Bubbles coming out of filter bed in manganese removal plant

[maurice]

We recently completed construction of a manganese removal water treatment plant and it's now in operation. All seems okay except that recently we started noticing increased amounts of bubbles coming out of the filter during operation.

Coincidentally, the filter runs are very short. Is this a simple case of filter air-binding or could it be a more serious case of a gas product of some kind? By the way our plant uses pottasium permanganate which is fed into the filter inffluent water. Any explaination will be appreciated as we are running out of our sanity on this issue.Can it be seasonal change of raw water temperature? We use ground water.

[Chris Maeder]

Carbon Dioxide gas is a by-product of the oxidation reaction which occurs when using potassium permanganate to oxidize manganese and or iron. This is likely the issue that must be addressed. The best way of dealing with this is to allow for reaction time and off-gasing of the carbon dioxide generated, upstream of the filtration process. We just went through this on a recent trouble shooting assignment for a client on one of their start-ups.

Thanks

Dennis