Sand/Pyrolusite filtration 1

[davidet68]

I'm suppling filter which have as media a mix of quartz sand and pyrolusite. The pyrolusite supplier says that pyrolusite and sand will remain well mixed during backwashing because they have similar specific weight and granulometry. But I understood that pyrolusite worn out. Do pyrolusite reduce his granulometry? And what happen in this case? Will pyrolusite form a layer diveded from sand? I have to replace the media or can I add pyrolusite? And how can I mix the added pyrolusite with the rest of the media?

Thank you!

 

[semo]

Depending on the media size and uniformity coefficient, it should stay mixed. I've used it in numerous filters with silica sand. Many up to 10 yrs old now and not showing any loss of media due to fracturing. In fact, I've seen some conventional sand/anthracite plants that generated a Manganese Dioxide coating on the media over the years. These plants used aeration followed by sedimentation and chlorine as the oxidant prior to filtration.

If the pyrolusite is lost, you should be able to add additional media on the filter prior to a backwash. When backwashed, it should settle into its respective zone. The same can be said for adding sand or anthracite to a dual media filter.