@article {Stone:2008:1938-6478:525,
	author = "Stone, Mark and Livingston, Dennis",
	title = "Flat Plate MBR Energy ConsumptionVillage of Dundee, MI",
	journal = "Proceedings of the Water Environment Federation",
	volume = "2008",
	number = "1",
	year = "2008",
	abstract = "In order to address growing demand and increasingly stringent permit limits, the Village of Dundee, MI upgraded their wastewater treatment plant (WWTP) from sequencing batch reactor (SBR) technology to membrane bioreactor (MBR) technology in June, 2005. Including a solids handling upgrade to aerobic digestion using membrane filtration, the total cost to retrofit the plant was 6.55M. Following the upgrade, effluent quality significantly improved, the capacity increased from 0.75 MGD to 1.5 MGD and solids handling costs decreased by roughly 35&#37;. As expected, plant energy demand also increased, roughly doubling SBR requirements. This paper proposes methods for improving plant energy efficiency and cutting power costs by &#62;50&#37;.<P></P>Although the plant has not been optimized for energy efficiency, the average demand of 1.44 kWh/m<SUP>3</SUP> (MBR Zone demand &#60;0.3 kWh/m<SUP>3</SUP>) in 2006 was less than some comparable greenfield facilities. For evaluation purposes, monthly energy demand is trended for roughly two years of continuous operation. The trended energy data shows a clear relationship between energy efficiency and treated flow. For example, the plant (total including HVAC, etc.) average energy usage in January (2006, 2007) was 0.95 kWh/m<SUP>3</SUP> at an average flow of 1.29 MGD. However, during periods of low flow (&#60;0.6 MGD), energy requirements have been as high as 2.69 kWh/m<SUP>3</SUP>. The primary reason for the disparity in efficiency appears to be system turndown capabilities and control limitations.<P></P>Although the plant has performed well (no violations) for over two years at a constant air scour intensity of 0.015 SCFM/ft<SUP>2</SUP> the setpoint was recently increased to compensate for a low recycle to flow ratio at peak demand. Proportional aeration is now being considered for optimizing MBR Zone energy requirements between 0.3 kWh/m<SUP>3</SUP> and 0.52 kWh/m<SUP>3</SUP> while the same time addressing known hydraulic constraints.",
	pages = "525-547",
	url = "http://www.ingentaconnect.com/content/wef/wefproc/2008/00002008/00000001/art00041",
	doi = "doi:10.2175/193864708788803406"
}