Case Study for Customer Location CO119:
Reservoir or Lake Use:
The Reservoir was constructed in the early 1980s, and serves as a cooling reservoir for Power Authority’s coal-fired power plant. There is no public access to the reservoir.
System Overview and Reservoir:
The Reservoir has a surface area of 480 acres in the main body and 15 acres in the intake basin. Maximum water depth is 65 ft and an average depth of 30 ft. The water source for the reservoir is secondary effluent from the City’s municipal wastewater treatment plant. This is an area with consistently high winds and wave action year round. Because of the heat load to the cooling water, lake temperatures remain above about 15°C even during the winter.
Reported Problem Before SolarBee Installation:
Because of high nutrient source water, this reservoir has had a long history of blue-green algae blooms; the dominant species has been Microcystis aeruginosa. Because of the warm water year round, Microcystis bloomed all year. This perpetual algal bloom kept pH values consistently above 9, increasing the amount of scaling in the cooling towers. The Power Authority was using 200 HP diffused aeration, which proved ineffective at resolving their water quality problems. Therefore, the primary SolarBee objectives were to control blue-green algae blooms and reduce associated elevated pH levels, and reduce chemical and operational costs associated with mitigating the scaling problem.
SolarBee Installation:
Date: July 2005, installed ten (10) SB10000v12 units in the main body of the reservoir and one (1) SB10000 in the 15-acre intake basin (this unit was subsequently moved to the northwest corner of reservoir for additional whole-lake treatment). Units are equipped with hoses and float arms specially designed for large lakes with high winds and waves.
Results:
The Reservoir was experiencing the Microcystis bloom when the 11 units were installed in July 2005. Within 6-8 weeks the water clarity improved from about 3 ft to 8-10 feet, and the Microcystis bloom had disappeared. In August 2006 water clarity was down to 9.5 ft, and pH values have remained consistently below 9. The Power Authority is pleased with the better water quality and lower pH values associated with blue-green algae bloom control – even with secondary wastewater effluent as the source water. PRPA also appreciates the chemical and energy savings by restoring lake water quality using solar power.
Photo shows one of the SB10,000v12 in the reservoir.
Updated: 04/23/2007
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