DIY Natureef Style Denitrator Build and Data thread...
- Thread starter mrx66699
- Start date
DRThompson
2018 FMAS President
My understanding is that the bacteria responsible for converting Nitrate into Nitrogen gas are anaerobic? If so, how do you lower the O2 levels fast enough for there to be enough time for the bacteria to do their thing before the next batch of oxygen/nitrate loaded water comes in?
Does the presence of O2 in the fresh (salt) water not kill of the bacteria?
I understand that this is a proven method of Nitrate Removal so I must be going wrong somewhere
Thanks.
Matt asked me to comment on this:
the SHORT Theory behind denitrification using a methanol chamber:
The denitrification is carried out under anoxic (low oxygen) conditions by a broad range of heterotrophic bacteria (mainly pseudomonas sp) through the process of nitrate dissimilation, in which nitrite and/or nitrate are used as the electron acceptor rather than oxygen. The bacteria can use either oxygen or oxidized nitrogen while oxidizing organic material. Thus, for the biological denitrification to be effective it needs to be carried out in the absence of oxygen. This is often the rate limiting step in the process for cycle completion.
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DRThompson
2018 FMAS President
I thought I should include some information about dosing.
Here is the equation for the anoxic reaction in the chamber to convert nitrate to Nitrogen gas using Methanol utilizing heterotrophic bacteria.....(roughly)
5 CH3OH + 6 NO3- ----> 3 N2(gas) + 5 CO2 + 7 H2O + 6 OH-
Our dosing method:
After a lot of research and experience with my own methanol denitrator we will be using a 3:1 Methanol to Nitrate dosing ratio. Again, we are going with a more conservative approach. Matt and I will dose adjust as we follow the first few cycles to completion.
Matt's water tested roughly 25mg/L of Nitrates, its probably higher but I thought we should be conservative. The volume of the chamber is roughly 30gal or approx 120L which gives us (25mg/L*120L=3000mg or 3grams of nitrogen)
At a 3:1 ratio it will take approx 9gm of Methanol to remove 3gm of Nitrate. Since the specific gravity of Methanol is approx 0.8 that would give us a starting dose of 11.25ml. To keep things easy we are rounding to 10ml of pure methanol for the initial dosing
.
Also, because of the volatility of methanol we will be using a 50% v/v solution of methanol and water. This changes the initial dose to 20ml.
After filling the chamber with tank water and seeding with a small amount of bacteria from my biodenitrater we started the first cycle at 9pm Feb 24th with 20ml of our 50% methanol solution.
Here is the equation for the anoxic reaction in the chamber to convert nitrate to Nitrogen gas using Methanol utilizing heterotrophic bacteria.....(roughly)
5 CH3OH + 6 NO3- ----> 3 N2(gas) + 5 CO2 + 7 H2O + 6 OH-
Our dosing method:
After a lot of research and experience with my own methanol denitrator we will be using a 3:1 Methanol to Nitrate dosing ratio. Again, we are going with a more conservative approach. Matt and I will dose adjust as we follow the first few cycles to completion.
Matt's water tested roughly 25mg/L of Nitrates, its probably higher but I thought we should be conservative. The volume of the chamber is roughly 30gal or approx 120L which gives us (25mg/L*120L=3000mg or 3grams of nitrogen)
At a 3:1 ratio it will take approx 9gm of Methanol to remove 3gm of Nitrate. Since the specific gravity of Methanol is approx 0.8 that would give us a starting dose of 11.25ml. To keep things easy we are rounding to 10ml of pure methanol for the initial dosing
. Also, because of the volatility of methanol we will be using a 50% v/v solution of methanol and water. This changes the initial dose to 20ml.
After filling the chamber with tank water and seeding with a small amount of bacteria from my biodenitrater we started the first cycle at 9pm Feb 24th with 20ml of our 50% methanol solution.
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DRThompson
2018 FMAS President
I'll be using the term PEAK reaction: For us the peak of the reaction happens when the system goes anoxic and the bacteria start removing the nitrogen(nitrates). IME, this usually happens about 3/4 of the way thru the cycle and can be instrumental in finding the end of a cycle.
Parameters we will be monitoring:
Expected Visual Observations:
Expected Test kit observations:
Nitrate: Salifert and API - Matt's Tank water tested at 25-50mg/L on salifert. (higher readings are harder to read) Obviously, it is expected to be near 0 at cycle completion.
Nitrite: API - At the peak of the cycle there should be a noticeable increase in nitrite. Our initial test at the start of the cycle was 0 on the API test kit.
ORP: We should see a drop in ORP (approx -100 to -200 at the peak of the reaction). Matt is still working on getting the ORP meter up and running.
Dissolved Oxygen: We will be using a RED SEA dissolved oxygen test kit. Normal Seawater will read between 6-7ppm. There should be a marked drop in dissolved Oxygen indicating the peak of the reaction. Also, at the end of the cycle it is expected to be around 1-2ppm.
We are somewhat limited by the accuracy of our home test kits but I am confident we should still be able to successfully locate the peak and end of the cycle.
At the cycle endpoint the water in the chamber should be:
When we've determined the endpoint of each cycle, the water will be flushed thru the chamber using an external pump (mag 7) and then the cycle starts over. Our observations showed it took the Mag7 approx 5 min to fill the chamber when empty. To ensure a proper flush we will run the mag7 for about 20min at the end of each cycle. Once there is a predictable cycle under 24 hours we will automate it with his apex. Our goal is to have this 30gal chamber cycle 3-4 times per day. At 3-4 cycles per day it would be like a 10-15% water change daily (comparatively speaking for removing nitrates)
An important note: we have positioned the output of the chamber so it dumps the water that is exiting the chamber on top of the skimmer intake. This will allow the skimmer to chew up most of the excess bacteria. While beneficial to the system it is WAY more than most systems can handle and would become food for nuisance algae if not properly skimmed out.
Parameters we will be monitoring:
Expected Visual Observations:
The growth of the bacteria is VERY noticeable. It is thick and slimy. It is clear to slightly brown in color.
Also, as the reaction nears completion nitrogen gas bubbles will often form on the eggcrate.
Also, as the reaction nears completion nitrogen gas bubbles will often form on the eggcrate.
Expected Test kit observations:
Nitrate: Salifert and API - Matt's Tank water tested at 25-50mg/L on salifert. (higher readings are harder to read) Obviously, it is expected to be near 0 at cycle completion.
Nitrite: API - At the peak of the cycle there should be a noticeable increase in nitrite. Our initial test at the start of the cycle was 0 on the API test kit.
ORP: We should see a drop in ORP (approx -100 to -200 at the peak of the reaction). Matt is still working on getting the ORP meter up and running.
Dissolved Oxygen: We will be using a RED SEA dissolved oxygen test kit. Normal Seawater will read between 6-7ppm. There should be a marked drop in dissolved Oxygen indicating the peak of the reaction. Also, at the end of the cycle it is expected to be around 1-2ppm.
We are somewhat limited by the accuracy of our home test kits but I am confident we should still be able to successfully locate the peak and end of the cycle.
At the cycle endpoint the water in the chamber should be:
Free of nitrates
Low in oxygen
Lower in pH than start
higher in Alk than start
Loaded full of beneficial bacteria
Low in oxygen
Lower in pH than start
higher in Alk than start
Loaded full of beneficial bacteria
When we've determined the endpoint of each cycle, the water will be flushed thru the chamber using an external pump (mag 7) and then the cycle starts over. Our observations showed it took the Mag7 approx 5 min to fill the chamber when empty. To ensure a proper flush we will run the mag7 for about 20min at the end of each cycle. Once there is a predictable cycle under 24 hours we will automate it with his apex. Our goal is to have this 30gal chamber cycle 3-4 times per day. At 3-4 cycles per day it would be like a 10-15% water change daily (comparatively speaking for removing nitrates)
An important note: we have positioned the output of the chamber so it dumps the water that is exiting the chamber on top of the skimmer intake. This will allow the skimmer to chew up most of the excess bacteria. While beneficial to the system it is WAY more than most systems can handle and would become food for nuisance algae if not properly skimmed out.
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DRThompson
2018 FMAS President
When I started my denitrator my first cycle took about 2 weeks. It really depends on your starting parameters and how fast you can get the bacteria to grow. It is highly unlikely anyone's first cycle will complete in 24 hours. As the bacteria populate the chamber the cycle time will shorten. I told Matt it may take a month or so to get a cycle time under 24 hours. As with most things in this hobby, patience and time are very important for success. We are posting our experiement on this forum to benefit anyone who may be interested in starting a biodenitrator.
We added fresh bacteria from my denitrator chamber to help seed it. At about the 20 hour mark, Matt's observed an explosion of bacteria growth in the chamber. He tells me the water is cloudy and full of thick slimy bacteria. This is GREAT; we are growing heterotrophic bacteria!:bounce3: Matt also tested nitrites and nitrates at around the 24 hour mark and they were both elevated. However, I don't think it has gone anoxic yet. I suspect his biopellet reactor is responsible for the bacterial bloom in the chamber. I'm not totally convinced we are getting the right bacteria to grow in the chamber. If we looked at the bacteria under a microscope I could maybe determine if it is gram negative (Pseudomonas sp) but have no way of identifying if it will eat up the nitrates once the oxygen is gone. Again, we lack specialized scientific equipment so for now we will just let it "cook" a bit longer to get in the anoxic stage.
He's is going to run oxygen, nitrite, and nitrate tests later today at about 4pm (43 hours into the first cycle). We'll post the results but I don't believe we are at the PEAK of the cycle yet.
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mrx66699
New member
This is all great info Matt and Dave! The scary part is Im actually starting to understand it....
For myself it always seemed a simple thing to understand on the surface level but I had no clue it was this deep and what was actually happening with the chemistry level and it wasnt until I started speaking with Dave that I have actually started to fully understand on a sub level what is actually taking place.....I had one on my first DT here in Florida and all I knew was it just worked better than any of the other setups that I had tried up until that point.....:beer:
mrx66699
New member
...thats a simple one I can handle without the phd lol The guy that invented this lives here locally and I believe his son now runs the company. One thing is sure though for what they accomplished in this wonderful product they lack in the marketing aspects for sure. This should be a standard piece of equipment with every new saltwater setup being sold just like a skimmer.
DRThompson
2018 FMAS President
We are using the natureef denitrater product as a model. The natureef denitrater was invented by Adolf Klostermann here in south Florida back in the 90's.
I'm not sure why is products never really took off. The chamber takes up a lot of space, on smaller tanks this could be an issue.
I'm not sure why is products never really took off. The chamber takes up a lot of space, on smaller tanks this could be an issue.
mrx66699
New member
LoL no problem just let me get this going and you are 1st in line.....
nivram
New member
A lot of the old timers in our club have said many times Adolf's products were ahead of his time.
Kudos to Dave and Matt for putting in the time and work to test this in a methodical way and share their findings.
Let me know what month's meeting you guys want to present at?
mrx66699
New member
A lot of the old timers in our club have said many times Adolf's products were ahead of his time.
Kudos to Dave and Matt for putting in the time and work to test this in a methodical way and share their findings.
Let me know what month's meeting you guys want to present at?
Funny you speak of that Marvin, Dave and I were just talking about that. Thought everyone would like to see things in person and I thought about making a custom acrylic one to give away for the raffle.
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