Ozone pre-filter suggestions

**John Galt** · 03-30-2010, 08:47 AM

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).

**Andy CWS** · 04-02-2010, 06:40 AM

[QUOTE=John Galt]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.
'Hardness' and 'very low' need to be quantified objectively because general subjective terms mean nothing when solutions are sought. One man's ceiling is another's floor. The 'no detectable' levels of chlorine: does that come after or before any current treatment equipment?

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.
Typical UVs will do nothing to remove chlorine. They are used as disinfection devices unless specifically designed to produce ozone by using a different wave-length (152nm). What is the 'chemicial treatment' you are using to remove chlorine?

Sediment-only filtration can be acheived with very little to no waste with proper equipment. Both ROs (90%+ rejection) and nano-membranes (50%+-) can be used. Ultra-filtration membranes have no (or little) waste water and should filter down to acceptable levels. These membranes can come in wound or tubular types.

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.
What are your energy restrictions? Are you depending on wind or solar or some other limited factor? Can you reduce energy in other areas to balance it--energy saving lights for example?

What do you imagine the energy costs of an ozonation system are? Is the ozone system to be a corona discharge or UV technology?

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.
Where does the water leaving the tanks go? Is that water recycled?

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.
DE filter? Do you mean a DI filter? (DeIonization). You say installation is NOT a minor concern but maintenance and labor costs are (minor concerns). Is that how you mean it?

Swimming pool filters don't have a high success rate when used in other applications. Flow rates and backwashing waste are not designed for 'drip systems'.

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.
I would like to see those cost analyses. How can an ozone system plus a carbon filter be cheaper to operate, let alone install, then just a carbon filter for removal as a dechlorination device?

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.
Again, energy costs of this approach vs that of an RO is puzzling. UV light appears in four wave lengths. You need to make sure the bulb remains at the given wave length and only expensive equipment can do that. Corona discharge ozone system also use a lot of energy and need monitoring and maintenance as well.

Educate yourself well on these technologies as they can be very effective but with shortcomings and limtations, are these the answers to your needs and concerns?

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).

I don't know what PBH 420s are.
Ultra-filtration membranes with dechlorination seems to be the answer for you. If you are taking this hobby that serious, then taking shortcuts will only cut you short.

**John Galt** · 04-02-2010, 11:32 AM

GH=5, KH=6, TDS=105, and there are traces of a multitude of heavy metals, SOC's and VOC's that are all well below actionable levels but still present. The chemical water conditioning that has been used in the past was a product called Prime, which is manufactured by SeaChem. The actual chemical reactions that take place are of no particular interest to me beyond the fact that the resultant treated water does an excellent job of supporting aquatic life.

The reference to "detectable chlorine" was not directed at any specific empirical test results, but rather just the smell. Not being too familiar with this forum I wasn't certain what level of expertise I was writing to so I attempted to stay with the flavor that I detected reading many of the other posts.

Pardon the misspeak, I do recognize the function and limitations of U.V. and ozone relative to chlorine removal. The U.V. is intended to provide additional prophylactic protection against microbial pathogens. Its inclusion was based purely on the fact that we already owned the equipment. The ozone was intended for chlorine treatment and a carbon scrub was intended for residual ozone control to prevent its escape into the surrounding atmosphere.

The significant efficiency advantages of corona discharge over the U.V. generation methodology would obviously eliminate U.V. from consideration for chlorine removal.

As for energy use considerations, potentially superfluous U.V. notwithstanding, every effort is being made to limit our consumption. Solar passive design with a good southern exposure is an integral part of the building. Trombe walls, earth tubes, air tightness and super-insulating practices that subscribe to E.U.'s Passive House Energy Standards are the essence of the building's construction.

50% of the building's heat loss is made up by passive solar gains. The remaining 50% of the building heat, as well as the heating of the hatchery tanks, is accomplished through a radiant hot water system. Lighting is through SolaTubes and L.E.D. fixtures. Energy consumption for the ozone generation and control systems is estimated at less than 300 watts. Although we are serviced by the local utility grid we also plan to install a PV system as well.

The tanks are to be supplied with a gravity fed constant drip supply system that will replace the entire tank contents every five days. The overflow is to be directed to an variety of plant and algae bio-filter/growing beds, before leaving the building, to reclaim nutrients and residual heat. From there the waste water is passed through a hydroponic greenhouse that includes a bog filter bed before being routed through a glazed passive solar trickle filter that will utilize available sunlight and gravity aeration for additional purification before reuse as non-potable water by several other end users.

DE, particularly as it applies to swimming pool filtration, would of course refer to Diatomaceous Earth, not DI. DE filters remove solids down to the 1-5 micron range and typically last for twenty years or more with the pumps being the weakest link. Most commercial tropical fish hatcheries and retail establishments utilize some form of swimming pool filtration in their operations with great success. The backwash issue is irrelevant since the backwash and rinse cycles are isolated from the normal flow circuit.

PBH 420's are a cartridge system that I had seen mentioned in numerous posts on this forum and are sold by Fast Filters.

**John Galt** · 04-02-2010, 07:17 PM

Don't you just hate it when someone, instead of just attempting to offer helpful information and answering a question, attempts to fill a page with self aggrandizing drivel and bloviations just to make themselves sound as though they are expert?

I must have been so mired in the minutia of your questions, while attempting to educate myself, that I somehow managed to miss a few of the pithy pearls that dripped from gods lips. Regarding your apparent issues of disbelief that a carbon only filter is less cost effective than ozone in our application, I'll attempt to be a bit more succinct without overwhelming you.

The number of jelly beans that operating a corona discharge ozone system requires is much smaller than the pile that a carbon only system requires.

This is especially certain in our situation since we will possess the ability to generate free electron flow from the sun. We are not however blessed with the necessary coal fields, coconut husks, cheap third world labor and lax environmental pollution standards necessary for the continued cheap production of bulk carbon. Since most of the carbon that is used in water filtration is of the cheaper rain forest origination type, and as such is destined to leach the highest unacceptable quantities of phosphates into the finished product, we felt that it was not wise to travel that path...an unfortunate side effect of our on-going attempts to self educate. Should anyone other than another half hearted aquarium hobbyists stumble across this I would like to further explain that these phosphates contribute to the growth of many forms of undesirable algae. The additional cost of controlling and or removing this is not a lemon that proves worth the squeeze.

The technologies, or rather the lack thereof, involved in the production of carbon are very inefficient and yet quite interesting in and of themselves. Given the pervasiveness of its use in water filtration I would presume that any expert worth his softener salts would have taken the time to acquire this knowledge already, especially if one were given to holding themselves out as some sort of condescending Jack or Jen expert.

While I have lived many years on this earth I have still as yet not found myself in the room where I was the smartest guy there, and by room I mean internet, and by smartest guy I mean a situation where I would feel compelled to speak to anyone as though they were a trifling idiot. While I applaud the intentions of all who attempt to assist and educate I would suggest that the tone and temper of any such attempts be respectful of the fact that you may not ultimately be quite as intelligent as you assume that you are. Check your premise.

**Driller1** · 04-02-2010, 08:30 PM

Originally Posted by John Galt

Don't you just hate it when someone, instead of just attempting to offer helpful information and answering a question, attempts to fill a page with self aggrandizing drivel and bloviations just to make themselves sound as though they are expert?

I must have been so mired in the minutia of your questions, while attempting to educate myself, that I somehow managed to miss a few of the pithy pearls that dripped from gods lips. Regarding your apparent issues of disbelief that a carbon only filter is less cost effective than ozone in our application, I'll attempt to be a bit more succinct without overwhelming you.

The number of jelly beans that operating a corona discharge ozone system requires is much smaller than the pile that a carbon only system requires.

This is especially certain in our situation since we will possess the ability to generate free electron flow from the sun. We are not however blessed with the necessary coal fields, coconut husks, cheap third world labor and lax environmental pollution standards necessary for the continued cheap production of bulk carbon. Since most of the carbon that is used in water filtration is of the cheaper rain forest origination type, and as such is destined to leach the highest unacceptable quantities of phosphates into the finished product, we felt that it was not wise to travel that path...an unfortunate side effect of our on-going attempts to self educate. Should anyone other than another half hearted aquarium hobbyists stumble across this I would like to further explain that these phosphates contribute to the growth of many forms of undesirable algae. The additional cost of controlling and or removing this is not a lemon that proves worth the squeeze.

The technologies, or rather the lack thereof, involved in the production of carbon are very inefficient and yet quite interesting in and of themselves. Given the pervasiveness of its use in water filtration I would presume that any expert worth his softener salts would have taken the time to acquire this knowledge already, especially if one were given to holding themselves out as some sort of condescending Jack or Jen expert.

While I have lived many years on this earth I have still as yet not found myself in the room where I was the smartest guy there, and by room I mean internet, and by smartest guy I mean a situation where I would feel compelled to speak to anyone as though they were a trifling idiot. While I applaud the intentions of all who attempt to assist and educate I would suggest that the tone and temper of any such attempts be respectful of the fact that you may not ultimately be quite as intelligent as you assume that you are. Check your premise.

Nice try Gary.....no cigar....