Thursday, June 24, 2010

RV Basics : Black Water Holding Tank Treatment Strategies

If you search the web for information on the treatment of RV Black Water tanks, you'll find several strategies listed. You'll see lots of people insulting each other and saying they know this and they know that and that the other person's strategy is very poor. Usually, they will insult an alternate strategy and then say "this works for me".

In over 8 hours of non-stop web surfing I found ONE and ONLY one person who actually took the time to objectively ask HIMSELF the question : Is my treatment plan working? He did it by inserting a small camera up into his black water tank and looking around. That made me smile, but at least this guy KNOWS.

This article is not to completely describe the strategies, but is meant to provide context to information people are seeing on the web. In follow up articles, I'll go into more details about different strategies.

Let's do put a single FACT on the table here: Black Water tanks are simply holding tanks and are not designed for TREATING waste. The next fact is that the toilet simply drops waste (I do not plan on being more descriptive) directly into the black water tank. At the far end of the black water tank, there is a valve to drain the tank. The tank is designed with a slope. All roads lead to the valve.

Black water tank goals :

  • Do not make the RV smell.
  • Always drain reliably.
  • Sensors read reliably.
  • Related to the prior two : Waste does not build up on the sides/bottom of the tank.
  • Honestly this SHOULD be a goal : Do not hurt the environment.

Most strategies for treatment hinge on the goals above. The following are strategies that seem to be in common deployment, with little empirical evidence they work.

Listing of Strategies for managing the black water tank for an RV. No particular order  :
  • Water Only. Just use lots and lots of water.
    • Pro - simple and probably does work. Since cleaning the tank is usually involved the tank should stay free of gunk.
    • Con - very, very, very wasteful of water. 
  • Geo Method. A concoction of dish soap, water softener and sometimes other stuff. Also recommends using lots of water with this method.
    • Pro - Probably works, but maybe no better than water only? Unproven.
    • Con - Chemicals. Lots of water. Unproven.
  • Deodorants. Typically chemicals of some sort. Lots of discussion about avoiding formaldehyde. For this article, just assume that none of these have formaldehyde.
    • Pro - Simple. Easy to understand how it works - it reduces the smells.
    • Con - Could be bad chemicals. Might allow gunk to build up.
  • Waste Digesters. Supposed to eat the gunk and liquify it. Supposed to use the same bacteria that are in  the environment to eat the waste and make it non-smelly, non-sticky-to-the-side, and easy to drain off. In my mind this makes sense, but.
    • Pro - If it really works, then you would have clean, non-stinky tanks.
    • Con - Unproven. No evidence found online but lots of stuff to BUY! Also, when bacteria eat, the put out smells too. 
  • Macerator. Imagine a toilet that when you flush takes the waste and basically runs it through a blender. Well, that is what it is. A $600 toilet!!! On one hand this also makes a lot of sense, but I'm not there yet.
    • Pro - doesn't address stinky. But sticky-to-the-tank and easy draining seems obvious to me.
    • Con - $600 plus the humiliation of using a blender on your dookey.

Well, there you have it, my outline of the basic strategies and why people do them. Soon, I'll start trying to fill in some of the details and along with that some more empirical evidence. I just don't accept some cranky person flinging insults at alternate methods saying that "his method works". That is baloney. RV'ers need to set a better example anyway. I hope you (the person reading this right now) do not flame people like that and act that way on the web.

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