The application of constant recycle solids concentration in activated sludge process

Area of Science:

• Environmental Engineering
• Biotechnology
• Wastewater Treatment

Background:

• The Ramanathan and Gaudy model is a key tool for activated sludge process analysis.
• Investigating its applicability to industrial organic wastewater is crucial for effective treatment.

Purpose of the Study:

• To validate the Ramanathan and Gaudy model using industrial bottling plant wastewater.
• To assess the model's accuracy at varying dilution rates and recycle solids concentrations.

Main Methods:

• Experiments were conducted on Pepsi Cola wastewater.
• Dilution rates ranged from 1/8 to 1/1.5 hr⁻¹, with recycle solids at 5000 and 7000 mg/L.
• Influent COD and hydraulic recycle ratio were controlled.

Main Results:

• A steady state for reactor solids and effluent COD was achieved at different dilution rates.
• Model predictions closely matched observed values below 0.5 hr⁻¹ dilution rate.
• Higher dilution rates (above 0.5 hr⁻¹) led to biological solids washout.

Conclusions:

• The Ramanathan and Gaudy model is applicable to industrial organic wastewater treatment.
• Model accuracy is dependent on dilution rate, with optimal performance at lower rates.
• Operational strategies must account for potential solids washout at high dilution rates.