APPLICATION OF CALCIUM BIOLEACHING BACTERIA FOR BIOPRECIPITATION AND BIOMINERALISATION OF CALCIUM CARBONATE (CACO3) IN INCREASING THE MICP (MICROBIALLY INDUCED CALCIUM CARBONATE PRECIPITATION) PROCESS FOR MATERIAL STRENGTH

• Main Author: Alexius Sitompul, Johannes
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/70145
• Institution: Institut Teknologi Bandung

The issue of soil stability is a problem that will be faced by Indonesia with increasing of development in Indonesia. Indonesia has a number of steel plants that produce large amounts of slag. There are several bacteria that can process the metallurgical waste into soil strengthening materials to address the issue of soil stability. Microbially Induced Calcium Carbonate Precipitation (MICP) can be a solution for the utilization of metallurgical waste and at the same time addressing the issue of soil stability. Calcium needed in the MICP process is obtained through the bioleaching process by bioleaching bacteria. A series of experiments were carried out to determine the optimum Ca-leachete concentration and bioprecipitation bacteria concentration as well as the optimum combination of bioleaching bacteria and bioprecipitation bacteria for the MICP process. Experiments were carried out at various bioprecipitation bacteria concentrations of 5% (1ml), 10% (2ml) and 15% (3ml) (v/v), variations in Caleachete concentrations of 5% (1ml), 10% (2ml) and 15% (3ml) ) (v/v) as well as a combination of CCOR and APKU bioleaching bacteria and Bismik 2 (1) and Sutina 3 bioprecipitation bacteria. The experiment was carried out by pouring 20 ml of bioprecipitation solution with a certain composition for 7 days. Then the samples were tested for soil physical properties, XRD, FTIR and SEM-EDS. The experimental results showed that the optimum concentration of bioprecipitating bacteria was 15%, the optimum concentration of Ca-leachete was 15% and the optimum combination of bioleaching and bioprecipitating bacteria was CCOR and Bismik 2 (1). The results of the FTIR test showed that a C=O bond was formed. The XRD results show that the mineral CaCO3 is formed in the sample. SEM-EDS results show the formation of mineral CaCO3 in the sample.