|Title||Hydrolysis rate constants at 10–25 °C can be more than doubled by a short anaerobic pre-hydrolysis at 35 °C|
|Author(s)||Zhang, L.; Gao, R.; Naka, A.; Hendrickx, T.L.G.; Rijnaarts, H.H.M.; Zeeman, G.|
|Source||Water Research 104 (2016). - ISSN 0043-1354 - p. 283 - 291.|
Sub-department of Environmental Technology
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||Anaerobic digestion - Cellulose - Hydrolysis rate constant - Low temperature - Tributyrin|
Hydrolysis is the first step of the anaerobic digestion of complex wastewater and considered as the rate limiting step especially at low temperature. Low temperature (10–25 °C) hydrolysis was investigated with and without application of a short pre-hydrolysis at 35 °C. Batch experiments were executed using cellulose and tributyrin as model substrates for carbohydrates and lipids. The results showed that the low temperature anaerobic hydrolysis rate constants increased by a factor of 1.5–10, when the short anaerobic pre-hydrolysis at 35 °C was applied. After the pre-hydrolysis phase at 35 °C and decreasing the temperature, no lag phase was observed in any case. Without the pre-hydrolysis, the lag phase for cellulose hydrolysis at 35–10 °C was 4–30 days. Tributyrin hydrolysis showed no lag phase at any temperature. The hydrolysis efficiency of cellulose increased from 40 to 62%, and from 9.6 to 40% after 9.1 days at 15 and 10 °C, respectively, when the pre-hydrolysis at 35 °C was applied. The hydrolysis efficiency of tributyrin at low temperatures with the pre-hydrolysis at 35 °C was similar to those without the pre-hydrolysis. The hydrolytic activity of the supernatant collected from the digestate after batch digestion of cellulose and tributyrin at 35 °C was higher than that of the supernatants collected from the low temperature (≤25 °C) digestates.