Department Sanitation, Water and Solid Waste for Development
Carbonization of Urban Bio-waste
Slow pyrolysis refers to the thermal decomposition (breakdown under heat) of biomass into a carbon-rich solid residue (char), with gases and liquids as by-products. This process does not require highly complex engineered systems and has already been applied to transform agricultural waste into char. Our projects target urban bio-waste treatment by slow pyrolysis.
The project “Carbonization of Urban Bio-waste in Dar es Salaam” is a research collaboration with the University of Dar es Salaam (College of Engineering and Technology) in Tanzania. The overall objective is to explore the potential of slow pyrolysis as a treatment and valorisation method for organic solid waste.
Publications Slow Pyrolysis
- Lohri, C.R., Sweeney, D., Rajabu, H.M. (2015): Carbonizing urban biowaste for low-cost char production in developing countries – A review of knowledge, practices and technologies. Joint report by Eawag, MIT D-Lab and UDSM.
- Lohri, C.R., Faraji, A., Ephata, E., Rajabu H.M., Zurbrügg, C. (2015): Urban biowaste for solid fuel production: Waste suitability assessment and experimental carbonization in Dar es Salaam, Tanzania. Waste Management & Research, Vol. 33(2), 175-182.
Hydrothermal Carbonization (HTC) is a thermochemical reaction that occurs in a pressurized reactor when a mix of organic matter and water is heated for several hours. In contrast to dry pyrolysis, HTC can process substrate that has a high moisture content, making it suitable for the wet fraction of municipal organic solid waste.
For experimental purposes, a bench scale prototype reactor that can handle 20 litres has been conceived, constructed, and is presently being tested. Current objectives are: i) to define optimal operational parameters and ii) to explore measures to increase the energy efficiency and autonomy of the HTC process.
Publications HTC
- Robbiani, Z. (2013). Hydrothermal carbonization of bio-waste/faecal sludge.
Conception and construction of a HTC prototype research unit for developing countries. Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland. (MSc Thesis, ETH) - Dea Marchetti, P. (2014). Hydrothermal carbonization of food waste.
Testing of an HTC prototype research unit for developing countries. (MSc Thesis, Sandec/University of Pavia).