Novel system configuration with activated sludge like-geometry to develop aerobic granular biomass under continuous...

Area of Science:

• Environmental Engineering
• Biotechnology
• Wastewater Treatment

Background:

• Aerobic granular sludge (AGS) formation is crucial for efficient wastewater treatment.
• Conventional methods like Sequencing Batch Reactors (SBRs) have limitations in continuous operation.
• Developing continuous flow systems for AGS cultivation is an active area of research.

Purpose of the Study:

• To investigate a novel continuous flow system with a "flat geometry" for promoting aerobic granular sludge formation.
• To establish correlations between system parameters and SBR operational characteristics for AGS cultivation.
• To determine optimal operating conditions for enhanced granule properties.

Main Methods:

• A continuous flow system comprising two completely mixed aerobic tanks in series and a settler was designed.
• Experiments were conducted varying the tank volume ratio, biomass recirculation rate, and settler upflow velocity.
• Aerobic granular sludge properties, including settling velocity, sludge volume index (SVI10), and diameter, were measured.

Main Results:

• The optimal tank 1/tank 2 volume ratio was 0.28, with a sludge recycling ratio of 0.25 and a settler upflow velocity of 2.5 m/h.
• Under these conditions, the aerobic aggregates exhibited settling velocities ranging from 29 to 113 m/h.
• The sludge volume index at 10 min (SVI10) was 70 mL/g TSS, and granule diameters ranged from 1.0 to 5.0 mm.

Conclusions:

• The novel continuous flow system successfully promoted the formation of aerobic granular sludge.
• The established operational parameters provide a basis for optimizing continuous AGS cultivation.
• This system offers a viable alternative to SBRs for efficient wastewater treatment through granulation.