title: Model of the sewage sludge-straw composting process integrating different heat generation capacities of mesophilic and thermophilic microorganisms.
abstract: A mathematical model integrating 11 first-order differential equations describing the dynamics of the aerobic composting process of sewage sludge was proposed. The model incorporates two microbial groups (mesophiles and thermophiles) characterized by different capacities of heat generation. Microbial growth rates, heat and mass transfer and degradation kinetics of the sewage sludge containing straw were modeled over a period of 36days. The coefficients of metabolic heat generation for mesophiles were 4.32×10(6) and 6.93×10(6)J/kg, for winter and summer seasons, respectively. However, for thermophiles, they were comparable for both seasons reaching 10.91×10(6) and 10.51×10(6)J/kg. In the model, significant parameters for microbial growth control were temperature and the content of easily hydrolysable substrate. The proposed model provided a satisfactory fit to experimental data captured for cuboid-shaped bioreactors with forced aeration. Model predictions of specific microbial populations and substrate decomposition were crucial for accurate description and understanding of sewage sludge composting.
authors.affiliation: Department of Systems Engineering, Faculty of Technical Sciences, University of Warmia and Mazury in Olsztyn, Heweliusza 14, 10-718 Olsztyn, Poland. Electronic address: irekb@uwm.edu.pl.
authors.forename: I
authors.initials: I
authors.lastname: Białobrzewski
authors.affiliation: Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore(1); Chair of Industrial and Food Microbiology, Faculty of Food Sciences, University of Warmia and Mazury in Olsztyn, Plac Cieszyński 1, 10-726 Olsztyn, Poland(2).
authors.forename: M
authors.initials: M
authors.lastname: Mikš-Krajnik
authors.affiliation: Institute of Biosystems Engineering, Poznan University of Life Sciences, Wojska Polskiego 50, 60-637 Poznan, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Dach
authors.affiliation: Department of Systems Engineering, Faculty of Technical Sciences, University of Warmia and Mazury in Olsztyn, Heweliusza 14, 10-718 Olsztyn, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Markowski
authors.affiliation: Institute of Biosystems Engineering, Poznan University of Life Sciences, Wojska Polskiego 50, 60-637 Poznan, Poland.
authors.forename: W
authors.initials: W
authors.lastname: Czekała
authors.affiliation: Department of General and Environmental Microbiology, Poznan University of Life Sciences, Szydłowska 50, 60-656 Poznan, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Głuchowska
mesh_terms: D000388:Air; D001673:Biodegradation, Environmental; D019149:Bioreactors; D006868:Hydrolysis; D007700:Kinetics; D008962:Models, Theoretical; D009930:Organic Chemicals; D012621:Seasons; D012722:Sewage; D012987:Soil; D013696:Temperature
chemical_list: D009930:Organic Chemicals; D012722:Sewage; D012987:Soil
keywords: Aerobic composting; Mathematical modeling; Mesophilic bacteria; Sewage sludge; Thermophilic bacteria