Any RO gurus on the forum?

[Canibul]

We need to source a 3000 gpd desalination system for the house. Do any of you guys have a lead for good pricing for a high pressure RO system?

[mobetah]

Canibul,

You might try the folks at SK watermakers, I have never had any dealings with them but I have heard great things from those that have. SK Watermakers

Good Luck

[Fishspearit]

Just curious how you came by the figure of 3000 gpd? Unless you're doing a community project that may be kind of large. The starting/stopping and idle time is what causes the problems and added maintenance of RO units. From a bottling plant RO perspective, I can tell you GE made the large high end systems. And since you're pulling from the shoreline of the shallow bank, you will need very good pre-filtering for good membrane life. Sorry I don't have any sources for you.

[Canibul]

we actually need 1000 gpd, but I was planning on running it a third of the time.

The water here is crystal clear, no turbidity to speak of. We would be pulling from a well drilled into fractured limestone.

[ed stewart]

I would also check out SK. I met the owner at a trade show, he told me most of his business is coming from people with houses out of the US. BTW I put one of their 600 gpd watermakers on my boat and it's working extremely well also easy to use with a minimum of maintainance.......Ed

[mobetah]

Canibul,

If your well is brackish you might be able to use a smaller unit. After all, the less salt in the supple water the more potable water your unit will produce. You might consider testing the water in your well to establish a salt content and discuss it with the manufacturer before you decide on a particular unit. Just a thought.

Again, Good Luck

[Canibul]

Its pure, gin-clear caribbean sea water.

[Tellie]

Originally Posted by Canibul

Its pure, gin-clear caribbean sea water.

Hi Canibul,

I glanced at your web site. It seems you are building alot of projects around the house yourself. Why not build your own watermaker? With extra room in a house and house power of 115V or 220V you could easily make your 1000 gpd or more for far less than buying a pre-made one. I'm building one now on my boat that should knock out 800 - 1000 gpd for just under 3K. If I could build one for a house a few items would be different and chances are less costly. I'd take the difference and apply it to extra membranes and up the gpd considerably. Ask anybody on the forum that's built their own and they'll tell you it ain't rocket science. Secondly, if you build it yourself you can eaisly fix it inside and out yourself. Service techs in your local could get pricey.

[Minggat]

35 years in the water treatment industry here. I am currently in Australia on a reclaimed water treatment project where the RO membranes are 18 inches in diameter. Threw that in just for interest.

I see a lot of yachties who seem to cling to the idea that bigger is better when they consider RO installations. In my opinion, that simply is not the case. Fishspearit has it right. (The starting/stopping and idle time is what causes the problems and added maintenance of RO units.) RO's like to run. I really would question your need for even 1,000 GPD. On my own boat (and I realize your not putting this on a boat), I bought as small a unit as I could get primarily for this reason, but also for the power savings as well as the small footprint and cost. I would also recommend you check out Village Marine watermakers. I will reserve my comment on anything GE makes.

Don
Islander
"Minggat"

[Tellie]

Hi Don,

Always interested in a pros perspective, so a few interjected questions and comments...

Originally Posted by Don Anderson

35 years in the water treatment industry here. I am currently in Australia on a reclaimed water treatment project where the RO membranes are 18 inches in diameter. Threw that in just for interest.

I see a lot of yachties who seem to cling to the idea that bigger is better when they consider RO installations. In my opinion, that simply is not the case. Isn't that relative to individual real needs Don? I think when most people consider a watermaker for the first time they certainly consider cost and needs together then go about trying to figure out a usage budget for their water. Usually, as I have read on this and other boards along with discussing it personally with others, they for the most part exclusively talk human consumption with the idea of some cooking and an extra shower now and then. If that were a sole use I'd agree with a smaller gpd output. But what about boat maintenace? I don't think most people investing in their first WM take this into serious consideration. Adding up the costs of exposed deck equipment, lines, chocks, blocks, anchor chains, flushing outboards, even the decks themselves, etc. this equipment becomes a serious investment for most. The idea of being able to at least give these items a good fresh water rinse giving extended life to these items to me is obvious. Of course I'm thinking more of longer term cruisiers, a WM for weekenders seems a silly investment. Fishspearit has it right. (The starting/stopping and idle time is what causes the problems and added maintenance of RO units.) RO's like to run. I really would question your need for even 1,000 GPD. On my own boat (and I realize your not putting this on a boat), As you state this for Canibul is not for a boat but a home. But same priciples apply, especially a home in the tropics next to a salty ocean. Throw in car washing, perhaps two bathrooms, not to mention if the kid is a teenage girl, home maintenace, all before human consumption it seems a 1000gpm a day could begin to seem a bit small when you consider that's about 40 gallons per hour and what length of running times you're willing to deal with. I bought as small a unit as I could get primarily for this reason, but also for the power savings as well as the small footprint and cost. What's the real cost when using house power (115V or 220V assumed) as opposed to small powered 12V units? I would assume running a larger 2-5hp elctric motor run once or twice a day would not be such a drain on the electrical budget when water could almost seem limitless. I agree that WMs like to be run but things do wear out and long extended running times hasten maintenace, rebuilds and new replacements on anything mechanical. Where Canibul lives maintenace by others would be heavy extra expense. So were is that line between small WM, large WM, and true cost effeicency? If I were living in the islands as Canibul with the room and power a house provides I'd lean towards a larger unit run less time everyday making more water. But I bow to 35 years experiance and would be really interested in your response. I would also recommend you check out Village Marine watermakers. I will reserve my comment on anything GE makes.

Don
Islander
"Minggat"

[Canibul]

This is all great input, and I thank you.

Ok, for the 1000 gpd part of it. That is what the landscaping people tell us we need for the first three months to get a whole bunch of buttonwood and mahogany trees established. Plus a lot of other plants...I don't remember them all. Bougainvilla, stuff like that. ( I am only a plant guy if I can eat it or the wood has characteristics I am interested in). I have been watching our normal household consumption for over two years, and it averages 150-170 gallons per day. We get just about enough rain to cover that. But obviously if the landscaping is taking another 1000 gpd, that's what I have to come up with.

The landscaping guru here also tells us that the water budget for the plants will drop about 25% in three months, and another 25% in six months. So, six months after the landscaping is in, we are projected to need to generate ( or buy) a maximum of 500 gpd to support them. And that will not be all the time, as we do have some rainy spells here. I am not including the household needs in that, because we pretty much have that covered with the rainfall, and buying the odd truck full of water. ( 2500 gallons costs us $ 150)

We want to "re-forest" this hilltop, because the construction of the house pretty much wrecked it. A steady supply of fresh water trickling down on all sides will do that. We have seen what the native flora does when it gets fresh water. This area is a "dwarf tropical forest" and it's dwarf because of lack of topsoil and water. We are hoping to get it from "dwarf" up to just 'stunted'. We designed the house, and picked the site, to be able to upgrade to renewable energy supplies as technology and budget allow. We got solar and wind out the wazoo. ( have you guys seen the new VAWGs from Mariah? Pretty impressive) If you looked at our blogsite, you have seen the photos of how torn up the ground is around the house. We need to fix that.

So, this is good news to me to hear that ROs actually like to run all the time. I have been looking at 3000 gpd setups thinking I needed to run them on a 30% duty cycle.

What I haven't yet done is work out the cost of running a pump full time, at about 40 cents a kwh.

So, thinking ahead, a year from now we need a lot less than 1000 gpd, total. Why have some excess capacity? Well, we wouldnt rule out a swimming pool....at a later date, for example. We also like the idea of being self sufficient. These islands have not had a serious hurricane in almost 50 years. When it happens, I am pretty sure we can forget about municipal water and electricity for weeks, or months.

As for putting together a system myself, I had not considered that. I am a okay handyman. (more like a hacker and wood butcher, but sometimes I am all we've got.) I understand the basics of how a high pressure RO works, I will start researching how to build one. I like that idea. Because, as with just about everything else down here, when it breaks it's gonna be me fixing it.

[Minggat]

Sounds like some simple math to me. How much would the capital investment cost as opposed to how much does trucked water cost over the time you expect to have the 1,000 gpd demand? At the the end of that high demand period, what can you justify? Taking out the "re-foresting" aspect, sounds like a 200+ GPD unit would handle things. Don't forget the cost of operation of course.

On the boat...As far as giving deck hardware a good freshwater rinse goes. RINSE is the key word to me. Flush with seawater, RINSE with freshwater. I too like ot be self reliant. But my personal philosophy is, the water maker is there to supplement what water I can take on, not to make all the water I would ever think if using on my boat. It's there to keep things going and especially to take care of me on long passages.

I see the swimming pool not as a drain on the RO, but as an occasional storage tank for RO product to help even out the run time load. Could come in pretty handy during those week or months of municipal utility downtime (cover it well during the hurricane). I assume you already have storage capacity in mind. That is where I would spend (some of) the capital savings of a smaller RO.

As with anything mechanical, yes, there will be the need for an outage. RO's like to run really means 2 things. 1- already mentioned is the wear and tear of startups. Shut downs on big units, for best maintenance, justify a flush with RO product. That means spending some of what you just produced. Not a significant wear and tear issue, just consider that you have to remake water for flushing . 2- Water quality after 24 hrs run time is better than it is after 1 hr run time. Not to any degree that a consumer would appreciate, but it is noticeable on the instrumentation I see. What I'm really trying to say to the consumer is- you don't get the best water out of an RO with short runs.

Don

[Canibul]

You are right, the math is pretty simple. Just looking at the proposed landscaping, apart from household needs ( which are pretty much already covered) It looks like the projected landscaping requirement would cost us $ 15,600. the first year if I buy the water a tankfull at a time.

Then, if I continued to buy the water from the water company, it would go along at about $ 10K per year to keep them trees and bushes happy, (and the pool filled.)

I have not looked at the operating costs yet, as I don't have a good idea what kind of pump I need or how much juice it's gonna eat. Thats where I start scratching my head...is it better to run a smaller pump 24 hours a day, or a larger pump 8 hrs. a day, etc. to get the same water output. The different manufacturers' pump specs are all over the place.

[Minggat]

Can't answere for operating cost of big vs small. But if they are close, I'd go bigger for the safety of over-engineering. That gives you more options if something didn't get figured in quite right.

[Tellie]

Canibul,

Sorry I haven't yet read much of your website which I plan to do. But just a few questions. Are you totally living off the grid or do you have power lines run to your house? If so what voltage do you have to work with? Will you be running things from that or will you be completely solar/wind generator? Are you running pumps for pressure or are you using a tower? If you're attempting to water landscaping you must have I asume substaintial holding tanks.
I'm no expert and I don't want to seem to question Dons experiance but 200GPD is about 8 gallons an hour. It would seem your WM would surely get ALOT of that required run time to keep up with your needs. I agree with Dons personal philosophy on water replacement on a boat if I were on it alone, but factoring in two females on board there is no such thing as just enough fresh water. Attempting to size a WM to just right makes little sense to me when all things are in flux in the future especially when it's for a home not a boat. Just for kicks I pulled this up on Yahoo

Health & Welfare:

- Personal usage should average 1,500 to 2,000 gallons per person per month
- Family of four – 6,000 to 8,000 per month

Landscape

- Lot size – 55 x 110 = 6,050 SF
- Reduced by footprint of house – 1,500 SF (Two Story)
- 2,200 SF (One Story)
- Reduced by Driveway – 700 SF
- Reduced by Sidewalks – 250 SF
- Total landscaped area – 3,600 SF (Two Story) or 2,900 SF (One Story)
- Local lawns need 1 inch of water per week
- 1 inch of water equals 600 gallons over 1,000 SF
- Landscaping requirements for One Story = 2.9 x 600 = 1,740 gal/week
- Landscaping requirements for Two Story = 3.6 x 600 = 2,160 gal/week
- Monthly requirements – One Story = 6,960 gallons
- Two Story = 8,640 gallons


Monthly Water Usage Requirements

- Health & Welfare – Family of 4 = 6,000 to 8,000 gallons
- Landscape = 6,960 to 8,640 gallons
- Total Usage = 12,960 to 16,640 gallons


This is for calculating my local usage in S Florida. Of course you have to figure out your personal usage including your landscaping. Using these figures at maxium usage as I would if I were looking at making water for a home my math says that 16,640 gallons divided by 30 days each month is 554 gallons a day which even I find high but cut down to even a third of that equals 184 gallons a day. The national average seems to be about 70 gallons per day per person not counting landscaping, car washing, pools etc. Boats and homes are two different thirsty animals. Unless I'm all wet (grin) I'd be looking a a higher GPD output than 200GPD.
Now this is were Don chimes in and shows me the err of my ways.