Advanced

Calibration of a mathematical model for anaerobic digestion with special emphasis on estimation of hydrolysis rate constants at 35, 55, and 60°C

Haghighatafshar, Salar LU ; Ossiansson, Elin; Kjerstadius, Hamse LU ; la Cour Jansen, Jes LU and Davidsson, Åsa LU (2013) Holistic Sludge Management
Abstract
Hydrolysis rate constants of sludge at 35°C, 55°C, and 60°C were found to be 0.32 d-1, 0.44 d-1, and 0.50 d-1, respectively in pilot-scale experiments with digestion of municipal sludge in semi-continuously operated reactors. The hydrolysis rate constants as well as estimated chemical oxygen demand (COD) fractions in the feed were implemented in a mathematical model for anaerobic digestion similar to Anaerobic Digestion Model No. 1 (ADM1). It was found that the original free ammonia inhibition model did not comply with the measured data; so that no inhibition of propionate oxidation was observed in the reactors. Moreover, relatively considerable free ammonia inhibition of acetotrophic methanogenesis was detected in the reactor running at... (More)
Hydrolysis rate constants of sludge at 35°C, 55°C, and 60°C were found to be 0.32 d-1, 0.44 d-1, and 0.50 d-1, respectively in pilot-scale experiments with digestion of municipal sludge in semi-continuously operated reactors. The hydrolysis rate constants as well as estimated chemical oxygen demand (COD) fractions in the feed were implemented in a mathematical model for anaerobic digestion similar to Anaerobic Digestion Model No. 1 (ADM1). It was found that the original free ammonia inhibition model did not comply with the measured data; so that no inhibition of propionate oxidation was observed in the reactors. Moreover, relatively considerable free ammonia inhibition of acetotrophic methanogenesis was detected in the reactor running at 60°C while no tangible accumulation of acetate occurred at 35°C and 55°C. Consequently a new free ammonia inhibition model was introduced in the model. Validation of the calibrated model was then done on two thermophilic reactors. The methane production rate in the validated model was about 5-10 % lower than the actual rate. The lower methane production was accredited to the low-estimated hydrolysis rate constants. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to conference
publication status
unpublished
subject
keywords
anaerobic digestion model, free ammonia inhibition, hydrolysis rate constant
conference name
Holistic Sludge Management
language
English
LU publication?
yes
id
18fb7961-0e75-40a0-85e1-1d2b873c37c0 (old id 3914255)
date added to LUP
2013-07-01 10:51:49
date last changed
2016-04-16 11:26:05
@misc{18fb7961-0e75-40a0-85e1-1d2b873c37c0,
  abstract     = {Hydrolysis rate constants of sludge at 35°C, 55°C, and 60°C were found to be 0.32 d-1, 0.44 d-1, and 0.50 d-1, respectively in pilot-scale experiments with digestion of municipal sludge in semi-continuously operated reactors. The hydrolysis rate constants as well as estimated chemical oxygen demand (COD) fractions in the feed were implemented in a mathematical model for anaerobic digestion similar to Anaerobic Digestion Model No. 1 (ADM1). It was found that the original free ammonia inhibition model did not comply with the measured data; so that no inhibition of propionate oxidation was observed in the reactors. Moreover, relatively considerable free ammonia inhibition of acetotrophic methanogenesis was detected in the reactor running at 60°C while no tangible accumulation of acetate occurred at 35°C and 55°C. Consequently a new free ammonia inhibition model was introduced in the model. Validation of the calibrated model was then done on two thermophilic reactors. The methane production rate in the validated model was about 5-10 % lower than the actual rate. The lower methane production was accredited to the low-estimated hydrolysis rate constants.},
  author       = {Haghighatafshar, Salar and Ossiansson, Elin and Kjerstadius, Hamse and la Cour Jansen, Jes and Davidsson, Åsa},
  keyword      = {anaerobic digestion model,free ammonia inhibition,hydrolysis rate constant},
  language     = {eng},
  title        = {Calibration of a mathematical model for anaerobic digestion with special emphasis on estimation of hydrolysis rate constants at 35, 55, and 60°C},
  year         = {2013},
}