Ice Melting / Control

Introduction

Ice formation in cold weather can present a number of problems:

Poor water quality around intakes.
Water stratification
Potential damage to boats, pilings, docks, or breakwaters from crushing pressure of ice.
Potential damage to mechanical equipment in outdoor, or intermittent use tanks, clarifiers, etc.
Ice formation blocking water intakes, clogging screens.
Prevention of alum addition for phosphorous precipitation in wastewater lagoons.
Reduced hydraulic capacity and storage volume.
Poor treatment performances of stormwater ponds due to channelling during spring melt conditions.

Solution

PNW propose two primary mechanisms for cost-effective ice melting in a body of water, mixing and scouring.

Mixing the warmer and denser water laying on the bottom to the underside of the ice layer at the surface.

Scouring the underside of the ice with circulated water and air bubbles.

Using an ADS aeration system to circulate warmer bottom water to the underside of the ice is an effective ice melting process until thermal stratification has been eliminated. When full destratification is accomplished, the result is an equalized temperature throughout the body of water. Water and air scouring continues to effectively melt ice even after destratification has occurred.

For larger and deeper bodies of water such as large ponds or lakes that have a significant bottom area, bottom soil heat is transferred into the water continuously during the process. The bottom laid ADS diffusers lower the warm water density by introducing oxygen. This reduction in density combined with the pumping action of the bubbles produces optimum warm water circulation and subsequent ice melting.

On an energy comparison basis, an ADS ice melting requires a fraction of the energy compared to mechanical system such as water pump or coarse bubble air systems.

Prevention of ice formation, and/or the reduction of ice thickness can also be achieved by installing insulated Armor Balls™ cover systems. These systems are easily installed in new or existing tanks or ponds and are maintenance free.

Result

ADS diffusers provides an extremely effective ice melting system. It is possible to reach ice reduction rates of 1" per hour of operation even at -30°C ambient temperatures.

Furthermore, frazzle ice damage to water intakes is effectively reduced with ADS. By introducing air/oxygen and mixing, the ice density is reduced which forces the frazzle ice to migrate to the surface leaving bottom intakes virtually free of ice.

For applications where aggressive mixing could have negative effects on the process in the tank (i.e. outdoor clarifiers or settling basins), Armor Balls™ cover systems for ice reduction can be a second alternative.