Characterization of sewage sludge and biomass ash mixture as future geotechnical material

Abstract

To reduce the environmental load due to waste generation, there is an urgent need of utilizing the industrial/municipal waste in the bulk. There is a large scope of utilizing the bulk amount of waste as geotechnical material. Several studies have been made to utilize the industrial waste such as fly ash, slag, red mud, mine overburden etc. as geotechnical material, however, the sewage sludge did not get much attention. So, this research has been presented as a preliminary study which includes the physical, chemical, and microstructural property of sewage sludge for futuristic geo-material. Further, the biomass ash has been added with the sewage sludge to know its effect. The test result shows that the sewage sludge contains high concentrations of chromium, mercury and nickel. Dewatered municipal sewage sludge (80%) stabilized with biomass ash (20%) was used as a soil amendment, to predict the behavior of soil under a controlled environment. The application of stabilized sewage sludge over soil sample resulted in a significant increase in pH and electrical conductivity of the soil sample. The effect of stabilized sewage sludge over macronutrients and micronutrients present in soil was also determined and the results of statistical analysis revealed that the usage of sewage sludge stabilized with biomass ash enhances the fertility of the soil.