(An)Aerobic granular sludge

Aerobic granular sludge is an improvement upon activated sludge, that is used for the biological treatment of municipal and industrial wastewaters.

1. The microorganisms in aerobic granular sludge consume organic matter more effectively ánd the compact structure of granular sludge results in better retention of active biomass. This leads to less excess sludge and more biomass to be used for bioenergy production or resource recovery.
2. Aerobic granular sludge also allows for simultaneous nitrification, denitrification and phosphate removal from wastewater in a single treatment tank. Aerobic granular sludge has a 50%-75% lower land footprint and 30%-48% lower energy footprint of wastewater treatment plants than conventional activated sludge [Nancharaiah & Sarvajith, 2019](https://www.sciencedirect.com/science/article/abs/pii/S2468584419300169).

1. Microbial Composition: Granular sludge is made up of a diverse microbial community, including acidogenic bacteria, acetogenic bacteria, and methanogenic archaea. These microorganisms work in synergy to break down complex organic matter into simpler compounds, ultimately producing methane and carbon dioxide.
2. Structure: Granules are spherical or irregularly shaped particles with a diameter typically ranging from 0.5 to 3 mm. They have a layered structure, with different microbial groups occupying distinct zones depending on oxygen availability and substrate diffusion.M
3. High Settling Velocity: Due to their dense and compact nature, granular sludge has a high settling velocity (e.g., 20–70 m/h), allowing it to quickly separate from the treated effluent. This property is crucial for maintaining biomass retention within the reactor.
4. Retention Within Reactor: Granular sludge remains suspended in the reactor due to the upward flow of wastewater, but its settling properties prevent it from washing out. This enables the reactor to maintain a high concentration of active biomass, essential for [efficient treatment](https://www.paquesglobal.com/wastewater-treatment/4-stages-of-wastewater-treatment).
5. Self-Immobilizing: Unlike other systems that rely on external carriers (e.g. in MBBR), granular sludge forms naturally through microbial aggregation without requiring artificial support structures.

Granular sludge retention enhances efficiency and stability in both aerobic and anaerobic wastewater treatment systems. Granular sludge in anaerobic systems enhances biogas production and organic matter breakdown. Whereas aerobic granular sludge first and foremost enables compact system design and enhanced biological nutrient removal.

The compact granule recovery system BIOPAQ® RISE is a great addition to your existing UASB, IC or EGSB system. It increases the treatment efficiency and longevity of your existing system based on granular sludge. This external, vertical module virtually always fits into your existing wastewater treatment installation and is very easy to clean.

Discover our new auxiliary module for granular sludge systems