Water Purification

[ssullivan]

Thanks for the compilation of information, Gord. Very nice. It adds to the thread from a reference point of view. I had looked at historical rainfall amounts in various areas we expect to be over the next couple years and found that we could *just* sqeak by with a tarp shaped like the part of our deck where we could rig it up. I may have to do a 2nd tarp to exceed our water demands.

In that case, we may be able to stay out all summer long this year without even tying to a fuel dock to get water and top off diesel. See, it was water that was our limiting factor last year, not fuel.

[hellosailor]

"Our collector is the roof of our house." Same thing in Bermuda, before the desalinization plant was built. Folks still routinely use their roof water, the price is better.<G>

[sv_makai]

Sean,

Sorry about the delayed response. I had to work.....

We used our bimini and would scrub it at the beginning of the rain and then let it rinse. After the rinse we would catch the rain water in container and using a dedicated small bilge pump, pump it from the catch containers through the filter and then into to tanks.

The reason I pump it through a filter is that one it cleans the water instead of pumping it into the water tanks. Even after a heavy rainfall you would be amazed at the stuff like leaves and bugs that the prefilter screens out. If you let a bit of dirt or bugs or.. in then a little here and a little there and before long you have a ton of dirt and gunk inside your tank. If you are collecting water regularly it adds up fast.

If we have been anchored for a time we would have our shade up. Infamously called the tent. It covers the boat from bimini to the bow out to the sides and drops down to the second life line. This really catches the water. Our best was 120 gallons of water in 3 hours. Of course it rained for 3 more days, but we just didn't have anywhere to store it.

Rain catchers are a great way to get additional water, but remember it must rain to catch rain water.

[Pura Vida]

Oddly enough we just received the quote for the installation and here are some of the highlights.

First Flush Diverter - Besides bird droppings I wonder if the fabric you use for the tarp will have any coating that might wash off and into the water.

Ozone disinfectant ( I used UV in the food plant years ago and it works as mentioned before but the light runs much of the time.)

100 micron filter before the pumps
20 micron filter prior to ozone treatment
10 micron filter prior to pipes to the house.

It looks like a really neat setup but I can't say how power hungry it is. As long as the water tastes like water and doesn't have any little black dots floating in it I'll be happy. One really neat feature is a "tank vacuum" that suck water and junk off the bottom of the tank when it is over filled, cleaning the tank.

[SkiprJohn]

Aloha Sean,
I don't want to worry you about diseases and such but there have been cases where the catchment area, i. e. roof has accumulated rat fesces and urine. If the catchment tank is small the result is a concentration that leads to a disease called leptospirosis and you can look that one up on the internet. It is imperative that your catchment tarp, cloth, sail has no rat or mouse stuff on it.
Kind Regards,
JohnL

[GordMay]

Invention uses ozone-treated water to kill bacteria and sanitize fruits and vegetables:
See the article:
http://www.theglobeandmail.com/servl...ry/Environment
The manufacturer:
http://www.tersano.com/index.shtml

[salvor111]

John, stop by my house and look at the electrostatic U/V system (I build systems commericaly) on county water, the bateria in my 30mic is some bad stuff. the county engineer warned me during the heavy rains of fecal matter, my baseline acid ph was 6.3. tena versicolor, and three strains of staph, just for starters. collecting rainwater is a simple matter of look whats in the air. however I have tested rain water 800 miles out to sea. other than no menerals at all, the water had neg response to a field chem test kit, acid baseline was almost alkiline 6.9ph
remember folks county water is only catchment treated with a little clorine gas,and if they are not smoking pocalolo that day, to say the least of the state of their nasty filters, they basicly wait till there is pressure loss of some vage baseline

[SkiprJohn]

Aloha Salvor,

Will call before I stop by and thanks for the invitation.
Kind Regards,

JohnL

[c.spots]

Great information.
Has anyone seen a plan for a rainwater catchment you could make (out of nylon)? You could keep it clean, then hoist it in the rigging before a rain.
This way you could avoid any issues about contaminating organisms, even from bird droppings.
I have a concern about chlorine levels in drinking water, because of the residual chloramines from the binding of chlorine to organic material. In a commercial setting, the chlorine quantities can be accurately calculated to give a minimum required amount, but on a boat, we probably add too much or too little.
If you empty you tank frequently, you should not have much of a problem, but if the water sits in your tanks for an extended time, “what grows there?”
Does anybody have a guide for how much household bleach to add per gallon of non chlorinated water?
Has anybody tried an ozone generator for the water tanks, since it does not leave any bad taste or residual. It will remove most bad tastes and odors from the water. It may also help the filter work better by causing the particulates to flocculate into larger particles. It is more effective than chorine, but doesn’t last long.
Granted, it is irritating to breathe at high concentrations, but much less so than chlorine. Any guidelines for how many PPM of ozone to run through how many gallons of water, and how often? It would allow you to maintain a very low chlorine level, like is done with hot tubs. Better yet, leave the chlorine out and don’t worry about it accidentally killing your watermaker.
I already have an ozone generator, and plan to use it for mold and (hopefully not) odor control. If you avoid the UV ozone generators, they last a long time and require very little energy.
Robert

[ssullivan]

I have had a recent concern about catching rainwater. Here in Maine, I have found most of the freshwater fish is nearly inedible due to mercury toxins that arrive in - you guessed it - rainwater. The toxins aren't even from here. The drift Eastward from the industrial areas farther west in the USA.

[Pblais]

Rain water isn't that pure untreated. The air has enough biologic content that you need to treat rain water with chlorine if you intend on putting in a tank even in the best of locations. Even if pollution is not the issue the collection of rain water comes with all the crap in the air it carries with it. We can assume you wash (or let it drain off for a bit) the deck first too to reduce the salt content.

[ronbo1]

Chesapeake Bay link:

Air Pollution

As Paul says, 'rainwater isn't all that pure'. In areas such as the Chesapeake Bay the "airshed" is some 6 times larger than the Bay itself. Pollution in this airshed comes down in rainwater from as far away as Indiana. Just as you can't assume a pristine freshwater stream is pure and drinkable you have to look upstream of your cruising area.

[senormechanico]

Sean,

It sounds like you should buy a boat on the West coast! You've got the air above the whole Pacific Ocean to cleanse your rainwater.

Steve B.

[c.spots]

Except, of course LA, where you "don't breathe anything you can't see".
Regardless of the chemical, particulate, and mold contaminants in the air, these are largely and quickly cleared out if the air with the rain. Mold levels in the air may increase after a rain. After discarding the first flow, the rest of the rainwater will be cleaner than any lake, river, or groundwater. After all, where did that water come from?
Fish may be another matter, since they concentrate the heavy metals.

That said, if the air is so dirty that you wouldn't drink rainwater, you had better stop breathing it, since the volumes you filter with your airways are enormous.

[little boat]

i've found that vinyl or plastic is the best for catching rain; a slippery surface collects rain much faster than a fabric that has to soak first before water runs down. a couple of capfuls of bleach in the tank from time to time is all i've done for a safety measure. a removable catch device is best, it stays clean. a sailmaking buddy of mine made me a custom catcher as a gift and it is great. its shaped like a triangle with a sort of pocket seam at the point and attaches to the forestay and the side shrouds with light lines and has a hose attachment on the curved belly that leads to my tank. takes no time to set up. many sailors stopped by to ask where i had gotten this. a filter at the sink pump might put your fears away as regards some sorts of contaminants.