Aerobic Granular Sludge Technology: The Future Of Wastewater Treatment

Technological advancement in recent times has enabled the wastewater treatment industry to develop new approaches focused on improving pollutants and nutrient removal methods, better efficiency and lower costs. Aerobic granular sludge technology is fast emerging as one of the promising and innovative methods to achieve wastewater treatment objectives.

The conventional Activated Sludge Process (ASP) system has been one of the most common methods used for biological wastewater treatment for a long time. A majority of treatment plants employ the ASP system. It involves microbial population in the form of flocs which are suspended in the wastewater. However, there are certain drawbacks related to the Activated Sludge Process system, which includes low biomass concentration, maximum floor areas and high energy for different purposes. Additionally, separate settling and aeration tanks are a must for this process and the poor settleable property of activated sludge results in low effluent quality and poor treatment efficiency. Aerobic granular sludge technology is capable of overcoming the drawbacks of ASP systems. 

Aerobic Granular Sludge Technology


The study of aerobic granular sludge was first reported in the early 1990s and has been extensively conducted in the past two decades to identify more sustainable options for wastewater treatment. These studies have reported the co-existence of both aerobic and anaerobic microbial metabolic activities in the granules allowing simultaneous processes of both nitrification and denitrification. This technology has also attracted attention from scientists due to the improved efficiency and potential of reducing the footprint of municipal and industrial wastewater treatment plants.

What is Aerobic Granular Sludge Technology?

Aerobic Granular Sludge has different physical, chemical and microbiological characteristics when compared to the activated sludge process. According to experts, this technology can be used for effective secondary wastewater treatment with or without primary treatment. It consists of a three-phase batch process which is finished in one tank. In granular sludge, the bacterial cells aggregate to form a dense and strong bond, as seen in biofilms.

To know more about biofilms: Harnessing The Power Of Microorganisms In Wastewater Treatment Using Biofilms ( 

 It consists of bio-granules used as biomass to treat wastewater biologically, as seen in the activated sludge process. However, it performs this function without mechanical mixing and in the presence of oxygen in a controlled environment similar to aerobic wastewater treatment.

The granules in this process can be defined as microbial aggregates that don’t coagulate due to reduced hydrodynamic shear and thus settles faster than activated sludge flocs. Moreover, when considering the microbiology of Aerobic Granular Sludge Technology, granules are layered, unlike loosely mixed microbial population in ASP.  The dense nature of the aerobic granule allows superior and rapid settling properties, high biomass retention and the ability to handle high levels of shock loads. Each of the granules consists of different zones like aerobic, anaerobic and anoxic. Thus, every granule is acts an a miniature treatment plant.

The AGS process enables the removal of carbon, nitrogen, phosphorus and bio degradation of toxic pollutants. It is a cost-effective treatment method for removing reduced and oxidized wastewater contaminants. 

Also Read : Reduction Of Pollutants In Wastewater

Other Advantages of Aerobic Granular Sludge Technology include:

  • 20% less surface area required for treatment plant
  • 30% lower power (energy) requirements
  • Minimum operation as treatment phases is completed in a single tank
  • Capital and operational cost savings
  • Less solids for de-watering/disposal
  • Does not require expensive media to support bacteria or membranes for solids separation
  • Retrofitting to wastewater treatment plants possible
  • Studies show 10 mg/L for BOD and TSS effluent characteristics. 


  • Relatively new technology and the majority of research is carried out in labs
  • Impact due to rapid changes in influent makeup or toxic shocks/spills is still unclear.
  • Comprehensive real-world data on industrial wastewater treatment is not available yet.

As you can see, Aerobic Granular Sludge Technology is believed to be the future of municipal and industrial wastewater treatment. As more research and progress will be made and more industries deploy this technology, the results will give a better understanding of its potential. 

Organica Biotech is a leader in developing sustainable, eco-friendly and advanced solutions for various industries. The wastewater treatment vertical has developed efficient biological treatment solutions for industrial and municipal wastewater treatment after 21 years of dedicated research in the field. The Cleanmaxx range of products contains a microbial formulation that degrades organic waste and powers the performance of the wastewater treatment plants. Use Cleanmaxx range of products to meet effluent standards in your region and protect the environment.

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Post by Priyanka Khaire