Traditional activated sludge systems are frequently used in sewage treatment plants to treat wastewater biologically. Due to the sludge's poor settling qualities, these systems often require vast surface areas for treatment and biomass separation units.
What are Aerobic Granules?
Aerobic granules are a form of sludge that has the ability to self-immobilize flocs and microorganisms into spherical, robust compact structures. Excellent settleability, high biomass retention, simultaneous nutrient removal, and toxicity tolerance are all advantages of aerobic granular sludge. Aerobic granular sludge treatment may be a viable option for treating high-strength wastewaters including nutrients and hazardous compounds.
The aerobic granular sludge is typically grown in an SBR (sequencing batch reactor) and used as a wastewater treatment for high-strength wastewater, hazardous wastewater, and household wastewater with great success.
Aerobic granule formation
In sequencing batch reactors (SBRs), granular sludge biomass is produced without the use of carrier materials. The majority of the prerequisites for their formation are met by these systems, including:
1: Feast – Famine regime: Short feeding intervals must be chosen to induce feast and famine phases, which are marked by the presence or lack of organic materials in the liquid media. The proper microorganisms to make granules are selected using this feeding approach. Granule-forming organisms have an advantage over filamentous organisms when the substrate concentration in the bulk liquid is high because they can store organic materials in the form of poly-hydroxybutyrate to be ingested during famine periods. This component is boosted when anaerobic feeding is used, reducing the need of a quick settling time and larger hydrodynamic forces.
2:Short settling time: This hydraulic selection pressure on the microbial population permits granular biomass to be retained in the reactor while flocculent biomass is washed out.
3: Hydrodynamic shear force: High shear forces promotes the production of aerobic granules and the physical integrity of granules, according to evidence. The Hybrid Activated Sludge (HYBACS) technique, which consists of an attached-growth reactor with a short retention time upstream of a suspended growth reactor, is also used to produce granular activated sludge in flow-through reactors.
Advantages of aerobic granulation
When compared to traditional activated sludge process, aerobic granules in an aerobic SBR offer various advantages, including:
1: Stability and flexibility: The SBR system is adaptable to changing conditions and can endure stress and hazardous loadings.
2:Low energy requirements: The aerobic granular sludge process has a greater aeration efficiency due to the increased height of operation, and there are no return sludge or nitrate recycle streams, as well as no mixing or propulsion requirements.
3: Reduced footprint: Because of the rapid settling velocity of the aerobic sludge granules and the lack of a final settler, an increase in biomass concentration is achievable, resulting in a significant reduction in the necessary footprint.
4: Good biomass retention: Larger biomass concentrations inside the reactor may be achieved, and higher substrate loading rates can be treated, thanks to good biomass retention. The presence of aerobic and anoxic zones within the granules allows different biological activities to take place at the same time in the same system.
5: Decreased investment and operating costs: The cost of operating an aerobic granular sludge wastewater treatment plant can be reduced by at least 20%, and space requirements can be reduced by up to 75%.
For wastewater or sewage of any kind, Netsol Water Solutions offer a complete spectrum of wastewater treatment products. Our engineers would gladly collaborate with your team to create the right design that meets your budget and objectives.