Human activities and urban lifestyle create municipal solid waste (MSW) all over the world in huge volume. Proper management of MSW is one of the important requirements/ responsibilities for a healthy environment of future generation. The proposed project aims at utilizing the MSW Incinerated (MSWI) products as secondary raw materials in geopolymer concrete, thereby converting these wastes into wealth (W2W). This also helps in satisfying the demand for raw materials in infrastructure industries.
MSW generation was estimated as 1.3 billion tonnes/year in 2012. With the growing population and increasing solid waste generated, this could reach a value as high as 2.2 billion tonnes in 2025. Currently, landfilling, incineration, recycling and composting are adopted as treatment categories for MSW. Of which, incineration is adopted for 150 kg out of 480 kg per capita generated in EU-28 countries. Incineration process reduces the mass and volume of the MSW and results in two main side streams besides electricity, viz., 20% of fly ash with hazardous heavy metals and organics, and 80% of bottom ash which is normally non-hazardous. Landfilling is the easiest solution to any non-hazardous waste. However, it has its own disadvantages such as, land requirement, sanitary maintenance, and ground water pollution. On the other side, with the growing need for infrastructure development, depletion of natural raw materials and demand for alternative materials is a well-known issue in construction industries. In specific, concrete is the second largest consumed material by mankind, just next to water. 70% of concrete is made of aggregates that are normally river sand, rock and gravel. Being the largest volume of solid material extracted aggregates are depleted in a threatening rate. Aggregate consumption on concrete production alone was estimated as 25.2 to 29.4 billion tonnes in the year 2016 and increasing with the demand, every year. This causes a demand in supply of raw materials, increasing the cost of the material. Further, transporation of the aggregate from the source to the site increases the overall project cost. The mentioned issues clearly highlight the need to identify alternatives for aggregate in concrete production. In this context, MSWI waste is also getting into limelight as an alternative material in construction industries. MSWI ash are reactive in nature due to the presence of silica and alumina which are activated by the high temperature involved in the incineration process. Hence, mainly studied as a cement replacement material. However, there is also possibility to pelletize the MSWI ash to be used as a replacement for aggregate that occupies larger volume (70%) of concrete.
The main aim of the research program is to develop treatment methods for MSWI bottom ash with minimum energy usage and to utilize 100% of the MSWI ash as a secondary raw material in concrete production. This was achieved by formulating three scientific objectives carried out as three work packages as below:
1. To optimize the treatment method for MSWI bottom ash and to understand the enhancement in the properties of treated MSWI bottom ash with advanced treatment technology (WP1)
2. To manufacture the artificial aggregate from the treated MSWI bottom ash (WP2)
3. To study the performance of the MSWI bottom ash aggregate as a secondary raw material in the geopolymer concrete application (WP3)
