How to choose the Right Water Purifier and Replace your RO

Here is the research I have done to get out of RO. I am no expert and I have tried to put it out in layman terms.

RO water leads to health issues, as it has no minerals. There is plenty of material online on this. RO is used for TDS greater than 900 ppm .

Where I live, with my TDS meter I have measured that I get an average TDS of 150 to 220 ppm on most days and it goes up to 600 ppm when tanker water is supplied.

Note that we can consume water with TDS till 300 ppm and after RO I get a TDS of 10 which is really too low and not good.

The Purifiers with TDS controller don't make sense to me  as they just mix untreated water with RO water to get the TDS . Why reduce the TDS by RO in the first place , if you don't need to.  

You might be able to convert your current RO machine to a non RO ( UF or NF) machine changing the inside membranes and cartridges.

I have tried to explain the below test in the Video too .

How to choose a water purifier , How RO works and How to Replace RO with UF +UV

Now which filter to use ? For that lets have a water purification crash course.

Water filtration has 3 main stages Pre, Actual and Post

For the a actual filtration we have 3 main choices Ultra , Nano and RO (Reverse Osmosis) . This is in sequence of their filtration strength. 

An ultrafiltration filter has a pore size around 0.01 micron. ( pore mean holes - 'Chalani' in Hindi or a water sieve )  to let the water pass through , Nano even shorter ( 0.0001 micron) and RO even shorter (0.0001 micron.) . So that’s how they filter. 

Ultrafiltration removes bacteria, protozoa and some viruses from the water. 

Nanofiltration removes these microbes, as well as most natural organic matter and some natural minerals, especially divalent ions which cause hard water. Nanofiltration, however, does not remove dissolved compounds. 

Reverse osmosis (RO) removes turbidity, including microbes and virtually all dissolved substances. However, while reverse osmosis removes many harmful minerals, such as salt and lead, it also removes some healthy minerals, such as calcium and magnesium.

RO pores are so small that some of the other water is not able to pass through and that is what leads to the waste water line. UF and NF don’t have the waste water line as their pores are bigger.

So when the TDS is maxed out (like above 500 ppm ) in your apartment, the most you need is Nano Filter not RO. If your TDS is above 900 then you need an RO . 

UF will not reduce TDS , NF will reduce TDS a bit and RO will reduce TDS drastically .

So this is sequence your tap water needs to go for filtration .

If my TDS is till 300 ppm

Spun  -- > carbon -- > sediment -- > UF  -- > UV - > done

If my TDS is from 300 to 900 ppm

Spun  -- > carbon -- > sediment -- > NF  -- > UV - > done

All the above stages are implemented by a membrane or a cartridge .

Here is the mapping of the stages Vs cartridge(s) that you will need 

Pre Filtration

1>Spurn Filter

This is like a sponge. Mud and harmful metals like arsenic, mercury which are found in small traces are filtered with the Spun Filter.

2>Carbon Filter 

Activated Carbon Filtration removes chlorine, organic chemicals such as pesticides, THMs like chloroform, and many VOCs (common ground-water contaminants.) that are components of gasoline, solvents and industrial cleaners. 

3>Sediment Filter

 A sediment filter acts as a barrier against different types of sediments or suspended solids. It sieves or holds back physical impurities like dust, dirt, sand, silt, clay, and other solid particles. Mostly the particles that are visible to the naked eye are treated by sediment filters during the process of water purification.

Actual Filtration

4>Ultra Filter / Nano Filter

           Based on pores filter the water.

Post Filtration

5>Ultra Violet (UV)

After filtration ultra violet rays send by the UV light kill pathogens ( bacteria virus, or other microorganism that can cause disease) . But an important thing is to use a stainless steel chamber for the water to pass when UV lights hit them .

I checked specifically with Kent and AO Smith they use aluminum and not stainless steel. So I had to look for a local vendor for this and I finally found one . Link below

Now about Converting my RO filter to UF or  NF  + UV :-

I have a filter that is about 12 years old and it has its default cartridges/ membranes that that company provides. RO is just a membrane inside the filter, I can ask the same company to give me the specific membranes that I want.

So my plan is that when my TDS is 600 ppm then I will use NF and when my TDS is till 400 I will use UF . I plan to do it manually by replacing the UF / NF filter .

I found a company is Mumbai which has all the membranes and parts and has the support system in Bangalore to implement it .

And because I don’t want to be dependent on other to service my purifier I will try to do this setup on my own .

Part details :-

All parts I could find here . I am going to try their parts the 1^st time .

https://www.itpl.online/index.php/domestic-products/quality-spare-parts

Pre Filtration

1.     Spun Filter Set

https://www.itpl.online/index.php/product/10-pre-filter-set

 

2.     Carbon Filter

https://www.itpl.online/index.php/product/inline-carbon-filter

3.     Sediment Filter

https://www.itpl.online/index.php/product/inline-sediment-filter

Actual Filtration

4.     Membrane Housing, then will be the home of either UF or NF membrane

 https://www.itpl.online/index.php/product/membrane-housing

 

In this housing we will put either 6 UF when (TDS is less than 300 ) or 7 when (TDS is greater than 400 )

 

 UF Membrane

 https://www.itpl.online/index.php/product/uf-membrane

OR

 NF Membrane

https://www.itpl.online/index.php/product/nf-membrane-60-

 

Post Filtration

5.      Ultra Violet Chamber:-

SS 304 UV Chamber with 11 watts lamp

https://www.itpl.online/index.php/product/ss-304-uv-chamber-with-11-watts-lamp

With

24 DC UV Ballast

https://www.itpl.online/index.php/product/24-dc-uv-ballast

For this Ballast . I took 24 volts input from the AC to DC Adaptor . The wiring of the Ballast to the UV Chamber needs certain specific things . I have mentioned it below .

One side of the Ballast , the red and black wire , connects to the DC input. The other end has 4 wires . Two set of them have a yellow strip the other two don't have that yellow strip.

The UV chamber has 4 wires coming out representing the two sides of the UV tube. Two in each end.

So we connect one of the Yellow end of the ballast to one the yellow connector (L2 ) of UV .

The next joined to this end of the ballast goes to L1 ( Red) 

The other Yellow end of the ballast connects to one the green connector (L3 ) of UV .

The next joined end connects to  blue connector (L4) of UV 

 Hope this information helps 

Update:- 

Success !! , I was able to do the changes as I had planned above . My Video below explains it .

How I converted RO Purifier to UF + UV

If you have an RO or a NF unit then there will be a lot of waste water generation that is let out in the drain by theses filters. You can re-use this water with some simple plumbing.  Here is a Video on how I have put up a tank.

How to utilize the Water filter's waste water