DIY - Projects & Ideas • Denitrate Tower - "Safe Denitrification"

[newfisher]

[quote="BenHugs"]Does the hydrogen sulphide stay in the water column or can it be "bubbled out"? Is it dangerous to the humans living in the room?[/quote]

Denitrators typically produce very low concentrations of H2S. Some of it may dissociate in water to form sulphuric acid, slightly lowering water pH. However, if a denitrator output is allowed to drip through air space before re-entering water, most of the H2S will become airborne. It is characterized by rotten egg smell (swamp gas odour), noticeable at concentrations of about 0.005ppm. I surmise that typical denitrator production would be well below 1 ppm, and notwithstanding pH changes, would present an odour nuisance at worse to humans.

On the other hand, H2S is extremely well known and respected in the oil and gas industry, where I've dealt with concentrations above 8% (80,000ppm) back in my oil and gas exploration days. It is heavier than air, flammable, and very toxic in higher concentrations. H2S causes eyes to burn within minutes at concentrations above about 50ppm and eyes are damaged above 100ppm, it will deaden the sense of smell above about 100ppm (often causing potential victims to be lulled into thinking the gas has gone), and cause immediate collapse at concentrations above 500 to 1000 ppm. Many oil industry workers have died trying to perform CPR on co-workers who have collapsed ... where there's often sufficient H2S remaining in the victim's lungs to cause his rescuer to collapse also on their first breath. Industrial personal and electronic sensors are typically set to alarm at 5 to 10ppm, above which emergency procedures are put in place and Scott Air Pack or central respirator use typically begins.

[kmuda]

Sorry for the delayed response, but please allow me to answer a couple of questions.

First, about attempting a "horizontal U-Tube" configuration. I've tried. It was not as effective. The primary problem is it is very difficult to get the tubes 100% full of media. Over time, the media settles and when the tube is placed horizontal this results in the media settling in the bottom leaving an open area at the top. Water will follow the path of least resistance, so the water ends up flowing on top of the media, resulting in much less effectiveness. I consider a filter where water is fed from the bottom and exits from the top essential for this type of filter (think Eheim Classic). Another option would be a very fat, shorter filter.

Secondly, please notice use of the term “safe denitrificationâ€Â

[BenHugs]

Well thanks for all the info Kmuda and Newfisher.
Kmuda I just couldn't possibly put such a large pipe in my living room but still being inspired I went a built the classic coil denitrator. It may not be as "safe" as the one you built but it fits into my stand so nobody can see it.
I couldn't beleive how easy it is to build one of these things. I hope it all works out

[kmuda]

Be sure to monitor the outflow of your coil denitrator for ammonia and/or nitrite. Coil denitrators are notorious for incomplete denitrification. You have to get the flow just right, constantly monitoring it.

[BenHugs]

Ya kmuda I have found similar info. To protect my system from what you mentioned it will have it's outflow going into my wet/dry filter which would just re-convert back into nitrates. My coil denitrator will be getting at most about 3gph so if anything maybe on the slow side?? Off the top of my head the coil section will have over 60' of tubing and the tower filled with bioballs is about 30" tall.

[kmuda]

It's a good ideal to have the outflow of your filter run through a standard aerobic filter. This will take care of both incomplete denitrification and/or hydrogen sulfide (entering the tank) concerns. I do, however, still recommend regular testing. It's the only way to know if the filter is working properly. If you detect nitrite or ammonia, the flow rate should probably be decreased. If you are still detecting nitrates (in the absence of nitrite), the flow rate should probably be decreased. If you smell rotten egg smell, the flow rate should be increased.

Also, if you are running carbon anywhere in the system, it should be removed as it removes the same stuff the denitrifying bacteria need to convert nitrate. If carbon is removing dissolved organics (which is what carbon does, on top of other things), this will increase the likelyhood of incomplete denitrification.

But it sounds like you've done the appropriate research, as would be logical for anyone constructing their own denitrator so you are likely aware of this. Please keep us informed as to the success (or lack of).

[jfly]

your daughter calls it "king kong's bong!?!?!?" hmm and how old is she.. i'd kill myself if my kid said that, then myself for my parenting faults

[BenHugs]

Thanks kmuda I was unaware of the carbon part but I don't run it in my system anyways. I was thinking of using up some carbon that I do have on the outflow of this denitrifier just incase I did get the rotten egg smell.

[mightyevil]

your daughter calls it "king kong's bong!?!?!?" hmm and how old is she.. i'd kill myself if my kid said that, then myself for my parenting faults

I doubt kmuda tought his daughter the word bong and what it does...

[kmuda]

My daughter is 23. If "bong" is the worst word she uses, I would consider that successful parenting.

Thanks kmuda I was unaware of the carbon part but I don't run it in my system anyways. I was thinking of using up some carbon that I do have on the outflow of this denitrifier just incase I did get the rotten egg smell.

You don't have to worry about it. As long as the outflow is running through aerobic filter media, if hydrogen sulfide is occuring bacteria will become established that will convert the hydrogen sulfide to sulfate, which will eliminate the odor.

[BenHugs]

Kmuda

[ncutler]

BenHugs just directed me to this thread since I'm looking at ways to decrease my Nitrates.

I'm definately will be trying to build a Coil Denitrator, but I had the idea today as to whether anyone has ever tried to use an air pump to create the flow for the denitrator.

In my mind, if I attach a vertical section on the output side of it, the venturi effect created by the air (much like a sponge filter) might move enough water through the denitrator to create 80 drops/minute as I have researched to be a good amount.

Perhaps this would make it harder to adjust, though I can't see why I couldn't add a ball valve before the air to adjust the speed.

Just curious as to your thoughts about it.

[tranced]

your daughter calls it "king kong's bong!?!?!?" hmm and how old is she.. i'd kill myself if my kid said that, then myself for my parenting faults

you would kill yourself, and then yourself?

i think you have more to worry about than your parenting skills

that aside, awesome project here, was a good read interesting stuff keep it up

[kmuda]

Sorry to dig up an old thread, but I wanted to update it with a final piece of data. The filter has yet to be broken down and cleaned, but it now needs it. It is no longer able to maintain zero nitrates. Nitrates are now increasing about 5ppm per week, which is still a significant reduction over what would occur if the filter were not in place.

So now I know.... I get about 6 months before it needs cleaned. Now it's time to replace it with King Kong's bong (filled with new media). The current filter will be broken down, the media cleaned, and in about 3 months, added back to the system, to run in conjunction with King Kong's Bong. So every 3 months, one of the two will be broken down and cleaned. In theory, I should be able to maintain zero nitrates almost indefinately. The next question to answer, is how long can I continue to recyle the media?

[BenHugs]

Kmuda have you looked into the np biopellets?