How to make active carbon filter cartridge

Activated carbon will take out organics and free chlorine. It is not wise to use them for particulate removal. Normally one uses a media filter upstream.

It is not necessary to make them as they can be had off-the-shelf readily.

10' and 20' in the US means 10 feet and 20 feet respectively. Those sizes would cost a small fortune to fill with activated carbon.

Typically, sand and gravel filters are used to remove particulates and small activated carbon filters are used at outlets for further purification.

I was invited to observe the purification of a lagoon on a dairy cattle farm by ozonation, and within several hours of operation, it was very evident that the turbidity of the water was reduced by about half, and I'd guess the volume of the lagoon is somewhere around 60,000 gallons based on the remembered diameter and depth of it.

Look up activated carbon filters on the GlobalSpec web site: http://www.globalspec.com/

Calgon Carbons is by far the biggest in the business. I recommend you ask for a coconut based carbon. I'm not sure what the equivalent codes are in the UK, but make sure what you purchase meets NSF42, not NSF61.

It won't be an enourmous cost by any means. The stuff sells for less than $1.00/lbs from a manufacturer (or at least it did when I worked in the industry).

As others have shared, there are many commercial sources for these products. KX Industries (www.kxindustries.com) is a very reputable source and there are many others.

My understanding is that much of the activated carbon is produced in China. The activated carbon granules need to be restrained in some fashion so that the particles do not contaminate the liquid being treated. In some cases, the particles are held in place by a screen. Some filter elements contain fabrics that have been coated or impregnated with the carbon particles so that they are physically or chemically attached to the surface. And, finally, the third kind of filter element contains activated carbon particles that are 'glued' together with a thermoplastic material something like a hot-melt adhesive.

It isn't hard to make these filters with materials you can purchase at any craft shop. But, to do so on a production basis for drinking water or other regulated applications requires an entirely different level of equipment and resources.

Is there a business opportunity that you would like to pursue?

Any idea what the thermoplastic material you refer to. It cannot be hotmelt adhesive! My understanding was what is used in making carbon block filters are a type of resin. I would really like to know what this material is as I myself is trying to make a low cost carbon block which can be used in rural communities ( as a social welfare project) - not a commercial venture. Any Engineer who thinks of helping the poor is welcome. I will share all my know how... for a better world!

http://www.bbafiltration.com/

This should give more info on how activated carbon is placed in a media. Hope you get clue here.

Limbkar

The information on the BBA website for their AQF products may be helpful. But, as far as I know, they do not produce a 10" (25cm) or 20" (50cm) cartridge - meaning a product that is about 2 7/8" (7.4cm) in diameter comprised of a porous 'block' of activated carbon. Rather, BBA produces a sheet of activated carbon that can be rolled into a cylindrical shape or used in several other configurations. KX Industries (and others) produce the porous block that I have just described.

In both cases, the activated carbon is bound to the structure with the use of a thermoplastic material. While describing that material is relatively easy (and there are many, many options), it is far more difficult to produce these materials in a continuous process that ensures consistent quality and at a price the market will bear.

Are we moving this discussion along in the right direction? If so, let's continue to delve into this subject. As several writers have commented, there is a world of need for these products. Let's see how we can contribute to the common good.

thanks for the info on KX & others for the public benefit. But many people in this world cannot afford US products. For eg in Asia a labourar may earn may be 2-3 US$ a day which is barely enough for daily needs. My quest is to develop a low cost product purely as a social service.

I myself have experiance manufactruring activated carbon for export to countries like US, Japan & Europe. We sell a Kg of Activated Carbon for around US$ 1-2. But by the time it is manufactured inj a developed country as a cartridge, the cost goes beyond the reach of the common man. What is worst is that the man in the 3rd world is the one who need these cartridges because their governments do not provide pure water on the tap unlike in the developed countries where it is not going to do any major harm even if you drink just off the tap.

Purpose of my writing is not to publish any political idea, but to demonstrate why a cheaper cartridge making technolgy (may be cottage style) is important for the world.

I would appreciate technical contributions from like minded to develop a low cost carbon block cartridge which i believe can be coupled to traditional candle filter which are used in this part of the world

Sisira,

I do understand what you are trying to do and believe you will be successful.

If activated carbon costs $1/kg, a binder material will cost about the same or less. You indicated you want to produce a 10" element so let's start on that product and save the 20" element for the future.

Now, a 10" element at 2.825" outer diameter and 1.000" inner diameter has a volume of approximately 57 cubic inches or nearly 1000 cc. I have seen data that suggests the density of the material can be as high as 0.5 g/cc so you will use about 500 grams of activated carbon and binder resin per filter element. That will cost you about $0.50 per element for the raw materials.

Then, start building a mold from aluminum or plastic that is the shape of the desired filter element and start experimenting. I'm sure you can find a way to manually pour the activated carbon into the mold. You can then add the binder in several ways to see which is best. For example, if you have a powder, you may want to mix it with the carbon black before placing in the mold; or if you have a material that is liquid, you may add after the activated carbon is added to the mold.

Your mold should last a long time so it's cost should be very low for each element. And, as you say, your labor costs will be minimal. So, if you find a suitable process, I would like to think you can produce finished filter elements for well be low the $1 price that you believe you can charge.

You appear to be committed to this program, Sisira, and this quick analysis suggests that you can meet your cost objective that meets the needs of your market. It's time for you to start working on the project.

Please keep us all posted on your progress. I am sure we will continue to help you with other issues as you move forward to your worthwhile goal.

Dear MillMatt,

Thanks a lot for your encouraging words.

Any suggestions you can give me on binder material.

I have tried using coal tar which works well but needs post treatment (heat in a tunnel kiln) so as a cottage industry may not be very popular. Also firing makes the cartridge brittle & porous.

What I understand is many commerical ventures use resins and it gives a clean hard product.

Do you have any suggestions?

The requirement is binder should be not water soluble. A small quantity should give a good bond so that addition of the binder will have the least effect on the activity level of active carbon.

Since the product is going to be used with water it should not be toxic and/or leachable.

$1 for 10in cartridge is my target! You have hit the nail on the head!!

I believe you mean 10 inch & 20 inch (not 10feet & 20 feet!). These are available from any stockist (most of the supermarket chains stock this item).

If you are thinking of making these for sale there are a lot of things (technical) you need to know- like selection of grade, type of carbon, pressure drop etc.

Should you need any assistnace do not hesitate to contact me on my email sisiraa@gmail.com. As a fellow engineer I will help you.