#7 Water

This entry took me longer to write than I hoped. Spring and summer here means there is a lot of work in a short time, and that leads to other things being placed on the back-burner. Writing was one of them...

Water: everyone takes it for granted. It is a key resource to have access to when going off-grid. In many ways, it's more important than electricity. I know that there are several methods to become independent of the public water works, but only a few of those make real practical sense in a northern climate. In addition, water doesn't just entail the clear stuff for drinking, washing and cooking: wastewater is equally important to deal with correctly so that it doesn't negatively impact your little piece of heaven in the long run. 

Sources of water

One of the popular ways to become independent of the public water supply is rain catchment. A lot of popular off-grid YouTubers use this method, think of Life Uncontained, Green Dream Project, and others. The problems with doing this in my climate is that a) the tank with water would freeze in winter unless I put it underground and b) for a substantial time of the year, water from the sky comes in the form of snow. The first issue could be solved (even though digging in my area would be difficult because of the bedrock) but the energy needed to melt snow makes this method infeasible for me. There are people in northern climates that use snow in winter as their source of water, for example Russel at Raspberry Rock - but it's labor and energy intensive, and doesn't really scale to anything bigger than a small cabin with basic needs.

A river or lake (or maybe even a spring) can also provide a source of water, and if you're lucky and the stream/river moves fast enough it can even be used in winter. Examples of this in northern climates include Shawn James over at My Self Reliance but I believe he's also exploring alternatives such as a sand point well since it, among others, adds convenience compared to hauling water from the stream or relying on pumps to move the water. I don't have access to a stream nearby, and I'm at the sea, so these options won't work for me either. A lake would also be problematic in winter due to the thick ice layer that develops. Even the sea freezes over completely here.

The main conclusion from all this is that with any easily accessible water you end up having issues in winter. The solution to this is a deep well (also called a borehole). Now, in contrast to many other places around the world, getting a borehole where I am is pretty straight forward and affordable. For one, you don't have to drill very deep: 40 meters is typical. Because of the bedrock, drilling down is also surprisingly cost effective per meter compared to loose soil, clay, or other stuff. I know this sounds contradictory, but because of the bedrock you just need about 6 meters of well casing at the very top of the well, the rest is just a hole in the bedrock. It just took a few hours of work to get my well drilled; the cost was €4500 including installation of the pump and water pipe.

The advantage of not having to drill very deep is also that you don't need a huge pump. I went with a Grundfos SQE 2-55, which is a 1kW variable speed pump with soft-start. This means it runs just fine on my small 'winter time' inverter I wrote about here. The pump is configured in a constant pressure mode with a 8 liter pressure vessel and the control unit. I was able to pick up the whole package with pump, CU301 control unit, pressure vessel, and 40m power cable for €1300. 

All in all, I think this is a pretty good deal to get a year-round reliable supply of nice and cool water. I understand that not everyone can do with just 40 meters; some places need 100 meters and more. This in itself also increases not only the cost of the drilling, but also the cost of the pump and its power requirements. 

Water quality

After I drilled the well I did a water quality analysis, which is something you should do no matter what your source of water. Based on some geological research I did on the area, I basically knew what to expect, but having it black on white on the test results paper definitely brings some additional peace of mind. The results showed that everything was pretty much perfect, except for these that were above recommended values:

- Iron (and Manganese) content too high
- Chemical Oxygen Demand (COD) too high
- Hydrogen Sulfide gas presence (smell)

The first one is typical for a borehole in most places. Iron in itself does not poses a health issue, but it discolors ceramics, clothes, etc. and doesn't taste good. Manganese has more recently been linked to developmental problems, so this one is more of a concern - but not in the quantities present. Iron and Manganese tend to go and in hand: when you have one, the other is most likely present as well.

Chemical Oxygen Demand (COD) is a way to check the amount of organics in the water. These organics in my case come from water seeping into the ground carrying tannin, lignin, and other plant material. This is very common in Finland, and for example most lakes here are very rich in these materials. They're not dangerous, but they give the water a certain taste and color that can be unpleasant.

The last one on the list is Hydrogen Sulfide gas. This gas is detected easily when smelling: its smell is often compared to that of rotten eggs. It is toxic in larger concentrations. It is naturally occurring as a result f decay and chemical reactions with soil and rocks. 

I have installed filters to remove all of these undesired properties, more on that later. In addition to the above, the test included analysis for other heavy metals such as lead, nitrates, nitrites, sulfides, cadmium, arsenic, etc. I also tested for E.Coli and Coliform bacteria in addition to a separate test for Radon gas. While I knew the chances of Radon were slim (because Uranium content was very low), it's still something I wanted to make sure of. Radon is created as a decay byproduct of naturally occurring Uranium, and can lead to health effects due to it being an alpha emitter, which can cause problems when ingested or inhaled.  

No matter what your water source is, you should run water quality tests on a regular basis and install filters. Rivers and lakes can change based on environmental factors, captured rain water can carry bacteria from e.g. bird droppings, and well water can also change based on seasons and other factors. I think it's worth spending the money making sure your water quality is good.

Filters

I wanted to have clean water for the house. While a little bit of iron is no big deal and hydrogen sulfide can be removed easily by for example aerating, even a small amount of iron can stain the shower, toilet and any clothes you wash. It also affects the taste. There are a few commonly available filters that can be used easily to make the quality of the water much better. Which filters to use depends on your exact situation; the ones I mention briefly below are specifically for my needs, but the general principles stay the same.

One of the most common set-ups is the so called 'Big Blue' trio set of filters. They look like this:

There are a variety of filter cartridges available such as for particles (which should be your first one in line in any case), iron/manganese, activated carbon, organic components, etc. including a whole bunch of specialty cartridges. The advantage of these is that they don't require any power and sit inline with the water supply. The disadvantage is that, depending on the quality of the water coming in, you need to replace the filter cartridges more often and some of them are quite expensive. Total cost for a typical set-up is around €400.

The other very common set-up is often confused with a water softener. It consists of a anion/cation ion exchange resin with the addition of e.g. KDF-85 to remove iron/manganese and hydrogen sulfide. These look like this:

The blue cylinder contains the filter resin, while the white box next to it is a salt brine container. The advantages of this filter is that the resin has a very long life time, a decade and more. The salt brine is used to regenerate the resin at regular intervals, and this salt becomes your only consumable and is significantly cheaper than the filter cartridges of the other type. The disadvantage is that this filter requires power for the resin regeneration process, and uses quite a bit of water during this (back-washing). It's also more expensive: typically around €1000. As I mentioned, this filter gets often confused with water softeners. While they work on similar principles (and as a result this filter also softens the water), a water softener is primarily used to remove calcium and magnesium from the water. 

So, which one do I use? The answer is: both. Having both filter systems installed gives me the most flexibility. I also use some cheap big blue filters as a pre-filter for the back-washing filter. This generally means I need fewer regeneration cycles for the resin, and I can use cheaper big blue filters since I only use it to pre-filter for some aspects and don't need perfect output. In case something goes wrong with either set-up, I can still get clean water by either putting the more expensive filters in the big blue, or rely on flushing the back-washing filter more often. In either case, I have clean drinking water from my well. The filter that works best for your particular case is entirely dependent on the quality of your source, so be sure to run the tests before buying anything.

If you have particular bad water, or you want to make sure the water is perfect, you could consider a reverse osmosis system. Personally I did not want to go through the expense for a full house system. I left the option to add a per-tap version in the future: they're much cheaper and just fit in the kitchen or bathroom under the sink. For the time being however, the installed system works fine. The feeling you get when your own source of fresh, clean water comes out of the tap is indescribable.

Wastewater

Something I definitely wanted to get right from the first time is what to do with the wastewater. Typically, people distinguish between gray water and black water, whereby the former is e.g. the shower, the latter is the toilet. The water from doing dishes however is sometimes also considered back water due to food-born pathogens (think salmonella, etc.) that can be present. I investigated setting up separate processing systems for grey and black water, but in the end I came to the conclusion it would become too complicated and unneeded. Instead, I opted for a system that deals with all the wastewater in an efficient and effective manner. 

Now, you may ask: isn't that just a septic system? Put in a tank, add a leach field, done? Well, no. For one, there are strict regulations in place in Finland to make sure the impact of wastewater at summer cottages or remote areas (there are a lot here) in rivers and lakes is minimized. For this, the wastewater has to have phosphorus and nitrogen (nitrate/nitrite) reduced before the processed water can be discharged in nature. This means among others precipitating phosphorus out of the water, which is done with a chemical like poly-aluminium chloride, just like in a large wastewater treatment plant at a municipality. As far as I know, this requirement is fairly unique to the Nordic countries. 

The other reason is that traditional septic systems require a pretty large leech-field, which would mean I would have to cut down a lot of trees. An alternative is to use an aerobic process instead of a typical anaerobic process in traditional septic systems. This has the benefit that the system can be much more compact without the need for a leech-field, just a small area with rocks where the water is discharged after treatment. The disadvantage is that it needs a fan to aerate (you might remember that I had that in my power audit) and thus needs some power, but it's a small price to pay.

I guess you realize by now that what I needed to install was a mini water processing plant. Something like this:

In a first stage, a sludge separation occurs. Anaerobic processes break down solids and remaining solids accumulate at the bottom for later removal. In the second stage, the aerobic processes further break down nutrients and potential pathogens. A container with poly-aluminium chloride sits under the kitchen sink and uses a timer to periodically dose some of this into the drain. This will remove phosphates up to 99% from the wastewater and can be removed at timely intervals from the septic system for processing off-site. The system has a BOD (Biochemical Oxygen Demand, a measure of the amount of oxygen required to remove waste organic matter from water in the process of decomposition by aerobic bacteria) reduction of 98% and total nitrogen reduction of 55%. The system I have installed is the "IN-DRÄN biobädd 5ce" designed by Swedish company Fann. It can handle about 900L of wastewater per day; plenty for a family of four. At the time I installed it, the cost for this plant was around 5000€. 

Conclusion

I think having a reliable and clean water source off-grid, and a way to process wastewater, is more challenging than any other resource. Power is easy in comparison. It's not just a matter of collecting rain water and you're done. In my environment, options for water sources are very limited and a drilled well is pretty much the only truly reliable one. Filtering and water quality testing is an added expense, but one that I really think should be done in any kind of off-grid water situation. Requirements for the treatment of wastewater vary worldwide, but in my case I'm actually quite happy that the regulations mean putting more thought in what happens with the wastewater after it goes down the drain. It not only means limiting impact on nature, but also makes sure that the wastewater I flush today doesn't end up contaminating my water supply tomorrow.

Have a nice summer (or what remains of it); I've just finished another layer of stain on the house, and I've been collecting the first mushrooms of the year - autumn is approaching quickly.