Best RO setup

[Tim]

Hi everyone,

I'm looking into making my own water again, i'm now on a water meter so just need some advise on whats the most cost effective setup.

TDS reading: 300-350

Yearly usage of pure: 50,000lts

Water pressure: unknown

Water production rate: at least 900lts in 24 hours.

any help would be great!

 

[spruce]

You only use about 190 liters of water a day. Why do you want to produce water so fast?

Did you get an IBC tank you advertised for a couple of years ago? Have you got storage space, ie. garage or shed?

One of the lads on the other forum has WP of 80psi in Bristol - don't know where he is though. Others are reporting around 65psi in the same place (Bristol.)

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[Tim]

I'm using about 400-550lts day. i will a have a static tank in the garden.

i want just know what the best RO unite to go for, as I'm going to be on a water meter, so i want a RO setup that doesn't waste loads of water.

i was using a 4021 RO before but the wastage was high around 2 parts waste to one part pure water. i would be happy with a 1 to 1 ratio.

do i go with a two 4021 RO which i've been told will give me a 1 to 1 ratio

or do i go for one the of these small RO units that 2-3 small RO and just replace them more often?

 

[spruce]

I'm using about 400-550lts day. i will a have a static tank in the garden.
i want just know what the best RO unite to go for, as I'm going to be on a water meter, so i want a RO setup that doesn't waste loads of water.

i was using a 4021 RO before but the wastage was high around 2 parts waste to one part pure water. i would be happy with a 1 to 1 ratio.

do i go with a two 4021 RO which i've been told will give me a 1 to 1 ratio

or do i go for one the of these small RO units that 2-3 small RO and just replace them more often?

This is something only you can decide.

I definitely wouldn't go for a twin 4021 setup but that's me. I guessing that the reason why this suggestion was made is that waste from the first r/o is feed into the second r/o which will reduce water usage. But it will also mean that the second r/o in line will have very high tds water going through it which it will reduce its life span. You will end up with one membrane needing replacement and the other 'half used'.

Replacing 2 x 4021 membranes will be more expensive than a single 4040.

A 4040 and well as a 4021 can be throttled back to give a 1 : 1 waste to pure ratio, but it could also mean that membranes will need replacing a little more often. (What's more often? Sorry, I haven't an answer to that one.) Throttling back your waste could mean that your r/o isn't operating at its best so you will have to compensate with a higher resin spend to polish that water off. Its all about getting the financial balance right.

A single 4021 will give you more than enough water per day. It will produce water fairly quickly when compared to smaller units so you will need to fit a water control that will switch the r/o off automatically when you are out.

IMHO a 450GPD will give you sufficient water for your daily requirements, but you won't have much left for growth, ie second user, especially in winter. (But you are in the enviable position of being able to buy water locally if you get short.) Again you can get a ball valve or gate valve on the waste and throttle the waste back to 1:1, but again your membranes will need to be replaced more often.

If you are going to have a tank in the garden then you will be better off looking for a black tank rather than a clear one.

You will also need to ensure your r/o is protected from frost.

There is also another discussion on choice of r/o. The cheapest r/o doesn't usually have quality membranes, so the small saving to begin with is false economy later on.

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[Den]

Love reading your posts Spruce, your words are always crystal clear to me.

 

[spruce]

Love reading your posts Spruce, your words are always crystal clear to me.

Thanks Den, I'm always glad if my experience is of help to someone. If nothing else then it just gives someone something else to consider when making decisions. What has worked for me these last 11 years wfp may not work for others.

I can also say that I have made some bad equipment buys over the years, but analyzing why they were bad helps one not to repeat the same mistake.

I get lots from these forums myself, so its only giving a little back that I've received from other's experiences. Like so many newbies, I hadn't a clue when we began wfp, so much of it was trial and error. It doesn't seem that long ago.

We just didn't have information forums like this back then.

 

[Den]

Life is so much easier if you can learn by other mistakes and successes, saves a mountain of headache and heartache, I have taken onboard lots of your suggestions/experiences and will be implementing them in the next few weeks to make my life easier and more efficient.

 

[Tim]

Thanks Spruce. Do you mind me asking what RO system you use?

 

[spruce]

Thanks Spruce. Do you mind me asking what RO system you use?

Started off with a 225GPD r/o which was a waste of time ( 3 x 75GPD membranes). I upgraded the membranes to 150GPD ones after a year so the r/o was a 450GPD. We used that r/o for 6 years but had to continually ration water, especially toward the end of the week. In the end it was being asked to provide 2 full time cleaners and a part time one with water. It ran virtually all the time. (I had to fill my van on Saturday, sons van on Sunday and hopefully by Monday evening we had a full IBC tank.)

Nothing stiffles your business and future growth more than not having enough water to do the job. In fact a bad weather day was good as it took the pressure off water usage.

That 450GPD was upgraded 4 years ago for a 4040 which provided the 3 of us with all the water we needed.

There isn't a massive price difference between the 4021 and the 4040. So for me knowing what I know now, I would opt for a 4040, even if it was just me on my own. I should have bought that 4040 10 years ago.

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[Tim]

Thanks spruce for your advice, it's very useful.

I'm just worried, that a 4040 would produce to much waste water. Then you had your 450GPD set up how often did you change your RO?

 

[spruce]

The 4040 runs best on our water at 1 : 1 waste to pure @Tim . Our tap water tds is 90 - 125 ppm; water pressure 50 psi. HF5 membrane working 4 years. Pure before di = 2 ppm.

The 450GPD had a 'fixed' (non adjustable) inline restrictor 3 : 1 which was standard in those days. If you lived in a hard water area then RoMan also sold a 5 : 1 restrictor. I have no idea how it would have performed with the waste restricted to a ratio of 1 : 1

I bought the first r/o (225GPD) second hand. It was part of a complete trailer system I purchased and was about a year old. I think the first time the prefilters were changed was when I bought it. The membranes lasted another year. The r/o efficiency dropped to around 94% and that's when I changed them. It was at this point that I upgraded them to 150GPD membranes. Those membranes lasted 6 years and prefilters were changed every 3 months.

About 5 of those 6 years were at a tap water tds of 255. Water pressure before the pipes were relined was 40psi.

They then relined the pipes and our tds dropped to what it is now. At 255 the r/o continually produced pure at 4ppm. It then dropped to 2 when the water quality improved. The membranes seemed to fail quite quickly so I had the choice of replacing membranes and adding another 450GPD r/o into the system (900 GPD) or putting that money toward a better r/o.

Upgrading to a 4040 wasn't an easy decision at the time. It was an expensive purchase as I built it to my spec and I was very worried about the cost of a replacement membrane even although my 450 GPD ones had lasted 6 years with regular prefilter changes. I also had my back up against the proverbial wall as our annual school clean was a few weeks away. We use twice the amount of water a week during that clean and we were providing water for a part time cleaner as well.

In those early days I read an article that GAC filters were better than the carbon block ones so that's all I used. It was only when I bought the 4040 and ordered some 20" GAC filters that I saw a label stating their service life was 2500 US gallons. At our water usage of 12,000 liters a month and a waste to pure ratio of 3 : 1 we were using 48,000 liters of water per month. We should have been changing those GAC filters every 5 days, not once every 3 months.

If I had to replace my 4040 membrane tomorrow, I would be quite happy as its earned its keep over the past 4 years. But as its performing the same as it did when new I would hope it will last another couple of years longer at least. I say this because I'm now a stickler for prefilter changes at the right time. We use Fiberdyne carbon block prefilters from Gardiners. The 20" ones are good for 78,000 litres, so they get replaced once those 78k are up (I have a water meter on the inlet into the r/o.) Those 78k are up at between 3 and 4 months, depending on water usage which is a bit less at the moment due to a number of reasons.

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