Elimination/Reduction of TTHMs
I am looking for a whole-house (POE) filter, and appropriate housing, that would reduce/eliminate TTHMs (Trihalomethanes) in my water in a 2 bathroom house. I understand TTHMs are a by-product of chlorination. My plumber would like to use American Plumber products, if possible. I am also concerned about significant water pressure drop with the use of a filter.
My plumber originally suggested a heavy duty 20” housing with a radial flow/GAC filter (100,000 Gal @ 4gpm, max flow rate 8 gpm). My concern is that the filter has a 25-micron wrap, and I thought the micron would have to be lower to remove TTHMs?? I thought a carbon block filter would work better, but I’m not sure if that is correct?
Help/postings are appreciated.
Use of a carbon filter will be effective for your purpose. The larger the filter, the better the flow rate.
Different carbon filters have varying effects on water. I use a whole house filter but mine is a refillable 20" clear cartridge. I put 2 lbs of KDF-55 in the bottom and fill the rest with GAC. The KDF will remove chlorine at a much great rate than the carbon, This greatly increases the shelf-life of the carbon and lets it do its job more effectively at removing, among other things, TTHMs.
I don't seem to have much noticeable pressure loss as this is a loose media.
Thank you for the quick response. Ok, sounds like the plumber is right on with what he proposed. I am unfamiliar w/KDF, as well as this whole process. So, I want to put 2lbs of KDF-55 in the bottom of the cartridge, and then the rest is GAC? Is that loose or in a filter that fits a 20" housing? Thanks again.
As for recommendations for your water filter. There are a couple of details that should covered. How much chlorine in ppm do you have to treat. What is your hardness, TDS. Make sure the city isn't using chlorimines.
Carbon doesn't remove chlorine as much as it converts to harmless chlorides.
My filter is a smaller than the one that was recommended for you. 10" x 2.5" with 3/4" in-out. If you use the larger on, you may want more KDF-55.
Also, shower filter can be used cheaply and easily. KDF is used here as well because heat doesn't affect it like it would with carbon.
Filterfast may have some suggestions on these filters.
Andy Christensen, CWS
Isn't there a difference between chlorine & TTHM? I thought TTHM was a byproduct of the chlorination process (done by our utility company). If we treat chlorine in our water, will it necessarily treat/remove TTHM? I have tried calling EPA, and I've researched this on the web...I can't seem to understand this issue, and the type of filter that would work for the whole house. I have emailed filtersfast, but any other information would be helpful as I try to navigate this process... Thanks.
THMs are a DBP (disinfection by-product) and studies reveal that and other DBPs are cancer causing agents.
Carbon can significantly remove THMs. There are different types of carbon filters depending on other water conditions and usage.
Does that help you at all?
Thanks, Andy. I think I understand that part. What I can't decide on is the type of whole-house (POE) filter, if one exists, we can use to take care of the TTHM problem. Some folks say a GAC filter will do the trick. Then others, like an email I received from Pentek (which owns American Plumber - the brand we were considering through the plumber) says a POE system will not reduce TTHM because the flow rate would not be slow enough. Instead, we would have to use a POU system w/a slower gpm rate. Then, the salesman for Sharp said they would install a POE system (that wouldn't affect water pressure) with a Calgon F400 filter specifically for TTHM, but when I looked that up, it is a GAC filter. I am finding conflicting information all over the place. The salesman wants to sell a unit. The plumber assumes all GAC is the same (and it may be). I guess that's where I'm at - are GAC filters similar, and if not, what characteristics do I need to look for in a POE GAC filter that will take care of TTHM? Sorry for the rant - I'm having a very difficult time boiling all this down. I appreciate your time. I haven't heard back from filtersfast yet...
I did some research and here is a list of the products we sell that claim to remove TTHM. Unfortunately these are the only products I could recommend for the removal of TTHM because they are the only ones that claim removal. Hope this helps.
Brita On Tap
Thanks, Roxanne. Ok, so my next question is... If we go ahead and pay the plumber to put in a regular GAC whole-house system to take care of color, odor & sediment, and then put in POU filters in the kitchen and showerheads for TTHM, is that really overkill and unnecessary? Is it not a good thing to "over-filter" the water?
There are always ways the SLOW the flow rater to allow sufficient contact time in order to achieve the removal of THMs from you water. So far we have been talking about GAC filters but nothing on size.
If you are using a POE system then consider a 8x48-inch tank containing about 0.7 cuft of carbon. In some cases a 10-x54-inch tank can also be used containing about 1.5 cuft of GAC. A small 2x10-inch refillable cartridge-type filter with KDF-55 can be placed ahead it. This will greatly increase the life of the carbon. These anks can last for years, depending on water conditions and quantity of water used.
These large tanks are just flow through (upflow) tanks and are easily refilled.
As for extra filters on shower heads, this won't hurt and adds an extra level of assurance. Flow will be affected by any device added the plumbing.
Brita, Waterpik and Pur are three most popular faucet-type filters and are certified. Loose media (carbon) and other media are not certified normally because they are sold in bulk and NOT part of a system that can be tested.
Here is a long list of products that remove/reduce THMs
Andy - thanks again - you have been very helpful.