Dunno myself but I had found this on the matter:
There is a simple and easy way to recharge you charcoal to reuse it or recycle it
Charcoal is carbon. Activated charcoal is charcoal that has been treated with oxygen to open up millions of tiny pores between the carbon atoms.
The use of special manufacturing techniques results in highly porous charcoals that have surface areas of 300-2,000 square metres per gram depending on how it was produce .These so-called active, or activated, charcoals are widely used to adsorb odorous or coloured substances from gases or liquids.
The word adsorb is important here. When a material adsorbs something, it attaches to it by chemical attraction. The huge surface area of activated charcoal gives it countless bonding sites. When certain chemicals pass next to the carbon surface, they attach to the surface and are trapped.
Activated charcoal is good at trapping other carbon-based impurities ("organic" compounds ), as well as things like chlorine. Many other chemicals are not attracted to carbon at all -- sodium, nitrates, etc. -- so they pass right through. This means that an activated charcoal filter will remove certain impurities while ignoring others. It also means that, once all of the bonding sites are filled, an activated charcoal filter stops working. At that point you must replace the filter.
So the carbon is basically blocked with organic solids , to release this organic fraction we need to introduce the carbon to something that will eat the organics so it becomes unblocked freeing up the blocked pores.
To do this we need to make the carbon part of a bio filter to utilise beneficial microbes as in worm composter , anaerobic digestion or in bokashi
Digester (which is anaerobic digestion) so during all of the above process’s there is a liquid (lechate run of ) that is the bi-product of the over all reduction in volume , chemical and biological actions of the above .
The filter is made up of just two things dry clean sand (not beach sand as to salty) and or a mixture of composted tree bark fines (smaller size that’s be graded ) this is how the layers are constructed.
The basic filter is 4/5 inches in depth of sand mixed with your used charcoal at a ratio of 50/50 , on top of this you place a layer of tree bark fines (does not matter how wide it is just scale up or down depending on the size of your worm composter/digester/bokashi unit ) .
And using this filter to clean up the liquid as it filters through the medium ,it takes about a week for it to become biologically active with anaerobic bacteria , the microbes feed on the suspended solids as the lechate filters through and with in a few weeks the charcoal is clean and working efficiently again.
There are a few other benefits to using this in so much as the bod (A measure of the amount of oxygen consumed by micro-organisms in breaking down organic matter in effluent during a certain period) is reduced ,the lower the figure the better (water has a low bod of 4/5 while raw sewage sludge or land fill lechate can be has high as 2/3000) the lower it is the better for your plants when used as a tea type feed.
So as you are going to be replacing you filter every 9/12 months depending on the type (approx) , this will then allow the reuse of the charcoal as you bio-filter .
To use your charcoal again just dismantle your bio-filter by first removing your tree bark layer and tipping the sand charcoal mix out , screening of the sand , allowing the charcoal the air dry and finally stick it in the oven on a medium heat for an hour or so , and there you go clean fresh charcoal.
The liquid run off or tea is in a much more beneficial state than just using the unfiltered liquid that in some case may have undesirables in it , you could use a small pump to oxygenate the liquid to really clean it up and encourage an aerobic bloom .
Especially with the worm tea as this will have lots of dormant beneficial microbes , fungi spores (from the tree bark composting process) that will bloom when oxygenated .
its not complicate and as your only changing your carbon , say on a yearly basis .. you have the time for a complete cycle.
ask away if your not sure ..but i have tried to keep it as simple ...
B)
it does work ... we used to use it in massive bio-filters in our composting (500 cubic metre in size ) sites for cleaning the run off liquid and as an air scrubber to remove VOC's
(volatile organic compounds released during the composting process ) its just a simpler version
e2a of course this is not going to suit every one ....but for those that like to recycle then you will see the benefits of this process and its a win /win situation to
and even if you can't be bothered to screen it out after it still make a really good bio-filter
Edited June 19, 2009 by ripthedrift
