I would like to find the best way to filter 2 cubic meters of water which is full of water-based paint.
This water is used in a closed-loop circuit in a Spray booth. The water does not need to be drinkable but just clear.
The recycling company comes twice a year to pump out the 2 cubic meters of dirty water. If I could find a filtering system, they could just pickup for example few kg of semi-dry paint/mud. We are based in Asia, the solution needs to be easy to implement and cheap.
Recycling company make you pay per kilograms of waste. 2 cubic meters makes 2000kg... If I would somehow filter the water and get the dry bits, I would pay much less.
I consider few options : Using steel drums to make whool or sand-based filtering system. (Either with a pumping system which would run once a week, or by manually filling them).
Using distillation process, using steel drums and gas to heat it up. (I need to make the calculus on gas consumption
Using belt press filter or press filter (they are widely used in the process of converting dirty water, to semi-dry sludges). In my case it is to expensive to buy this machine, just to use it once a year. The solution of my problem will be some DIY genius.
The whole point if to keep the water as clear as possible for the longest time before the company comes to pump it up.
MOZ Filtering System
Moz suggested in his answer to use some clothing, as he was doing in his company. see comment below.
I tried the filtering system with mesh wire and clothes suggested by Ӎσᶎ. Unfortunately it did not work, the dilution between paint and water being very high.
Sand filter, gravity based
I tried Moz solution again today with 10 gallons tank (big water tank for water fountain). At the neck, I putted 6 layers of clothes. Filled the tank with water : just went through. Even if I made the opening smaller with a valve at the end. Then I switched for 6 layers of silk (used to print logos on wood). Same result.
Then I kept the 6 layers of silk at the end of the bottle, Added a mesh wire inside and some stones. Finished with some sand. The flow was completely blocked, the sand was stuck in the neck of the bottle... therefore no throughput. I think it is because the sand can go through the mesh wire. Tomorrow, in the inside I ll swap the mesh wire for silk (sand does not go through), and it might work much better. The very low (nonexistent) throughput could be because I am experimenting on a small tank -> not much pressure.
See schematic above, its a classic gravity filter.
Pump-assisted Sand Filter
I made three different designs of filters, with gravity, pump and pressurized. I would like to get your advices about it. Even if its not drawn, all the pump have valves in order to regulate the throughput.
The problem of the filter below is that the pump has to stop sometimes to prevent overflow... Is is a slow solution. But once again, I will run the filter only few times every 6 months. So why not.
For the filter below, since its pressurized, maybe the sand level should be higher ?
Thanks for your help, I will keep you up to date.