Ok lets look at it for a second. In a dsb we are trying to reverse a couple of inevitables. One is that a dsb can only do a low ammount of bioload because the nitrification/denitrification process is slow. also it only handles an ammount of what is put in thier (nitrogen based) the balance stays and builds up. and then the problem with P leeching. In order to help the above problems along we need to adress them, possible with some filtration design. So one by one then,
The low bioload: The ammount a bed can handle in regards to waste/detritus and so on is low for what most folks want in a tank. If we can figure out how to remove some or eliminate some we can have a win here.
The build up: Now the pure idea of having a wasteing or draining system under the plenum (or what ever we call this) will fight this battle, so I think we are on the right road already.
P leeching: a little more tricky, but I think it will fall in line with the fix of the above problems.
Ok back to solids. helping to remove the solids will help the bed in the ammount of bioload it can handle. Also you have to look at what is associated with the solids and how thier removal will benefit us. As mentioned prior bacteria feed by excreting microbes in a enzyme type fuild (snot) they will surround the solid and begin to reduce what parts of the solid they need. with in and around the solid will be this snot, which is loaded with the byproducts, products they cant reduce, bacterial flock, the protienious bile (snot) and so on, removing it or allow it to drop into an area where we can remove it it a big win against both the build up and bioload problems. I am not saying go after all of it, but I think we should allow what ever can drop into the lower region to do that, it is a huge form of exportation and I think a major key. We are not going to be relient on it totally and will still have the vast majority of the bed performing the Nitri/denitri processes. But I think this will allow for the kind of processing ability that a dsb needs to be.
The waste and so on that would get trapped in the top portion of the bed is where the works needs to be done. this is the area that gets clogged the easist, the ammount of waste coupled with the biproducts and goo (lol) is what makes the region go anaerobic. My thinking is that if we make that area with larger particles we will help to keep it aerobic. Also the larger particles will allow for more diffision into the anaerobic zone, this will lessen the probem with being so relient on bugs for this operation, Win win.
On the removal of organics. build ups, detritus and so on that goes into the plenum area i dont like the concept of constant wasteing. When you pull water and all that is associated with it out of the plenum zone you are screw around with the integrity of the each zone. the areobic zone will feel no impact, the anaerobic zone is going to take a hit, it will be saturated with oxygenated water and will convert the bacteria to oxygen fixation instead of nitrate for the period of time that th oxygen is present, if you are constantly wasteing you are keeping this zone in an internal state of flux, I dont think that going to benefit us. For me once every 3 months or so we give it a good draw, This will hurt the anaerobic zone, but it will also flus the aerobic zone so thier wont be an immediate need for the denitrification as the waste has to go through the nitrification process from scratch. the time should balance itself out
