Impact of substrate feed patterns on solids reduction by the Cannibal process.

Area of Science:

• Environmental Engineering
• Wastewater Treatment Technologies
• Microbial Ecology in Waste Management

Background:

• Field observations revealed inconsistent solids reduction in single-stage, high sludge age processes.
• Variations in solids reduction in biological treatment systems necessitate further investigation.
• Conventional activated sludge systems can exhibit suboptimal solids yield.

Purpose of the Study:

• To investigate the Cannibal process for biological solids reduction.
• To understand the impact of feed cycle variations on solids reduction efficiency.
• To compare the Cannibal process with conventional activated sludge systems.

Main Methods:

• Laboratory-scale sequencing batch reactors were utilized.
• A control activated sludge system was operated.
• Two side-stream anaerobic reactor (Cannibal) systems were tested with different feed cycles (5-minute and 4-hour).

Main Results:

• The Cannibal system with a 5-minute feed cycle achieved up to 80% less biological solids compared to the control.
• The Cannibal system with a 4-hour feed cycle produced fewer solids than the conventional system but more than the 5-minute feed system.
• Feed cycle duration significantly influences solids reduction efficiency in the Cannibal process.

Conclusions:

• The Cannibal process, particularly with a short feed cycle, offers substantial biological solids reduction.
• Optimizing feed cycle parameters is crucial for maximizing the efficiency of anaerobic side-stream reactors.
• The Cannibal process presents a promising alternative for enhanced solids management in wastewater treatment.