Wastewater
Aeration System Demonstrates High Oxygen Transfer
By Mazzei
Mar 14, 2006 - 2:58:00 AM

Bakersfield, CA -- The ratio of oxygen transfer in process water compared to the oxygen transfer in clean water, also known as the Alpha factor, is a critical consideration when designing an activated sludge wastewater treatment plant (WWTP). Mixed Liquor Suspended Solids (MLSS) can cause lower Alpha factors for some aeration processes.

In order to evaluate the affect a high volume of suspended solids has on the Alpha factor for the Mazzei Airjection® process, a series of tests were conducted in a sludge digester at a municipal WWTP that utilizes Mazzei AirJection equipment.

Test Procedure: Off-gas sampling was conducted on the Mazzei Airjection process installed at the Butler County, Ohio WWTP sludge digester. Measurement of the oxygen concentration in the off-gas samples provided an accurate assessment of the affect the high volume of suspended solids has on the Alpha factor for the Mazzei AirJection process.

The Butler County sludge digester was operating at a MLSS of 19,900 mg/l at the time of sampling. Testing followed the ASCE “Standard Guidelines for In-Process Oxygen Transfer Testing” Section 3.0, Off-Gas Method.

The off-gas was collected under a 4’ x 8’ hood with a 1.5’ peak. Off-gas oxygen concentration was measured with a Teledyne 320P/D Oxygen Analyzer. Dissolved oxygen and temperatures were measured with a Royce Model 900 DO meter.

Results: Oxygen transfer efficiency (OTE) is calculated by comparing the concentration of oxygen in the off-gas samples to the concentration of oxygen in atmospheric air. The OTE for the sludge digester system is 31%.

Test results show that the Alpha factor at the Butler County Sludge Digester exceeds 0.95 and verifies that a high level of suspended solids does not reduce the OTE of the Mazzei Airjection process.

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