Utilization of Incinerated Biomedical Waste Ash in Concrete and Its Leachate Analysis

Abstract

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 stabilize it against alkalinity and heavy metals leaching. The present research work has been carried out to evaluate the feasibility of the utilization of incinerated biomedical waste ash as fine aggregate replacement in concrete. Tests for compressive strength, splitting tensile strength, water absorption, chloride permeability, sulphate resistance and Toxicity Characteristic Leaching Procedure (TCLP) were performed up to the age of 365 days. The concrete mix has been designed to conferring to Indian standard BIS: 10262:2009 to achieve a strength of 26.6MPa on 28-day. Controlled and bacterial treated IBWA, i.e., IBWA and IBWA-B, have been used as fine aggregate partial replacements, and five replacement levels were made (0, 5, 10, 15, and 20%). The fine aggregate replacements corresponding to 0-20% without bacterial treatment (IBWA) were designated as IBWA0, IBWA5, IBWA10, IBWA15, and IBWA20. Concrete incorporating bacterial treated ash (IBWA-B) were named IBWA5B, IBWA10B, IBWA15B, and IBWA20B. In this study, an alkaliphile bacterial strain named Bacillus Haloduran was used to lower the heavy metal concentration and alkalinity of IBWA. The effect of pH, temperature and NaCl effect was investigated on the growth of strain. The alkaline IBWA was treated with Bacillus Haloduran, and changes in alkalinity and heavy metal were studied. The Bacillus Haloduran treatment given to IBWA for 15 days has significantly reduced alkalinity and heavy metal vi concentration. The initial alkalinity of fresh IBWA was 1450 mg/l which decreased to 521mg/l after Bacillus Haloduran treatment. Whereas the pH of the IBWA has reduced to 8 on the 15th day when compared to the 1st day pH that is 11.33. United States Environmental Protection Agency (U.S. EPA) Toxicity Characteristic Leaching Procedure (TCLP), SEM-EDS, and XRD test 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 were within permissible limits. The bacterial treatment of IBWA has made a positive impact on concrete properties.