Rain water harvesting and slow sand water filters

Update, May 15:
44 percent of Washington state is in drought emergency condition From the department of ecology’s website: “24 of Washington’s river basins are in a declared drought emergency.” Some of our neighbors, who are on public water systems, have already received notices of water use restrictions.

Update; April 2:
The SWE (Snow Water Equivalent) is less than 50 percent for most of Washington state.

Update; March 25:
Drought has been declared in three areas

from the above website:
“Currently snowpack statewide is 26 percent of normal and the forecast calls for little to no snowfall into the spring and warmer-than-normal temperatures through the summer.”

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A large percentage of the snowpack in the Casacde mountains has melted. By Friday, February 13, the freezing level is forecast to be above 10,000 feet. Snow will melt. 

Rainfall totals are near average here for January and February to date, and temperatures have been above average for this time of year.  Unfortunately, this has caused lots of snow to melt in the Cascade mountains.  This means that unless we have some really cold weather and a lot more snow in the mountains, there may be water shortages this year in some areas. Those who have rain water harvesting systems set up will have plenty of water. People who depend on snow melting may have issues with water; it just depends on how much snow falls in the coming months in the mountains. There could be more cold weather and snow on the way for the mountains and that would help considerably. By next week at this time the forecast is for some cooling. Let’s hope it snows up there a lot. However, it is nearly the middle of February and enough snow to make up for what has been lost is not likely. If the summer gets hot and dry, and it may very well do just that, things could get quite uncomfortable. Be prepared, set up your rainwater harvesting systems now.

We found the 5 gallon slow sand filter design to be inferior to the 55 gallon design. The five gallon filters just don’t work as well. They are less efficient at removing biological contamination at best; and actually introduce contamination at worst.

Another study totally not related to ours found basically the same results (the need for 2 separate containers because 1 five gallon container was not enough to provide adequate filtering):

http://faculty.mercer.edu/lackey_l/documents/CompletedThesis.pdf

(see page 56 in the conclusion section)

When constructing a slow sand water filter, make sure the sand used is not contaminated.
Make sure the sand source provides the correct type of sand.
Running some chlorinated water through the filter before starting it running with unfiltered water is a good idea. If the sand is contaminated with bacteria, the filter may not produce clean water. Running five gallons of chlorinated water through the filter initially, will kill any residual bacteria present in the sand. Do not use chlorinated water after the first decontamination run, just the first time the filter starts, that’s it. After that the filter will build up a biolayer on the top of the sand where it is supposed to be.

Filters 1, 2, 3, 4, and 5 are still operating and producing clean water. The three pond filters are also still operating. Filter 1 was started in 2007.

We are working on a pdf that has the most usefull information from all three websites and this blog summarized in one document. This will be available for download sometime in the near future (2 or 3 months).

Only two of the five gallon filters are still running. The others have been removed from use because they just do not work dependably enough. The two five gallon filters still running are set up in series. Water from the first flows directly into the second. So far, it looks like this set up may work; however the flow rate is very, very slow; not much more than 1 litre per hour.

For the past 4 years, we have been working with a biological sand water filter applied to filtering water that is used in a pond. The  preceding link takes you to one of our other websites where the assembly of the filter is shown in detail, along with some photos of the pond. The filter has continued to work flawlessly since August of 2010. As of today (December 23, 2014) the filter is still working and keeping the water crystal clear. Birds, and squirrels use the pond continuously. The water stays absolutely clear 24/7, with the exception of the times when it is frozen. Every year so far, the pond has frozen along with the filter. There has been no damage with the exception of the water level falling considerably when the pond freezes over. There are no fish in the pond, but there is an abundance of organic material constantly falling into the pond. We clean out the bottom once a year. That is all we have to do with the exception of adding some harvested roof water during the summer months. 

All that is used in the filter is sand and gravel. The sand does not need to be changed. The only filter maintenance needed involves taking the top off of the barrel and gently agitating the surface of the sand inside to break loose the heavy layer of active organisms in the biolayer. That’s it. Very simple. Organisms in the water grow on the surface of the sand and literally eat the organic material in the water leaving only purified water to flow down through the rest of the sand and back into the pond. The filter has an overflow that directs back into the pond so no output flow regulator is necessary. Gravity does all that work on its own.

It is now November 21, 2014, and all of the filters that were frozen have thawed out and are running again. All of the filters here, with the exception of filter 2 and filter 3, were frozen for 10 days. The temps were below freezing for 8 nights in a row. Filter 2 and 3 filter water from a surface well that has a pump that runs water heated by a 100 watt light bulb. This was enough to keep the filters from freezing up at temps of 23 degrees F at night and 33 degrees F during the day for 8 days. The water runs 24/7 through the filters at a very slow rate of 20 gallons per hour. Nothing has been done on the 5 gallon filter. All but 2 of the 5 gallon filters were removed from service because they did not work. The two remaining filters run in series with the coarse sand filter first, and the fine sand filter second. No tests have been possible because of freezing weather. Now the 2 5 gallon filters will need to run for at least 2 weeks before a test is possible. The weather may not hold. It may be well into next year before any tests are possible.

A wind storm came through, early this month,  with very strong winds from the north northEast and wind chills of 10 degrees. (That is really, really cold for this area). We very seldom get strong winds from the east or Northeast.  In 65 years I do not remember another time we have had strong winds from the north east here. The storm blew down a huge tree on one of our buildings and that has taken all of my spare time to clean up. Much damage and much repair and clean up yet to do.

Water can be taken for granted if it is conveniently available. That is a huge mistake. Without water, a person cannot survive much longer than 4 or 5 days at the very best. Lots of things can happen that will interrupt access to water. One such situation nearly happened in 2012, but it was not a catastrophe thanks to a near miss. Quote from the NASA website: “Two years ago, Earth experienced a close shave . . .” “but most newspapers didn’t mention it. The “impactor” was an extreme solar storm, the most powerful in as much as 150+ years.”

Read that article closely. Then read this: http://en.wikipedia.org/wiki/Solar_storm_of_1859

Now, what on earth does this have to do with water. If you read both articles carefully, you will find that a geomagnetic solar storm (sometimes referred to as a coronal mass ejection) of significant strength is capable of shutting down electrical power to nearly everyone on earth. This means no gps, no electricity, no internet, no electric heat . . .  .   The one in 1859 caused arcing on telegraph lines, and caused fires in the telegraph offices. In this day and age, a storm as strong as that one (like the one that missed us by about a week in 2012) would shut down the internet, and the electrical power that brings water to most people everywhere. There would be no usual public water anywhere, at the worst, at best it would be very difficult to find.

Please, don’t take my word for it, read what the scientists say. At the wikipedia site, there are referenced 41 (some scholarly) articles on this type of occurrence.

This does not mean panic, and get paranoid. Things would be back to normal all over within several years or less, and there should be disaster plans in effect all over that would be able to handle this type of event in a few weeks or so. But, in the mean time, finding water will be a real pain, to say the least.

Set up a couple (maybe more than a couple) of rain barrels and a water filter; you may be really glad you did.

For the past eight years we have been building, testing, and operating small slow sand filters. What we have discovered here coincides very closely to some of what is covered in this document published by the State of Washington in 2003.  If you are interested in finding out more about slow sand filtration, this document is excellent. There is more information for larger filters in the pdf at the link to the 2003 document, but the theory of operation is basically the same for the smaller filters we describe here at this location.