Utilization of Portland Cement and Municipal Solid Waste Incineration Fly Ash for Solidification/Stabilization of Sewage Sludge

摘要

A solidification/stabilization (S/S) process by using municipal solid waste incineration (MSWI) fly ash wasapplied to sewage sludge in order to find a safer way for the two wastes (sewage sludge and MSWI fly ash)disposal. The behaviour of pastes fabricated with various mass ratios of Portland cement/MSWI fly ash hasbeen analysed in terms of mechanical strength, microstructure and leaching characteristics. The resultsshowed that the unconfined compression strength (UCS) of solidified sludge decreased with the mixingamount of MSWI fly ash. However, with the addition of 5% MSWI fly ash represented 28 days UCS of 0.31MPa, satisfying the landfill threshold of 0.3MPa. Scanning electron microscopy investigations revealed thata large amount of ettringite was present in solidified sludge, leading to a crystallizing network in the solidifiedproducts, and therefore, the enhancement of the strength. Environmental assessment of the final productsin compliance leaching tests demonstrated that the concentration of heavy metals was below the detectionlimits..