FORMATION AND APPLICATION OF AEROBIC GRANULAR BIOMASS IN AIRLIFT REACTOR WITH CONTINUOUS FLOW

• Main Author: Yulianto, Andik
• Format: Dissertations
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/44122
• Institution: Institut Teknologi Bandung

The paradigm shift in waste treatment is carried out to get additional benefits from treated wastewater. By using appropriate treatment methods, wastewater can be converted into a resource. The application of granular aerobic biomass (BGA) has the potential to meet these objectives, especially the treatment of nutrients in wastewater. So far, the use of BGA for wastewater treatment is based more on the Sequencing Batch Reactor (SBR). Studies in the use of SBR reactors for BGA show satisfactory performance both in formation and utilization. SBR with BGA has also been applied at full scale. Nevertheless, the use of SBR is not free from problems. These problems include the need for additional land for buffer tanks and the difficulty of changing the mode of operation from conventional activated sludge to SBR. This gives room for further research on the use of different types of reactors. This study aims to analyze the possibility of BGA formation and application by using a continuous reactor based on Biological Airlift Reactor (BAR). The study was conducted at several stages with artificial waste water using sodium acetate as a substrate. The initial stage is to examine the factors that influence the formation of BGA on SBR. These factors are the aeration rate, ratio of height to reactor diameter (H/D) and COD/N ratio. In each of these factors variations were carried out, so that the best composition was obtained, namely aeration rate of 3 l/min, COD/N ratio of 100: 20, and ratio of H/D of 1:14. The next step is to design and conduct initial trials on BARs, and make modifications to BAR operations in the form of intermittent aeration and modifying reactors on BAR top clearance. The experimental results on the SBR show the aeration rate has an influence on the characteristics of the granular formed. Supervicial air upflow velocity (SUAV) above 1.53 m/min can create hydrodynamic shear forces that are too large for granular aerobic formation to be optimum so that the formation of granular aerobes is not running optimally and will damage the formed granular aerobes. The experimental results show that the aeration rate of 3 l/min gives the most optimum results for the SBR reactor. In addition, the formation of BGA on SBR is also influenced by variations in the H/D ratio, where at a high H/D ratio it will more quickly reach optimum conditions. Based on the results of the study, the optimum conditions for granular formation with the SBR system were at an H/D ratio of 14 with an optimum operating time of 18 days. The C/N ratio also affects the formation and stability of the BGA in the SBR reactor. From the experimental results obtained the ratio that has the best quality of 100: 20. A continuous flow BAR that is designed based on aeration rate of 3 l/min, COD/N 100: 20, and H/D ratio 1:14 with a load of 2.5 Kg COD/m3.day can form a BGA. BGA begins to form in the third week and has the characteristics of SVI, diameter and deposition speed below the BGA on the SBR which is used as the basis for design. This is influenced by HRT and the selectivity of BGA-forming microorganisms. The smaller the HRT, the higher the SVI value, reducing the BGA diameter and deposition speed. This can be corrected by intermittent aeration and modifying top clearance. The intermittent aeration mode of operation improves and maintains the formed BGA. With intermittent aeration, flow conditions in the reactor will improve the selectivity of microorganisms on BGA formation. A continuous flowing BAR with intermittent aeration, with a residence time of 6 hours and a load of 2.5 kg COD/m3.day, has a maximum COD removal efficiency of 83.7% and ammonium 57.4%. Compared to SBR with aeration rate of 3 l/min, H/D 1:14 and COD/N 100: 20 have a maximum COD removal efficiency of 83% and ammonium 60%. So there is no significant difference in the efficiency of COD and ammonium removal.