The aeration tank is smaller (by up to a factor of three) but needs to be gas tight; the clarifier is the same size.
GAS VOLUME USED IN OXYGENATION PROCESSES 1% of gas volume in aeration systems
OPERATING DO LEVEL IN MIXED LIQUOR 6 to 10 mg/l
Figure 7.35.2 compares the use of air and oxygen in activated-sludge wastewater treatment. An air-sparged plant treating 1 mgd of wastewater with a BOD level 300 ppm and a BOD removal efficiency of 90% removes about 2250 lb/day of BOD. It produces about 1350 lb/day of MLVSS in 10,000 lb/day of sludge cake.
In this system a 35-hp compressor injects 1200-scfm air in the 48,000-cu-ft aeration tank (Nogaj 1972). This air contains 1250 lb/hr of oxygen or 13.33 lb of oxygen per
Air Plant: BOD removal 90%: 2250 lb/day
Was this article helpful?