Ro/di units

[Rich wain]

Hi all, I've been traditional cleaning for about a year now and recently I've been looking at building my own wfp trolley, seen some good tutorials on here. My question is to do with the Ro and Di units, I understand how they work and what they are for but I'm having some confusion with where I put them, would I fit them inside my van leading to a large tank from which I fill up my trolley? Or on my trolley so I can take water from the large tank purify it as it goes in to my smaller trolley tank. Also I live in a hard water area do I need both Ro and Di units?

Cheers

 

[Rich wain]

Also if anyone could give me any advice on which system to buy it would be much appreciated

Cheers

 

[spruce]

Hard water area = r/o + di. An r/o will not remove 100% of the minerals in your water, so a di vessel full of resin will remove or 'polish off' the remainder.

Ex. Water at 300ppm at the tap should be reduced to 6ppm with the r/o at 98% efficiency. The remaining 6ppm will be removed by passing water through the di.

If you have a tank in the van you can put the r/o in the van and process water directly into it. Problem is that a small r/o needs to work and so you will have lost valuable processing time when you are out working during the day.

Hence most who are able to process water into a second hand, cleaned out 1000 IBC tank. They cost about £50. We have ours in the garage. The idea is that whilst you are out working the r/o can be left on filling up the IBC tank. We pump water from that into our van tanks. On the occassion that we need to refill the van during the day (we have to do this with one commercial job we do) there is always water.

If you process directly into the van's tank overnight then you aren't able to do this.

In the early days I bought a self contained trailer and I processed water directly into it overnight. If I started off filtering water at 10pm I would usually have a trailer with full tanks by 6.00 am the following morning. Sometimes it processed water faster (higher overnight water pressure?) and was overflowing and wasting water and sometimes I got 1/2 a tank. One time I got nothing at all (unexplained) and I had several occassions where I forgot to switch the tap on (or someone turned the back tap off before going to bed) - hence no water the following day. In the winter with colder water, I had to start just after I got home.

The best move I made was that IBC tank.

 

[spruce]

Also if anyone could give me any advice on which system to buy it would be much appreciated
Cheers

If you have room to store water then I would always recommend that option. You will also need a transfer pump (submersible pump works fine but the top of the IBC tank will have to be 'modified' so the sub pump can be put in. So you will need power, water and a drain in and near your garage/shed.

Personally, if you have a tank on the van then I would dispense with the trolley idea. I would see a better option using a van mount system (hose reel, 100m of hose, pump, controller and leisure battery.)

The best size tank for a single operator in a van is 500 liters (minimum 400). Whenever I look on Ebay there are usually lots of 250l tanks for sale. They are too small. On average you can expect to use about 350+ liters a day once you get into the WFP groove.

If you are a single operator the min size r/o I would get would be a 300GPD processing into an IBC tank. The 2 of us just managed with careful planning with a 450GPD r/o. Anything less that 300GPD is going to restrict your future growth.

If you want the r/o on the van, then the mimimum you should get is a 4021, but most suppliers supply 4040's. You will also need a shutoff valve when the tank is full.

Now we have a 4040 which processes water at 2lpm which means we have plenty when we need it.

We have the r/o in the garage. Water goes from r/o through di and then into storage. This means we didn't have to have a di vessel in each van.

I would suggest a minimum 6 liter di vessel.