Study of recycling Singapore solid waste as land reclamation filling material

Green waste management technology was proposed, transforming Singapore incineration bottom ash (IBA) and marine clay (MC) into engineering applicable filling material for land reclamation, named as MC-IBA matrix. Geotechnical and environmental behaviors of MC-IBA matrix were evaluated. Firstly, the shear strength was tested. Pozzolanic reaction between the two raw materials and stabilizer was explained as the possible reason for strength development of matrix. Then, various leaching tests were performed to study heavy metal leaching behavior. Characterization leaching test NEN 7371, compliance leaching tests EN-12475, toxicity characteristic leaching procedure (TCLP) and long term leaching test multiple TCLP (MTCLP) were employed. Compliance tests results were compared with selected European criteria and Singapore criteria for environment assessment. The comparison shows that Singapore IBA could be accepted as non-hazardous waste under EU landfill directive. Recycled MC-IBA matrix material was qualified as construction material based on Denmark and German environmental criteria. In addition, the long term environmental concerns were also proposed based on MTCLP result analysis. It was notable that, unlike most of others elements, Ba and Tl started leaching in later stage.