SONGXiao-ya.Abnormal Methane Content in a Thermal Hydrolysis Anaerobic Digestion Tank and Countermeasures[J].China Water & Wastewater,2024,40(24):59-63.
Abnormal Methane Content in a Thermal Hydrolysis Anaerobic Digestion Tank and Countermeasures
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第40卷
Number:
第24期
Page:
59-63
Column:
Date of publication:
2024-12-17
- Keywords:
- thermal hydrolysis; anaerobic digestion tank; volatile fatty acid; acidification; temperature control; methane
- Abstract:
- In view of the obvious decrease of methane content in a thermal hydrolysis anaerobic digestion tank, the changes of volatile fatty acids, alkalinity and biogas yield were analyzed and compared with those in a normal digestion tank. The content of volatile fatty acids in the abnormal digestion tank exceeded 5 000 mg/L, indicating the accumulation of volatile fatty acids, i.e., acidification. The effects of organic load, residence time and temperature on acidification were further analyzed. Excessive temperature was the main factor leading to acidification, and 51 ℃ was an important critical point. The emergency measures taken for abnormal conditions were to reduce the temperature of the digestion tank by reducing the amount of inlet sludge and cleaning the heat exchanger. The methane content index was the most sensitive in the recovery process of digestion tank, followed by volatile fatty acids, and alkalinity was the least sensitive. The optimization suggestions of thermal hydrolysis anaerobic digestion tank are temperature control and establishment of monitoring system. Temperature control should take 50 ℃ as the warning value in the near future, and facilities and automatic control transformation should be considered in the long term. The methane content detection is recommended as the preferred monitoring index in monitoring system, using a portable detector with frequency of week.
Last Update:
2024-12-17