Related Experiment Video
Updated: Jul 6, 2026
06:10
Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge
Published on: September 26, 2016
Is sludge retention time a decisive factor for aerobic granulation in SBR?
1Division of Environmental and Water Resources Engineering, School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
Bioresource Technology
|March 12, 2008
Summary
Sludge retention time (SRT) does not promote aerobic granulation in sequencing batch reactors (SBRs) without hydraulic selection. Hydraulic selection pressure is more effective than SRT for successful heterotrophic aerobic granulation.
Area of Science:
- Environmental Science
- Biotechnology
- Chemical Engineering
Background:
- Aerobic granulation is a crucial process in wastewater treatment.
- Sequencing batch reactors (SBRs) are commonly used for biological wastewater treatment.
- Understanding factors influencing aerobic granulation is essential for optimizing treatment efficiency.
Purpose of the Study:
- To investigate the role of sludge retention time (SRT) in aerobic granulation.
- To evaluate the effectiveness of SRT compared to hydraulic selection pressure in SBRs.
- To determine the decisive factors for successful aerobic granulation.
Main Methods:
- Aerobic granulation was studied under negligible hydraulic selection pressure.
- Various sludge retention times (SRTs) ranging from 3 to 40 days were tested.
- A comparative analysis was performed between SRT and hydraulic selection pressure.
Main Results:
- No successful aerobic granulation was achieved at any of the studied SRTs.
- Hydraulic selection pressure, specifically minimum settling velocity, was found to be more effective.
- SRT was not identified as a decisive factor for aerobic granulation in SBRs.
Conclusions:
- Sludge retention time alone is insufficient for inducing aerobic granulation in SBRs.
- Hydraulic selection pressure plays a more critical role in enhancing aerobic granulation.
- Optimizing hydraulic conditions is key for successful heterotrophic aerobic granulation in SBRs.
More Related Videos
Related Concept Videos
01:30Biological Treatment of Effluent and Waste Water
Biological wastewater treatment relies on the metabolic activity of microorganisms to remove pollutants from sewage. In modern treatment systems, this process is organized into sequential stages that progressively reduce solid material, dissolved organic matter, and microbial contamination. Each stage plays a distinct role in improving water quality and preparing the effluent for safe discharge or reuse.Primary and Secondary TreatmentPrimary treatment is a physical process that removes large...
01:18Bioreactor Controls-II
In aerobic fermentations, oxygen is vital for microbial growth and metabolite production. Since air comprises only about 20% oxygen and the gas is poorly soluble in water—just 9 ppm at 20°C—supplying sufficient oxygen becomes a critical challenge, especially in high-demand processes like yeast growth or citric acid production. Even a fully saturated broth may offer only a few seconds of oxygen availability.To address this, sterile or scrubbed air is introduced into the fermentor via a sparger...
01:29Bioreactor Design and Operational System
Bioreactors are engineered vessels designed to cultivate microorganisms under controlled conditions for industrial bioprocessing. They maintain sterility and allow precise regulation of pH, temperature, oxygen, and nutrient levels to optimize microbial growth and metabolite production. Bioreactors range from small laboratory units of 1 liter to industrial systems holding up to 500,000 liters, though only about 75% of their volume is actively used for fermentation. The remaining headspace...
01:14Scale-Up Processes
The scale-up of microbial fermentation processes is essential in industrial biotechnology, allowing the transition from laboratory-scale experiments to commercial-scale production while aiming to maintain product yield and quality. This process requires meticulous adjustment of equipment design, process parameters, and contamination control strategies to accommodate increasing culture volumes.At the laboratory scale, cultures are typically maintained in 1 to 10-liter glass or autoclavable...