ECHOcommunity Conversations

Clay Pot Water Filtration

What experience do you have with this system? Is it effective? Could it be used with rain water?

Seeking this as an option for refugees in the Middle East who due to COVID and recent government action have been left with no NGO support - including water and food supplies. Moringa trees are not currently existing in the areas impacted most heavily by this (and might struggle growing outside of a greenhouse setting due to the cold winters). Looking for alternative options made with locally available resources to turn rain water (or snow from the mountain peaks and small streams in the spring) into a drinkable water source.

Rainwater needs the least filtration and is generally safe to drink:

Yes, clay pot filters can be effective:
https://www.cdc.gov/safewater/ceramic-filtration.html

It takes a lot of energy to make ceramic.

Packed bed filters are an alternative:

as is the slow sand filter:

how can i get these filters in Malaysia? I like the slow sand filters but i will take anything Craigggg@gmail.com

Hey Kayla!

The Potters for Peace filter has been proven to be an effective and appropriate method for filtering water, especially if there are local potters to set up a small business producing and selling the filters. There has been, however, a significant improvement in the manufacturing process of these filters. An organization called Agua Pure has come up with a way to incorporate the colloidal silver in the clay before firing. This prevents it from wearing off like the surface coating of the PFP method. The difference is a filter that can last up to 5 years vs. 1. If you have a potter that could make them, I could put you in contact with Filter Pure (also known as Agua Pure) to see if they could help set up a training. (See attachment for more info)FILTER_PURE_CERAMIC_FILTER.pdf (153.2 KB)

As far as other options, if the catchment for the rainwater is clean and you keep the water from further contamination, it will likely be very low turbidity. Thus you may not have to filter it at all, just treat it for biologicals. As long as it is below 5 NTU, you have plastic water bottles less than 4 inches in diameter, and you have 6 hrs of full sun, you could do solar disinfection (SODIS). Another effective and cheap option if water turbidity is low, is to treat with chlorine. There are many resources out there, but cawst.org is a good place to start to find more information.

God was so wise to make a way to purify water. Take a plastic bottle of water and set it in the sun. UV will break down the DNA of the bacteria in a few minutes, an hour if it is cold. This is providing the water was filtered with a rag and does not have much dirt in it. Bacteria can hide in dirt.

Once the water hits the ground, God provides Paramecium. As the water drops down thru the soil, paramecium eat E Coli and other dangerous bacteria. Thats why well water is usually next after rain water in purity.

This is also why a slow sand filter does a good job. It imitates Gods perfect system described above. As water drops down thru the sand, paramecium works there also. Someone needs to be the “Water Person” and wet the sand filter every day to keep the Paramecium from dying. All you need is a barrel with a pan for clean water to drain into at the bottom. Fill the barrel with sand. In a few days a disgusting green color may appear n top. This the living paramecium, doing it’s job.

For extra purity add layers of charcoal. It will grab impurities out of the water. Once a month the barrel should be emptied, cleaned out and new clean sand put in.

In many places sawdust is put in clay when the Pots are made. The sawdust is so fine it is called wood flour. During the firing process, the flour burns up leaving a tiny void to catch dirt. The director at one orphanage in Haiti said he had been using the same filter for 1 year and none of the 30 children there had ever gotten sick. Another person told me the clay pots are fragile and his broke as they were driving it home.

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Good morning, Kayla, we should be able to help. We are a small NGO specializing in water treatment using locally available materials (to date, primarily in Uganda). www.wedevwater.com We don’t sell any products. We provide the knowledge for you to work with what you have.

We have a design for slow sand filters from a garbage can. You’d have to sift the sand to the right particle size and you’d need a bit of piping. Also, slow sand filtration takes about 20 days to build up a schlamm (mud) layer before it begins to effectively remove bacteria. They are effective, but keep in mind, a slow sand filter in a garbage can only produces enough drinking water for a family of five in about 24 hours (There’s a reason it’s called a slow sand filter). You can build them larger, but that gives you a feeling for how much it produces. It lasts a long time.

Elliot is correct. The main drawback for the clay pot filters is that the silver layer wears off. I haven’t used Aqua Pure’s version, but it sounds like it’s addressed that issue.

SODIS is also effective and one that you can start almost immediately. The important thing to remember here is achieving low turbidity (could use a rapid sand filter) and you need to be sure to mark the bottles. Typically, you’d do a day on/day off method, leaving one set of bottles for each day, treating it, using it and refilling, while the other set of bottles is being prepped for the next day. It’s just very important not to mix the bottles. Rain water is a good candidate here. Any residual bacteria from the roof runoff (bird poop and the like) would be killed by SODIS.

We have another design for a rapid sand filter in a barrel. We’d typically use a water storage tank for a community of about 100 persons, but you can adapt it to your needs. It reduces the turbidity to under 10 NTUs. In our research, 10 NTUs is enough.

Lastly, in regards to Elliot’s comment on chlorine, we’ve developed a simplified salt chlorinator in a water bucket (a simplified version of the one developed by GE). Simply a car battery, titanium electrodes and salt (works better with solar, if you have access to that. The energy consumption is very small). Biggest drawback here is access to titanium electrodes. But once you have them, it’s very effective. A 10 liter bucket produces enough in 20 minutes for about 100 persons. It does require supervision and some understanding of the process (It’s easy, but very important)!

I’d be happy to consult with you, if you have access to any conferencing platforms (Teams, Skype, Zoom, etc.) It’s just faster to find the best fit for you than posting. (We’re free, by the way).

info@wedevwater.com

Blessings,

Michael

10 NTUs is not a recommendation, by the way, merely an observation based on our field work. We always recommend achieving <5 NTUs whenever possible. But don’t give up if you can only achieve 10.

Lastly, don’t forget about boiling. If you have nothing else available, at least you can boil…