Since I deal with coils that are over office buildings I have always had to deal with recovering water.
As a side benefit I also had to learn about filtration very quickly too because initially I cleaned filters with mobile ultrasonic machine.
After 40 filters or so, the machine still cleaned very well, but the water took on an odor that was transmitted to the filters.
Since I had already invested tens of thousands of dollars into the ultrasonic method, I had to build filtration system that could remove contaminants down to less than 5 microns and reuse the water over and over again all day.
The reason for that was because the water had to sit for 24 hours or be run for at least 15 minutes for the ultrasonic process to work. The water had to be "conditioned" and all the air bubbles had to be removed from it in order for it to work.
So I spent almost a year experimenting with filtration. I had another business paying our bills, so I had plenty of time to spend on this each day.
I tried numerous pumps and replaceable swimming pool filters. Most pumps were not sturdy enough and would break frequently. The swimming pool filters would fill up VERY quickly and choke off the system. The other problem was power. I had to design something that could run off a normal generator without going into specialty generators because of the cost. Lastly I had to deal with the space issue, I only had so much space in the van I was using (UPS truck style)
Eventually I had the water go through a polypropylene filtration media to get the big stuff out, then through a carbon filter, then through a DE swimming pool filter that I could backflush regularly throughout the day. I also built a chlorine injection system that also helped deal with the smell. That combination worked, till eventually it could not keep up when we were doing roofs with 200 to 500 filters on them.
I was using a 90 gallon ultrasonic machine and that filtration system could bring the tank from black to a pee yellow that was clear enough to read a quarter on the bottom of the tank in less than 5 minutes. It was a pretty decent system.
It was very compact:
We have added it to our reclaim trailer for those rare instances where he have no other access to water.
Here was an early swimming pool filter after only TWO cleaning cycles!!!!
It all had to fit in this small space:
If you will notice in the picture above, I had a small area for the filters to sit for a couple of minutes after they were cleaned. Up under that shelf I had a row of UV lights to kill bacteria. Jim and Robert use the same technology today. I don't think Jim had ever even heard of UV till I met him in 2008.
I also told Jim about the DE filter. He says you can't use it for some reason for what he does. But I know for a fact that there is no more economical final polishing filter than a DE filter as long as you do the job of prefiltering before it gets to the DE filter. IT will produce near swimming pool quality water if done right, even if there are true emulsifiers (soap) in the water. Our ultrasonic machine used it's own special soap.
So I started filtration a few years ago.
We started reclaim early on with portable vacs, then moved up when we needed to.
We now have one of the largest environmental cleaning contracts in our area for cleaning large restaurant grease spills. That was the main reason we invested in the system we have now. Note: we didn't spend the money first, then look for the magic accounts, we spent the money as we got the accounts.
