title: Simulation of substrate degradation in composting of sewage sludge.
abstract: To simulate the substrate degradation kinetics of the composting process, this paper develops a mathematical model with a first-order reaction assumption and heat/mass balance equations. A pilot-scale composting test with a mixture of sewage sludge and wheat straw was conducted in an insulated reactor. The BVS (biodegradable volatile solids) degradation process, matrix mass, MC (moisture content), DM (dry matter) and VS (volatile solid) were simulated numerically by the model and experimental data. The numerical simulation offered a method for simulating k (the first-order rate constant) and estimating k(20) (the first-order rate constant at 20 degrees C). After comparison with experimental values, the relative error of the simulation value of the mass of the compost at maturity was 0.22%, MC 2.9%, DM 4.9% and VS 5.2%, which mean that the simulation is a good fit. The k of sewage sludge was simulated, and k(20), k(20s) (first-order rate coefficient of slow fraction of BVS at 20 degrees C) of the sewage sludge were estimated as 0.082 and 0.015 d(-1), respectively.
authors.affiliation: Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Beijing 100101, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Ding
authors.initials: D
authors.lastname: Gao
authors.forename: Tong-Bin
authors.initials: TB
authors.lastname: Chen
authors.forename: Guo-Di
authors.initials: GD
authors.lastname: Zheng
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Chuang
authors.initials: C
authors.lastname: Ma
authors.forename: Song-Lin
authors.initials: SL
authors.lastname: Guo
authors.forename: Wei
authors.initials: W
authors.lastname: Du
mesh_terms: D019149:Bioreactors; D003198:Computer Simulation; D007700:Kinetics; D008962:Models, Theoretical; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D012987:Soil; D013696:Temperature; D014908:Triticum / Q000378:metabolism
chemical_list: D012722:Sewage; D012987:Soil