We have very good municipal water to start with, 7.2 pH at the tap with little to no chlorine detectable through most of the year, and very low TDS. Our General hardness and Ca hardness are also very modest.
We're relocating a tropical fish hatchery, that has been a hobby and is now grown too big for the house, to a new building. With the move we'd like to improve the quality of in-coming water and have decided to try using ozone and U.V. for chlorine removal rather than carbon alone or the chemical treatment that we currently use. The issue is in trying to decide how to pre-filter any sediments before they hit the ozone reactor and U.V.
Many people in the hobby/biz use R/O, but we were trying to avoid the waste water and membrane replacement costs,...we have enough waste to recycle/recover already. We're also trying very hard to manage energy consumption so an R/O system capable of a 2,000 gal./day volume and the required booster pump energy would be prohibitive.
The in-coming water is principally used to replace water in the fish habitats through a constant drip system so the demand/flow is fairly constant at a little under 5 liters per minute.
Initial thoughts were of adapting a large swimming pool DE filter and possibly 3 stages of mechanical filtration for sediments. Installation cost is not a minor concern but maintenance costs and labor are. Weekly checks and service are best but daily is too much. The DE head pressure may end up competing with what the R/O booster pump consumes so we're looking for some alternatives to consider.
We had also looked at using carbon alone for the chlorine removal, but between the initial and annual operating costs the ozone with a carbon wash works out much cheaper. We were also looking for information on the effects of U.V. when combined with ozone. I've been told that the U.V. intensifies the effectiveness of the ozone, but I've nothing empirical to gauge that by. Without understanding that part of the process better we'll probably use the carbon to scrub residual ozone before it hits the U.V.
Any insights or recommendations would be greatly appreciated, especially suggestions on the mechanical stages; sets of PBH 420's in pairs with pressure relief allowing bypass to the second unit vs. washable cartridges or whatever...Ultimately we're trying to get as close to R/O as possible without wasting as much water, energy or money (guess that's all about the same thing when you get right down to it).