Thanks, Andy, for your reply.
I have a new well with a Manganese (Mn) problem.
It's 100' deep and flows 15 GPM. The well pump - Goulds 5GS series w/ 3/4 HP motor - needs to pump to a 2500 G storage tank which is 110' higher than the wellhead. Add to that the 40' pump depth makes a total lift of 150'. My actual water usage at this point is very low - approx 80G / WEEK. (Probably best to double or triple that usage estimate once I no longer have to carry my water)
I had the water tested and these are the problem areas:
<> Iron (Fe) = 0.83 mg/L - 2.7x limit
<> Mn = 0.5 mg/L - 10x limit
<> ph = 6.3
<> hardness =130 mg/L - (or 7.6 grains)
<> DO is assumed to be low as it's coming up from 100'
My goals are:
<> to get the Fe & Mn down to unnoticeable levels - no stains and no taste problems (and I have no idea what those #'s would be) (I'm not going to worry about the hardness at this point unless it were somehow integrated into the Fe / Mn system)
<> Do this while avoiding objectionable chemicals like chlorine & potassium permaganate.
<> Keep the project as simple & reliable as possible and spend no more than necessary.
Because the water is going to sit in a storage tank where it'll be exposed to the atmosphere for the first time I want to get the Fe & Mn out of the water *before* it hits the tank. So I plan to do the filtering right after the wellhead. My question is what type of Fe/Mn removal system to use. I've done a bunch of reading but when I start talking to suppliers I get very conflicting advice. The problem is obviously the Mn. As I understand it Mn would ideally like to see a ph level of 9.0 to 9.5 in order to ionize readily. (But if the ph is over 8.5 then supposedly there's a risk of the Fe turning into a colloidal state)
Here's what's been suggested so far:
(1) A 1/2 or 3/4 cu ft Filox / Catalox tank
PROs: Most effective media w/o using nasty chemicals. Long media life. Supposedly will remove up to 3.0 mg/L Mn - but no mention of at what ph levels
CONs: requires a high backwash rate (but my pump can handle that - 7 GPM @ 50PSI) But just how effective can this be on Mn removal if the ph is still sub 7 and the DO is still low?
Planning on using a 1.5 GPM Dole valve on the output of this tank to slow down the flow through the tank and double the contact time. Any thoughts on what this would do to the effectiveness of this system?
(2) Filox / Catalox tank w/ hydrogen peroxide (H2O2) injected upstream (w/o a separate mixing tank) to boost oxygen levels. My question here is can I be sure the H2O2 is completely broken down & gone by the time I drink the water? What breaks down the H2O2? And will oxygen do the job if the ph is still low?
(3) A "mixed media" / Air tank w/ Birm & Calcite This uses a Fleck 7000 valve which traps an air pocket in the tank and then the incoming water picks up *some* oxygen passing through the air pocket. Then the Calcite raises the ph level and the Brim supposedly ionizes the Fe / Mn w/ the aid of the elevated ph levels. (Birm is used here because Filox would never backwash effectively w/ the added weight of the Calcite in the tank.)
I'm pretty skeptical of this one. IE: how much is the ph raised? How do you adjust the ph level - add more Calcite? And how much can the DO level actually be raised by falling through an air pocket? Birm has a much shorter life than Filox and is less effective - used here only because of the backwash problem. And when you're all done your high levels of hardness are even higher.
I'd very much appreciate hearing the thoughts of any of you who have had experience w/ these or similar systems. Thanks.
Thanks, Andy, for your reply.
I have a little iron, enough maganese, and way too much hydrogen sulfide. The next approach here is to use a diaphragm air pump to pump air through an ozone generator into the holding tank (1000 gal) 24 hours a day. Then the pressure pump (30/50) 'sucks' the water out and sends it through a sand filter on the way to the house.
I've had a couple ozone generators from Enaly; each failed within a year. A local aquarium guy suggested the Ultralife 360 from ultralifedirect.com, for about $320. That will be my next try.
My diaphram pump is a Whitewater LT11 Linear Air pump - very reliable for 2 years now. The energy usage is too low to care about. Without the ozone generator, I'm just blowing air into the tank right now, 24 hours a day. It's doing well.
The sand filter is old iron filter, but filled with sand instead of some media. It includes a manual backflush capability.
My neighbors and I have tried a variety of systems of the years, including blowers and media filters. I had ozone for about a year; that was the best. It seems to cure the manganese and iron as well, but I don't know the mechanism. My best guess is it oxidizes both into a solid particle which is filtered out by the sand filter.