Microbial Water Filtration

I was wondering what were some good methods of removing microbes from water supplies. Primarily I am thinking in a manner that is used inside the home before the water comes out of the faucets or at least before it enters the home. Secondarily I was thinking in a method that would filter the water for large scale distribution (say 2-4 homes).

I understand using activated charcoal (and how to make it) to remove harmful chemicals but I am uncertain of the microbes at this point.
Any ideas or solutions would be appreciated.

I've looked at purifying water before and here are the methods I've found:

To get rid of microbials means two things, removing bacteria and viruses.

-reverse osmosis (push the water through a membrane so small only a H2O molecule can get through (while the membrane may allow any chemical molecule equal in size or smaller, this membrane is too small for even a virus to get through);
-ceramics which are made in such a way to so the way through for water is too small for viruses and bacteria (my MRS Mini has a ceramic filter which disallows bacteria which I've used repeatedly in the badlands of NM and AZ);
-ultra violet light but I'm not convinced this would kill a virus or all bacteria I suspect UV only retards bacterial growth rather than out right kill all bacteria;
-boiling, but your temperature has to be really high for a 30 minute (some say less or more.) period (I am suspicious of this because there are heat loving bacteria in the magna vents in the ocean...some might point out these bacteria won't harm us?);
-catching only the steam from boiling water, condensing this back into water (oh yeah.  no bacteria can change phase and live to my knowledge);
-chemically poison the bacteria/viruses (no thanks, I'm drinking that water and....short answer hell no.).

Here's my recommendation:
No money and stuck in the wilderness:
-boil it after running it through (grass/sand/grass/charcoal/grass/sand) layered in two or three water bottles now ubiquitous to most of the world (this works I watched someone pour muddy water in one end and clear water came out the  bottom);

Alot of money
reverse osmosis  wins every time (I was in a coal plant whose RO filters produced 99.99999% water which is poisonous to a human cause it leaches/attaches chemically to all human body nutrients but most RO systems aren't that good);

Not so much money but enough for a distiller or the skills to build a distiller
boil water to create steam, catch the steam and condense it

Ceramics but you'll need to know how to create a new one once it becomes plugged -I currently don't know how to make a ceramic filter correctly for microbials

good luck!

Orin Raichart wrote:I've looked at purifying water before and here are the methods I've found:

To get rid of microbials means two things, removing bacteria and viruses.

-reverse osmosis (push the water through a membrane so small only a H2O molecule can get through (while the membrane may allow any chemical molecule equal in size or smaller, this membrane is too small for even a virus to get through);
-ceramics which are made in such a way to so the way through for water is too small for viruses and bacteria (my MRS Mini has a ceramic filter which disallows bacteria which I've used repeatedly in the badlands of NM and AZ);
-ultra violet light but I'm not convinced this would kill a virus or all bacteria I suspect UV only retards bacterial growth rather than out right kill all bacteria;
-boiling, but your temperature has to be really high for a 30 minute (some say less or more.) period (I am suspicious of this because there are heat loving bacteria in the magna vents in the ocean...some might point out these bacteria won't harm us?);
-catching only the steam from boiling water, condensing this back into water (oh yeah.  no bacteria can change phase and live to my knowledge);
-chemically poison the bacteria/viruses (no thanks, I'm drinking that water and....short answer hell no.).

Here's my recommendation:
No money and stuck in the wilderness:
-boil it after running it through (grass/sand/grass/charcoal/grass/sand) layered in two or three water bottles now ubiquitous to most of the world (this works I watched someone pour muddy water in one end and clear water came out the  bottom);

Alot of money
reverse osmosis  wins every time (I was in a coal plant whose RO filters produced 99.99999% water which is poisonous to a human cause it leaches/attaches chemically to all human body nutrients but most RO systems aren't that good);

Not so much money but enough for a distiller or the skills to build a distiller
boil water to create steam, catch the steam and condense it

Ceramics but you'll need to know how to create a new one once it becomes plugged -I currently don't know how to make a ceramic filter correctly for microbials

good luck!

I've looked into reverse osmosis and the problem is that it doesn't seem sustainable at all.
Part of my problem is I always look at thing from a SHTF perspective and this wouldn't be sustainable or a easily done diy solution plus like you said cost is ridiculously high.

I've only recently heard of the ceramics and easy working my way to the research there.

I was looking the distilling option but I am wondering if there is a way to set this up passively without excessive fuel usage. Such as solar for example. The only problem with solar is it would be extremely slow.

Thanks for the suggestion though Orin its given me some things to look more into.

Richard Force wrote:
...
I was looking the distilling option but I am wondering if there is a way to set this up passively without excessive fuel usage. Such as solar for example. The only problem with solar is it would be extremely slow.

.....

If you noticed the Boot at Wheaton Labs, Josiah, worked on a solar device which melts glass. He used a fresnel lens which creates a super hot beam of light from normal sunlight. These lens can be found in big old 50" tvs (but not all old 50 inchers, research it first). The reason I didn't bring this up is because I wasn't sure if that was in the realm of what you would actually do.

With a little experimentation, you can easily get water to boil in a very short time and not melt your metal water tank with sunlight and a fresnel lens.

There is also the Rocket Stove Water heater which, if you build in such a way neither air nor steam can get trapped, will do the job also.

One method requires regular dependable sunlight and the other requires a small amount of wood and some skill so your device doesn't explode.

Orin Raichart wrote:

Richard Force wrote:
...
I was looking the distilling option but I am wondering if there is a way to set this up passively without excessive fuel usage. Such as solar for example. The only problem with solar is it would be extremely slow.

.....

If you noticed the Boot at Wheaton Labs, Josiah, worked on a solar device which melts glass. He used a fresnel lens which creates a super hot beam of light from normal sunlight. These lens can be found in big old 50" tvs (but not all old 50 inchers, research it first). The reason I didn't bring this up is because I wasn't sure if that was in the realm of what you would actually do.

With a little experimentation, you can easily get water to boil in a very short time and not melt your metal water tank with sunlight and a fresnel lens.

There is also the Rocket Stove Water heater which, if you build in such a way neither air nor steam can get trapped, will do the job also.

One method requires regular dependable sunlight and the other requires a small amount of wood and some skill so your device doesn't explode.

I just started looking up those frenel lenses and all I can say is wow! I have never heard of them before but I love the idea. Plus it can be used on metal, glass and other materials when needed. That is a major bonus.

Solar pasteurization of potable  water is  quire common www.solarcooking.org/pasteurization/solarwat.htm. Household quantities would be a pretty big system. Problematic when seperating potable from non-potable if that was a consideration.

Robert Ray wrote:Solar pasteurization of potable  water is  quire common www.solarcooking.org/pasteurization/solarwat.htm. Household quantities would be a pretty big system. Problematic when seperating potable from non-potable if that was a consideration.

I personally would be fine with only potable water coming into the homes so long as harmful microbes were eliminated as much as possible.

I know it may not be needed for say washing clothes but non the less I'm okay with that so long as there is not an excessive waste of energy in the process.

I would take a two part approach to this.
1) Solar hot water heater to kill most microbes.
2) Add water kefir grains, to culture good bacteria they will A) actively kill bad microbes, B) enhance the body defense system, C) displaces bad microbes

What makes you think there is a need to treat the water.
If you have a 20,000L tank the water is self cleaning

UV light of the proper size for flow will kill bacteria. It's legal in sanitizing water used in dairies. I use to dairy and raise horses and cattle.
Reverse Osmosis uses pressure to push water molecules thru a membrane. Things bigger than a water molecule won't go thru and are flushed away. But it's not like filtering water. Only about 1/4 to 1/3 of the water goes thru, the rest is used to flush and carry away the rejected contaminates. You also use filters before the membrane. Lots of info on line. I'm retired and live on a big boat. I use RO to make fresh water from salt or unknown fresh into safe fresh.  Membranes are rated at 77°F. Colder water, less output. Many RO systems on eBay. I built my own, 40 gph from salt water, much more from fresh.
If you live in a rural area that didn't have mining, no feedlots, etc., spring water and small creek water may be drinkable with filtering and sanitizing with a UV light or some added sanitizer, but get it tested. Rural meaning not many people nearby, no cities over the hill, no interstate hwy putting pollutants in the air, water is either coming out of the ground where it's collected or a flowing stream you can trace to it's source. I used spring water on the dairy.

Possible solutions
Filter: Ceramic/LifeStraw, Reverse Osmosis
Chemical: Chlorine, Ozone, Hydrogen Peroxide, etc
Energy: Ultra-Violet, Electrolysis, Heat/Boiling, possible ultrasonic
Misc:Sand Filter, Aeration, Fermentation

If I had the budget for an off the grid system to design myself, I would go with defense in depth.  

First, harvest rainwater, unless I had a deep water well.  A mechanical diverter to allow the first inch or two off the catchment surface to run off, then collect water.  Two socks in the pipe filling the underground cistern, first filled with sand, second filled with activated charcoal, both with access hatch to change them and a way to secure them so that water has to go through them to get into cistern.  For extra peace of mind, a dozen or two dozen UV LED lights along the main cold outlet pipe, sealed so that water can't short out the electronics and hooked up to a battery bank.  

A pump to get enough water up to a 1/2" inside diameter pipe and small tank to have water pressure.  A solar hot water heater with a point of use rocket stove hot water heater to supplement as necessary would be enough to insure peace of mind on the hot side of the water supply.  

I might boil and cool water for a few critical uses, such as infant formula, otherwise, minimize nasties such as blackwater bacteria from getting in in the first place, filter, and UV or heat treatment.  

In an emergency, I think I would just boil water.  If it wasn't clear, I would filter it through sand or multiple layers of cloth first.  I am amazed that I can filter clay slurry through one layer of flannel and get clear water dripping from it.  I wouldn't drink it without boiling it, but it is clear of visible clay.  

As for ocean magma vent bacteria, I doubt that they would survive a trip to your property or mine without significant human assistance.  As long as water is reasonably microbe free and I have a reasonably healthy immune system, I know that my body will deal with a few without issue and there are only a limited number of really nasty disease microbes out there in the water.  Cholera, dysentery, some forms of HPV are the biggies I can think of off hand.  Filtration or distillation will take care of most to all chemical contamination such as lead, mercury, and pesticide residue.  I assume that just because I don't use any chemicals on my lawn doesn't mean no one "upstream" on the watershed does either.  

Hmmm... studies are showing that fungii and rolly pollies can actually remove heavy metals and other contamination from the ground.  I wonder if a fungal bioremediation bed with a rolly polly farm would clean greywater or runoff water enough to be potable?  I would want to be careful to keep any fungii and rolly pollies grown under those conditions isolated from the food chain to prevent contamination as they biodegrade.  

Just some rambling thoughts on the subject.  

I don't know how official you want to be about it, but a simple slow sand filter seems to be one of the easiest ways to go, although the details of the process could take some work to get right.  From what I understand, the process relies on biological growth in the medium (sand), gradually filtering the water as it travels downward through it.  I have no idea how the chemical/biological aspects serve to purify the water.  They just...do.

It takes a fairly large volume of sand to supply a large number of people because the effectiveness of the filter relies on the percolation rate, which should be slow and I'm pretty sure continuous.

But for quick and easy I've been collecting rain from a canvas tarp directly into a pair of plastic storage tubs for the past six months and I seem to be still alive and healthy.  My only precaution is that I leave the tubs' lids on anytime it isn't raining to keep out insects and sunlight.

There is a layer of sediment, including dirt and leaves, at the bottom of crystal clear water with no noticeable flavor.

From what I understand, if I were to build an actual cistern down in the ground I could fill it up, let it sit for a period of time (?), and then draw from settled, largely self-sterilized water.  I think this is because micro-organisms gradually consume all organic material and then each other.  I'm sure dipping into the sediment would be a bad idea, since that's where any remaining goodies will be.

I admit that I could easily contract a disease from deposited bird droppings on my tarp and I really don't know what sorts of chemicals were used in my tarp.  So, you know.  I might die.  But I think the danger of raw water collection is largely overstated, provided you take some basic precautions and expect your immune system to go through a period of acclimation after you begin consuming water at a new location.  I think I had the squirts on and off for the first month, but ever since I have had no problems.

Hi guys,

I am following this topic because I want to build a waterfilter (for drinking and gardening) myself.. But Its still a bit difficult finding one way with so many opinions regarding safety, maintenance and health.
I hope you still have some suggestions regarding my specific project:

We are going to rebuild a concrete cisterna and build our house next to it. We will collect it from the roof.
The house itself will be connected to the 'ordinary' system for grey water use. Because of the use of chlorine i want to use/create a seperate system for drinking and the garden.

For gardening the cistern can be straightforward i think. A filter to remove leafs and big dirt in the gutter and a pipe to the cistern. Cleaning once a year.
For drinkink water ofcourse it will be something else. I am not sure about RO and distilliation because it will eliminate as well good minerals? Also, i would like to keep it as simple as possible.
Like nature is meant to be just using (volcano) rocks, pebbles , sand and charcoal.
I would like to make a 2nd small cisterna attached to the big one. So the water flows like this:

From the rooftop, in a big bucket of big vulcano rocks, a big bucket of pebbles to do a 'first' filter. Then going into the cisterna.
And from there to a smaller one (as we dont need all water for drinking) to the second filter of sand, gravel and charchoal.

Also does someone knows how often these filters need to be cleaned/ renewed? And i guess the slower the speed of filtering the best using small holes from the one filtering to the other filtery layer. Its difficult to find.

Looking forward to your reactions!

Regards, Sas

We are going to rebuild a concrete cisterna and build our house next to it. We will collect it from the roof.
The house itself will be connected to the 'ordinary' system for grey water use. Because of the use of chlorine i want to use/create a seperate system for drinking and the garden.

I'm going to recommend that you consider a smaller, second cistern for the garden, or simply a shallow wellpoint for the garden.  I'd wager that you're going to have more than one downspout off the roof anyway, and having two separate cisterns; one dedicated towards human consumption, the other for all other concerns; will allow you to focus your filtration and sterilization efforts upon only that portion of water that you're likely to drink or otherwise expose yourself to.  This will allow you to avoid the additional costs & maintenance of a unified, high quality water system; as the actual volume of water required for human consumption inside an average household is a minority of water use.  If you're using traditional water-flush toilets and a septic system, plumbing the toilets (and only the toilets) from the non-potable water storage will save you quite a bit in future filtration and sterilization costs; and if you decide to add livestock to your homestead, the garden water cistern will likely be of high enough quality to supply them also.

Additionally, placing two smaller cisterns rather than one large one may also permit you to reduce costs due to the plumbing required to move rainwater from a downspout on the far side of your roof.  You will find that this is expensive in it's own right, and you may just choose to not use that far roof area at all.

"Potable", safe to drink water is required for all sinks, all showers and bathtubs, dishwasher & washing machine, and water taps on the outside of the house.  Any tap that runs from the garden/non-potable water storage should be marked "non-potable" or " not safe to drink"

Thanks for the tip!
The cistern will be partly above ground (the top anyway). The roof will be mostly 1-sided, so we can use most of its surface without to much plumbing
No big costs there luckily. Costs also are not really my main concern, but i do would like to be as off-grid, just as low-tech as possible.
As i see it, it will be 2 cisterns indeed:

- a big one: partly pre-filtered with volcano rocks and so that no leaves and any other organic material falls in.
- a small one: completely filtered with pebbles, sand and charcoal to have drinking water

We don't need any extra plumbing from the cistern to the house. We will just tap the (drinking) water right away from the cistern and fill some glass bottles.

FROM the  Scientific American magazine https://www.scientificamerican.com/article/how-humans-get-in-the-way-of-clean-water/

A 2009 study that evaluated use of ceramic filters in 13 villages in rural Cambodia found that filter use declined at a rate of two percent each month, due mostly to breakage of spigots, containers and ceramic filter elements. Four years out, filtering had practically ceased. And a 2016 study of ceramic candle filters in a village in South Africa found that the filters stopped working properly months earlier than expected due to higher-than-expected levels of use. Eight months after distribution, people were still using the filters, but none produced water free from contamination.

This articles talks about efforts to get clean water to communities.
Heating water certainly works, but having 3 rd communities heat water consumes resources hat are limited and adds to the issue of smoke related deaths in those communities.

Some snippets

 Some studies, with mixed results, have examined whether establishing leadership roles for women—who are often responsible for a household’s water supply—could improve long-term adherence to water treatment.

In a study in Kenya that ran from 2007 to 2011, chlorine dispensers were placed right next to pipes providing continuous water flow where villagers went daily to fill up their jugs.
After filling a container, all the villager had to do was place it under a chlorine dispenser and turn a knob.
The walk home took care of mixing. That convenience seemed to pay off:
Three and a half years later, 51 percent of village participants had adequate levels of chlorine in their water, compared with only 6 percent of people in similar villages.
Those people received only promotional messaging about the value of chlorine, then had to go pick it up themselves.

Kremer, who worked on the project, says he’s excited about efforts to go one step further and design completely automatic chlorine dispensers that apply the right amount of chlorine as water is collected at taps.
Removing extra steps also applies to payments, he says: People will pay for access to water, but often not the cleanliness of water.
Thus, bundling the costs together should be more effective than adding a separate fee on top.

I realise some of the above will not relate to us all, but it points out something that works.
And in 1st world countries the chlorine can be eliminated by sitting an open container on a table for a while.
If you dont want to use Chlorine, for what ever reason, heating is the only alternative method I think, but it has issues, fuel containers of boiling water.

But as I have mentioned before, letting water sit in large tanks for a long time also works.

John C Daley wrote:F
If you dont want to use Chlorine, heting is the only method I think.

Not the only method.  Expanded silver filtration is also a proven method.  That's the method used in a "Big Berkey" water filter.

I have seen oyster shells used to trickle water over repeatedly to clean waste water.
It may work for drinking water.

Don't know if anyone has said it yet, but google "slow sand filter".
The whole city of London gets it's water from the river Thames, one of the most polluted rivers around I do believe.
I use one that's built from a plastic 55 gallon barrel to filter drinkiong water collected from my roof.