“A semi-industrial scale investigation of the factors controlling the bio-conversion of biodegradable wastes into a consistent solid recovered fuel (SRF) product for use as an auxiliary energy source by the cement industry”. (Sept. 2005 – Aug. 2008)

This Project was funded by the Cyprus Research Promotion Foundation. The participants are: Isotech Ltd (host organization), Imperial College London (Partner 1), IWI (Partner 2), Vassiliko Cement Works (Partner 3).

Background

European Landfill Directive requires the phased reduction of biodegradable municipal waste (BMW) disposed to landfill by EU Member States to 75%, 50%, 35% of the quantity disposed in 1995 by 2006, 2009 and 2016, respectively (CEC 1999). Composting and mass burn incineration are the two most widespread techniques for diverting BMW from Landfills. However, these techniques are not ideal solutions in all EU Member State. Incineration requires a high and constant throughput of waste with high calorific value, which is not the case for many countries, whilst the economic viability of composting depends largely on the presence of separate collection schemes for BMW that have been adopted only in a small number of countries.
Mechanical biological treatment (MBT) offers an alternative to composting and mass burn incineration for treatment, re-use or disposal of municipal solid waste. BMW is mechanically sorted and treated by a bio-drying process and blended with other high calorific value waste to produce a solid recovered fuel (SRF). The bio-drying process utilizes microbially generated heat during aerobic decomposition, to drive off moisture and increase the calorific value of the waste. SRF product can be used for power generation or as an auxiliary fuel in the cement industry. Bio-drying can be an effective approach to achieve compliance with the Landfill Directive and also reduce greenhouse gas emissions through significant fossil fuel replacement.

Objectives

The main objective of the research is to quantify the main factors controlling bio-drying and the quality of SRF using a semi-industrial rotary drum bio-reactor. The project also aims to optimise the bio-drying process and the quality of the end product and also assess the effect of using SRF in cement production on the quality of cement.