174 

 

 

Energy audit/benchmarking conducted to identify priorities for energy efficiency improvements  

 

Utilization of energy conserving operational methods (e.g., optimization of primary 
sedimentation to reduce utilization of pure oxygen) 

Energy efficient retrofits of equipment in the water and wastewater treatment and conveyance systems. 
Nearly all motors have been converted to VFD or soft start controls. At the WRF, 5 positive displacement 
blowers were replaced with 3 energy-efficient turbo blowers.  

LED lighting is being retrofitted throughout the system to replace outdoor floodlights and indoor office 
lighting.  

Performance Measures & Results  

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Reduction in energy usage at the WRF As a result of the installation of turbo blowers at the WRF 
for aeration basins, energy costs have been reduced by $60,000 per year.  

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Reduction in energy use throughout conveyance system As a result of the installation of new 
drives on motors throughout the sewer pumping stations, there has been no appreciable 
increase in total electrical cost over the past five years – even with the addition of 4 new pump 
stations (bringing the total to 79 stations).  

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Reduction in cost through lighting upgrades This is an ongoing project therefore cost savings 
cannot be quantified as yet. We fully anticipate cost reductions from the longer life of the LED 
bulbs and the reduced energy consumption.      

 

ENERGY GENERATION & RECOVERY  

 

Internal energy sources evaluated (e.g., biogas, hydropower, heat in wastewater), and/or 
renewable energy sources evaluated on an ongoing basis (e.g., solar, wind, co-digestion)  

 Create a biodiesel fuel from used cooking oil to use in Utility trucks and equipment.  

Performance Measures & Results 

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Gallons of cooking oil recycled into biodiesel fuel We collect approximately 400 gallons per 
month of used cooking oil which converts to 100 gallons of biodiesel. The cost of collecting and 
making the fuel is more than offset by the reduced maintenance and reduced SSO incidence 
within the sanitary sewer collection system. 

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Cost savings over the purchase of diesel fuel It costs approximately $1.00 to make biodiesel 
(using the free feedstock of recycled cooking oil) and we produce about 1200 gallons per year. In 
previous years when petroleum-based diesel approached $5 per gallon, we saved $4800 per 
year. Recently we have seen a more modest savings as the cost of petro-diesel have come 
down.