Manganese release in drinking water plant
First of all, slow down throughput time by performing more frequent and thorough washing of filters.
Pre-ozonation also works for oxidation of Mn, just as when a lot of oxidant is injected upstream of filtration.
What are the raw water concentrations, filter throughput, and injected reagents (air, permanganate, etc.)?
Replace 2/3 of sand with MnO2; it's simple and very effective.
I have been using this technique since 1998 and it has worked in four plants.
MnO2 works very well indeed, however you need to make sure your pH is > 7.4.
Thank you for all your feedback. I will look into these possible solutions.
Is the treatment biological or physicochemical? You have to treat the iron and the manganese.
Oxidation tank, therefore physical, so watch the pH.
Here in Canada, the ideal treatment method for manganese is ion exchange, because filtration after oxidation requires high pH (+8.2) as well as a prolonged contact time.
The parameter to monitor is the ORP, which should be measured at plant input and output. It regulates precipitation of iron (Fe2+ becomes Fe3+) and manganese. If all the iron (and all the manganese) is not oxidized before filtration, it is inefficient.
Chlorine dioxide reacts with manganese: an avenue worth exploring.
But that depends on your network and your treatment system