Filtering for iron bacteria with softener

[Rzupancic]

I bought a house with a preexisting softener system and filter. It has two resin tanks I have not been able to identify and a 10” filter on the intake side. It works fine for softening, but we have reoccuring iron bacteria. I shock and it gets better, but always returns. The intake filter was originally a 10 micron spun, I tried a carbon filter with no real change but I recently swapped it for a KDF. It works well and seems to help with the bacteria growth. Unfortunately it only last about 1.5 months before it starts impacting water pressure. I am wondering what would be the most efficient filtering design. My thought is a a spun and/or carbon pre-softener and then the KDF after the softener. Anyone have experience with something similiar? Is it worth the effort to add a filter housing after the softener?

 

[JustaDIYer]

I had iron bacteria at one time. It came from the well, I sanitized it with chlorine tablets. There's procedures to do it on this forum and I'm sure online.

 

[Sponsor]

 

[Reach4]

I shock and it gets better, but always returns. The intake filter was originally a 10 micron spun, I tried a carbon filter with no real change but I recently swapped it for a KDF. It works well and seems to help with the bacteria growth. Unfortunately it only last about 1.5 months before it starts impacting water pressure.

I think a more robust sanitizing will extend the time that the sanitizing/shocking works. https://terrylove.com/forums/index....izing-extra-attention-to-4-inch-casing.65845/ is my write-up for sanitizing. It is more work than most, but I think it is more effective. It is best done in warmer weather, but gathering the materials in advance is good.

I am wondering what would be the most efficient filtering design. My thought is a a spun and/or carbon pre-softener and then the KDF after the softener. Anyone have experience with something similiar? Is it worth the effort to add a filter housing after the softener?

I don't know. Does your KDF filter backwash? A very high rate compared to the cross-sectional area is needed.

 

[Bannerman]

A more effective and reliable method when there is any recurring bacteria issue, will be to treat the water continually as it is being supplied, by injecting chlorine into the supply line after the pressure tank. To extend the time for the chlorine to neutralize the bacteria, a contact tank will often be utilized directly following the injection location.

The injection of chlorine is often accomplished utilizing an injection pump such as made by Stenner, which becomes activated whenever the well pump is operating. The best method will be to control the injection pump with a flow meter, which can permit the injection pump to vary the chlorine feed rate based on the water flow rate passing through the flow meter.

As the food for iron bacteria is ferrous iron (fully dissolved in the water), iron bacteria is commonly called Iron Reducing Bacteria. The presence of IRB will signify some amount of ferrous iron is present. As chlorine is an oxidant which will oxidize ferrous iron, converting it to a ferric state (not dissolved), the resulting ferric debris (aka orange/brown rust) will precipitate out from the water as a sticky sludge.

In speaking with well drillers, I'm told they often find chlorine tablets that were dropped into a well, being wedged between the drop pipe and well casing, so the tablets will not come into contact with the water and will therefore accumulate and will remain ineffective. When a well is much deeper than the pump depth, I'm also told, the tablets will often accumulate undissolved for sometimes years, since the water at the bottom will be excessively cold, and there is often little if any water movement at the well bottom. Water pH will also have a bearing on the effectiveness of chlorine.

Repeatedly adding chlorine into a well will usually cause ferrous iron to be oxidized directly within the well. which will increase the ferric debris at the well bottom, which often results in an eventual rust problem from the water supplied directly from the well. This is why a repeated ongoing iron issue is best treated after the water has exited from the well.

When a contact tank is utilized following chlorine injection, the tank will be best equipped with a conical bottom and a bottom purge valve to periodically allow any ferric accumulation to be easily flushed away to drain.

There are alternate iron filtering methods including backwashing media filter systems such as those containing Katalox Light media. Although the KL media alone will often remedy a ferrous iron issue, when any bacteria is present, then chlorine injection at the entrance to the KL system is the most recommended method, but a KL filter system equipped with an Ozone generator will often be effective.

There are also KL system that utilize air or hydrogen peroxide to supplement oxidization of the ferrous iron before the KL media filters out the solid ferric debris, but because the oxygen will cause bacteria to proliferate, neither air nor peroxide are recommended as either will increase the amount of oxygen, which can cause a bacteria issue to worsen.

Whichever method is chosen, these are usually followed by a backwashing carbon media filter system, to remove any residual chlorine/ozone and many other contaminants, and to filter out ferric iron particles which may exit from the contact tank. A cartridge type filter does not contain much carbon media so the service life will be short and will therefore require frequent replacement, and the effective flow rate will be low, especially for a point-of-entry application. A backwashing media filter such as one containing 1.5 ft3 or more of GAC (granular activated carbon), will effectively remove chlorine, ozone, and many other contaminants for several years, even while supplying reasonable flow rates for point-of-entry applications.

KDF media is extremely heavy. To remain effective, it requires regular backwashing at a high flow rate, to prevent the service flow rate from becoming reduced and for the media to remain effective. Backwashing will cause expansion of the media granules, and will eliminate sediment and debris that has collect within the media granules.

Because the backwash flow rate requirement is governed by the tank diameter, for residential applications, KDF will usually be installed within a 'Media Guard', which is a small diameter, multi section tank which is inserted within the tank opening of a backwashing carbon filtration system or water softener. The water entering that filter or softener, will then first flow through the KDF media before contacting the media below. The filter's or softener's backwash cycle, will then also backwash the KDF media at the same time, but the filter's or softener's drain flow rate will need to be increased above the usual rate, to satisfy the backwash rate required for the KDF Media Guard.

 

[Rzupancic]

A more effective and reliable method when there is any recurring bacteria issue, will be to treat the water continually as it is being supplied, by injecting chlorine into the supply line after the pressure tank. To extend the time for the chlorine to neutralize the bacteria, a contact tank will often be utilized directly following the injection location.

The injection of chlorine is often accomplished utilizing an injection pump such as made by Stenner, which becomes activated whenever the well pump is operating. The best method will be to control the injection pump with a flow meter, which can permit the injection pump to vary the chlorine feed rate based on the water flow rate passing through the flow meter.

As the food for iron bacteria is ferrous iron (fully dissolved in the water), iron bacteria is commonly called Iron Reducing Bacteria. The presence of IRB will signify some amount of ferrous iron is present. As chlorine is an oxidant which will oxidize ferrous iron, converting it to a ferric state (not dissolved), the resulting ferric debris (aka orange/brown rust) will precipitate out from the water as a sticky sludge.

In speaking with well drillers, I'm told they often find chlorine tablets that were dropped into a well, being wedged between the drop pipe and well casing, so the tablets will not come into contact with the water and will therefore accumulate and will remain ineffective. When a well is much deeper than the pump depth, I'm also told, the tablets will often accumulate undissolved for sometimes years, since the water at the bottom will be excessively cold, and there is often little if any water movement at the well bottom. Water pH will also have a bearing on the effectiveness of chlorine.

Repeatedly adding chlorine into a well will usually cause ferrous iron to be oxidized directly within the well. which will increase the ferric debris at the well bottom, which often results in an eventual rust problem from the water supplied directly from the well. This is why a repeated ongoing iron issue is best treated after the water has exited from the well.

When a contact tank is utilized following chlorine injection, the tank will be best equipped with a conical bottom and a bottom purge valve to periodically allow any ferric accumulation to be easily flushed away to drain.

There are alternate iron filtering methods including backwashing media filter systems such as those containing Katalox Light media. Although the KL media alone will often remedy a ferrous iron issue, when any bacteria is present, then chlorine injection at the entrance to the KL system is the most recommended method, but a KL filter system equipped with an Ozone generator will often be effective.

There are also KL system that utilize air or hydrogen peroxide to supplement oxidization of the ferrous iron before the KL media filters out the solid ferric debris, but because the oxygen will cause bacteria to proliferate, neither air nor peroxide are recommended as either will increase the amount of oxygen, which can cause a bacteria issue to worsen.

Whichever method is chosen, these are usually followed by a backwashing carbon media filter system, to remove any residual chlorine/ozone and many other contaminants, and to filter out ferric iron particles which may exit from the contact tank. A cartridge type filter does not contain much carbon media so the service life will be short and will therefore require frequent replacement, and the effective flow rate will be low, especially for a point-of-entry application. A backwashing media filter such as one containing 1.5 ft3 or more of GAC (granular activated carbon), will effectively remove chlorine, ozone, and many other contaminants for several years, even while supplying reasonable flow rates for point-of-entry applications.

KDF media is extremely heavy. To remain effective, it requires regular backwashing at a high flow rate, to prevent the service flow rate from becoming reduced and for the media to remain effective. Backwashing will cause expansion of the media granules, and will eliminate sediment and debris that has collect within the media granules.

Because the backwash flow rate requirement is governed by the tank diameter, for residential applications, KDF will usually be installed within a 'Media Guard', which is a small diameter, multi section tank which is inserted within the tank opening of a backwashing carbon filtration system or water softener. The water entering that filter or softener, will then first flow through the KDF media before contacting the media below. The filter's or softener's backwash cycle, will then also backwash the KDF media at the same time, but the filter's or softener's drain flow rate will need to be increased above the usual rate, to satisfy the backwash rate required for the KDF Media Guard.

Thanks for the great feedback Reach4 and Bannerman. Bannerman, would an all in one like this be effective if added before my softener: https://www.cwts.ca/products/whole-...ox-light®-filter-media?variant=39271972732998
Or is there any specific equipment you would recommend?