ORWARE – A simulation model for organic waste handling systems. Part 2: Case study and simulation results

Results from simulations with the ORWARE model (ORganic WAste REsearch) are presented. The model was tested on a medium-sized Swedish city. The scenarios were planned to illustrate the consequences of different waste handling systems. The modelled processes for organic solid waste were; incineration, landfilling, anaerobic digestion and composting, for the wastewater they were sewage plant and source separation of urine. Each transport and treatment facility was modelled with respect to incoming waste. Each process model generates an energy balance, liquid and/or gaseous emissions and residual products as outputs. The simulation results show that source separation of solid waste, followed by biological treatment, is beneficial with respect to the recycling of phosphorus and environmental effects. The negative results for these systems are their energy balances. Source-separating human urine seems to be the only way to get a high degree of nitrogen recycling. The results also stress the importance of including liquid waste to get an overall picture of the transports needed to get the residues to arable land. Landfilling organic waste generates the largest negative environmental effect. A model description is presented in a companion paper.