New sulfur denitrator working great!

[Belgian Anthias]

The issue I described having with the SD is happening at the moment.

After about 6 months, I start to notice the formation of a form of mulm in the reactor and it starts to coat and eventually bind and clump the sulfur beads together. When this happens, the water no longer flows through the sulfur beads and the pressure of the circulating pump “lifts” the entire sulfur and calcium carbonate media off the bottom plate of the reactor, as shown in the picture.

This forces me to open the reactor and wash the sulfur media, killing the bacteria in the process and restarting the colonization process in the reactor from scratch (just in case, there’s way too much mulm to rinse with aquarium water and requires a lot of water to rinse). In the past, I have noticed the corals don’t like this.

Has anyone experienced this or have any thoughts as to how to prevent this from happening?

Does the reactor has a closed-loop?
A closed-loop makes it possible to manage the internal flow without influencing the actual effluent flow rate and may prevent this to happen. Another closed-loop on the pump itself makes it possible to manage the internal flow of the reactor running the circulation pump at normal speed.
Another reason may be the effluent flow rate is controlled by a valve in the outflow instead of the inflow. In this case, one may try to solve it by fully open the outflow valve or disconnect the outflow from the restrictor. Clean the clogged outflow valve. The reactor disconnected from the system.

Using the reactor as an MBR ( moving bed reactor) will solve this. Pressure should not be able to build up in the reactor.

If the reactor has a closed-loop one just has to increase the internal flow in a way the media moves around removing created tunnels and any blockages. One can also back-wash the reactor, disconnected from the system, without opening it.

In an MBR the media moves around very slowly, not too fast to prevent too much biofilm erosion, preventing clogging.

What is the actual flow rate? What is the max flow rate for the normal operation of this reactor?

 

[StlSalt]

Mine has been up for right at 6 months, and has some mulm but it isn't lifting. I also see a lot of bubbles at the top of your reactor. That doesn't seem normal, mine all went away in the first month or so. What pump are you using to feed it, and how many drop per second do you have the output set to? What sulfer media did you use?

 

[Randy Holmes-Farley]

Gypsum is found in SLAD systems, making use of BADES for cleaning groundwater for consumption. ( Zhang 2004)
Making use of the MAAO method, using separate reactors, it was shown produced sulfate precipitates in the calcium reactors and is removed replacing the substrate. This limits calcium and sulfate production if it is gypsum, which was not determined? In such calcium reactors, the influent may have a pH far below 7 pH, depending on the nitrate removal rate in the BADES reactors.

FWIW, gypsum is very soluble in seawater independent of pH..

Gypsum solubility in seawater, and its application to bauxite residue amelioration​

Gypsum solubility in seawater, and its application to bauxite residue amelioration

The solubilities and dissolution rates of 3 gypsum sources [analytical grade reagent (AR), phosphogypsum (PG), mined gypsum (MG)] with 6 MG size fractions (>2.0, 1.0–2.0, 0.5–1.0, 0.25–0.5, 0.125–0.25, <0.125 mm) were investigated in triple-deionised water (TDI) and seawater to examine their...

www.publish.csiro.au

"The solubilities and dissolution rates of 3 gypsum sources [analytical grade reagent (AR), phosphogypsum (PG), mined gypsum (MG)] with 6 MG size fractions (>2.0, 1.0–2.0, 0.5–1.0, 0.25–0.5, 0.125–0.25, <0.125 mm) were investigated in triple-deionised water (TDI) and seawater to examine their suitability for bauxite residue amelioration. Gypsum solubility was greater in seawater (3.8 g/L) than TDI (2.9 g/L) due to the ionic strength effect, with dissolution in both TDI and seawater following first-order kinetics. "

 

[2Wheelsonly]

Ok, so this thing has been working well and I am holding steady at my target no3 (2.5) with po4 at 0.02. My biggest issue is that with my calcium reactor my ph is 7.9 during the day and 7.6 at night (7.59 according to my recently calibrated new lab grade probe on my apex).

Should I be worried?

Is it possible to potentially feed the calcium reactor with my denitrator? I am worried that running this low pH at night will affect me sps long term. My in home co2 is very low, I have two meters that I tested and my home is currently at 188ppm so I know my house isn't too closed up.

 

[Randy Holmes-Farley]

I have two meters that I tested and my home is currently at 188ppm so I know my house isn't too closed up.

That doesn't really seem believable. What does that same meter read outside? Why would it be lower than outside air?

That said, both of the methods you are using (CaCO3/CO2 reactor and sulfur denitrator) will tend to lower the pH. Sufficient aeration alone will bring the pH to normal if the home does not have elevated CO2.

 

[2Wheelsonly]

That doesn't really seem believable. What does that same meter read outside? Why would it be lower than outside air?

That said, both of the methods you are using (CaCO3/CO2 reactor and sulfur denitrator) will tend to lower the pH. Sufficient aeration alone will bring the pH to normal if the home does not have elevated CO2.

I'm an idiot, I just realized I put 188 for my Co2 meter...it should have read 688 (actually fluctuates between 550-750 based on how many people are in the house throughout the day). Still what I would consider fairly ok? I already have outside air plumbed into my skimmer venturi. I just created an aeration chamber for my denitrator output with an air stone. I ordered an air pump with an inlet so I can pull from outside air into the aeration chamber.

 

[Belgian Anthias]

FWIW, gypsum is very soluble in seawater independent of pH..

Gypsum solubility in seawater, and its application to bauxite residue amelioration​

Gypsum solubility in seawater, and its application to bauxite residue amelioration

The solubilities and dissolution rates of 3 gypsum sources [analytical grade reagent (AR), phosphogypsum (PG), mined gypsum (MG)] with 6 MG size fractions (>2.0, 1.0–2.0, 0.5–1.0, 0.25–0.5, 0.125–0.25, <0.125 mm) were investigated in triple-deionised water (TDI) and seawater to examine their...

www.publish.csiro.au

"The solubilities and dissolution rates of 3 gypsum sources [analytical grade reagent (AR), phosphogypsum (PG), mined gypsum (MG)] with 6 MG size fractions (>2.0, 1.0–2.0, 0.5–1.0, 0.25–0.5, 0.125–0.25, <0.125 mm) were investigated in triple-deionised water (TDI) and seawater to examine their suitability for bauxite residue amelioration. Gypsum solubility was greater in seawater (3.8 g/L) than TDI (2.9 g/L) due to the ionic strength effect, with dissolution in both TDI and seawater following first-order kinetics. "

The conditions in an anoxic reactor producing calcium and sulphate, I assume the ionic strength effect of the water present in the reactor will be different.
Why Gypsum accumulation does take place in SLAD reactors, also in TDI solubility is high? If it is possible in SLAD reactors, why not in MAAO reactors using seawater?

 

[Randy Holmes-Farley]

The conditions in an anoxic reactor producing calcium and sulphate, I assume the ionic strength effect of the water present in the reactor will be different.
Why Gypsum accumulation does take place in SLAD reactors, also in TDI solubility is high? If it is possible in SLAD reactors, why not in MAAO reactors using seawater?

No, the ionic strength is not appreciably different in a reactor 9any kind of reactor) than in the aquarium. Ionic strength of seawater is essentially a measure of the salinity. It does not detectably change with any of the processes we use on a reef aquarium.

I don't know who or why someone suggested deposition of calcium sulfate is happening in a sulfur reactor using seawater. It doesn't seem plausible to me.

In freshwater, where calcium sulfate is less soluble, it is reported to precipitate:

https://www.jstor.org/stable/25053725?seq=1

 

[Jon_W79]

Ok, so this thing has been working well and I am holding steady at my target no3 (2.5) with po4 at 0.02. My biggest issue is that with my calcium reactor my ph is 7.9 during the day and 7.6 at night (7.59 according to my recently calibrated new lab grade probe on my apex).

Should I be worried?

Is it possible to potentially feed the calcium reactor with my denitrator? I am worried that running this low pH at night will affect me sps long term. My in home co2 is very low, I have two meters that I tested and my home is currently at 188ppm so I know my house isn't too closed up.

I think you could feed the calcium reactor with the sulfur denitrator if the effluent flow rate of the SD is not too fast for the calcium reactor, and if the effluent ph of the denitrator is fairly stable. You could put a tee fitting between the sulfur denitrator and calcium reactor and you could connect another paristaltic pump to the tee fitting if you need to increase the flow to the calcium reactor. Connecting them would make your co2 tank last longer(obviously). I like this idea.

 

[2Wheelsonly]

So right now I have the sulfur denitrator going into an aeration chamber with an air pump that pulls air from outside the home. The denitrator enters lower, chamber drips out the top into the sump. Air stone is in the chamber bubbling away... my effluent into the tank went from 7.2 to 7.9.

It's interesting that my nightly ph still drops to 7.61 at night and 8.1 during the day. It can't be my in home Co2 because when I test my new salt water from my circulating mixing container in the same room as my sump the ph probe shows 8.0 vs 7.61 (in tank). I don't even need to do the outside test as my in-home non tank water is perfectly fine. Can't figure out what causes it to drop so low at night esp when my denitrator and calc reactor drip 24/7...

Must be biological at this point.

 

[Belgian Anthias]

No, the ionic strength is not appreciably different in a reactor 9any kind of reactor) than in the aquarium. Ionic strength of seawater is essentially a measure of the salinity. It does not detectably change with any of the processes we use on a reef aquarium.

I don't know who or why someone suggested deposition of calcium sulfate is happening in a sulfur reactor using seawater. It doesn't seem plausible to me.

In freshwater, where calcium sulfate is less soluble, it is reported to precipitate:

https://www.jstor.org/stable/25053725?seq=1

Thank you for the info but I am still not convinced.

The change in the content of nitrate, calcium, sulphate, bicarbonate, etc.. in the limited environment of a reactor must have a huge influence on other reactions taking place in the reactor?

What happens if the reactor water gets saturated? There where the action is? Precipitation occurs when any combination of anions and cations can form a solid. Is it impossible for gypsum to be formed within the substrate of the reactor? There were sulfate and calcium are produced?

The formation of a sparingly soluble CaCO3 coating around the gypsum particles in alkaline seawater greatly reduces the rate of gypsum dissolution.
Calcium, sulphate, bicarbonate etc.. are an endproduct of BADES taking place on a sulfur/calcium carbonate substrate.
Once gypsum is formed in this environment I think it may not dissolve as easily.

For managing a BADES based system it is important to limit the risks for clogging and tunneling, clogging caused by gypsum, or something else.

 

[Belgian Anthias]

The formation of gypsum does occur in SLAD systems ( Zang 2004). These are facts. It is a recognized problem concerning SLAD system management as it glues the calcium carbonate substrate together and may clog the filter bed. In SLAD systems measures are taken to prevent clogging.

It is a positive thing gypsum formation will not occur in seawater BADES systems but for the moment I am still not really sure it does not happen. Using seawater BADES systems, anoxic sulfur denitrators, it is reported the substrate is glued together. Other precipitations and changes may take place.
I am still wondering if this could be caused by gypsum formation.

To minimize clogging and tunneling an MBR can be used.

In a normal BADES system, the flow rate is high compared to most sulfur denitrators and the reactor has a closed-loop which makes the internal flow independent of the system flow rate. The risk for clogging is minimal

It has been shown sulfate accumulates on the maerl used in MAAO. The sulfate content of the maerl substrate increases in time. In MAAO, problems caused by the formation of gypsum are as far as I know never reported. Separate reactors are used and maerl is cleaned on a regular basis.
Calcium reactors can be back washed and internal flow managed independently from the system flow rate creating a moving bed reducing the risk for clogging to 0
I do not know if the original BADES system is still in use but it is used for + 10 years.

 

[Randy Holmes-Farley]

Thank you for the info but I am still not convinced.

The change in the content of nitrate, calcium, sulphate, bicarbonate, etc.. in the limited environment of a reactor must have a huge influence on other reactions taking place in the reactor?

They may do many things as they go up or down a bit, but none of those changes a big effect on ionic strength.

 

[tworegtdi]

i have set up a denitrator about a month ago (not sulfur based, reactor is filled with bio balls). Flow rate is turned down to about 1 drop per second, tested effluent yesterday nitrator level was the same compare to tank water. ORP meter hovers around +220. Anything i did wrong? Why would orp not drop as it should? TIA!

 

[2Wheelsonly]

I honestly think because the reef stuff that was seeded with bacteria is hard to find many of us are using those prills from Amazon. I honestly think it just takes them forever to seed with bacteria; I didn't notice anything in mine for 6 months and after around 8 my denitrator kicked in full gear. I went from 40 no3 in my 350G to dosing just to keep it at 1-2. They all work, just can take way more time than others.

Just let it cook. You're using bioballs vs sulfur so I assume it's going to be a very long process.

 

[tworegtdi]

I honestly think because the reef stuff that was seeded with bacteria is hard to find many of us are using those prills from Amazon. I honestly think it just takes them forever to seed with bacteria; I didn't notice anything in mine for 6 months and after around 8 my denitrator kicked in full gear. I went from 40 no3 in my 350G to dosing just to keep it at 1-2. They all work, just can take way more time than others.

Just let it cook. You're using bioballs vs sulfur so I assume it's going to be a very long process.

wow 6 month eh? Guess I shouldn't complain too much only 1 month into this

 

[ReeferBud]

The issue I described having with the SD is happening at the moment.

After about 6 months, I start to notice the formation of a form of mulm in the reactor and it starts to coat and eventually bind and clump the sulfur beads together. When this happens, the water no longer flows through the sulfur beads and the pressure of the circulating pump “lifts” the entire sulfur and calcium carbonate media off the bottom plate of the reactor, as shown in the picture.

This forces me to open the reactor and wash the sulfur media, killing the bacteria in the process and restarting the colonization process in the reactor from scratch (just in case, there’s way too much mulm to rinse with aquarium water and requires a lot of water to rinse). In the past, I have noticed the corals don’t like this.

Has anyone experienced this or have any thoughts as to how to prevent this from happening?

I’ve been a bit disconnected for the last couple of weeks dealing with the Texas winter storm and aftermath.

I went 31 hrs without power and the mulm increased significantly. It completely clogged the reactor and I’ve had to take it down to clean the sulfur media. This has happened to me several times, seems like every 6 months and there are a few common themes I notice.
- I measure ORP and try to keep it at -170mv. The first thing I’ll notice is the ORP going more negative until it maxes out on what my apex can read. Likely due to slowing recirculating flow and higher delta-pressure in the reactor.
- then the media will start to lift as I showed in my previous post.
- mulm will form and increase to the point where I can no longer see the yellow color of the sulfur beads

pictures below

If the sulfur needs to be removed, I think you can do a small water change, and put some of the old water in a bucket(and some of it in another container), put the sulfur from the SD in the bucket of water, stir it well with your hands(you could start removing cloudy water and start and keep replacing with old tank water until the water is clear, while occasionally stirring the sulfur), and then put the sulfur back in the sulfur denitrator. I think the SD can be back to working well soon if you do thi

Mine has been up for right at 6 months, and has some mulm but it isn't lifting. I also see a lot of bubbles at the top of your reactor. That doesn't seem normal, mine all went away in the first month or so. What pump are you using to feed it, and how many drop per second do you have the output set to? What sulfer media did you use?

It takes me about an hour and a lot of water to clean the sulfur. No way I could do this with tank water.

the bubbles aren’t normally there. I was troubleshooting and got some air into the reactor before taking the pic. I use a masterflex to feed the reactor and adjust the flow to keep the ORP around -170mv, which is typically 140 ml/min

other than this issue, I really like the sulfur denitrator and it’s great at keeping my nitrates in check. It definitely works! But this is a major inconvenience and would love to be able to solve it.

ideas welcome!

 

[2Wheelsonly]

I’ve been a bit disconnected for the last couple of weeks dealing with the Texas winter storm and aftermath.

I went 31 hrs without power and the mulm increased significantly. It completely clogged the reactor and I’ve had to take it down to clean the sulfur media. This has happened to me several times, seems like every 6 months and there are a few common themes I notice.
- I measure ORP and try to keep it at -170mv. The first thing I’ll notice is the ORP going more negative until it maxes out on what my apex can read. Likely due to slowing recirculating flow and higher delta-pressure in the reactor.
- then the media will start to lift as I showed in my previous post.
- mulm will form and increase to the point where I can no longer see the yellow color of the sulfur beads

pictures below




It takes me about an hour and a lot of water to clean the sulfur. No way I could do this with tank water.

the bubbles aren’t normally there. I was troubleshooting and got some air into the reactor before taking the pic. I use a masterflex to feed the reactor and adjust the flow to keep the ORP around -170mv, which is typically 140 ml/min

other than this issue, I really like the sulfur denitrator and it’s great at keeping my nitrates in check. It definitely works! But this is a major inconvenience and would love to be able to solve it.

ideas welcome!

That looks like your calcium media is melting and turning to mush. Have you measured the pH coming out of the reactor?

 

[ReeferBud]

That looks like your calcium media is melting and turning to mush. Have you measured the pH coming out of the reactor?

I don’t think it’s the calcium since when I cleaned it out, the calcium media did not appear to be melted.

 

[mtfish]

No, that was definitely bacteria growth. I had to just clean my reactor and start over myself.