title: Mathematical modeling of olive mill waste composting process.
abstract: The present study aimed at developing an integrated mathematical model for the composting process of olive mill waste. The multi-component model was developed to simulate the composting of three-phase olive mill solid waste with olive leaves and different materials as bulking agents. The modeling system included heat transfer, organic substrate degradation, oxygen consumption, carbon dioxide production, water content change, and biological processes. First-order kinetics were used to describe the hydrolysis of insoluble organic matter, followed by formation of biomass. Microbial biomass growth was modeled with a double-substrate limitation by hydrolyzed available organic substrate and oxygen using Monod kinetics. The inhibitory factors of temperature and moisture content were included in the system. The production and consumption of nitrogen and phosphorous were also included in the model. In order to evaluate the kinetic parameters, and to validate the model, six pilot-scale composting experiments in controlled laboratory conditions were used. Low values of hydrolysis rates were observed (0.002841/d) coinciding with the high cellulose and lignin content of the composting materials used. Model simulations were in good agreement with the experimental results. Sensitivity analysis was performed and the modeling efficiency was determined to further evaluate the model predictions. Results revealed that oxygen simulations were more sensitive on the input parameters of the model compared to those of water, temperature and insoluble organic matter. Finally, the Nash and Sutcliff index (E), showed that the experimental data of insoluble organic matter (E>0.909) and temperature (E>0.678) were better simulated than those of water.
authors.affiliation: Department of Chemical and Environmental Technology, ESCET, Rey Juan Carlos University, 28933 Móstoles, Madrid, Spain. Electronic address: ioanna.vasiliadou@urjc.es.
authors.forename: Ioanna A
authors.initials: IA
authors.lastname: Vasiliadou
authors.affiliation: Department of Environmental and Natural Resources Management, University of Patras, G. Seferi 2, GR-30100 Agrinio, Greece.
authors.forename: Abu Khayer Md
authors.initials: AK
authors.lastname: Muktadirul Bari Chowdhury
authors.affiliation: Department of Environmental and Natural Resources Management, University of Patras, G. Seferi 2, GR-30100 Agrinio, Greece.
authors.forename: Christos S
authors.initials: CS
authors.lastname: Akratos
authors.affiliation: Department of Environmental and Natural Resources Management, University of Patras, G. Seferi 2, GR-30100 Agrinio, Greece.
authors.forename: Athanasia G
authors.initials: AG
authors.lastname: Tekerlekopoulou
authors.affiliation: Institute of Chemical Engineering Sciences, FORTH, Stadiou Str., Platani, GR-26504 Patras, Greece; Department of Chemical Engineering, University of Patras, GR-26504 Patras, Greece.
authors.forename: Stavros
authors.initials: S
authors.lastname: Pavlou
authors.affiliation: Institute of Chemical Engineering Sciences, FORTH, Stadiou Str., Platani, GR-26504 Patras, Greece; Department of Chemical Engineering, University of Patras, GR-26504 Patras, Greece.
authors.forename: Dimitrios V
authors.initials: DV
authors.lastname: Vayenas
mesh_terms: D001673:Biodegradation, Environmental; D018533:Biomass; D002138:Calibration; D002482:Cellulose / Q000737:chemistry; D019649:Food Industry; D006813:Humidity; D006861:Hydrogen Peroxide / Q000737:chemistry; D006868:Hydrolysis; D007220:Industrial Waste / Q000032:analysis*; D007700:Kinetics; D008031:Lignin / Q000737:chemistry; D008962:Models, Theoretical; D031658:Olea / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D010101:Oxygen Consumption; D015203:Reproducibility of Results; D012987:Soil; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods
chemical_list: D007220:Industrial Waste; D012987:Soil; D002482:Cellulose; D008031:Lignin; D006861:Hydrogen Peroxide; D010100:Oxygen
keywords: Biological processes; Compost; Kinetics; Modeling; Olive mill solid waste