Iron & Manganese Control With Active Hypolimnetic Circulation
When a lake or reservoir stratifies, the bottom portion of the water column (known as the hypolimnion) can become anoxic. If anoxic conditions occur, iron & manganese can dissolve from the reservoir sediments into the water column and into the water plant intake. Concentrations as low as 0.05 mg/l can cause aesthetic and operational problems for water utilities while long-term consumption of water containing manganese at concentrations above 0.4 mg/l has also been associated with adverse human-health effects.
How to remove it
Iron and manganese must precipitate and fall out of the water column. Any precipitate coming into the plant intake can be removed by filters before entering the treatment plant itself.
Iron oxidizes within seconds & is the easiest of the two to precipitate out.
Manganese however is more nuanced. It can be in the presence of an oxidizer for 24+ hours and still not precitipate.
How active hypolimnetic circulation can help
SolarBee® Lake Circulators can be set for hypolimnetic withdrawal in the deepest hole near the water treatment plant intake. By pulling up the anoxic, highly concentrated iron and/or manganese bottom water and exposing it to the oxygen-rich upper water column (known as the epilimnion), more precipitation can occur helping to make your incoming water more more easily treatable.