Fine Pore Diffuser Case History for Frankenmuth, Michigan

摘要

Frankenmuth is a community of 4,000 people in central Michigan. About 25-30% of the flow and 50-70% of the BOD load to the wastewater treatment plant are contributed by a brewery. In January 1986, conversion from a stainless steel broad band coarse bubble diffuser system to fine pore aeration was completed in all of the six existing aeration tanks. The Frankenmuth retrofit was designed with in-situ wastewater oxygen transfer efficiencies (OTE) at average air flow and peak flow based on off-gas tests at other locations. These values were adjusted to account for the significant high strength industrial component of the influent wastewater. The design OTE at 2 scfm/diffuser was only two-thirds that used at 1 scfm/diffuser (alpha SOTEs of 16.9% and 11.0%, respectively). In spite of lower than expected OTEs, the Frankenmuth retrofit to fine pore diffusers was an economic success. The actual capital cost of installation was slightly more than estimated during the evaluation period, but the projected energy savings appeared to be slightly greater as well.