Effect of bacteria on strength properties and toxicity of incinerated biomedical waste ash concrete.

A large amount of biomedical waste is generated worldwide, and this waste is hazardous and infectious. The ultimate solution for the issue of disposal of such waste is incineration and then landfill. This incinerated waste is called incinerated biomedical waste ash (IBWA). After incineration, the IBWA is still toxic because of the presence of heavy metals and alkaline metals as they get leached out and have a lethal effect on the environment. This study aims at the use of IBWA in concrete as fine aggregate replacement material. The IBWA was given bacterial treatment to stabilise it against alkalinity and heavy metals leaching. Fine aggregate was replaced with IBWA with ratios having replacement levels from 0%, 5%, 10%, 15%, and 20%. Strength tests performed were compressive strength and splitting tensile strength up to the age of 365 days. United States Environmental Protection Agency's (U.S. EPA) toxicity characteristic leaching procedure, SEM-EDS, and XRD tests were performed. Leachate generated from the concrete mix incorporating IBWA (with and without bacterial treatment) was studied, and the aim was to bind the metals to ensure that the metals leached out are within permissible limits.