Individual Surface Water Treatment Options 2

[edwards1800]

I need to design small surface water systems for individual homes. To my knowledge, there aren’t any regulations directing certain disinfection requirements for individual homes in my area (MN-WI-MI).

Situation: water is from Lake Superior, which is relatively good, but may have minor unpredictable (at least for me) seasonal changes. The system needs to be suitable for cold climates. The biggest constraint is size, whatever purification I use needs to fit in a small closet.

Here’s the kicker: Due to the lack of regulations, my supervisor would like to meet requirements as if this were a small non-community surface water system. Without the rigorous testing criteria, I believe this means that I need a filter and disinfectant.

I am looking at home membrane filters (Homespring), and UV treatment (Hallett, Trojan, Wedeco, etc). I also need more guidance on the intake screen/structure/holding tank.

Question: Am I going down the right path? Does anyone have any tips on a small setup like this?

 

[bimr]

Yes, you probably are going down the wrong path.

Rather than worry about individual intakes on a large lake, you should recommend individual ground water wells. A Lake intake will have all sorts of issues such as permitting, seasonal water quality, weather, etc.

The ground water wells will probably have the same water quality as the Lake, except all the seasonal sediment will be gone. I doubt that you will have any treatment if you use a well.

You also will not have to address water quality issues like giradia.

 

[edwards1800]

I'm sorry; I failed to mention that the homes in this particular area cannot get good groundwater. That is why they use the surface water.

 

[BigInch]

Isn't it just safer to follow the requirements for surface water protection that are in place for community systems, but without the testing program? The minimum standards are there and it shouldn't really matter if there are 25 people drinking it or only one. If I was the #1, I wouldn't want to drink worse water just because it was only me, I'd want better water, because it is just me.

Anyway, here's the min MN standards for surface water protection. If you want to be successful in your business, I'd recommend following them and selling it to your customers. Leave the poor quality stuff for the non-professionals.

http://www.health.state.mn.us/divs/eh/water/swp/index.htm

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[edwards1800]

BigInch,
Yes, you hit the nail on the head. Given space constraints, I'd like advice on how to meet community requirements (without the reporting requirements) for small homes. I believe that means making a system that gets water from the lake (which may be frozen on top), through a filter, and disinfected.

 

[bimr]

What do you mean when you say that you "cannot get good groundwater"? Are you talking about flow or quality?

In regards to the lake intake, you will probably find that it is difficult to design an inexpensive intake.

Do you have permission to put a pipe out into the lake?

How do you plan to keep the intake from freezing?

A municipality would probably directional drill the intake pipe out several hundred feet into the lake bottom and then come up through the bottom of the lake. At that location, an intake screen would be installed. You would also have to be concerned about zebra mussels fouling the intake.

That design is of course impractical for a small homeowner.

I would think that you would probably try to directional drill a well under the lake bottom rather than try to pull off surface water.

You mentioned other homes, what type of intake do they have?

In so far as treating the lake water, the state of the art treatment right now is membrane filters and disinfection.

 

[Zambo]

bimr seems to have a point that a borehole would seem to be a good solution and relatively inexpensive. The borehole should not have the problems of variable seasonal quality. What are the reasons for the groudwater not being available?

 

[edwards1800]

Thanks again.

Poor excuse: the decision to go to surface water was made before I got here. Existing wells in question were high in lead, cadmium, boron, strontium, and others. I'll have to look into the legitimacy of these claims.

Cost might be a factor. I'd like to get a single system that I can apply in different situations, with only a couple variables, costing under 20k.

One current system is using a gravity intake from the lake into a buried tank. It is then pumped through membrane and UV in the house. We are having trouble with the UVT of the water here. It seems that the water coming out of the faucet has lower UVT than water I can scoop from the lake. This is degrading the UV performance. Water testing has shown that the lower UVT is due to tannins. I think there may be some organic material in the buried tank causing the tannins.

Other current systems are experiencing similar problems. I am evaulating the possibility of using a tannin removal system (something like ion exchange)or switching to Cl disinfection. I think Cl is higher maintenance than the original designers wanted.

Since available space is the limiting factor in both the above options, I am wondering if there is a pre-fabricated insulated shed (maybe 6'x6'x6') that can be equipped with pump, pressuretank, filter, and disinfection apparatus. This could then be placed on sites, and then the intake structure and insulated (heated if necessary) pipe to the house could be added. Can you recommend a shed like this (I imagine it might be easier to build on site)?

 

[bimr]

plastifab sells such sheds:

http://www.plasti-fab.com/shelters/shelters.html

 

[edwards1800]

bimr,

I ashamed to think about the amount of time I spent looking for those sheds. Thanks, I should have checked here long ago. If I can use those, then a design would be much easier.