CR4 - The Engineer's Place for News and Discussion ®
Login | Register for Engineering Community (CR4)


Previous in Forum: Ransomware 2017   Next in Forum: Fridge Powered by Rubberbands
Close
Close
Close
12 comments
Guru

Join Date: Aug 2012
Posts: 1547
Good Answers: 26

Home Water Filtration Systems--Which Is Better?

02/26/2017 9:22 PM

I am getting ready to replace our old RO water filtration system in our kitchen. I ran a TDS test on our old system and the TDS are only slightly lower than our tap water - tells me that the RO isn't working. The water also doesn't have that nice clean feel or taste, like it did a short time ago. The tank also isn't holding as much water as it did before and the faucet is looking old, so it's time for a new system.

I actually bought another RO system, but my concern is that it'll waste a lot of water. I may return the RO system and buy a non-RO system. I did some digging and I found a non-RO system that looks pretty good, but I'm not an expert on water filtration, so I don't know which is better.

Here's some info on our household. We go through about 1 gallon of filtered water a day. A must is for the filter to be able to provide water that is free of "unhealthy" things and also to have a good taste. Finally, we want to be good to the environment, so using less water is an important consideration (though not a deal breaker). I also don't want the system to use much electricity, or none at all (no distillation systems).

Here is the information on the non-RO system I like. https://www.pelicanwater.com/pdf/PDF-1000VF_PDS.pdf

Here is the information on the RO system I bought, but haven't installed. http://products.geappliances.com/appliance/gea-specs/GXRM10RBL

Someone told me that I should install the non-RO system in front of the RO system - he said that would provide the best water filtration. Someone else told me that would be overkill and the RO is the only one I need.

I appreciate any advice. I'd like to install the system next weekend.

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 16895
Good Answers: 963
#1

Re: Home water filtration systems - which is better

02/27/2017 2:20 AM

When considering a water filter system, it's important to know what you are targeting for removal, and the cost of the maintenance on the system....This then requires a comprehensive water test to begin with, and identification of contaminants to be removed or reduced, and levels acceptable.... Community water systems providing water to 100,000 or more people must post the reports online....

I use a Culligan faucet mounted activated charcoal type filter to remove chlorine taste...

http://www.consumerreports.org/cro/water-filters/buying-guide

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply Score 1 for Good Answer
Power-User

Join Date: Mar 2011
Posts: 154
Good Answers: 8
#2

Re: Home water filtration systems - which is better

02/27/2017 8:25 AM

The better the filtration before the RO, the longer the RO will perform properly. It will make the expensive RO filter last longer.

Register to Reply Score 1 for Good Answer
2
Guru

Join Date: Apr 2008
Location: Chicago
Posts: 1753
Good Answers: 58
#3

Re: Home Water Filtration Systems--Which Is Better?

02/27/2017 3:48 PM

I recommend purchasing a small whole house cartridge system and plumbing it into your cold water tap at the kitchen sink. It will filter 10,000 plus gallons at full pressure for months on end at the lowest cost possible.

__________________
I bring out your wurst
Register to Reply Good Answer (Score 2)
Guru

Join Date: Aug 2012
Posts: 924
Good Answers: 80
#4

Re: Home Water Filtration Systems--Which Is Better?

02/27/2017 11:00 PM

Got to figure out what you want!

The non-Ro unit will not reduce TDS. Question is, is TDS reduction your goal? Or is it a concern of water quality (pathogen reduction etc.).? It may make a difference in taste.

Household RO sysytems aren't typically too expensive, but they do require maintenance- basically filter replacement. most have at least 2 prefilters, then the RO membrane and often a polishing filter that may also filter water from the pressure tank (as this can be breeding ground for bacteria!). If the prefilters load up they will slow throughput, also the last one is usually a carbon filter that removes chlorine (which can eat a thin film RO membrane). They usually have to be replaced a couple times before the membrane is shot.

I wouldn't bother putting the other one before an RO. It's not going to make an effective difference to the critical parameters for the RO. In industry, water purification and usage savings are mainly from multi pass RO and de-ionization polishing, RO is normally considered an initial step after sediment removal and normal filtration.

Register to Reply Score 1 for Good Answer
Commentator

Join Date: Nov 2015
Location: England
Posts: 83
Good Answers: 1
#5

Re: Home Water Filtration Systems--Which Is Better?

02/28/2017 4:42 AM

Good filtering will ensure longer RO membrane life, so yes putting one before the other may help extend useful working life, carbon filters are better for chlorine removal, though bacterial infection post carbon can be an issue.

We have a 100,000 L/day system at work and the pre-pre filters last 2-3 months when supplier is on borehole supply, and 2-3 weeks on abstracted river water, this is from a city wide potable water supply, the carbon filters similarly are shorter life on abstracted water, due to the very heavy chlorination.

So I'd opt for both in series, with one caveat, you've going to need to maintain and sterilise regularly to keep things safe, if it's only a 'taste' issue the tap type filters as suggested by SolarEagle are a better idea.

Register to Reply Score 1 for Good Answer
Guru

Join Date: Apr 2008
Location: Chicago
Posts: 1753
Good Answers: 58
#6

Re: Home Water Filtration Systems--Which Is Better?

02/28/2017 8:22 AM

If you want to cook, make coffee tea. etc. with clean tasting well filtered and fresh water the little tap based systems are woefully inadequate.

More than one filter type can be ganged into a setup like this one for pennies.

Solar.. I'd give this a strong consideration next time you're at the tap. You need to set a timer to get a potful of water from those little ones on the tap head.

The big filters cost less and will filter 10-40K gallons over 2/400G for the one on the tap.

__________________
I bring out your wurst
Register to Reply Score 1 for Good Answer
Guru

Join Date: Apr 2008
Location: Chicago
Posts: 1753
Good Answers: 58
#7
In reply to #6

Re: Home Water Filtration Systems--Which Is Better?

02/28/2017 9:52 AM

oops! forgot a pic.

add valves before and after for changing the filter.

__________________
I bring out your wurst
Register to Reply Score 1 for Good Answer
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 16895
Good Answers: 963
#10
In reply to #6

Re: Home Water Filtration Systems--Which Is Better?

03/03/2017 2:20 AM

I'm in no hurry....I've used these for years, they work well and are cheap....Adequate for drinking water and coffee....I pre-fill plastic water bottles and keep them in the refrigerator, after a drink, a quick top-off and bottle switch = constant cold water supply with minimum refill time....no more than three seconds...coffee pot maybe 20 seconds for 6 cups....Takes that long to grind the beans anyway....

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply Score 1 for Good Answer
Guru

Join Date: Apr 2008
Location: Chicago
Posts: 1753
Good Answers: 58
#11
In reply to #10

Re: Home Water Filtration Systems--Which Is Better?

03/03/2017 4:51 PM

You're grinding the beans!?

__________________
I bring out your wurst
Register to Reply
Associate

Join Date: Dec 2014
Posts: 32
Good Answers: 2
#8

Re: Home Water Filtration Systems--Which Is Better?

02/28/2017 10:27 AM

If you look over your water provider's periodic analysis reports, you will see halogenated hydrocarbons in ppm. There are other minor players as well that can be of concern. Some of these are as a result of the treatment chemicals added for sanitation required by law, others to balance water chemistry. Chloromethanes and fluoromethanes are examples. Some are potential carcinogens, but provide healthy water. These can be removed at the point of consumption by a good RO system.

I have had a good RO system for 10 years. My experience tells me that a whole house pre filter will save some money and aggravation. Our municipal system has frequent roily water incidents that necessitate changing the filters. Using a whole house filter will protect the appliances in your home as well as the RO system, saving money and effort. As far as a good RO system, my experience is to have one that has a 10 micron sediment filter, a primary activated carbon filter, an RO filter that has a capacity about twice the gpd that you think you will need, then a secondary activated charcoal filter, finally storage tank 1.5 x the amount you think you will need. I upgraded my system recently for extra volume and have been happy. Above all else, follow meticulously the installation and maintenance instructions.

Register to Reply Score 1 for Good Answer
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 25644
Good Answers: 673
#9

Re: Home Water Filtration Systems--Which Is Better?

03/01/2017 11:58 AM

There is always a side-stream in any separation process, as what is wanted is extracted from what isn't.

  • Filtration will remove Total Settleable Solids [TSS] - "particulates". It will do nothing for TDS⇓. Whole-house cartridge filters do not in themselves consume power, though the pressure drop through it will introduce a little additional electrical load onto domestic pumping loads for private supplies, which is trivial in comparison to other costs. The waste stream is a sludge, which leaves when the cartridges are changed.
  • Reverse Osmosis [RO] will reduce Total Dissolved Solids [TDS] - the ionic species present. It will do nothing for TSS⇑. RO is likely to respond badly to TSS in the form of persistent membrane fouling and, for that reason, filtration is carried out upstream of RO. Sometimes anti-foulant materials are injected upstream of an RO unit, depending on the water quality being treated. The only reason to use RO in water for consumption is to reduce TSS to, or below, the criterion for World Health Organisation guidelines for potable water, the quantities for which can be found using an internet search engine. RO consumes electrical power in the order of 0.5-2kWh per tonne delivered on non-sea sources and up to 5kWh/t on seawater; for that reason major municipal and marine installations use "pressure exchanger" equipment to reduce the overall kWh/t. RO systems need to be kept running continuously for best results as start-up and shut-down needs to be done according to a sequence. RO is used in specialised applications such as converting seawater into potable water both on land and on vessels and drilling platforms. There is always a continuous RO waste stream, usually labelled the "reject".
  • Activated carbon [AC] will reduce odour and taste issues. It can be thought of as carrying out a catalytic combustion of the organic odour and taste substances that may be present. However AC also removes free chlorine, which is usually introduced into municipal supplies at the water works to prevent bacteria growing in the distribution system downstream of the works, thereby removing the bacterial resilience from that point downstream of the AC. Therefore water that has passed through an AC unit needs to be consumed immediately, and not stored. AC responds badly to TSS in the form of cartridge fouling, and therefore TSS filtration needs to take place upstream. AC cartridges do not in themselves consume power, though in the case of private supplies the pressure drop through them introduces a little in the way of electrical load, which is trivial in the context of other operating costs. The waste stream is usually a biofilm, which leaves with the cartridge upon changing.
  • Once bacterial resilience has been lost, or if bacterial resilience in the form of free chlorine has not been provided at the supply source, bacterial protection can be effected using ultraviolet light [UV] equipment. However, UV responds badly to TSS in the form of fouling of the glass elements, reducing effectiveness, and therefore TSS filtration is normally carried out upstream. An UV will consume typically 60-80W continuously whether the water is being drawn or not. Water that has passed through an UV unit needs to be consumed immediately, and not stored. There is no waste stream, as the product water will contain dead and deactivated bacteria, which are generally safe to consume.

So it depends upon what the issue is with the incoming water as to the treatment solution(s) to be applied to it. There is no hint as to what the issue is within the original post apart from taste and odour issues, so the above needs to be considered as suitable treatment methods for whatever might be causing the distress.

<...a non-RO system...> This term is meaningless in the context of the above.

  • Municipal tap water in most developed countries is usually safe to drink from the faucet without further intervention. In that context, retail bottled water for consumption can be considered a confidence trick.
  • Private supplies in most developed countries are different, and a minimum of TSS filtration and UV zapping should be considered the norm. In the UK, private supplies are assessed by the Local Authority every 5 years and this body will advise on any treatment recommendations once a full analysis of the sampled water is to hand. Once a private supply is properly managed, retail bottled water for consumption can be considered a confidence trick.
  • Where the above cannot be assured, retail bottled water for consumption is usually a wise precaution.
__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply Score 1 for Good Answer
Guru

Join Date: Aug 2012
Posts: 1547
Good Answers: 26
#12

Re: Home Water Filtration Systems--Which Is Better?

03/03/2017 11:18 PM

Our water company tells us that we have a " safe" amount of arsenic in our water. There's also small amounts of other things that are questionable, however it's below the EPA threshold so we're not suppose to be concerned.

I'm not an expert so I can only use my understanding of chemistry and some common sense, which tells me to filter my drinking water.I chose to err on the side of caution.

Heck, I'm getting older and I need too consider my health.

Register to Reply
Register to Reply 12 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Autobroker (1); harley (1); JE in Chicago (4); JNB (1); Neiljohn (1); Petor2 (1); PWSlack (1); SolarEagle (2)

Previous in Forum: Ransomware 2017   Next in Forum: Fridge Powered by Rubberbands

Advertisement