• Sulphur Denitrators - 18 years and Counting

    Just like to share this article I wrote:

    Professor Guy Martin from Ecole Nationale Supérieure de Rennes was believed to be the first person to applied the sulphur denitrification into freshwater treatment for public. In 1991, Marc Langouet, who is a student of Prof. Martin decides to test this method on seawater. After 3 years of testing without apparent toxicity, Marc proposed the idea to Michel Hignette - Curator of MAAO Paris. And the rest, as most will say, "Its History".

    I have a Korallin C1502 Calcium Reactor which I have converted to Sulphur Denitrator 2 years ago but disconnected after I kept Nitrate in check. However, as I added more fishes Nitrate began creeping up to about 4-5ppm. As I currently do not run any other Nitrate Reactor or Bio-Pellets Reactor, I decided to do a simple experiment before I install into my main tank.
    In Sulphur De-nitrifications, Thiobacillus denitrificans and Thiomicrospira denitrificans, are able to use reduced sulfur compounds as electron donors and respire on nitrate in the absence of oxygen. What it means in layman terms is that the bacteria will strip Oxygen from Nitrate and by-product will be Nitrogen.

    According to Randy Holmes-Farley, herewith is the equation - 2 H2O + 5 S + 6 NO3- → 3 N2 + 5 SO42- + 4 H+.

    Korallin Sulphur Denitrator, this reactor has be disconnected from my main tank 2 years ago, as you can see the media (Sulphur & Carbonate) has turn black in certain parts.

    Water container A and B. Both container will contains similar amount of water from my current tank.

    DD Test kit, in my opinion this is by far one of the best I have used. It allows you to both test for NO3 and NNO3.

    Nitrate Test on Container A = +-4ppm

    Nitrate Test on Container B = +-4ppm

    Container A will be connected to the Sulphur De-nitrator while Container B will be Control.

    Container A and B in position

    Both container will remain in the semi-darken sump area of my tank for 1 week. No additional intervention.

    .... Day 7 ....

    Water from Container A of the left and water from Container B on the right. Notice water from A is brownish due to dirty Reactor. This picture is taken before adding reagent.

    Side by side comparison of water from A and B. A with Sulphur de-nitrification read 0 while B is 0.50 on the low range test of DD test kit.

    Short kick-in time compared to carbon based de-nitrator
    No hassle of constant feeding of ethanol
    Efficient even for Nitrate below 5ppm
    No need for additional feed pump (Applicable for Korallin and similar designed reactors)
    Prolonged used may lower pH

    FAQ extracted from - http://reefkeeping.c...1/diy/index.php

    How long does the media last? About 3 years according to the manufacturer.

    Is it hard to adjust? Not harder than a calcium reactor. The only daily adjustment you have to make is to degass the system from the top valve. About 5 seconds.

    What is the effluent's pH? The pH out of the effluent in my unit reads 7.5

    I smell rotten eggs out of the effluent? The bacteria are not getting enough food (nitrates). At this point the unit needs higher flow or some of the media needs to be removed.

    Can I store the media for later use? Yes, wash the media thoroughly with RO/DI water and store in a sealed container for future use.

    Do I have to use aragonite on top of the sulfur media? No, but it helps to buffer the pH a bit and it buffers your tank at the same time. Don’t count on this to replace your calcium supplement anytime soon.

    Do I still need to do those dreadful water changes? Yes, water changes help dilute some of the more toxic compounds in your water and replace all the lost and absorbed trace elements in your aquarium.

    Do I need a recirculation pump? Yes, all figures are based on this. Recirculating reactors are much more efficient and are better at preventing media channeling. It also prevents air pockets within the media that kills the anaerobic bacteria which we're trying to culture.

    Can I use a bigger recirculation pump? Yes, you will have to throttle it back with a valve to prevent the media from fluidizing and becoming mush in there.

    Does Hydrogen Sulfide accumulate when using one of these denitrators? In most cases, no harmful concentrations of H2S will occur. If you are overly concerned about this there are two way to combat it:
    (1) Maximize aeration. A high oxygen level drives hydrogen sulfide oxidation, and high aeration will drive some off as volatile H2S gas.
    (2) Pass the water over iron oxide/hydroxide (GFO) to convert hydrogen sulfide to elemental sulfur.

    What are the cons of running a sulfur reactor? Your Alkalinity levels will drop faster than without using a sulfur reactor. It is imperative that you keep an eye on this parameter.

    So will I be adding this reactor to my reef tank? Yes for the time being as I am experiencing higher nitrate than I normally used to. However, I will dis-connect and reconfigure into a Calcium Reactor once I am done and have the CR run permanently when I am tired on dosing 2 parts solution plus magnesium.

    Happy Reefing.

    This article was originally published in forum thread: Sulphur Denitrators - 18 years and Counting started by Gouldian View original post

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