Off-Grid water filtration system

AGB · March 2022

Hi
I have a situation that I am not able to finds reasonable solution for. I live Off-Grid both water and PV electricity. My current water source is from a river pumped though three stage filters (50 micron, 10 micron and 5 micron) I also have a large carbon filter that I haven't connected yet. The water look clean but we are not using it from drinking or cooking instead we use bottled water for that.
I am thinking what would be the cost effective way to treat the water for domestic use including drinking. Before I invest heavily into any system, I figured I would ask fellow Off-Griders.
One option I am thinking of is to use UV filter to sterilized the water just after the pressure tank. Another option is to invest in reverse osmosis system. Another option is to dig a well and pump from there instead of the river. The only problem with the well is the water is hard even along the river back so that will also require desalination.
Any suggestion is welcome.
If this has already been discussed on this platform, please direct me there and disregard this thread.
Thank you all.

Photowhit · March 2022

With a sociopath on the warpath, the empath in me has pondered what I could do to make my rainwater catchment potable...

I know the UN uses simple ceramic filters in 3rd world countries to filter out most contaminates, I use a ceramic filter for water I drink and cook with even though I'm on county water system.

Ceramic Filtration | The Safe Water System | CDC

Some ceramic filters work down to the virus level of filtration, silver impregnated also add a level of security, an addition UV exposure would be added security.

Berkey has tested down to virus levels and claims it removes 99.999% of material in that range, and calls their Berkey black filters water purifiers. (I think California doesn't like this claim, fwiw.)

Does Berkey Remove Viruses? (berkeyfilters.com)

I would be comfortable showering with your level of filtration, and think you are on the right track. If Thermal Nuclear War breaks out tonight. I'll live with filtering rain water through 2 ceramic filters...

UpNorthMan · March 2022

We use this at our cabin. We refill our 5 gallon water jug from a local spring. It filters pretty much all solids. Nothing dissolved. I rigged a pull system to raise and lower. They also make larger capacity systems. They are easily cleaned.

Ed

https://lifestraw.com/products/lifestraw-family-emergency-water-filter

Graham Parkinson · March 2022

We use a low power LED-UV Arrow 5 unit for treating roof rainwater at our off grid cabin.

Acuva makes a range of sizes from van camping / boat sized to sizes for larger cabins. We are very pleased with ours. We have a 20 micron filter upstream to get the coarse sediment out. The UV units come with a silver impregnated carbon post filter to remove chlorine and other objectionable tastes from your water.

https://www.acuvatech.com/our-products/

They have significant advantages over the old fluorescent tube UV lamps. The new UV LEDs have sufficient joules/cm2 to disinfect, much lower power draw and longer life. Most importantly they incorporate a flow sensor and are instant on so there is no warmup time requiring flow lockout solenoids and complex controls. As a result of the flow sensors their standby load is vanishingly small.

BB. · March 2022

Have you sent your water in for Analysis? Different water "contaminants" may need different solutions.

-Bill

AGB · March 2022

Thank you all for the suggestion. BB, I haven't sent the water for testing yet but that is a good starting point.
Graham, I love the LED UV filter. Power efficiency longer service life is key.
The ceramic filter sounds good. That would be a good stopgap while I figure out all the pieces.

Wheelman55 · March 2022

Here’s another option that has a flow rate of 10 gallons per minute and uses no electricity.

https://www.uswatersystems.com/us-water-silecte-quantum-disinfection-system.html

I just bought this with two prefilters: a 5 micron for sand (we use rain water) and the US Water “Interceptor” cartridge for heavy metals.

https://www.uswatersystems.com/us-water-interceptor-4-5-x-10-222-filter-cartridge.html

SolarTexan · March 2022

We get our water from a 3.5 acre pond on our property. The water is initially filtered by a "pond filter" in the pond, and then it passes through two coarse "screen" type filters before being injected with a chlorine solution (digital proportional metering) and entering a 55 gallon tank, the first of three tanks in our water room. The water then passes through a 50 micron filter and then a 20 micron carbon filter into a second 55 gallon tank. From the second tank, the water passes through a 10 micron carbon filter, a 5 micron filter, a UV filter, and then a 1 micron filter and into a final 330 gallon tank where we have our pressure pump that pressurizes our water system. It might be a little overkill, but it works. Our flow rate between the tanks is about 3 gpm. The final tank to the house is about 15 gpm at 50-70 psi, with a pressure regulator set at 50 psi at the house.

AGB · March 2022

SolarTexan said:

We get our water from a 3.5 acre pond on our property. The water is initially filtered by a "pond filter" in the pond, and then it passes through two coarse "screen" type filters before being injected with a chlorine solution (digital proportional metering) and entering a 55 gallon tank, the first of three tanks in our water room. The water then passes through a 50 micron filter and then a 20 micron carbon filter into a second 55 gallon tank. From the second tank, the water passes through a 10 micron carbon filter, a 5 micron filter, a UV filter, and then a 1 micron filter and into a final 330 gallon tank where we have our pressure pump that pressurizes our water system. It might be a little overkill, but it works. Our flow rate between the tanks is about 3 gpm. The final tank to the house is about 15 gpm at 50-70 psi, with a pressure regulator set at 50 psi at the house.

That is great. What is the chlorine injector you are using? Als do you have some pictures to share please?
This sound like a possible solution for me.

mike95490 · March 2022

I've got a complex, low power system, that will sanitize our pond water.   A slow sand filter.
   https://en.wikipedia.org/wiki/Slow_sand_filter
no chemical usage, properly strain the gunk out of the water before going into the filter.   It takes a month to develop the organic digesting " Schmutzdecke ".
Since it's a low flow, continuous flow ( mine is sized for 7GPH ) filter you need a holding tank.   I have a 1,500 gal holding tank that uses a
Ozone generator and a airstone to give the water a final polish and keep it fresh while sitting. ( 50 watts for UV tube & air pump, 24/7 )
Either system properly installed, gives 99% pure water, stacked in tandem, it's pretty reliable.
Maintenance consists of at least weekly inspection that things are flowing right, and nothing clogged.
   All tanks are gravity fed from raw, to roughing filter, sand filter, holding O3 tank, and then gravity feed to the house at 70psi
Raw water is pumped from pond in daylight hours, to raw water storage, about 180' above the house, on a hillside.

inside the 1,500 gal storage tank:

Flow regulating meter for slow sand filter: ( 0 -25GPH via Grainger )

failed electrostatic ozone generator:

Image: https://us.v-cdn.net/6024911/uploads/editor/3y/63pkm4w5ndu9.png

While the electrostatic / silica /solid state O3 generators work, they require DRY air ( I eventually tried stacking 3 silica air driers, but they would only last a couple days before they were depleted and needed regeneration in the oven.) Barely passable in summer at 20% RH, but unworkable in winter with 60% RH. So I have gone back to the 8W UV light, to generate the ozone, using a deepwater aquarium pump to drive the system. The UV tube has a phosphor port on the side that glows while the tube is working.
Been using this over 12 years, and just keeping the parts clean is the only work, new UV tube every 18 months, and a new $60 aquarium pump every 2 years ( the rebuild kits only have the check valves, no diaphragms. ) I use washable aquarium filters instead of a $20 cartridge every week.

Off-Grid water filtration system

Comments