Re: The Geo Method / Black and Gray Water Holding Tank
murfette,
The natural bacteria that is in your waste tanks when you use them will break things down in a fairly short time, under normal circumstances. That is what makes a septic system such as most rural homes use, work as it does. There are additives that are designed to encourage or enhance that natural action in either a septic system or in the RV waste tanks. Since we are talking RVs, if you look in any RV supply store you will find all kinds of products for waste tanks. There are several chemicals, bacterial products and also oxygenation products which just speed and enhance the action of natural bacteria that is already there. In a wast tank there are two types of bacteria, aerobic and anaerobic. The aerobic bacteria are those that thrive in an environment that has a good supply of oxygen and that is why the oxygenation products are out there. The bacterial products also add aerobic bacteria to speed the process in that way. When you use large volumes of water you encourage the aerobic bacteria growth since all water has free oxygen dissolved in it. All of the bacterial products work on that basis.
Anaerobic bacteria is bacteria that flourishes in low oxygen environments and it is also what creates the odors that come from waste tanks. Most of that odor is from grasses that are high in sulfur compounds such as hydrogen-sulfide. Free oxygen will kill most anaerobic bacteria if it is there in large enough quantities. And that is one of the reasons for the oxygenation products.
The various chemical products work in totally different approaches from either of these. What they do is to kill all bacteria or as nearly as they can, to thus prevent growth of anaerobic bacteria and prevent odors. They then also supply chemicals which break down the solids chemically, rather than naturally. They were the first products on the market for the purpose and were the only ones for a long time. Today they are considered by most people to be environmentally unfriendly. In large enough quantities they can effect the operation of septic systems or even city sewer systems. Most studies support the belief that it would be quite unusual to see a large enough quantity to cause problems, but since this is a hotly debated subject that most of us are not expert on, the majority of the RV world is moving to the more environmentally friendly products to make sure.
As a seven year +, fulltimer I have found that most who stay fulltime for long sooner or later stop using much of anything by way of chemicals and just be very generous with the use of water, thus to take advantage of the natural bacterial action. That works well for most of us, but we are also mostly traveling with only two people so the tanks fill fairly slowly and that allows more time. In hot weather we do use an oxygenation product from time to time, and we have also used bacterial additives on occasion, but mostly we are generous with the use of water in both the black and the gray tanks. I think that most fulltimers also from time to time add a 1/2 tank or so of water and some strong detergent before travel to slosh around inside of the tank while traveling and thus to clean it.
The "Geo Method" is the invention of Charles Bruni, who also uses his website to generate an income. I have known quite a number of people who have tried his home brew and some say it works, others disagree. I have not tried it since we find that water does the job just fine and I really do not see any reason to waste money on either commercial products or on some home brew. I also contacted the Calgon company to ask if their product had any positive effect on this process and was told that it would not. At the same time, I really doubt that it will do any harm either if you always use ample water when you flush and are careful to not use too much bleach since that will kill the natural bacteria if used in large enough quantity. But I have not tried it and I don't plan to do so. For that reason, I don't support it but that same thing is true of commercial products as well, and those I have used. Mostly I just don't like to waste money. But reading this thread should make you aware of the strong feelings of many on this subject. My advice is that you use a septic friendly toilet paper and use generous amounts of water in both tanks and go from there. If you want real expertise, I suggest that you contact some waste treatment operators and engineers and also an environmental chemist as well. Since there are none of either that post here (to my knowledge) most of what you read by any of us is just opinion.
