OPTIMIZATION OF BIOFLOCCULATION PROCESS TOTAL SUSPENDED SOLID OF GOLD TAILINGS RUNOFF WATER USING BIOSURFACTANT PRODUCING BACTERIA SERRATIA RUBIDAEA STRAIN SKC-11

• Main Author: Aurelia, Cindy
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/57388
• Institution: Institut Teknologi Bandung

Flocculation is one of the vital stages in the solid-liquid separation process, especially in wastewater treatment. The particles that want to be flocculated are very small fine particles suspended in solution. In the gold processing, a residue called tailings is produced. Problems occur when the produced tailings are stored in Tailing Storage Facility (TSF) so that when they are exposed to rain or running water they will end up producing mine runoff water. This mining wastewater contains suspended solids or Total Suspended Solid (TSS) which is difficult to settle. Therefore, flocculation was carried out with the addition of flocculants to facilitate their deposition. The flocculation agent used was bacteria because it is biocompatible, safe for human health, and environmentally friendly compared to organic and inorganic flocculants. In this research, samples of gold tailings runoff water from PT X were bioflocculated to reduce the suspended solids concentration using the bacterium Serratia rubidaea strain SKC-11 grown in SKC-1 media. The experiment began with a literature study on bacteria and the mechanism in the bioflocculation process. Then, a series of experiments were conducted to select bacteria that can live at high cyanide concentrations and can produce biosurfactants. From these experiments, five bacterial strains and SKC-1 media were selected. After that, a preliminary bioflocculation experiment was carried out by mixing TSS and bacteria. Next, the TSS concentration was measured using a TSS meter. Preliminary experiments were conducted to determine the optimum residence time to precipitate TSS. Furthermore, a core bioflocculation experiment was carried out with various types of bacteria to determine the most optimal bacteria. With the same method, an experiment was conducted to determine the optimal percentage of inoculation. Subsequent experiments used variations in the dimensions of the graduated cylinder to determine the diameter and height of the TSS so that the quality standard was achieved. The results showed that the most optimal bacteria in reducing the concentration of TSS with the highest deposition rate was Serratia rubidaea strain SKC-11. The optimal percentage of bacterial inoculation was 15%. The dimensions of the graduated cylinder so that the TSS concentration reached the quality standard of 200 mg/L was a diameter of 6.7 cm, the height of the supernatant discharged at 8.39 cm and the settling rate of 6.94 ppm/minute for 120 minutes.