Sewage sludge ash for soil stabilization: A review

Abstract Rapid industrialization leads to an increase in the quantity of combustion deposits like ashes. Currently, most of these ashes are disposed of in landfills. However, in India, the facilities for disposing these waste is very limited. Many states in India doesn’t have a proper disposal mechanism for such wastes, and thus the improper dumping of waste will affect the natural ecosystem. The waste management by reuse or recycling is crucial in the present-day scenario. With the fast growth in the volume of sewage sludge obtained from sewage treatment plants, it is crucial to reuse and reduce sludge. Sewage sludge ash (SSA) obtained from the burning of sewage sludge has significant dissimilarities with the fly ash/bottom ash in terms of chemical, physical and cementitious characteristics. Soil stabilization is indispensable due to the increase in the construction of structures. The studies dealing with soil stabilization has more focus on the use of chemical additives which are expensive and unsafe. Improving the ground using waste materials is one of the most essential and cost-effective methods. The commonly used additives such as cement and lime for stabilizing poor ground can be replaced with waste material, leading to a sustainable and environment friendly approach for discarding the industrial waste. This paper briefly describes the production, properties and application of SSA in civil engineering even though the focus was on the utilization of SSA for soil stabilization. Studies have already reported that SSA possesses pozzolanic properties and has the potential to stabilize the soft ground. This paper also addresses a broad review of the index and engineering properties of soil improved with SSA.