Aquarium keepers have known about it for over a century, very old books mention it, just not by the term 'biological regeneration'; the old books just say old carbon is more valuable than new, and that new carbon must be aged.
In these very old books, undergravel filtration and/or box filters was/were probably the method of filtration in use. Back in that day, carbon and floss were the filtration media the hobby had available to it. Eventually, carbon stops doing its "thing" - removing odors, discoloration - and becomes biological media. This is widely accepted. It was probably an exciting discovery and along with gravel, I bet carbon was an early biological media. There is specifically engineered biological media now which does a much better job than carbon or gravel for colonizing nitrifying bacteria. But this is not why most people use carbon...
If you are using ample amounts of old carbon in your filter, I am sure it is doing a fine job neutralizing ammonia and nitrite. But will years old carbon remove discoloration and odors from the water? Will it remove dissolved organic compounds? Will it absorb pheromones and metabolites? Medications? This is what people expect carbon to do.
In my opinion, the pine tree growing out of the boulder has almost nothing to do with what you are proposing. What you are saying is merely that not all plants need soil and many of them can get enough nutrients from rocks. This is well known, and many plants actually thrive in rocky conditions. In Greece there are plenty of fig trees growing out of the sides of buildings, and a little ways from the beach there are plenty of flowers growing in nothing but sand. Plenty of our food is grown hydroponically. What this has to do with bacteria cleansing the carbon and keeping it infinitely useful in our aquariums is lost on me, unfortunately.
If science only discovered microbial regeneration 30 years ago, but select hobbyists have been in on "the secret" for years, how come we don't hear more about this? We've already figured out the secret formula to Seachem's Excel and how to duplicate it, how to use PMDD instead of liquid proprietary ferts, how to use alternative substrates which work as well or nearly as well as proprietary substrates...
WinstonCourt said:
I believe carbon sellers are the only ones who would will resist the apparent ability of carbon to biologically regenerate itself, indefinitely.
Aquarists from all around the globe are constantly looking for ways to save money - you would think there would be some expert out there saying "don't replace your carbon - in an aquarium, it cleanses itself!" :screwy: We already know how to recharge Purigen, Zeolite, crushed coral gravel - why would we not have proliferated the information that carbon recharges itself in an aquarium and continues to function over a span of years? (In the capacity it was intended for...see above.)
I am sorry if I seem narrow minded, but I am just concerned you are spreading misinformation. The scientific literature you link to, in many ways does not apply to aquariums. I feel I cannot apply reports like this:
http://www3.interscience.wiley.com/journal/104537200/abstract?CRETRY=1&SRETRY=0
Where they are filtering volatile organic compounds (alcohol, ketones, esters, aromatic and chlorinated compounds) to carbon and its role in filtering dissolved organic carbons/compounds in an aquarium.
You are oversimplifying, I believe - taking one concept in one application and applying it to situations that are not equivalent.
I cannot articulate the scientific explanation for why carbon doesn't last forever in aquariums, and why in laboratories it can be microbially regenerated, but I don't think it microbially regenerates in aquariums simply because
we would have heard by now if it did.
Perhaps, there is a difference between the bacteria needed to regenerate carbon and the bacteria present in our aquariums. There's all kinds of bacteria out there - even bacteria that eat oil. Only certain bacteria is in our aquariums. Perhaps saturating carbon in "sludge remover" or some other kind of heterotrophic bacteria concentration would in fact cleanse the carbon. Perhaps it needs denitrifying bacteria such as that found in anaerobic zones...and none of these are practical to culture vs. the cost of replacing spent carbon. Perhaps aquariums have some of this bacteria, but not enough to cleanse the carbon. Because again, more than a handful of alert hobbyists such as yourself would have noticed carbon cleansing itself...(although many have noticed that it is a fine growing media for nitrifying bacteria).
I am sorry if it seems like I am bashing you or your post. I don't mean to, I would hate to see a newbie just rinsing their filter cartridges and thinking they are continuing to work. They should either use biological media and floss, or replace the cartridges regularly. How regularly all depends on a multitude of factors.
Lastly, this article is an interesting read:
http://www.thetropicaltank.co.uk/carbon.htm
Granted, I understand your tap water is far from ideal. 