Family Emergency Planning

Family Emergency Planning

Frequently Asked Questions for Doulton Ceramic Filters

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In a nutshell, Doulton/Berkefeld ceramic water filters remove bacteria from water, making it safe to drink. They do it the same way nature does, by using gravity to move water through tiny pores of crushed fossils - pores that are big enough for water molecules to get through, but too small to allow bacteria and water-borne pathogens to pass. The technology has been in use since the early 1800s and is the filtering method of choice by missionaries and relief organizations all over the world.

What is the history of Doulton/Berkefeld Water Filters?

John Doulton founded his first pottery in 1815. As early as 1827, Henry Doulton developed ceramic filters for removing bacteria from drinking water. The Thames river was heavily contaminated with raw sewage; cholera and typhoid epidemics were rampant.

In 1835, Queen Victoria commissioned Doulton to produce a water filter for the Royal household. Doulton created a gravity fed filtration system that used a ceramic filter. With Pasteur's advancement in microbiology, Doulton's Research and Development department created micro-porous ceramic cartridges capable of removing bacteria with better than 99% efficiency.

Today, Doulton ceramics are used in over 150 countries. In 1985, the British Berkefeld brand was acquired by Doulton Industrial Products, the manufacturer of Doulton water filters. Today, the Doulton and British Berkefeld names are the preferred choice for water purification products in worldwide locations where outbreaks of illness are associated with unreliable water supplies. These water filters have truly stood the test of time.

How does the system work?

Just add water into the upper chamber. Gravity causes the water to flow through the filters to the lower chamber. A two-filter system using 7" filters will produce about a two quarts per hour. Using four filters will produce about 4 quarts per hour.

What is the technology behind the filter elements and why are they so special

  • Doulton invented the ceramic filter for water filtration in 1827.
  • The ceramic filters are called "candles". They are made from crushed diatomaceous earth that is liquified, formed, then baked in a kiln.
  • Water molecules slowly work their way through the ceramic to the hollow center of the candle, then the water drips into the lower compartment of the filter. Sediment, bacteria and other micro-organisms are too large, so are trapped by the ceramic in the upper compartment of the filter.
  • The ceramic contains tiny grains of silver, which is toxic to bacteria. The silver prevents the captured bacteria from reproducing on the filter (unlike paper filters that provide an excellent growth medium). The silver also prevents Mitosis or Grow-Through, a condition that makes filters made from paper and plastic unusable after a short time.
  • Pore size: less than 1 micron
  • Removes 99.99% of Cryptosporidium, Giardia, E. Coli, Vibro Cholerae, Salmonella, Dysenteria.
  • The center of the ceramic filters is filled with GAC (granular activated carbon). Carbon removes bad tastes and odors as well as pesticides, herbicides, organic solvents, trihalomethanes.
  • Ceramic elements last much longer than paper filters because they can be cleaned 50 to 100 times or more. See below.

What are some of the water sources I can use?

Water from ponds, creeks, lakes, rivers, wells, cisterns, rain, or even water you have stored yourself can be used for drinking and cooking with peace of mind.

Water Production Rate

The rate of water production depends upon 1) the number of ceramic candles, 2) the size of the candles, and 3) whether the candles are clean or starting to get clogged. Doulton/Berkefeld stainless steel filters can be equipped with either one or two candles, and the candles can either be 7" or 9" long. More (or longer) candles just means there is more surface area, so the water filters through faster.

With two 7" candles, you will get about 2 quarts per hour. Four 7" will provide about 4 quarts per hour. If you use 9" candles, you'll see a slight improvement in filtering speed, but once the water level drops 2 inches, there will be no difference in filtering speed between the 7" model or 9" model. 9" candles are sold only under the Berkefeld name and are more costly.

Stainless Steel or Plastic Body?

Doulton/Berkefeld filters have traditionally been made of stainless steel. The bodies are made in India, then shipped to London where they are packaged and the ceramic filters are added. This is what makes the stainless option a bit pricey.

In 2008, Doulton USA introduced the Aqua Cera, which is a plastic-body filter, made in the USA. It is packaged with genuine ceramic filters from the factory in London. The Aqua Cera is larger than the stainless steel model, and it can be fitted with 1,2,3,4 or 5 ceramic filters. It will also accomodate the larger 10" ceramic filters in addition to the 7" and 9" that fit the stainless model. The 10" ceramic candles are sold only under the Doulton name and actually cost less than their 9" Berkefeld brothers.

Can I Make My Own Filter?

Absolutely. St. Paul Mercantile offers Bucket Filter Kits that include any number of ceramic candles, plus a spigot. You provide two buckets (2.5 gallon, 5 gallon, any size). This is the most cost-effective way to go. Equipped with 5 10" Doulton ceramic candles, the Aqua Cera will produce about 6 quarts of fresh drinking water per hour.

Detailed instructions for building a bucket filter can be downloaded here:
Click Here to Download Bucket Filter Instructions

How Long Do Ceramic Candles Last?

This requires some explanation, so read carefully. The manufacturer recommends replacing 7" ceramic candles after 535 gallons, and 9" candles after 700 gallons. So if you had a filter containing two 7" candles, the manufacturer recommendation would be to replace the candles after filtering 1070 gallons. If you pay about $60 for two 7" candles, you are getting about 18 gallons of clean water per dollar.

The primary reason that Doulton recommends replacing filters at that many gallons is that the granular carbon at the center of the candles ceases to be effective at about that point. If your primary use of the filter is to remove bacteria, however, the ceramic will continue to do that for a very long time. It is not uncommon for people to continue to use the ceramic candles for many years, cleaning them only 1-2 times per year. The candles can be cleaned at least 50-100 times, so you do the math.

If you are depending upon the carbon center to remove chemicals or odors, you should replace the candles more frequently. Or, you can purchase an inexpensive charcoal filter (a coffee strainer and bag of granular activated carbon are sufficient) and use the charcoal as either a pre- or post-filter. The activated carbon will remove chemicals, then the ceramic candles will remove the bacteria, so you can continue to use your ceramic candles.

When do I clean the ceramic filter element?

As water is filtered, the pores on the outside surface of the ceramic candle will get clogged with particulates from the water, or with bacteria. This will cause the water to soak through the candle more slowly, so your water production rate will decrease. As long as the filter is still making water fast enough to meet your needs, then don't bother cleaning it. But when the time it takes for the water to filter into the lower chamber decreases to the point where it is no longer meeting your daily water needs, it is time to clean.

How do I clean the filter elements?

Hold the ceramic element under clean running water while scrubbing lightly with a 3M ScotchBrite pad or toothbrush. Cleaning should be performed evenly, working from the threaded end up to the top. The cleaning process removes the outermost clogged ceramic pores from the candle, therby exposing a fresh unclogged surface. The rinse water might be cloudy white. That is due to the outermost white ceramic particles being removed. Rinse and reinstall the ceramic candles. If the water production rate has not returned to normal, repeat the cleaning and rub a little harder this time. The candles can typically be cleaned 50-100 times before they become too thin and fragile. If the candle cracks, discard it, as bacteria will be able to get through the crack.

How do I determine when the granular carbon in the ceramic element is exhausted?

When bad taste and odor of the source water is no longer removed. The ceramic shell will continue to remove pathogenic bacteria even after the carbon is exhausted. If your water tastes bad, you may continue to use your Doulton/Berkefeld to remove bacteria, and either pre-filter or post-filter the water with an inexpensive carbon filter, such as a Brita, or even a coffee filter filled with granulated charcoal, available at any pet store in the aquarium section.

Is it possible to reactivate or regenerate the granular carbon in the filter element once it becomes saturated with chemicals?

Sometimes. Some chemicals such as chlorine can be removed from the carbon by simply boiling the ceramic filter element in water for five minutes. Note: To avoid cracking the ceramic shell, place the element in cool water and then bring the water to a boil. Never place a cool element in boiling water or a hot element in cool water. Note that the carbon in the center of the ceramic candle cannot be replaced.

Can I prolong the need for cleaning the filter elements?

Yes. You can pre-filter the water through a coffee filter before pouring the water into the Doulton. This will reduce the chemicals in the water and remove the larger particulates, leaving fewer particulates to clog your ceramic candles. However, this is not necessary for proper functioning.

How does the Doulton/Berkefeld compare to other types of water filtration systems?

  • Inline Systems: useless if you do not have water pressure
  • Hand Pump Units: great for camping, but hard to pump. Not practical for long term emergencies. Short life span.
  • Resin or Carbon-based gravity filters: short life span, typically 250 to 1000 gallons.
  • Ceramic-based Gravity Filters: no water pressure required, long life span of elements.

Who uses the Doulton/Berkefeld Emergency Filters?

  • Relief Organizations like the Red Cross, Unicef and the Peace Corps. 58,000 units were used in Sarajevo after their water treatment plant was destroyed by the Serbs. In 1998, thousands of units were shipped to relief organizations in Honduras. And in 2010, many thousands were sent to Haiti after the earthquake.
  • Missionaries all over the world (more than 140 countries) have used ceramic filters for many decades.
  • Populations in third world countries where water supplies are frequently contaminated.
  • Churches and non-profit agencies frequently have water projects all over the world. St. Paul Mercantile assists these projects by providing ceramic filters at substantial discounts.
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John J Squires
St. Paul Mercantile
494 Dixon Road
Friendsville, MD 21531
phone: 301-616-7549
tollfree: 888-395-1164
fax: 775-640-2355

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