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Use 'charred' biomass to clean/filter/purify water - BIOCHAR! Use 'bone char' to remove fluoride!

Posts: 104
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hello permies.  i didn't know best place to file this post!  help me if i filed it in wrong forum.

I wrote a blog post about what I learned about water filtration methods, and wanted to share here.  i'll post an excerpt about methods employing biochar, but a post about all methods I learned about can be found here: https://impressionsofaholobiont.com/2018/03/28/drinking-water-solutions-filters/.  i didn't want to clutter this post with everything, since i thought most people would be interested in the biochar solutions, so I just copied and pasted the biochar-related stuff.   I understand that others have posted stuff already about using biochar to filter water, but I thought the way I wrote about this might help someone understand it - as I found it difficult to comprehensively grasp these concepts, as I would find a piece of information here.... and a piece there....

Use ‘charred’ biomass to clean/filter/purify water – BIOCHAR!
may 14, 2018 by holobiont, posted in drinking water
Many wonderful people have been addressing the issue and lack of healthy water in communities around the world for many years through non-profits and NGOs.  Although these efforts address the most acute threat – microbiological organisms which quickly cause illness and death, they have not addressed the equally lethal contaminants that lead to chronic illness and slower death – namely industrial chemicals, heavy metals, and agricultural chemicals, also known as organic contaminants.  If it were not for these chemicals, filtering water through clay would be sufficient to remove the microbiologicals, and wouldn’t require energy during filtration.  Even boiling water would be sufficient to kill pathogens, although boiling does not remove, and actually concentrates the endotoxins from the pathogens.  But as things stand today, removing just microbiologicals is no longer sufficient to prevent disease.

I recently learned about one organization addressing BOTH issues — the organization is called Aqueous Solutions, and was founded by Josh Kearns.  He has created a website with videos and tutorials so that we can all benefit from the knowledge his scientific research team and development team have amassed and tested.  Josh Kearns explains in this YouTube video how his team started with the biosand filter, and expanded the concept to effectively filter out heavy metals and other organic contaminants as well as microbiologicals.  Their knowledge is critical to the improvement in health in developing nation communities, who have no municipal water purification or water treatment systems in place, and yet are often the ones literally living downstream from the factory making the consumer goods for first world nations, and dumping all the chemicals into the river the locals use to survive.

Although I have access to treated water from municipal treatment plants in my city, there is a need for us to learn these methods as well, particularly as they could eliminate the chemicals that still remain in the treated water, and are sometimes added during the treatment process, such as aluminum salts, in addition to the fluoride which is added to supposedly ‘medicate’ the public’s ailing teeth.   We need to bring water purification back home, and interrupt yet another way that we continue to pollute our natural resources, and ourselves.

There are five main ways to treat water, as shown in the list below, but Josh Kearns focuses on #4: filtering media – in gravity-fed systems.  In this post we will discuss both multi-stage pressurized systems and gravity fed systems.

1. Distillation
2. Deionizer, with or without exchange resin
3, Reverse Osmosis
4. Filtering media – used in multi-stage pressurized systems OR gravity-fed systems
5. Ceramic
6. Activated carbon or biochar
7. Sand
8. ***Harvesting and filtering rainwater

Before we get into the details, it is important that before you select and build any water treatment system, it is important to identify which contaminants reside in your water.  This knowledge will allow you to target a solution that effectively cleans your water.  For example, if you are drawing from a well, you may not have to worry about filtering fluoride.   Read this post first to learn how to assess your water: https://impressionsofaholobiont.wordpress.com/wp-admin/post.php?post=477&action=edit

Short version: almost all water contaminants can be filtered with activated carbon or biochar made from the common coconut shells, and ALL contaminants (including fluoride) can be filtered with activated carbon or biochar made from bones.  The easiest way for those of us in urban or suburban areas to use commercially manufactured activated carbon filtes is in an under counter multi-stage system.  The second easiest way is to use commercially manufactured filters in a gravity system such as the Berkey system, and the most ecologically friendly way to use these materials is in a Slow Sand Biofilter/Biochar Adsorber, as shown in the following hilarious video from the PunPun farm in Thailand.  

[youtube]youtube  [youtube]https://www.youtube.com/watch?v=BADUXU7PRk0[/youtube][/youtube]

Carbon (Activated)

Char, which is essentially burned material, such as wood or other biomass like coconut shell, has been used as a water filtration media for ages.  However, we are regaining some of this knowledge and research continues.  Carbon is simply the result of biomass (like wood, or coconut shells) that has been burned at high temperatures in a low-oxygen environment.  Commercial manufacturers grind the burned biomass into fine powder, and through proprietary processes, form the powder into cylindrical filters.  The best carbon filters available from manufacturers like Berkey are ‘activated carbon from coconut shells.’

There are several carbon filter manufacturers.  I will focus on Berkey (New Millennium Concepts), because I have personally used their carbon filters.

Although these coconut-shell activated carbon filters remove bacteria, viruses, and numerous heavy metals (see their test results), they DO NOT filter out fluoride after the first hundred gallons or less, as Berkey explains on their website, because ‘filtration elements that reduce fluoride begin to lose that ability quickly,‘ and that ‘it takes a very large amount of media to reduce small amounts of Fluoride.  Therefore, there is not enough media in filters to reduce fluoride effectively over the long term.‘

The PF-2 filter that you can purchase/add to your Berkey system, designed to filter out fluoride and arsenic, consist of aluminum oxide, which is one of the very few materials that can remove the insidious fluoride.  However, this aluminum filter may release aluminum into water that you’ve worked so hard to gravity filter in the first place.  Berkey’s knowledge base says:

“Pure aluminum is water-soluble, it is highly reactive and it is associated with negative health effects.  By contrast, aluminum oxide [that we use as the media to filter out aluminum in the PF-2 filter] is not water-soluble; it is inert, is very stable, and is not associated with negative health effects.”  

While aluminum oxide filters may be effective in reducing fluoride for a limited time, and in limited situations (see below for limitations related to water pH),  peer-reviewed scientific study is needed to convince me that aluminum is not being released from this filter.  I consulted aluminum ecotoxicologist Christopher Exley regarding alumina, and he advised that we should be avoid filters with activated alumina (which is simply aluminum), until studies demonstrate the safety of alumina in their various product applications.  Fluoride is damaging in the body, and I’ve read that it can aid aluminum in its ability to cross from the gut to the blood, but I must weigh pros and cons.  If fluoride levels are below 0.5 ppm (mg/L)  in the water, I believe the fluoride may be less of a concern than the potential aluminum released from the PF-2 Berkey filters.

However, if the pH of the water is 7 or higher, the PF-2 filters won’t work anyway!!!  This limitation is stated on the Berkey website, but I feel is almost always missed by purchasers.  It actually seems a tad scummy that Berkey doesn’t put this limitation in bold and underlined verbiage on the PF-2 product page.  The median pH of my city’s water was 7.26 in 2016 — so, the PF-2 filter wouldn’t work for me.  Plus, they must be replaced much more often than the black carbon filter, which is good for 3,000 gallons.  Remember, ‘it takes a very large amount of media to reduce small amounts of Fluoride.  Therefore, there is not enough media in filters to reduce fluoride effectively over the long term.‘


Before buying a Berkey water filter, you should also consider that the water must be used up/moved/added at least every three days, to inhibit the growth of bacteria in the virtually enclosed space of the system, and that the system should be cleaned with water and vinegar once a month.  That means if you leave for vacation for a few days, you have to take some extra time to care for your filters.  The filters contain silver to prevent bacterial growth within the actual filters themselves, which is good, but saddens me.  We are benefiting while the poor people that work in the silver mines are working in horrendous conditions, and die very young from health problems and diseases resulting from their work in the mines.  But this is the case with all metals – gold, silver, zinc, etc.


Biochar is made differently than activated carbon; however, it performs similarly.  It is essentially biomass burned at 900 degrees F in a low-oxygen environment.  Different biomass could yield different results; for example, biochar made from bones, like this bone char 20×60 mesh from Ebonex has the ability to filter out fluoride, whereas biochar made from other things like coconut shells do not remove fluoride.  Bone char can be bought in bulk from a variety of corporations for use in refillable cartridges meant for use in under counter multi stage filter systems, or for use in gravity fed filter systems, but one should ask for exact process spec regarding the char process, so you can ensure that the char was created at 900 degrees C in a low oxygen environment for best filtering results.  To learn more about biochar made from bones specifically, read the post called: Make your own fluoride filter, from bones!

In the graph directly below, Josh shows that biochar, when made correctly at high temperatures (900 degrees C), performs better than biochar created at low temperatures (350 degrees C), or intermediate temperatures (625 degrees C).

Josh Kearns

Josh and his lab team measured performance of high temperature biochar to be on par with or better than commercially made activated carbon used in carbon filters, such as the ones Berkey sells.  This is one of the most amazing things I have ever learned or found on the internet.

Carbon has been used as a water filtration media for ages.  However, we are regaining some of this knowledge and research continues.


1. Multi-stage pressurized systems

First, a low-tech DIY solution for under or over counter, using pre-made or refillable cartridges, explained here in the following video: [youtube]youtube https://www.youtube.com/watch?v=WCC4TOYYGF8[/youtube]

The narrator of the video shows how to build a multi-stage system in the cheapest way possible.  You don’t have to follow his recommendations on the media filtration cartridges though.  Instead, you could select the following filters for your system:

1. sedimentation filter
2. char filter made from bones
3. char filter made from bones
4. char filter made from coconut shell or other biomass

He briefly reviews refillable cartridges in the video (PurelyH20 Carbon DI Resin Refillable 10" Cartridge Canister), but it is important to understand refillable cartridges function differently than the one-use manufactured/ready-to-use-out-of-box-one-use filters.  In the one-use filters the water is forced through all sides of the filter, from the outside to the inside, and the water continues to the next stage from there.  In refillable cartridges, the water is forced through from bottom up, not the sides.  You can use these refillable canisters to experiment: https://www.amazon.com/dp/B00JFB0CF8/?ref=exp_inf_pl_designedbyinstinct.  Refillable cartridges would be really useful if you are making your biochar from wood or other biomass to use in place of the commercially manufactured activated carbon filter, or if you are making biochar from bones (bone char) to filter out fluoride.  Bone char can also be purchased in bulk bags….and then you could fill the refillable cartridges.  Remember, if you are making your own biochar, you must burn the material at 800-900 degrees C, in a low oxygen environment.  You can find out how to do this simply with these instructions.

2. Gravity-fed systems


1. Berkey type with pre-made activated carbon filters (made from coconut shell biomass) or DIY copy of Berkey made with 5 gallon buckets, etc.
3. Slow Sand Biofilter/Biochar Adsorber (essentially a Slow Sand Biosand filter with an added step consisting of biochar).

[vimeo]vimeo 167670842 w=640 h=360[/vimeo]

The Aqueous Solutions website has many useful appropriate technology low-tech tutorials, including tutorials on how to build the slow sand/biochar adsorber biofilters!!! ---- http://www.aqsolutions.org/

Little maintenance is required of these system.  The first tank in the system should be ‘cleaned’ 1-2 times per year, by closing off the tank, and opening the drain valve in the bottom and letting all the water out until it runs clearer.  Every year, the second tank in the system should be cleaned by stirring up the top of the sand layer until the water becomes turbid, and then opening the drain valve until only a little water is left. the Biochar in the third tank should be replaced at least every three years.  

The biggest pitfall in the slow sand systems is that the systems need fairly consistent use, especially when there is a lot of organic material in the water; this is because the biofilm that develops in/on the sand needs dissolved oxygen to keep it from going anaerobic.  If you leave the sand and the system for too long, you will need to run fresh water through the system to recondition the biofilm.  For this reason, building a very large system that is used by many people can be the best way to ensure the system will always be operating effectively, as there is less chance the system will go unused for even a day.

The concrete rings used the video above from Pun Pun farm are made with a metal form and have a couple metal wire rings in the top and bottom.

A ferrocement tank would be even stronger than the concrete rings.  Some people build the tanks by laying fired brick, putting some rebar in between rows, and then plastering the inside with sand and cement, and then just cement and water.  If you want to be hardcore, you could make your own cement (portland) by heating limestone and clay.  I have no idea how that would work out.  The leaders of Aqueous Solutions have also made bamboo cement tanks….not sure what that means exactly.

The Aqueous Solutions website also has tutorials on how to build biochar gasifiers, so you an make your own biochar!  Traditional char was made using kilns, but unfortunately these don’t reach the 800-900 degree C needed to make the most optimal biochar, and the process takes a long time, from 5-10 days, to 1 day.  So Aqeous Solutions features another method (gasifier), which requires steel drums, as shown in this video, and the process only takes a couple hours.



Make your own fluoride filter, from ‘charred’ bones – BIOCHAR!
may 14, 2018 by holobiont, posted in drinking water

Bones are an amazing thing.  They regrow inside of our bodies and the bodies of animals, millimeter by millimeter, many times throughout our lives.  They store minerals, and have a interesting structure.  Some native American tribes in the California area used to hunt rodents, and crush/eat the entire animal, bones and all.  Today, we often make mineral-rich bone broths to nourish ourselves.  Sepp Holzer in Austria even uses bones to make a ‘bone sauce’, which he then flicks onto saplings to deter deer and other creatures from eating and damaging them.  After all of these things, I was only a little bit surprised, and thoroughly delighted to learn that bones may provide us with yet another solution: water filtration.

To use bones for water filtration, the bones must be burned at high temperatures in a low oxygen environment.  This process results in biochar.   Typically ‘biochar’ is the term used to describe this process when done at home, on the farm, or in smaller amounts.  ‘Activated carbon’ is the term used when this process is done using specific commercial industrial processes of which I’m not too familiar with.

Biochar can be made from different materials, such as wood, or coconut shells (often used for commerical activated carbon), or bones!  The resulting biochar from each material will have different properties.

When the biochar is made from animal bones, it is sometimes called ‘bone char’, and unlike the other materials I mentioned biochar made from bones has the unique ability to remove fluoride.  Thus, for those living in areas where the municipality is still attempting to ‘medicate’ the public by adding the neurotoxic, IQ-lowering, industrial aluminum processing by-product known as fluoride, then biochar made from bones could be very useful in your water treatment system.
If biochar is made sub-optimally, at temperatures lower than 800 – 900 degrees C, the biochar will be less effective in water filtration.  This is the case as far as I know, regardless of what material is used to make the biochar, whether it be wood, coconut shells, bones, or other types of biomass.

Some people in the DIY community have taken matters into their own hands, and have begun testing their success with fluoride meters.  These at-home experimenters tested water filtering products, such as the ‘Waterite’ reverse osmosis (RO) filter, and found that if the product was used correctly, the first year of use they found zero detectable fluoride in the filtered water.  After two years of use, they found approximately .05 PPM of fluoride in the filtered water.  Based on this, the user believes the RO membrane should be replaced somewhere around three years.  However, one has to remember that RO membranes will become damaged and not work properly if the RO membrane is exposed to chlorine in the source (tap) water, which is why the pre-filtration cartridges must be used and replaced regularly.  I’m not sure how one would test in order to know how often they need to be replaced.  Waterite RO products might be found from distributors for around $250 or less.

I was surprised to learn that fluoride meters, such as the Low Range Fluoride Colorimeter from Hanna, appears to be accurate (+-0.1 PPM), it requires the use of mercury reagants.  As with most common water tests, to determine the amount of a substance in a water sample, a chemical (in this case, mercury) is added to the water, and the resulting color or chemical change communicates how much, if any, of the substance is in the water sample.

Mercury reagents available to react with and detect fluoride in water.
“These reagents follow the SPADNS Method in which the reaction between fluoride and the reagent causes a colorless complex in the sample. By simply adding 2 mL of SPADNS reagent to two cuvettes, and subsequently 8 mL of deionized water to one and 8 mL of sample in the other, the reaction will take place and the HI729 will determine the concentration from the color that is produced. The results will be displayed in ppm of fluoride. These reagents are designed to be used with samples that have an expected range of 0.00 to 2.00 ppm (mg/L) fluoride.”

I was very surprised to learn that mercury is required to react with and detect fluoride!!!  I have to shake my head — the pickles we get ourselves into in industrial society!  I believe fluoride is a neurotoxic substance and should never be added to water.  I believe that no ‘medication’ should be added to the water supply, as everyone has different needs.  I don’t believe fluoride is a medicinal substance, but there are still many people who believe it is medicinal, or necessary in order to maintain healthy teeth.  The Fluoride Action Network’s website has incredible information regarding this topic.  To read more, please visit the post about fluoride here.
To find more information about Reverse Osmosis and other water filtration methods, read the post: Drinking Water: Solutions & Filters.
The DIYers I have mentioned suggest biochar made from bones as an alternative to reverse osmosis (RO) or other filtration methods.  They suggest using bone char in combination with a post filter of coconut shell activated carbon, in order to remove the taste and odor of the bone char which may remain.   Meaning, the water would first go through a bone char filter or tank filled with bone char to remove the fluoride (which coconut shell biochar does not do), and then go through a filter or tank filled with biochar made from coconut shell to remove the odor and taste of the bone.

As is the case with most filtering media, water must be in contact with the bone char for a minimum required time in order to effectively remove fluoride (or other contaminants, for that matter).   The smaller the size of the filtering system/container, the less contact time will result, and therefore, the less potential fluoride removal.  Therefore, sizing the system/container can be an important factor in theory.  “Empty Bed Contact Time” (EBCT) is the industry term typically used for measuring the  time the water comes into contact with the filtering media, which is the volume of media used in the filter, divided by maximum flow rate.

Here are some approximate EBCT (with bone char) guidelines to keep in mind based on home experiments kindly shared by DIYers:
    - < 10 seconds EBCT = poor results
    - 15 seconds EBCT = acceptable results.  
    - 30 seconds EBCT = really good results (ideal EBCT target)

One might expect 90-100% fluoride removal with one gallon of bone char, in the first 800 gallons of water filtered.  Experiments showed 90% fluoride removal after 1,100 gallons of water filtered, and 70% fluoride removal after 1,500 gallons of water filtered.  Therefore, it might be a good idea to replace the gallon of bone char after around 1,000 gallons.
I’ve never built a water filter system, nor have I even created my own filter; however, I want to share information regarding how others have done so.
To source the bone char, you might start with contacting a company like Ebonex Corporation: http://www.Ebonex.com, and ask for their 20 x 60 mesh size bone char, which DIYers have found useful for water filtration.  Feel free to review the data sheet for this bone char here.  I’m not sure if you can order directly from them or if they are only a wholesale distributor.  There may be many other companies supplying bone char.  The quality of the bone char could be differ depending on the temperature employed during charring.  Be sure to ask if temps in the range of 800 – 900 degrees C were used!

DIYers order a bulk bag of bone char, and use the char either in refillable ‘cartridges’ placed within filter housings, or within a Slow Sand Biofilter/Biochar Adsorber in the third tank.  These two ways to use biochar are described above.
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Peter, thank you for sharing.
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