DOMESTIC WASTEWATER TREATMENT USING IMMOBILIZED SLUDGE FLUIDIZED-BED REACTORS

Abstract

Bench-scale fluidized-bed reactors using the immobilized activated sludge process were studied for the treatment of domestic wastewater. Different intermittent aeration patterns were investigated in order to improve the total nitrogen (TN) removal. The best TN removal at 74.4% was achieved at an HRT of 6 hours (with corresponding BOD loading rate of 0.766 kg/m³/d) and an aeration-pattern of 1,3 (the hours of aeration and non-aeration time cycle). The removal efficiencies for organic carbon, NH⁺ ₄ -N, TKN and TSS were not affected and remained at more than 90%. Simultaneous organic carbon and nitrogen removal was accomplished in a single immobilized sludge reactor. The impact of various influent feed patterns on the treatment was examined. The continuous feed pattern was recommended as it ensured good TN removal without any adverse impacts on the removal of organic carbon, NH⁺ ₄ -N, TKN and TSS. The immobilized sludge beads exhibited satisfactory mechanical stability without apparent breakage over the 180-day experiment period.

Keywords:

• Immobilized sludge
• Domestic wastewater
• Fluidized-bed reactor

ACKNOWLEDGMENT

The authors acknowledge the research funding provided by the Natural Science and Engineering Research Council Canada.