floculant in drinking water

[aussieta]

in melbourne, australia, we have had a very funky storm last week
it dropped an incredibly fine red dust into all the swimming pols in the metro area
it passed straight though sand filter with glass media and cartridge filters
clarifiers or floculants were the only remedy
unfortunately the tank water has also been contaminated
this dust just will not settle on its own,
one unused horse trough is still completely cloudy
i am thinking to add a small amount of floculant to the tank water
will this still be safe to drink
ingredient is poly aluminium chloride complex
msds https://cdn.shopify.com/s/files/1/0148/2240/8246/files/Clark-Rubber-Filtrite-Supa-Floc-203.pdf
thanks, andrew

 

[AUSpool]

Alum is one of the floculants of choice in commercial treatment plants but it is managed through multiple settling tanks. If adding it to a tank I think one of your problems will be mixing it and the risk of stirring up the existing gunk of the bottom. If you rang the LoClor customer info number I guess their response would be no. From their perspective its not formulated for potable water.

 

[setsailsoon]

Aussietta,

In my former life I ran a small water treating facility at a large chemical plant complex. We had upsets occasionally that caused a similar problem. In those days alum was acceptable for water treating so long as we used it within specified limits. If the manufacturer doesn't recommed for potable water see if they can help you find some rated for potable water. It worked very well but will almost certainly plug your pool filter equipment and require a media change. We had large clarifiers and pumped most of the used floc from the bottom of the tank. But we still had problems with the finishing filters for the next couple of weeks. We used bottled water in the offices etc just as a precaution until the treatment was complete. If it were me, I'd add a small under sink RO unit for long term. They're around $200 in the US and extremely easy to install. They remove literally everything bad including all but the smallest virus particles. We've been using them for years at our home and when we lived on a boat for about 6 years. Membranes last at least 5 years and we just do an annual change of the particle filters.

I hope this helps.

Chris

 

[JoyfulNoise]

A large spun cotton or polypropylene cartridge filter rated for 5 microns or smaller should be able to capture and remove most of the particulate matter. Rarely do physical particulates from dust and combustion (from the wildfires no doubt) generate particles smaller than that. You could also treat with a GAC (granulated activated charcoal) filter to help remove any heavy metals or organic compounds.

Treating potable water with a floc is not easy without the right tanks and equipment. And no, polyaluminum chloride is not good for you. It can leave aluminum metal compound behind if not used properly and it will increase the chloride content of the water. Ferric alums are better suited for water treatment but must be used within their proper limits.

 

[aussieta]

thanks all for your insight

 

[AusPhil]

A large spun cotton or polypropylene cartridge filter rated for 5 microns or smaller should be able to capture and remove most of the particulate matter. Rarely do physical particulates from dust and combustion (from the wildfires no doubt) generate particles smaller than that. You could also treat with a GAC (granulated activated charcoal) filter to help remove any heavy metals or organic compounds.

I couldn't find any data yet on the current dust storms but i did find data for the same type of red dust storm the blanketed Sydney in 2009, the analysis of the particulate sizing had distinct peaks at 0.6, 4.5, 10 and 20 um. Extremely high levels of particulate matter were recorded, with daily average levels of coarse matter (<10 μm) peaking over 11,000 μg/m3 and fine (<2.5 μm) over 1,600 μg/m3
CSIRO article on the sizes -> Unusual Sydney dust storm and its mineralogical and organic characteristics

It's the fine stuff that ultimately suspends in the water, colours it red/brown and is near impossible to filter out of you pool and water tank.

 

[AUSpool]

I don’t think I’ve actually needed it but I’ve always use filters for our drinking water. A pre filter followed by a carbon block filter. The last ones I used were both 0.5micron. 0.5micron is maybe a bit much for both and think I’ll do a 5micron pre filter followed by a 0.5micron carbon next. With at least one at 0.5 micron you protect against cryptosporidium and Guardia which is good if your on tank supply. I’ve used a few cheaper filters but now use Pentek exclusively, I just get better, consistent results with pentek.