Assessment of the influence of thermal pre-treatment time on the macromolecular composition and anaerobic biodegradability of sewage sludge.
Laboratory and pilot-scale experiments were carried out in order to evaluate the influence of thermal pre-treatment time on waste-activated sludge properties and anaerobic biodegradability. Six experimental conditions were analyzed from 0 to 30 min of hydrolysis time. Solubilization of macromolecular compounds, changes in the main sludge properties and anaerobic biodegradability of the sewage sludge were evaluated. A similar carbohydrate solubilization degree was achieved, from 53% to 70% and 59% to 75% for lab- and pilot-scale experiments, respectively. In the case of proteins, the values of solubilization were lower in the pilot-scale experiment than in the laboratory, with 31-45% and 47-70%, respectively. Ammonia and volatile fatty acid did not undergo important changes; however the sludge dewaterability enhanced at increased pre-treatment times. All the pre-treatment conditions had a positive effect with regard to anaerobic biodegradability and by fitting experimental data with a simplified mathematical model, it was concluded that the maximum biogas production rate is more influenced by the pre-treatment time than the total biogas production.
Donoso-Bravo
A
A
Department of Chemical Engineering and Environmental Technology, University of Valladolid, Prado de la Magdalena s/n, 47011 Valladolid, Spain. adonosobravo@gmail.com
Pérez-Elvira
S
S
Aymerich
E
E
Fdz-Polanco
F
F
D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D056804:Biofuels / Q000032:analysis; D057919:Biological Oxygen Demand Analysis; D002241:Carbohydrates / Q000032:analysis; D006868:Hydrolysis; D007700:Kinetics; D046911:Macromolecular Substances / Q000032:analysis*; D008697:Methane / Q000032:analysis; D010865:Pilot Projects; D011506:Proteins / Q000032:analysis; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage / Q000382:microbiology*; D012995:Solubility; D013696:Temperature; D013997:Time Factors
D056804:Biofuels; D002241:Carbohydrates; D046911:Macromolecular Substances; D011506:Proteins; D012722:Sewage; D008697:Methane