title: Urban biowaste for solid fuel production: waste suitability assessment and experimental carbonization in Dar es Salaam, Tanzania.
abstract: The poor state of solid waste management in Dar es Salaam (DSM), Tanzania, the large fraction of organic waste generated and a high charcoal consumption by city residents has triggered this research on carbonization of municipal biowaste. Char produced by the thermochemical conversion method of slow pyrolysis can be briquetted and used as cooking fuel alternative to wood-based charcoal. To explore the potential of biowaste carbonization in DSM, the most suitable organic wastes were selected and pyrolyzed in a simple, externally heated carbonization system developed as part of this study. A Multi-Criteria Analysis framework allowed to assess prevailing biowaste types regarding availability and accessibility, and respective suitability in terms of physical-chemical properties. The assessment, using data from a survey and lab analysis, revealed the following biowaste types with highest overall potential for char production in DSM: packaging grass/leaves (PG) used for transportation of fruit and vegetables to the markets, wood waste (WW) from wood workshops, and cardboard (CB) waste. Best practice carbonization of these biowastes in the pyrolyzer showed satisfactory char yields (PG: 38.7%; WW: 36.2%; CB: 35.7% on dry basis). Proximate composition (including volatile, fixed carbon and ash content) and heating value (PG: 20.1 MJ kg(-1); WW: 29.4 MJ kg(-1); CB: 26.7 MJ kg(-1)) of the produced char also compare well with literature data. The energy and emission-related aspects of the system still require further research and optimizations to allow financially viable and safe operation.
authors: Eawag: Swiss Federal Institute of Aquatic Science and Technology, Department of Water and Sanitation in Developing Countries (Sandec), Dübendorf, Switzerland christian.lohri@eawag.ch.
authors: Christian Riuji
authors: CR
authors: Lohri
authors: Department of Mechanical and Industrial Engineering, College of Engineering and Technology, University of Dar es Salaam, Dar es Salaam, Tanzania.
authors: Adam
authors: A
authors: Faraji
authors: Department of Mechanical and Industrial Engineering, College of Engineering and Technology, University of Dar es Salaam, Dar es Salaam, Tanzania.
authors: Elia
authors: E
authors: Ephata
authors: Department of Mechanical and Industrial Engineering, College of Engineering and Technology, University of Dar es Salaam, Dar es Salaam, Tanzania.
authors: Hassan Mtoro
authors: HM
authors: Rajabu
authors: Eawag: Swiss Federal Institute of Aquatic Science and Technology, Department of Water and Sanitation in Developing Countries (Sandec), Dübendorf, Switzerland.
authors: Christian
authors: C
authors: Zurbrügg
mesh_terms: D002244:Carbon / Q000032:analysis*; D002947:Cities; D017745:Incineration / Q000379:methods*; D062611:Solid Waste / Q000032:analysis*; D013636:Tanzania
chemical_list: D062611:Solid Waste; D002244:Carbon
keywords: Biochar; carbonization; energy recovery; multi-criteria analysis; organic solid waste; slow pyrolysis