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-Paradigm Shift for BGA Control
The following memo summarizes our experience regarding the ecological relationships in
lakes, ponds and reservoirs associated with the control of blue-green algae (cyanobacteria)
blooms through SolarBee circulation. There are now over 300 such water bodies benefiting
from SolarBee circulation. Our experience and knowledge continues to increase greatly, and
we have strengthened considerably both the scientific and empirical support for the ecological
relationships described below.
-SolarBee Experience in Inhibiting Submersed Macrophyte Growth
After 10 years of very consistent empirical evidence, we have considerable confidence that
SolarBee-induced circulation can reduce and inhibit the growth of certain invasive aquatic
weeds in freshwater lakes over time. Although we are still fine-tuning SolarBee deployment
parameters, best results have occurred when the units were installed in the fall and the intake
hoses were placed below the depth of the macrophyte beds.
-Improving Wastewater Oxygenation and Mixing Efficiency The Problem
Ice Prevention in Potable Water Storage Tanks with Solar-Powered Active Mixing
Water bodies, like human bodies, require good circulation to function properly” (Hudnell, 2009).
Quiescent waters in potable water storage tanks are associated with water quality problems
such as thermal stratification, biofilms, excessive disinfection byproducts and disinfectant
residual loss. Ice formation in distribution-system reservoirs is another challenge faced by
water utilities in northern climates during winters. Thick layers of ice often form at the surface
in storage tanks during prolonged periods of subfreezing weather.
-Solar-Powered Circulation: Applications in Electrical Power Utility Waters
Solar-powered circulation (SPC) of water is used to solve a variety of water quality problems in
drinking-source and recreational reservoirs, potable-water storage tanks, wastewater lagoons,
storm-water runoff ponds and industrial water bodies. This report describes SPC technology
and current applications in electricity generating utilities.
-Increasing Contact Time and Reducing Short-Circuiting In a Clearwell Tank
In 2005 the City of Bend, Oregon’s Water Division commissioned a new reservoir, known as
Outback Reservoir #2, which functions as a clear well. The reservoir is welded steel above
ground tank, which is 120 feet in diameter and has a maximum depth of 35.4 feet. The reservoir
has a capacity of 2.9 million gallons (MG), however typical operating depth is about 26.6 feet or
approximately 2.23 MG. The well was designed with separate inlet and outlet pipes, which are
located directly opposite each other at the bottom of the tank.
-Mixing, De-Stratification, And Break-Point Chlorination
The San Francisco Public Utility Commission (SFPUC) is an innovative leader in potable water
distribution system research and operation. The SFPUC continually strives to improve water
quality by conducting research and implementing operational improvements to surpass
increasingly stringent regulatory standards. In 2002, the SFPUC planned a 2004 transition to
chloramines as a secondary disinfectant to reduce disinfection byproduct concentrations. The
SFPUC anticipated nitrification problems when chloramine decayed, releasing free ammonia
to the water.
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