Iron & Manganese Removal Guide
Iron & Manganese Removal Guide
Iron can be a pain when it’s present in your water supply. Iron has a tendency to hang around after water evaporates, leaving unsightly red-brown markings, not dissimilar to rust. If you’ve ever looked in your bath and seen a brown streak or stain, then it could mean you have high iron content in your water.
Similarly, manganese leaves black marks wherever it can be found. This can look particularly foul around taps, in baths and sinks, toilet bowls and so on.
There are several different products on the market that are all designed with the removal of iron and/or manganese from water. Which one should you use? How are they different? This guide goes into some detail on the various options available and will hopefully make you a little wiser on which product is best suited to the job.
We start with Ecomix, the iron and manganese all-in-one treatment media blend, which also softens the water. Ecomix comes in a few different forms, however we’ll mostly be concentrating on Ecomix-A today.
Ecomix-A is a homogenous blend of five different medias and ion-exchange resins. It has several advantages over the other iron & manganese removal medias, the most important being that it is exceptionally reliable in removing manganese up to 3ppm (parts per million) with no other chemicals required and over a wide pH range of 5.0 to 9.0.
Ecomix-A also removes Iron up to 15ppm, reduces hardness in the water up to 750ppm, and can treat Ammonia (reductions up to 4ppm). Ecomix-A has also proven beneficial in reducing organics in the water as well. Finally, you’re looking at a lower backwash flow rate than you would typically expect from other medias (its about half the service flow rate).
Finally, Ecomix-A uses regular softener salt for regeneration.
For those looking for a more lightweight solution, there’s also Ecomix-P. This blend does not offer the Ammonia reduction properties, but is otherwise similar to Ecomix-A, just at a reduced cost. Handy, if Ammonia is not a factor in your water supply.
When is it useful?
If you have both iron and manganese in your water, then Ecomix is the ideal solution. It’ll treat both and it’ll soften the water as well (not to mention the additional ammonia reduction capabilities). All this and you just need to buy Ecomix – no need to buy two different filter medias to treat the varying contaminants like with other systems, or run it alongside a water softener to treat hardness, as it already does that too.
Pyrolox & Filox
Both Pyrolox and Filox are essentially the same but have different trade names. They are iron, manganese and hydrogen sulphide removal medias. Both work by oxidising the iron and manganese, which means the iron and manganese need to be in their dissolved states. For manganese removal, this isn’t an issue as manganese almost always is in its dissolved state, however iron can prove more problematic.
Quick science lesson now, iron and manganese in water is often found in the following common forms; dissolved, suspended, organic and colloidal. For the most part, you would expect iron & manganese to be dissolved into the water, however suspended or colloidal iron (microscopic insoluble particles of iron that are “suspended” in the water) is also quite common. Oxidisation requires iron and manganese to be dissolved, so that the oxidisation process is actually possible.
In the case that the water has a low redox potential (eg: not much oxygen in it), then it may be necessary to introduce an oxidant to the water before it reaches the Pyrolox/Filox media. The most common oxidant for this job would be chlorine, although air can be used to a lesser effect.
It is advised to backwash Pyrolox/Filox every day. Due to their high specific gravity and bulk density they do require high backwash flow rates, which means that the borehole pump capability should be fully known before installation. If it does not produce the required volume then either two smaller vessels should be used or a “clean water” backwash should be considered.
When is it useful?
For oxidised iron contamination, Pyrolox and Filox are good choices. In the event that the iron isn’t oxidised, then further pre-treatment in the form of an oxidant is required, as mentioned, so this is worth keeping in mind.
Manganese remains a difficult mineral to remove even when all the parameters are met and more so when the manganese level is high and the iron level is low or when the iron to manganese proportions are equal to or are approaching each other. For high levels of iron and low levels of manganese however, Pyrolox/Filox works just fine.
BIRM, Pyrolox Advantage & Katalox Light
BIRM is an acronym for Burgess Iron Removal Media, whilst Pyrolox Advantage and Katalox Light are trade names. All are similar in that they are manganese ore with slightly differing coatings (such as silica sand in slurry form and fast dried). As they are alike, they have very similar operating parameters and limitations.
BIRM has a quoted operating pH range from 6.8 to 9.0. However, to have any chance of removing manganese, the pH needs to be between 8.0 – 9.0.
But, to be effective against iron the pH should be below 8.5. This gives a very tight operating range between 8.0-8.5, most UK water sources are either acidic or neutral (pH 7.0 or below), which means that the pH will need to be raised and controlled. In raising the pH it is very likely that iron will precipitate (fall out of solution) and can quite easily block the pH correction media.
All the medias are coated which means that they do not like a vigorous backwash as the attrition caused will remove the coating which may cause an increase in manganese rather than a decrease. Due to this attrition, the life time of the media is severely reduced.
None of the medias are good with any additional chemical such as chlorine (which is often used to help with oxidation) as this can have the effect of breaking down the coatings used.
When is it useful?
Honestly, it’s less useful than the other medias that we’ve highlighted above. These sorts of products have largely been left behind by Pyrolox and Ecomix. However, with the correct pH, and in some systems, BIRM etc. may still be required.
Need More Help or Advice?
One final note. Turbidity is it’s own beast, and all the above medias will require the use of Filter Ag+ (turbidity media) upstream if there is turbidity or iron in suspension (already precipitated).
This guide covers the main operations and points of the various medias on offer. However, as with all things, you may have more specific queries, or unique issues with your water supply. We’re always glad to help so if you’ve got any questions or enquiries, then feel free to pop them over to us and we’ll do what we can to help.
You can contact us by sending us a message (Click here), or alternatively give us a call on 01538 399 048.