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Volcanic Ash, Repurposed

Inferring from news headlines, you might think that volcano eruptions are rare–maybe a couple a year.  This is definitely not the case!  As of April 14, 2023, there were 49 volcanoes in eruption, 75% of them along the “Ring of Fire” where the Pacific Ocean meets land masses on the west and east.   To see the names and places of these active volcanoes, check out this page in the Smithsonian’s Global Volcanism Program.

Volcanoes emit several things when they erupt.  Gasses are composed of water vapor, carbon dioxide (CO2), sulphur dioxide (SO2), and hydrogen sulphide (H2S).   In actuality, lava can also contain 6% or more of its mass as gasses.  The gasses come out of solution from the lava when it erupts from the ground, in the form of bubbles or explosions.  (Volcanoes) Lava can flow in many forms above ground, below ground, and underwater.  The chemical composition of the lava causes it to have different viscosities and take different shapes as it cools and solidifies.  This page has a detailed description and fascinating photos of the many different types of lava.  

When gas and solids are emitted at the same time from a volcano–watch out!  Pyroclastic flows are the most dangerous type of eruption, where the hot pressurized gas can carry fragments of rock and ash for long distances.  Boulders can be thrown for miles if the eruption is particularly energetic, but the main danger for nearby residents is lava, fragments of rock called pumice, hot ash and gasses.  It was once thought that the residents of Pompeii perished due to suffocation of ash, but new evidence points to extreme heat.  (The Hazards of Pyroclastic Flows)

Clouds of ash can travel thousands of miles in the atmosphere.  It can disrupt airplane traffic and cause air pollution in distant cities, but when “the dust settles”, volcanic ash can be a good thing, as it’s used for many purposes.

Solid particles emitted from volcanoes are collectively called tephra.  Products made with tephra can be from ash (fragments of rocks, minerals, and volcanic glass ranging in size from sand to clay-like (from 2 mm to less than 0.004 mm in diameter) which is hard and abrasive), or milled/crushed from larger rocks and pumice.  Here are a few examples:

• Bricks made with 10-20% ash of Mt. Etna, a very active volcano in Italy, were less porous, more compact and less susceptible to decay, with a small loss of strength that was still in acceptable parameters. (Producing Bricks with Volcanic Ash from Mount Etna)
• Concrete made with 30-50% ash vs. 100% Portland cement is less energy-intensive to make and is stronger. (Cities of the future may be built with locally available volcanic ash)
• Volcanic ash can make soil incredibly fertile due to the different minerals it contains. 
• Volcanic rock can be used to purify water.  This use is discussed in the rest of this article.

Zeolites are natural volcanic minerals with unique characteristics. They are aluminosilicates, meaning that they are composed of varying quantities of aluminum, oxygen and silicon.  Zeolites were formed when volcanic ash was deposited in ancient alkaline lakes. The interaction of the volcanic ash with the salts in the lake water altered the ash into various zeolite materials, creating “pores”.  The pores have typical diameters of 0.5 to 0.7 nm, which are slightly larger than the diameter of a water molecule. Positive ions are present in the channels, which can be exchanged for other ions.

This substitution of ions enables zeolites to selectively adsorb certain harmful or unwanted elements from soil, water and air. A good example is the removal of calcium from hard water, also called "softening".  In this case, zeolites exchange sodium ions for calcium ions, which result in soft water. Zeolites also have strong attraction for certain harmful heavy metals such as lead, chromium, nickel and zinc. (Zeolites)

The oldest evidence of use of volcanic rock in water purification exists at Tikal, a Mayan city in northern Guatemala.  The Maya collected zeolite and quartz from a crystalline tuff (a light, porous rock formed by consolidation of volcanic ash.) about 30 km northeast of the city between ~ 200 BC and 1000 A.D. They used these natural volcanic mineral resources to purify large volumes of drinking water in a tropical forest environment, which was complicated by catastrophic cyclones, volcanic events, droughts, and subsurface drainage; this is the oldest known zeolite water purification system. (Zeolite water purification at Tikal, an ancient Maya city in Guatemala)

Zeolites can also be synthesized  from volcanic ash.  In an effort to reduce landfill disposal of the ash surrounding Mt. Etna in Italy, two samples of ash were processed to form a synthetic zeolite that could adsorb cesium (a radioactive element) from polluted water. (Synthesis of zeolite from volcanic ash: Characterization and application for cesium removal)

For those whose interests lie more in beauty products, volcanic material has moved beyond pumice stones used for foot exfoliation and now the ash is having a moment in skin creams, masks and primers.  The minerals in volcanic ash (including sulfur) are antibacterial, anti-inflammatory (when used temporarily and correctly) and some products can be used to exfoliate and dry especially oily skin.  Three dermatologists weigh in on volcanic ash’s skin-clearing properties in this article.

How can you use volcanic ash or zeolite around your home? (Zeolites-applications)

• For adsorbing odors: in shoes, carpets and kitty litter
• For absorbing fat runoff in barbeque pits
• For adsorbing moisture in closets and cabinets
• As a filter medium for your fishtank (adsorbs ammonia)
• As a filter medium for an air purifier (removes ammonia, formaldehyde, and other VOCs)
• As a filter medium for water purifiers and softeners
• As a garden soil additive for drainage, minerals and for landscaping textural interest

The minerals and rock formations of volcanoes vary endlessly in composition and uses.  Volcanic ash and zeolite are another of the earth’s natural filters and cleaners.   As our air and water become more polluted, we expect these resources to be used in many more ways–another example of taking “waste” and repurposing it for a cleaner environment.

Is there KDF in your water filter?

If you’ve ever shopped for a water filtration system for your home, you’ll know that there are a lot of different systems out there!  Starting with the size, you can go from pitcher (1-2 liters) to countertop, to under-counter, to whole-home systems.  Then, there are the different methods used to remove different pollutants.  Do you want a passive system that just uses gravity, or a system that uses the water pressure to filter, and/or a system that back-flushes contaminants to “clear” the filter?

Many filtration systems use granule-type media, which can be made from activated carbon, catalytic carbon, copper and zinc particles, mixed media like gravel and resin, activated aluminum or manganese dioxide.   Copper and zinc particles are what is used in kinetic degradation fluxion (KDF) filters, and depending on the ratio and granule size, KDF media can reduce the levels of water-soluble heavy metals, chlorine, iron, and hydrogen sulfide. It also manages scale, bacteria, and algae in the water. (aquasana.com)

Kinetic degradation fluxion describes how this type of media purifies water.  It works in a reduction/oxidation process (also known as “redox”) in which, as the water travels through the media, some molecules gain electrons (reduction) and some molecules lose electrons (oxidation).  Although this sounds counter-intuitive, reduction and oxidation refer to the oxidation states of the atoms, where gaining an electron reduces its oxidation state, and losing an electron increases its oxidation state.  The oxidation state is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom. (Britannica.com)  For example, as lead, hydrogen sulfide and chlorine (found in many water supplies) flow through KDF media, some of the harmful contaminants are changed into harmless components, while others are electrochemically bound to the KDF media: (waterfilterguru.com)

• Soluble lead cations (positively charged ions) are reduced to insoluble lead atoms, which are electroplated onto the surface of the media (they stay in the filter and can only be removed by recycling it) . (KDF Reticulated Foam)

• Dissolved chlorine gas is reduced to water-soluble chloride ions, which pass through with the water as harmless ions that no longer have oxidation properties.  The KDF media donates two negatively charged electrons to each molecule of chlorine to reduce it to the lower oxidation state of chloride. (What are KDF Process Media and How Do They Work?)  (You can check out an animated visual of the transformation of chlorine gas into chloride ions on the same page!)

• Hydrogen sulfide: the copper in the KDF media loses an electron and the sulfur gains an electron, so that copper sulfide and water are formed. The copper sulfide is insoluble in water and can be backwashed off the KDF filter media.

As you can see, this type of filter works on a lot of different contaminants, and even microbes.  Copper and zinc are anti-microbial metals.  They kill bacteria by direct electrochemical contact and by the flash formation of hydroxyl radicals and hydrogen peroxide, both of which interfere with a microorganism's ability to function. (LennTech.com)  Because other filters can be more prone to microbial growth (like activated carbon), using a KDF filter before the carbon filter prolongs the life of the carbon filter.   

KDF was invented in 1984 by American Don Heskett “accidentally”.  He used a brass ballpoint pen to stir some chemicals and discovered that it removed chlorine from water.  He worked on the formulation for several years and patented it, also forming the KDF Fluid Treatment (KDFFT) company.  Raw KDF media are produced by KDFFT and sold to many filter manufacturers, to be used alone or layered with other media in their water filtration systems.  There are 4 types of media produced: KDF 55 (55% copper and 45% zinc, removes chlorine, heavy metals and bacteria), KDF 85 (85% copper, 15% zinc, best for iron and hydrogen sulfide), KDF Fines (best for chlorine and bacteria removal when incorporated with other media) and KDF Coarse Mesh (for reduction of heavy metals and chlorines).  (KDF Products)

The benefits of KDF media are many:

• It removes a wide range of contaminants

• It is cost effective.  KDF media can be replaced every 9-12 months, or if the system allows and you have the means, can be backwashed and reused for over 6 years!

• It can be recycled. 

• It can be used in warmer water than other media (for example in showerheads or dishwasher feed water, whereas activated carbon cannot be used in warm-water applications)

• It releases no toxins into the water, so is completely safe. (KDF doesn’t require registration by the EPA as other “pesticides” do, like silver-impregnated carbon.)

Disadvantages include:

• Periodic backwashing is required unless you prefer to just replace and recycle the filter. Unfortunately, backwashing must be done at 30 gallons per minute, or the media will not be adequately flushed.  In places where water is expensive or scarce, this would be difficult to maintain.

• KDF media doesn’t remove organic chemicals such as VOCs, pesticides and herbicides, organic cysts, nitrates, fluoride, viruses, arsenic, and pharmaceuticals, so you’ll have to add another type of filter if these are present.  (waterfilterguru.com)  It also doesn’t remove chloramines (some water suppliers disinfect with chloramines instead of chlorine, which are very difficult to remove).

A Sticky, Fragrant Solution to an Old Problem

While reading a new scholarly article on creating water filters from ceramic pots with nanoparticles of silver in them, I thought, I’ve read about this before; it’s not new.  This type of system has been used in Africa and other disadvantaged areas that lack access to clean drinking water.  In fact, the authors disclosed that “Using silver particles for water filtration is not the main innovation. Others have used this technology in the past. The key is controlling the release of nanoparticles, which can reduce the usable life of the filters.”

This filter has roots in proved science: that silver is antibacterial.  Silver has positively charged ions that fight bacteria in three ways (check out our article to understand them).  Silver nanoparticles can also penetrate through the bacterial biofilms (the slime that bacteria make to live on surfaces) to completely destroy them and can even prevent microbes from developing biofilms.  (This is a great attribute for water pitchers, where standing water can allow biofilms to develop.)

So, the new part about this water pitcher/filter is what the silver nanoparticles are suspended in: pine resin.  Apparently, pine resin is an old source of a “newer” category: polymers.  Polymers have gained a lot of attention in the last few years because they have a lot of desirable properties such as versatility and durability.  By definition, polymers are large molecules made by bonding (chemically linking) a series of building blocks. The word polymer comes from the Greek words for “many parts.” Each of those parts is scientists call a monomer  (which in Greek means “one part”). (Explainer: What are polymers?)  DNA and keratin (the material our hair and nails are made of) are natural polymers. 

Pine resin is the hardened form of the sticky sap that runs out of pine trees when they are cut, but inside the tree it carries water, nutrients, sugar and mineral elements throughout tree trunks—similar to how blood functions in the human body. (5 Uses for Pine Sap: How to Harvest and Utilize Pine Resin) 

Although it’s possible to get resin from the tree by cutting into it to harvest sap, this kind of damage can kill the tree.  Otherwise, you can collect resin crystals that have formed on the outside of the tree from natural damage, heat them, and use the liquid resin for many means, such as firestarters (pine resin is high in turpenoids, the VOCs that make it smell like a pine tree), herbal remedies and soap, and natural glue.

This semi-solid, sticky nature of pine resin is also what makes it great for coating the inside of a water pitcher filter.  Without it, the silver nanoparticles could react quickly to chemical impurities, which would make them unavailable for killing bacteria.  The following diagram shows how silver nanoparticles embedded in the pine resin can be released more slowly to allow the pitcher to last longer as a filter.

(And, in fact, the other new part about this outreach was that the community in need of these filters is in the United States.  According to this article from March 2023, the Navajo Nation reservation stretches across 27,000 square miles in Arizona, Utah and New Mexico. Fifteen to thirty percent of the 170,000 people who live there do not have access to clean, reliable drinking water.  Although estimates vary according to the EPA vs. the tribe, it’s the “why” this continues…according to an EPA article, in 2003 the Navajo Nation estimated that up to 30% of the population did not have piped water to their homes.  The EPA and HUD have worked to reduce this number, which they estimate has helped lower the percentage of the population without access to piped water to their homes to about 15%.  Twenty years later, many must drive miles to haul water home or use unregulated water sources, which are susceptible to bacterial contamination and/or exceed drinking water standards for uranium and other chemicals, because some homes are located near abandoned uranium mines.)

Source: Pottery Becomes Water Treatment Device for Navajo Nation 

Since the pottery and the resin are very natural elements that the Navajo respect and use, this type of filter could be very important to many in easing their burden of getting clean drinking water, and even after every home receives piped water (but given the history of this project, the “when” is not in sight).  At HypoAir, we like natural elements too, so learning about the properties of a material that has been all around us for centuries is very exciting!  

“Rust” in your sinks and toilets?  Iron in your water can mean iron bacteria in the water

Wait–is that rust in my toilet?  Why is the toilet looking rusty?  You might initially think that the pipes supplying the water might be rusting, and that could be a problem (however, it’s rare).  But if you know that there are no iron pipes supplying your water (if you live in the country with your own well), then you know that pipe rust is not the source of the problem.  Most likely it has to do with high iron content in the water itself, and a certain bacteria that consumes iron. At least 18 types of bacteria are classified as iron bacteria, long thread-like bacteria that “feed” on iron and secrete slime. Unlike most bacteria, which feed on organic matter, iron bacteria fulfill their energy requirements by oxidizing ferrous iron into ferric iron. (Iron Bacteria in Surface Water). 

Iron bacteria are small living organisms that naturally occur in soil, shallow groundwater, and surface waters. These bacteria combine iron (or manganese) in the soil, and oxygen to form deposits of "rust," bacterial cells, and a slimy material that sticks the bacteria to well pipes, pumps, and plumbing fixtures.  These iron bacteria don’t cause disease, but they can create an environment where other disease-causing microbes can grow (like coliform bacteria).  Iron bacteria can get into the well when the water in the well comes into contact with the soil surrounding it, or lakewater, or any rivers and streams.  (Iron Bacteria in Well Water)

If you haven’t had any work on your water system done, and you’re still suspecting the bacteria are feeding on iron pipes, here are the most common types of pipes (from 7 Types of Plumbing Pipes Used in Homes):

1. Rigid copper pipe (water supply)

2. PEX pipe (water supply)

3. PVC pipe (water supply and drains)

4. ABS pipe (drains and vent lines)

5. Flexi Pipe (water supply)

6. Galvanized steel and cast iron (outdated for water supply and drains)

7. Black pipe (only used on natural gas lines)

So, you can see that out of the 5 water supply line types, only 1 has iron in it (#6) and those are considered outdated.  The cast iron and steel pipes that were used in the 1950s have gradually been replaced by one of the other plastics mentioned above.  (A Brief History of Pipe Materials)  Therefore, if your home was built after the 1960’s, it would be very common for you to have iron in the water supply lines. 

Other than causing brown stains, iron bacteria can also cause the following (Iron Bacteria in Well Water):

• Smells: Swampy, oily or petroleum, cucumber, sewage, rotten vegetation, or musty smells, which may be more noticeable after the water has not been used for a while.

• Colors: Yellow, orange, red, or brown stains and colored water, or a rainbow colored, oil-like sheen.

• Deposits: Sticky rusty, yellow, brown, or grey slime, or “feathery" or filamentous growths (especially in standing water).

These are not the kinds of things you want to see in your sink or toilet!  It can also have detrimental effects on any water softening system, making the water running through it to have an off taste.  To confirm that the problem is iron bacteria, you can get the water tested by a lab.

If you do have iron bacteria, and states like Minnesota have a lot of it, it can be hard to get rid of.  Here are some steps you may consider: 

• If you have a heavy concentration of iron bacteria, the best first step is to have the contractor remove and clean the pumping equipment, and scrub the well casing with brushes.  Make sure that they do not lay any of the equipment on the bare ground, as this could re-contaminate it!  

• Next is chemical treatment, which is also for minor contaminations.  Treatment involves 3 steps: disinfection (or oxidation), retention time, and filtration. (How to Remove Iron Bacteria in Your Water)  Chlorine (bleach), hydrogen peroxide and ozone are frequently used.  Although many companies call all three of these “disinfectants”, the fact is that only chlorine is a disinfectant; hydrogen peroxide and ozone are oxidizers.  Disinfection is the act of killing bacteria, while oxidation causes a molecule, atom or ion to lose an electron (which also kills bacteria as a consequence).

• Chlorine (bleach): Although bleach is cheap and will disinfect, its reactions to organic matter that may be in the water are not good–like haloacetic acids (HAAs) and trihalomethanes (THMs), which are classified as possible human carcinogens.  For more information on these byproducts, check out our article here.  

• Of the two remaining, ozone is a stronger oxidizer than hydrogen peroxide, but hydrogen peroxide systems are less expensive and more readily available from water treatment companies.  According to USWater, extreme amounts of iron and hydrogen sulfide can be removed from the water supply effectively and consistently, it does not need a “contact tank” for retention time, and it does not cause maintenance issues with injection pumps as chlorine does.  (Chlorine or Hydrogen Peroxide – Which is Better for Treating Water?) does not have these byproducts and in addition, has several benefits: it can also rid water of hydrogen sulfide (H2S) smells (rotten eggs), and activated carbon filters used after disinfection last much longer than when used with hydrogen peroxide than with chlorine. (Eliminate Well Water Odors: Four Reasons Why Hydrogen Peroxide Water Treatment Is Best)  According the to Minnesota Rural Water Association, potassium permanganate is also a strong oxidizer that is in common use in Minnesota to remove iron and manganese. (Iron and Manganese)

• Retention time is needed for chlorine to work, therefore the chlorine must sit in the well for a certain period, or if you are using chlorine as a continuous disinfectant, a holding tank is usually set up, with the size being dependent on your household’s normal flow rate (water usage rate).

• Filtration is necessary to remove by-products (in the case of chlorine) and iron products (in all cases).   When chlorine contacts iron in the water, it changes the iron from a ferrous state to a ferric state, making it an insoluble particulate.  This is the state that can be easily filtered.  There are various types of filters available, the most common being activated carbon.  Reverse osmosis and some other types of filtration can remove iron from water without oxidation, and treating your water from the point it enters your home is important for all your appliances, but the iron bacteria may still thrive in your well and cause clogs up to the water treatment point. Iron can clog wells, pumps, sprinklers, dishwashers, and other devices over time. (Iron in Well Water)

If you notice these signs of brown or different colored stains, bad smell or slime deposits in your sinks or toilets, it’s a good idea to get your water tested for iron.  If iron bacteria are present, it’s likely a common problem in your area, and there are local companies who can provide the equipment needed to remove it.  However, it’s best to do your own research on these solutions to make sure that a company doesn’t try to sell you unnecessary equipment (such as a retention tank for a hydrogen peroxide system), and also it’s a good idea to get references and reviews from actual customers.