Problems in the Field and Solutions

Problems in the Field and Solutions

Problem: Miscommunication

The most basic of all problems with regard to “filter” use comes from the choice of words. In some information given out by PFP/Filtron, and in studies conducted in the field, clear distinctions were not made between the filterelement (the filter that is made of clay and coated with colloidal silver), the receptacle (the plastic bucket or clay receptacle in which the filter element sits), and the complete product called Filtron in this manual.

For example, the report from the Centro para la Investigación En Recursos Acuáticos de Nicaragua refers to the filter element that is coated with colloidal silver. In many field surveys and some studies, distinctions are often not made between the receptacle and the filter element. If you are inquiring about the process of cleaning, you must be clear about whether you are referring to the filter element, the receptacle or both. If you are making an observation about cleanliness, you must be clear about whether you are referring to the filter element or the receptacle you are referring to.

Likewise, in giving instructions, it is important to use specific words such as “filtered water,” “boiled water,” “chlorinated water,” rather than “clean” water. Clean water generally refers to appearance and nothing else.

Solution:

Be careful and specific when giving instructions or responding to questions.

Problem: Clogging/Slow Filtration Rates

Filter elements become clogged by vegetable matter or by silt, fine particles of dirt or clay.

A frequent complaint by users was that water filtered too slowly for household use even though users complied with instructions. Until recently, some instructions provided by PFP read “if your filter appears dirty, use a clean cloth or corncob (or soft toothbrush) to dislodge whatever materials are clogging the pores of the filter” (Ceramica por la Paz, 2000 from Prueba de la aceptación del filtero de ceramica impregnado con plata coloidal en el barrio El Ocotol be Guinope, Honduras). This approach proved wrong. Cleaning with a soft cloth does not dislodge materials from the pores, nor does a soft toothbrush do this well. Scrubbing with a corncob only deposits more residue in the pores. The frequency of cleaning also posed a problem as people were advised to clean their “filter” every eight days. In the Alethia Investigation, many people reported cleaning their “filters” every two days.
Solutions:

Leave it alone

Do not remove the filter element and scrub it unless it is clogged. Removing the filter element increases the possibility of contamination and breakage.

Maintain “Head Pressure”

Keep the element full. As the amount of water in the filter element decreases, so does the pressure. A filter element that is only ¼ full will barely flow.

Scrub it vigorously

In the Alethia Investigation, flow rate was greatly improved by scrubbing with a stiff toothbrush (see table below). Baking the filter element did not increase flow rate and actually slightly decreased it. Baking the filter element also provide possibilities for breakage, but should not damage the silver.

When flow rate slows noticeably the filter element should be removed and scrubbed vigorously with a stiff brush. The scrubbing will also dislodge some particles of clay. Each time the filter element is scrubbed, some of the clay and silver is lost. So, to preserve the silver in the filter element for as long as possible, prefiltration or sedimentation is recommended to reduce the need for scrubbing.

Filter Mancotal-6 / Flow (L / hour)
In field, with well water / 0.40
In laboratory, with Managua water / 0.52
After scrubbing with toothbrush / 2.1
After baking in household cooking oven overnight / 1.9

Each time the filter element is removed from the receptacle the user should:

1)Wait until there is no water in the filter element (see Breakage).

2)Thoroughly wash hands with soap.

3)Wash a plate, cloth, or the lid of the receptacle (plastic only) with soap and filtered or boiled water and rinse with filtered or boiled water.

4)Place the filter element on the plate, cloth or lid.

Prefilter

If water has much turbidity, use a cloth to prefilter. The cloth should be thin, a fine mesh, and easy to wash out. The cloth should be secured to the top of the Filtron and ideally should not hang far into the water. Because the water will be filtered, it is not necessary to keep the cloth sterile. It should be tied over the side of the receptacle. This will also serve to keep out insects or dust.

Sedimentation

Water to be filtered can be kept in a lidded container close to the Filtron and can be left to settle. But, increased risk of bacterial growth should be considered.

Problem: Microbiological Contamination

This is by far the most serious problem when it comes to health. Field tests of filtered water were not conducted for protozoa, but tests for bacteria indicated a high level of contamination of filtered water.

Early instructions did not give specific directions for how to clean the receptacle. Some instructions warned about using chlorinated water. Some instructions only said to wash and rinse with “clean” water. A large percent of families reported using source water (water that is drawn from the well, spring, river, tap). PFP’s suggestion for weekly washing opened up routes of contamination for both the receptacle and the filter element. The Alethia Investigation, with regard to research done by ICAITI, summarized “ICAITI recommended that users refrain from touching the element during its useful life.” Because the filtered water has no residual antimicrobial qualities, post filtration contamination in the receptacle is a major problem. It is a problem in all home filtration systems that do not rely on chlorination.

In laboratory tests filter elements achieved removal rates of 99.7 to 100% of bacteria. For these tests the filter elements were placed in receptacles that were washed with detergent and rinsed with boiled distilled water. On the contrary, in field studies, very few water samples from the receptacles achieved this. This indicates that contamination of the water is occurring in the receptacles and is not a failure of the filter elements.

A 1999-2000 field study done by Mariele Mena Valeria, a Nicaraguan social worker, reported that 60% of the families cleaned their “filter” with water directly from the contaminated source. The 2001 Alethia Investigation reported that “the majority of families (78%) clean the filter with water from the source, which has not been filtered, and thus families unintentionally contaminate the receptacle as they clean it.”

In the Alethia Investigation, results of field tests in 24 homes indicated that only one filter (Filtron) removed Total Coliform, six (of a possible 22) removed H2S producing bacteria, and eight (of a possible 15) removed E.coli.

In some cases, (table below) filtered water was more contaminated than source water.

CIRA – UNAN Enumeration
Total Coliform / Fecal Coliform / E. coli / Fecal Streptococcus
Source Water / 124 / 70 / 0 / 0
Home 1 - after / 190 / 160 / 15 / 95
Home 2 – after / 2100 / 48 / 0 / 21
Home 3 - after / 4900 / 4320 / 1920 / 0

In most communities, families collect their water from the source in plastic containers and buckets. These are typically stored in the house until used, creating another route for contamination.

Solutions:

Cleaning.

Methods for cleaning the filter element and the receptacle are very different. Under normal conditions, neither should be cleaned more than once a month.

The filter element does not need disinfection because it has colloidal silver throughout. It is only necessary to clean the filter element when the pores are clogged. If you suspect the outside of the filter element is contaminated, washing the outside with soap and rinsing with just boiled water is a good solution. Rinsing with filtered water that has been treated with iodine or colloidal silver is a good solution.

On the other hand, it is very important to disinfect the receptacle. When the Filtron is first assembled the receptacle is not sterile. A solution of chlorine and boiled or filtered water (see filter instructions) is recommended for disinfection because it will leave residual chlorine in the bottom of the receptacle. For plastic receptacles the chlorinated water should be left for at least 30 minutes. Thoroughly wash the inside of the receptacle. (To clean a clay receptacle that has not been treated with waterproofing see the next section.) A portion of the solution should be drained through the faucet so it is disinfected. The chlorinated water can be put into other storage containers to disinfect them. The concentration of chlorine in the water is greater than that recommended for disinfecting drinking water, so don’t drink it. This procedure should be repeated each time the receptacle is washed.

Soapy water can also be used to clean the receptacle. The soap should be added to water that has been filtered, boiled, distilled or commercially bottled (not water that could be contaminated). Soaps or detergents help loosen and remove microbes but do not kill them. The procedure of running the water out through the faucet should be repeated and the remainder should be discarded.

When washing the receptacle, use the remaining chlorinated water to rinse all storage containers. Avoid having source water sit for long periods of time before use. Keep storage containers lidded.

Colloidal Silver Saturated Clay.

Another option not yet tested is placement of colloidal silver impregnated disks, pellets, spheres or grog in the bottom of the receptacles. This may reduce greatly the need for even monthly cleaning but has not yet been researched.

Problems: Contamination of Clay Receptacles

Clay receptacles have been used for centuries to cool water. Water is absorbed into the walls of the receptacle and then evaporates from the outside acting as an evaporative cooler. But bacteria can also be absorbed, and the walls of the receptacle provide nutrients. The clay receptacles are harder to clean.

A great advantage of the clay receptacle is that it can be coated on the inside with colloidal silver just as the filter element is. The silver will be absorbed into the clay and will remain in the receptacle and prevent growth of bacteria. A clay receptacle potentially might never need cleaning. This has not been tested.

Solutions:

Cleaning

Ceramic receptacles can be cleaned as per the instructions for cleaning receptacles. Cleaning with chlorinated water, rather than soapy water is recommended. Instead of thirty minutes, chlorinated water should be left in the receptacle for at least two hours. Instead of ¼ full the receptacle should be filled to the halfway point or to a point slightly higher than the normal water level. Using a brush, thoroughly scrub the inside of the receptacle and follow the standard instructions.

If, the Filtron produced water with high levels of contamination on the first and second visit, on the third visit try the following:

1)Instruct the user to let the chlorinated water sit in the receptacle overnight.

2)Instruct the user to make sure that chlorinated water is drained through the faucet.

3)Instruct the user to wipe off the outside of the faucet.

4)Instruct the user to rinse off the outside of the filter element according to instructions in “Testing”. Review those instructions.

If, on the fourth visit the Filtron is still producing water samples with high contamination, the receptacle can be coated with colloidal silver (see below) or replaced with plastic.

1)Remove the filter element from the receptacle (always do this when the filter element is empty) and put it in a plastic bag in a safe place.

2)Drain all the water from the receptacle.

3)Put the receptacle in a protected sunny place untilit is to dry to the touch. This will probably take at least a day even in the dry season.

4)Mix a solution of 2 ml of 3.2 colloidal silver to 250 ml of distilled water or filtered water.

5)Apply this to the inside of the receptacle to at least 10 cm above the normal water level. If the receptacle is dry this should be absorbed into the clay immediately. Let it sit overnight.

6)Replace the filter element.

7)Do not drink the first ten liters of filtered water.

If on the fifth visit the Filtron is still producing contaminated water, you can assume that the filter elements needs to be replaced.

NGOs purchasing Filtrons should be advised that plastic receptacles have been shown to be more effective in microbial reduction that ceramic receptacles.

Problem: Breakage and Malfunction

Most element breakage occurs when the filter element is lifted while filled with water. The lip is a weak point in the filter element. Breakage of the lip occurs in a large percentage of filter elements. When a chunk of clay breaks off the lip leaving a hole it opens a route for pathogens. It is easy to spill source water into the hole, and bacteria can also enter via air and insects. If there is no hole then the broken lip is not a problem. Breakage of faucets is another frequent problem. Breakage of clay receptacles has also been reported.

Solutions:

Leave it alone

Only scrub the filter element when it is clogged. Only remove it monthly when the receptacle is cleaned. Weekly or semiweekly cleaning greatly contributed to breakage.

Take care in handling

Only remove the filter element when it is empty. Use both hands and firmly but gently support the edge. Always place the filter element in a safe place.

Protect from contamination

If there is a hole where the lip has broken off it is very important to take care to pour source water into the other side of the filter element. If there is a hole it is more critical to keep the Filtron lidded.

Replacement

If the hole is too large or if the filter element or receptacle are warped to a point where there are openings then it should be replaced.

Secure the Filtron

The Filtron should be place in a safe location where it cannot be knocked over. If possible put it in a place where the Filtron can be secured to the wall or a post.

Producer suggestions

Modify the mold to produce a thicker lip. Reinforce the lip by applying a coil of clay underneath immediately after pressing.

Problem: Lack of Materials for Cleaning and Replacement Parts

Filtron users often do not have access to replacement filter elements and often do not have the basic necessities for cleaning and maintaining the Filtron.

Solution:

At the time of distribution a local distribution point should be established for replacement filter elements and supplies. Promoters in the field should be provided with supplies for their clientele that needed for cleaning and maintenance and when appropriate for coating receptacles with colloidal silver. Supplies should include scrub brushes, chlorine, supply of colloidal silver, field test packets, distilled water, faucets, and pieces of cloth for pre-filtration. These costs should be considered in the purchase of Filtrons for distribution.

Problem: People Stop Using the Filtron

People stop using the Filtron for various reasons. Some feel that their water supply is “clean.” In some cases the filter element has broken and there is no replacement. Some decide it is better utilized for feeding chickens or planting flowers.

Revolving Loan Fund

Studies showed that Filtron users who paid at least part of the cost of purchase were more likely to continue using it. A revolving loan fund and subsidies for Filtron purchase can make this possible. It assures a basis of funds to continue purchasing replacement filter elements, parts, and supplies. The Tienda Campesina in Achuapa sells the Filtron for 50% of the wholesale price and has been successful in receiving payments on most of the sales.