DSB controversy...spanning the boards.

[ChrisRD]

this wasn't only in response to you, Chris. i was just trying to add clarity to my own point.

You quoted me directly so I assumed it was intended for me - sorry.

that said, to you i now ask, why would the decomposition stop at any given point?

Actually, it doesn't have to stop for there to be an accumulation. It just has to slow down to a point where there is less being processed/reduced than there is coming in. This is what happens in a septic tank.

also, i am willing to bet that if you ran enough clean water (no herbicides, etc.) through a semi full septic tank that you could successfully empty it of solids.

Again, I have no idea Pod, but if these solid wastes could simply be dissolved in clean water, why wouldn't we just flush septic tanks instead of pumping them out? Why do wastewater treatment plants accumulate organic solid waste that ultimately has to be reduced/treated and disposed of?

 

[alienzx]

I have a DSB about 5-6" and I would have to say it definitely has detrius in it. If you drag your finger through just the top you can see a ton of crude get kicked up. And it's not your regular sand dust it is definitely organic.

I have plenty of hermits and other assorted lil guys to clean it up, but now I worry. I've been battling high nutrients for awhile. The sand isn't as fine as oolitic sand, could that be a problem?

 

[Anonymous]

Again, I have no idea Pod, but if these solid wastes could simply be dissolved in clean water, why wouldn't we just flush septic tanks instead of pumping them out? Why do wastewater treatment plants accumulate organic solid waste that ultimately has to be reduced/treated and disposed of?

to clear a septic system using water would take a long time and a lot of water. especiallly if you don't want to flood the neihbors out. as you said, who knows how accurate a septic tank analogy is

 

[liquid]

Well, I have the sample in the ashing oven right now so I should know in a couple hours how much burned off.

Shane

 

[Anonymous]

(holding breath)...

 

[Anonymous]

bump

 

[Anonymous]

Hey Alien how big is your tank. Why 5-6 "?

 

[liquid]

Well, initial results seem to show that I had about 5% of my upper 1" of my sandbed was ashed away in the ashing oven. So that should equate out to an organic content of about 5%. wow.

What I think I'd like to do is to work out a sampling mechanism and do some additional research and then maybe get some people to supply me with some of their sand and see what other people's sand ashes out at. I'd really be curious to see where Len's levels are compared to other peoples since his sandbed is 9 yrs old.

Any takers?

Shane

 

[Anonymous]

I would gladly send you a core! 150 with a 4-5 inch sandbed, 1 year old.
I also have a remote sandbed with macros growing in/over it. It seems like it might be and interesting comparison.

 

[Anonymous]

Righty, if you do, try what I posted above for sampling methods, it always works for us in the field. With 3/4" pipe, we've gotten about 2.5 feet deep. Make sure you freeze the sample and then pack it in dry ice (if possible) or ice packs and ship it overnight. This will help prevent mineralizing bacteria from altering the true organic content of the sample at the time of its extraction.

 

[Anonymous]

Shane: Total C(org) Percentages, normalized for one gram of sand/sediment.

Coconut Island, Hawai'i
Reef Flat
- Coral Sand near living corals: 5.1%
- Coarse reef edge sand: 3.3%
- Detrital sediments: 2.5%
Lagoonal Shallows
- Detrital silt/sand: 8.0%
- Coral sand/near living corals: 0.3%
- Fine coral sand among benthic algae: 1.6%

Majuro atoll, Marshalls
Windward Flat
- Coral sand: 1.0%
Lagoonal coastal reef
- Coral sand among corals: 1.5%
Lagoonal patch reefs
- Fine mucus coral sand under living corals: 3.0%
- Fine detrital sand among benthic algae: 6.0%
- Detrital sediment: 1.2%

Davis Reef, GBR
Reef Flat
- Coral sand: 2.6%
Patch Reefs
- Coral sand: 1.4%
Lagoon
- Silted coral sand: 3.4%

Lizard Island, GBR
Reef Flat
- Coral sand among near living corals: 3.5%
- Coral sand on seagrass beds: 2.8%

Source:

Hansen, Y.A. et al. (1987). Coral Reefs. 6: 63-70.
Moriarty, D.J. et al. (1985). Mar Biol. 85: 285-292.
Moriarty, D.J. et al. (1990). Aust J Mar Freshwater Res. 41: 785-794.
Sorokin, Y.I. (1978). Arch Hydrobiol. 83: 281-323.

 

[alienzx]

Seawiz, It's actually in a 30gal refugium below my 55gal. 5-6" was what I was told would be a good depth. Previous to that I had a plenum in the 55gal with the sand. That didn't really do much and ate up a lot of the room in the tank.

Wish I could send a core sample, but I think the % would be way too high.

 

[Anonymous]

bumping again

 

[liquid]

Galleon,

Did they happen to list their testing procedure?

Shane

 

[liquid]

So far only two people have said they are interested in sendig me some sand: Righty and Len. Len mentioned that he might have two other people that he could sample.

Anyone else interested?

Shane

 

[wade1]

I'll readily toss in a sample. Also, for those with enough interest to get into the science of it, I have posted a pdf of a recently published article you might find interesting (2 really):

http://www.earthandh2o.com/temp/sandfiltration.pdf

http://www.earthandh2o.com/temp/nutrien ... atolls.pdf

Wade

 

[Anonymous]

Liquid, I'll have to double check, those numbers are republished (secondhand). If I had to guess, I'd say frozen samples that were ashed out, this is usually the most common way of doing it (especially with the estuary work I've been privy to).

If I had a DSB, I'd ash out a sample at our geo lab. But, alas

 

[liquid]

Specifically I'd be interested in:

• Ashing temperature
  Ashing duration
  Sampling size
  If they used a published standard testing method that I could review -- like ASTM

Any help you could provide me would greatly accelerate anything I'm planning to do.

Wade: Sounds good.

Ideally I'd like to get at least a dozen people that would send me sandbed samples. It'd be interesting to see what kind of variation is out there.

Shane

 

[Anonymous]

Shane, I'm going to look for some of the references on my lunch hour, I've also e-mailed one of our marine geology professors to see if there is a standard.

 

[liquid]

Cool. Keep me posted.

Shane