m3 d)−1 and 0.26 kg m−3 at 5.0 kg (m3 d)−1. The solubilization rate of 40.9% by thermal hydrolysis was confirmed through the lab-scale tests to determine its full-scale applicability.
ISSN:1996-1073
1996-1073
DOI:10.3390/en13010088