Medical waste fly ash recycling for possible use in geoenvironmental applications

In the past few years, public concern over medical waste management has manifestly increased. The permeability and compaction characteristics of soil-fly ash mixtures made with dilferent percentages of medical fly ash are compared to evaluate the elfectiveness of recycling medical waste ash. The fly ash is mixed with a residual deposit of in-situ weathered and degraded weakly cemented calcareous/gypsiferous silty sandstone material locally known as Gatch for future possible use in geo-environmental applications. Fly ash is the byproduct of incineration; the only technique used for reducing the massive volumes of medical waste generated in the country. Such practice will help reduce the volumes of fly ash disposed and minimize its potential risk to the environment. An extensive laboratory-testing program was carried out to determine the properties of white Gatch. Fly ash was then added in dilferent percentages (0%, 0.1%, 1%, 2.5% and 5% by dry weight of soil) to Gatch samples. The fly ash-Gatch mixtures were then examined to evaluate their engineering performance. A general enhancement of soil properties attributed to the characteristics of fly ash is noted, facilitating its possible use in geo-environmental applications (e.g. landfill liners). Generally, as the % of medical fly ash increased, the permeability of fly ash-Gatch mixtures decreased up to a content of 1%; a point from which any further increase in fly ash content showed little to no significant change in permeability values.