[Heb Alpha]

Hi guys,

The workshop we have been renting for the past 7 years didn't have a water metre - happy days! One was fitted a couple of weeks ago so I'm guessing we're going to start getting significant bills in the next couple of months.

We purify about 4000 litres a week using a Merlin RO. I'm guessing we're actually drawing down a lot more than that, because a lot more goes down the drain than goes into the tank.

Is there another method of purifying the water which uses less water? We go from tap (100ppm) to the merlin which brings it down to 000 - 002 and we also run it through the DI tank before going into a 1000 litre IBC tank and from there we pump it into the tank in the back of the van, as and when required.

Thanks

Rob

[Smurf]

Might be worth investigating changing the merlin ro to a more efficient ro for a start as so I've heard merlin ro's are one of the worst for waste to water ratio production.. I'm sure if you give Doug a call from Daqua he will advise further.

Other option is to go DI only for a while and see in the long run will work out any cheaper than using ro/di setup being on a water meter an all.

Last but not least it might to be worth considering if harvesting rainwater is a viable option depending on the type/size of the workshop roof as a top up to your pure water production needs.   

[Walter Mitty]

Hi guys,

The workshop we have been renting for the past 7 years didn't have a water metre - happy days! One was fitted a couple of weeks ago so I'm guessing we're going to start getting significant bills in the next couple of months.

We purify about 4000 litres a week using a Merlin RO. I'm guessing we're actually drawing down a lot more than that, because a lot more goes down the drain than goes into the tank.

Is there another method of purifying the water which uses less water? We go from tap (100ppm) to the merlin which brings it down to 000 - 002 and we also run it through the DI tank before going into a 1000 litre IBC tank and from there we pump it into the tank in the back of the van, as and when required.

Thanks

Rob

As you surely know, 100ppm is a bit too high to make resin only viable.
I would suggest changing from a Merlin to a less wasteful RO at some point.
Obviously it varies a lot but but you could be throwing 10,000 litres down the drain to make those 4000 litres of pure per week.  If your Merlin is giving you 000-002, possibly even more as they tend to be less efficient than some other types of RO.
So assume 10,000 litres of waste per week.  Maybe £2 per 1,000 litres - so £20 a week to waste.  Using a 4040 (HF4 or HF5 depending on water pressure) the 4,000 litres of pure ought to cause about 4,000 litres of waste.  So maybe 6,000 litres a week difference = about £12 a week.
I'm not sure but say 4040 + housing = £360 for easy numbers.  It would take 30 weeks to start breaking even  Obviously my numbers may be a fair way off but, at some point, the saved waste will start paying for itself.  Additionally, you could probably sell the Merlin too - though second hand value probably won't be very much.  Sometimes it's better to keep such things as spares in case something goes wrong.

[Matt.]

I use a merlin mate and get about a 1/3 pure to waste so that's easy 10000 maybe 12000 litres of waste water
Am a bit cheeky and use customers water as all work is commercial but u do find some are better than others so tend to target certain jobs for water 

4040 would be more efficient for u but just check pressure as above says will depend on which is best for u. 

[Heb Alpha]

Aye, we used to use DI only at start but at 100 ppm we were having to change the resin every 3 or 4 days which was a bit of a pain.

I'll look into the 4040 and harvesting rainwater also sounds like a plan - I reckon I could have filled the tank a thousand times with the rain that's come off the roof of my car in the last 9 months!