Sulfur denitrator experiment

[Delphinus]

Ok new update. I was out of town last week and got back Monday so on Tuesday (Jan. 2) I was able to finish off the mods for upflow and get the reactor going again on my test tank.

So after a couple of days, there's been a bit of an "interesting development" as well as a "slight disappointment."

The bad news for me is that the nitrate monitor I ordered came yesterday and it appears to be defective. I can't get a reading out of it despite many calibrations, and the readings I get on the calibration fluids, after calibrating, are whacked out. (For example, 93ppm on the 10ppm calibration fluid). Bummer.

But, I did some old-school tests and came up with these readings:

NO3 of tank water - 50ppm
NO2 of reactor effluent - 0
NO3 of reactor effluent - 25ppm

I'm somewhat suspicious of the #'s since they're indicative of a nearly complete cycle at 2 days already, so it will be interesting to see what the numbers are at in another 2 days. I was expecting the nitrite #'s to be non-zero for a while yet, if it went non-zero and came down then I've missed it already. Since they hadn't come down after 4 weeks on the previous trial I'm at a loss to explain the profound difference.

I should mention that besides changing the unit to a non-pressurized upflow design, I also have the flow-through cranked way, way back. Unfortunately due to the flow control being on the input, getting a consistent flowrate day after day is a bit of a challenge, but the last time I measured the flowrate it was approximate 3ml/min. That's 180ml/hour, or assuming a total water volume of 115gal, about a 0.04% volume turnover per hour, or just under a 1% volume turnover per day.

[BCOrchidGuy]

Tony, Not sure how the numbers work out but have you considered using garden irrigation drippers? I used a 1/2 gallon per hour dripper on my old Ca reactor, yes it clogs up after a couple of months but changing them is easy and they are affordable.

Doug

[Delphinus]

That's a cool idea! I can see that working well for a Ca reactor. Unfortunately that flowrate is far too fast for cycling this thing, since what we need is an oxygen-free zone to kickstart the anaerobic bacteria, so have to really restrict the amount of oxygen being introduced. I almost wonder if it's better to close the input altogether and open it slightly only once per day just to get the cycle going. Once the bacteria is settled I should be able to open up the flowrate, after all 1% volume turnover per day is not going to touch the tank's nitrates in any scenario.

[Psyire]

Glad to see some encouraging results!

[andresont]

Two days and 25ppm NO3! what a difference pressure can make. May be you already had bacteria there, and when Bacterial headache is gone they just got hungry !

[Delphinus]

Still being somewhat suspicious of the #'s I tried testing again tonight using a different test kit. The first were done with Salifert, so tonight I tried with Elos.

I suspect that the Elos kits strengths are in the lower ranges. I took two test tubes side by side and did the input and output water together. I had to stare at the colours for a long time before deciding that one did indeed seem "less pink" than the other. The only sorta downer is that the pink matches more like 75ppm and 50ppm. I think I must be colourblind because I really have a heck of a time staring at pinks and trying to compare to the colour chart. They're all "fuscia" to me.

I talked to American Marine earlier today and I'm told that I'm the first one to call about any problems with their nitrate monitor. (Yay me! Go team!! Wooty!! ). Anyhow he gave me some suggestions but there really isn't a lot to work with (short of leaving the probe in the calibration solutions longer). The readings, if not clamped at over-range, are hugely fluctuating. For example tonight I got it to read anywhere from 30ppm to 100ppm to over-range on the 100ppm sample. I'm going to talk to them again tomorrow or Monday, hopefully we can get it working right or determine that it can at least be replaced if nothing else. I'd love to see what the readings are with something that can tell me real #'s as opposed to "in the neighbourhood of 50 to 75ppm".

[Delphinus]

Well ... I'm at a loss again.

At the end of day 7 I tested NO3 on the tank and the reactor output, using Salifert.

Tank - 25ppm
Reactor - 25ppm

I'm completely puzzled by this. Did the reactor start outputting at 25ppm earlier like I thought it might have been, and it's pulled the tank down to 25ppm in the days following even though the feed is super-duper slow?

Or is it more likely that the chaeto in the tank, which has suddenly kick started a growth spurt, has sucked up some nitrate?

So .. tonight (day 9) I test the reactor effluent with my Elos test kit.

You're supposed to add the reagents, then shake for 5 minutes to wait for the colour to settle. Well within 30 seconds the colour was darker than the darkest colour on the colour chart (much like before on trial #1), which in the Elos NO3 testkit is 75ppm. So the reactor is outputting >75ppm again? Huh? What gives? Does the Elos test kit colour actually fade in the 5 minutes unlike other test kits where it gets darker the longer you wait? Or am I messing up the testing? Or is the reactor outputting a super high nitrate for real and my Salifert test kit is out of whack?

I'm completely at a loss to theorize what's going on here.

The one tool I had hoped would help clarify things, the nitrate monitor I bought on Boxing Day, is seemingly defective, and has been sent to American Marine directly to troubleshoot and repair or replace if need be. In the meantime I'm out the $300 and I'm out the unit until it gets sent back to me. (I trust the issue will get resolved satisfactorily .. I'm not knocking the service I've gotten, I'm just disappointed I can't use the unit as a yardstick for my nitrate levels because trying to make heads and tails of these test results ... simply sucks!)

Gonna try rearranging my reactor feed situation and see what I can come up with. I'm determined to see successful results dadnamitall!!

[andresont]

If i could only have as much patience, determination and drive as you do!
There are like gazillion people watching this...
How about we do a mass consciences experiment and visualize the following:
All test kits are accurate
Denitrator is working properly
And nitrate monitor comes back very soon in perfect working condition !

[Psyire]

On day 9, what did the salifert test kit show? Still 25?

[Delphinus]

Didn't get a chance to test with the other test kit, by the time I got around to the testing I had only a few minutes before the tank lights turned off, and the (as yet undeveloped) basement is too dark at night without the tanks on. You're absolutely correct though in that I need to do both testkits at once and do a side-by-side comparison to try to makes heads or tails of this.

What's weird though is that my nitrate/nitrite litmus test strips that I was using previously to tell if there was nitrite or not, are not registering any nitrate or nitrite, three tests in a row now where a strip has been dipped and there's been no colour change on it. It is an old set of test strips though, so more than likely the explanation for this one is they finally hit their expiration and I should just toss the rest.

I should be doing the testing at high noon and comparing the test tube colours outside in full sun. I bet then I'll get some lower #'s!