Zeolites

[reefgeezer]

Thanks Randy, I did not know about phosphate bonding.

Anecdotally, I dose kalk via a reactor and do not have unwanted algae growing on the live rock. I've dosed for about a year. The 75 gallon tank gets about 1.5 gallons of saturated lime water every day. I get a slight greenish brown haze on the glass every 3 or 4 days if I don't clean it, but that's about it.

After the Kalk enters the water in my sump, it flows across an area where the speed of the water is momentarily reduced (where my fuge used to be). This causes settling. I vacuum this area weekly during water changes.

I removed my deep sand bed, mud bed, and macroalgae because I was carbon dosing and thought they just were depressing my pH too much. That's the reason for the 10 ppm of nitrate right now. It was down to nearly 0 before I started tearing stuff out. I know, never satisified... oh well. I've also limited the carbon source for a while since I don't know how much is in MB7 so I may not have a good bacteria population right now. I'm starting to increase the carbon source weekly.

I do have one observation that I can't explain. I had tried to dose MB7 per the high nutrient system instructions without any sort of substrate in the sump for six days. I had to stop when my fish started to show signs of stress and Dino's started to appear. I've now added MB7 to the reactor for 4 days and not only have the fish not shown any signs of stress, but they have actually started to look better and I haven't had a Dino ourtbreak. :thumbsup:

 

[solos2]

I think I lost you there Randy.

Can an equilibrium be achieved such that:

a) when there're free ammonia in the water column, zeolite will bind them through a process of ion-exchange, before bacteria can colonize the surface;

b) when there're no more free ammonia in the water, and bacteria are introduced to the zeolite, colonized the surface area and somehow alter the local environment enough to reduce ammonia binding, such that the newly colonized bacteria can benefit from the ammonia "unlocked" from the zeolite;

c) when all the bound ammonia are freed and used up by the bacteria, additional ammonia will continue to be consumed by the bacteria but not bound to the zeolite surface;

d) if somehow the bacteria colonies are reduced dramatically (say through the daily pumping of zeolites inside reactor), then certain surface area of the zeolite are exposed again and will be able to bind free ammonia in the water column again?

Can this process repeat itself until the daily pumping of zeolite no longer able to reduce the bacteria colonies enough to expose zeolite surface area, thus the zeolites are no longer capable of binding free ammonia (and need to be replaced)?

 

[Randy Holmes-Farley]

a) when there're free ammonia in the water column, zeolite will bind them through a process of ion-exchange, before bacteria can colonize the surface;

Yes, that seems to be a likely possibility, if there is sufficient ammonia in the water.

when there're no more free ammonia in the water, and bacteria are introduced to the zeolite, colonized the surface area and somehow alter the local environment enough to reduce ammonia binding, such that the newly colonized bacteria can benefit from the free ammonia;

When would there not be any free ammonia? Fish and other organisms are constantly excreting it. Is there any evidence that bacteria driven to grow with organic carbon sources are ammonia-limited?

But suppose somehow free ammonia disappears, then the ammonia can come back off the zeolite. It is an equilibrium process. If you add zeolite with bound ammonia to ammonia free water, some of that ammonia will be released. Bacteria could possibly cause the ammonia to be released to the water column to a greater extent. Could they catch and consume some of that ammonia? Possibly.

when all the bound ammonia are freed and used up by the bacteria, additional ammonia will continue to be consumed by the bacteria but not bound to the zeolite surface;

Yes, assuming the bacteria continue to alter the surface sites (by pH or whatever), preventing binding. The question is whether the direct ammonia consumption is all that ever happens. Is there any evidence it isn't?


if somehow the bacteria colonies are reduced dramatically (say through the daily pumping of zeolites inside reactor), then certain surface area of the zeolite are exposed again and will be able to bind free ammonia in the water column again?

I do not know if that happens (or can happen). I suppose it depends on what process one is hypothesizing for bacteria to remove ammonia from a zeolite, and whether one actually strips the zeolite bare (unlikely, IMO) or leaves a thin layer coating the substrate (seems reasonably likely to me).

So I'll concede that I cannot prove these things cannot happen, but it seems like a lot of hand waving, trying to allow something to happen for which there is zero evidence and a poor molecular level mechanism even proposed.

When it comes right down to it, why would one think it does happen?

 

[Randy Holmes-Farley]

I do have one observation that I can't explain. I had tried to dose MB7 per the high nutrient system instructions without any sort of substrate in the sump for six days. I had to stop when my fish started to show signs of stress and Dino's started to appear. I've now added MB7 to the reactor for 4 days and not only have the fish not shown any signs of stress, but they have actually started to look better and I haven't had a Dino ourtbreak.

Without knowing what is in MB7, it is hard to say what the reason might have been, but providing a suitable substrate to keep bacteria localized a bit may be a very desirable thing, whether it is a zeolite, GAC, live rock, or soemthing else.

IMO, my removal of bacteria by cleaningmy GAC once a week exports a lot more material than would otherwise be happening.

 

[Randy Holmes-Farley]

If you can get this paper (and read chinese), this might give some useful info on the potential for this process via direct removal. Unfortunately, the abstract doesn't answer the question:

The mechanism of bio-regeneration process of natural zeolite. Zheng, Nan; Wen, Yue; Li, Jian-bo; Zhou, Qi; Yang, Dian-hai. State Key Laboratory of Pollution Control and Resources Reuses, Tongji University, Shanghai, Peop. Rep. China. Zhongguo Huanjing Kexue (2009), 29(5), 506-511.
Abstract

Pilot-scale zeolite bed was constructed to discuss the influence upon the regeneration efficiency of zeolite by aeration, heterotrophic bacteria and nitrifying bacteria. The regeneration efficiency of zeolite was enhanced by 0.5%-1.0%, 20.9%-31.1% and 120%-180% with the present of aeration, heterotrophic bacteria and nitrifying bacteria, resp. Nitrifying bacteria played a major role in the regeneration process of ammonia-satd. zeolite, followed by heterotrophic bacteria and aeration. When heterotrophic bacteria and nitrifying bacteria coexisted in a reactor, a synergistic effect had been obsd., which could not only improve the regeneration efficiency up to 100%, but also increase the regeneration rate about 10%. The influence of ion-exchange, aeration and heterotrophic bacteria alone or in combination on the regeneration efficiency of zeolite fitted the first order kinetic reaction. And the curves of regeneration efficiency with nitrifying bacteria was described by y=kx and the Monod equation (R2>0.99). Through investigation on the change of SEM on zeolite surface before and after zeolite biol. regeneration, the mechanism of bio-regeneration process of ammonia-satd. zeolite was revealed.

 

[Randy Holmes-Farley]

Here's another interesting one:

Zeolite bed multistage biofilm system for treatment of coking wastewater. Zhao, Wentao; Huang, Xia; He, Miao; Zhang, Pengyi; Zuo, Chenyan. Department of Environmental Science and Engineering, Tsinghua University, Beijing, Peop. Rep. China. Zhongguo Jishui Paishui (2008), 24(13), 18-22.
Abstract

The zeolite bed multistage biofilm system was used to treat coking wastewater. The adsorption characteristics of ammonia nitrogen by zeolite media, start-up, pollutants removal and function zones of the system were investigated. The results indicated that the adsorption of ammonia nitrogen by zeolite media followed the Langmuir adsorption isotherm equation, with max. adsorption capacity of 0.318 mg/g at 25 C. The start-up time of the system was about 40 days, consisting of 7 days for biofilm formation, 3 days for nitrobacteria domestication and 30 days for heterotrophic bacteria domestication. When the NH3-N loading in the system influent was less than or equal to 0.10 kg/ (m3d), the av. effluent NH3-N and COD concns. were (2.41.2) mg/L and (13434) mg/L with av. removal rates of 98.1% and 85.8%, resp. The NH3-N met the national first class discharge std., and the COD met the national second class discharge std. Three different pollutant removal function zones, named as decarbonization zone, decarbonization/nitrification zone and nitrification zone existed in aerobic stage.



The research of the film formation and start-up of zeolite biological aerated filter. Li, Xiaoqin; Wang, Yonghui; Zhou, Jiandong. Donghua University College of Environmental Science & Engineering, Shanghai, Peop. Rep. China. Huanjing Kexue Yu Guanli (2008), 33(9), 91-93.

Abstract

Zeolite biol. aerated filter was used in the test of the pre-treatment of micro-polluted source water, and the start-up was studied. The results showed that the removal of CODMn didn't keep in pace with that of NH4+-N in the process of film formation. While the increasing rate of the aerobic heterotrophic bacteria is higher than that of the autotrophic nitrobacteria, ZBAF had a high removal efficiency of NH4+-N, and the removal rate went up to over 90%. Ion exchange was the major contributor to ammonia-nitrogen removal at the beginning, and nitrification reaction played the main role in the end, while the removal of CODMn couldn't keep stable, so the end of the start-up phase was basically signaled by nitrification attained stable state not by the total ammonia removal rate and the removal rate of CODMn.

 

[solos2]

Thanks Randy,

I'm asking this because I've been thinking how exactly does the ZEOvit system works.

Apparently there're lots of successful case of ZEOvit systems, but the more I read about it, the more I think the zeolite's ion binding capability has nothing to do with the whole system.

Correct me if I'm wrong, but here's what I do think is going on with ZEOvit system.

a) Zeolite is introduced as an ammonia binding media, but its capacity is used up in days if not hours;

b) Once its ion binding capacity is used up, it's nothing more than a fancy named media for bacteria growth, similar to GAC / live rocks or even bio-balls. But they do make a great bacteria housing media because of their porous structure;

c) I'm not sure if it has been proven, but ZEOfood7 is most likely to be a carbon source, similar to vodka dosing. So the whole ZEOvit system is nothing more than a carbon dosing system using zeolite has the bacteria housing media;

In my own system, I didn't use vodka dosing but I used the NP bio pellets, after using a 1mm coarse sponge in the reactor, it was completely clogged after 3 days. This give me an impression that bacteria that utilize carbon source grows REALLY fast, which brings up the next item;

d) Due to the porous structure of zeolite, it makes a great media for growth of certain strains of bacteria that utilize carbon source to absorb NO3/PO4. However also due to this rapid growth it's very likely all surface of the zeolite become clogged very similar to the sponge I used in my NPBP reactor. Thus the daily pumping is designed to reduce the bacteria coating.

e) So basically the whole ZEOvit reactor is very similar to the "fluidized sand bed reactor" that was once popular back in the days when I first started keeping reef aquarium (some 12+ years ago) - the only difference is, it's housing bacteria that utilize carbon source and not housing nitrifying bacteria.

And due to the rapid growth of the bacteria strain that utilize carbon source, it's possible that eventually all the porous structure of zeolite become clogged to a point it's no longer capable of housing more bacteria, thus they need to be replaced.

Which brings up another idea - if vodka dosing is used in a system where there're not a lot of live rock to house the bacteria, then the results may not be so impressive, simply because the number of bacteria available in the system is vastly inferior compared to a system with a zeolite reactor.

This is rather interesting since it may be possible to utilize the old fluidized sand bed reactor again, and use sugar grain sized coral sand as the media, along with vodka dosing, to achieve the same result as a ZEOvit system without the need to pump the zeolite every day.

And if the bacteria is capable to alter the local environment such that pH is lowered to a point it'll gradually dissolve the coral sand, all the user need to do is regularly add new coral sand to the fluidized sand bed to replace the dissolved media.

What do you think? Did we just hit another gold mine of the next generation of ULNS filtration system?

 

[solos2]

p.s. I'm currently using 300ml of NPBP in my system, but NPBP aren't the best bacteria housing media, simply because bacteria can only colonize the surface area and I don't think the pellets are that porous.

And unlike vodka dosing, most of the bacteria should only colonize the surface of the pellets as it's where they'll get their food.

So to test my theory, I just added some 50-100g of fine grain coral sand into my reactor, it may boost the bacteria housing capability of my NPBP reactor by a few folds, who knows ;p

 

[Randy Holmes-Farley]

but here's what I do think is going on with ZEOvit system.

I think that is a reasonable assessment, IMO.


Which brings up another idea - if vodka dosing is used in a system where there're not a lot of live rock to house the bacteria, then the results may not be so impressive, simply because the number of bacteria available in the system is vastly inferior compared to a system with a zeolite reactor.


That is certainly possible. I'm not sure what happenns in a surface area limited system. But I can imagine the results could be less than optimal.

This is rather interesting since it may be possible to utilize the old fluidized sand bed reactor again, and use sugar grain sized coral sand as the media, along with vodka dosing, to achieve the same result as a ZEOvit system without the need to pump the zeolite every day.


A fluidized system might tear away the bacteria before they can really thrive, but I supppose it depends strongly on the movement of the grains. Maybe only fully fluidize it occasionally.

 

[reefgeezer]

My original question was based on the same basic theory.

I believe the Zeovit to be more or less a substrate for microbial colonization, Zeobac to be a bacterial seed, and Zeofood to be a carbon source. I had originally planned on using bio-balls in the reactor, but opted for Zeovit to see if there was any value. I plan to change over to bio-balls after 6-8 weeks to see if anything changes. I chose MB7 simply because it was available locally, but I'm not even sure its required as carbon hungry bacteria already exist in a tank, but are carbon limited until dosing is started.

It is also interesting that the trace elements tha Zeovit is reported to remove are the very ones associated with color in corals including Potassium Iodide and Iron.

I hope my trial will show (in a non-scientifiic way) that it's the carbon dosing, presence of a suitable substrate that can periodically be purged of microbial film, and addition of selected trace elements and water changes that produce the great colors produced by the Zeovit system.

 

[kaskiles]

The advantage of the fluidized sand filter over a trickle filter is the amount of surface area per reactor volume. The trickle filter's advantage is the oxygenation. Since the bigger risk with organic carbon dosing is lack of oxygen (vs. not enough surface area for bio-films), wouldn't the trickle filter be the better choice?

Oh, I remember reading someplace that aragonite sand does not fluidize well, maybe it was particle shape or something like that.

 

[reefgeezer]

I considered a fluidized bed, but opted for simplicity. Also I couldn't see how it could be used to culture and distribute "mulm". I've built my reactor to hold 4X the required quantity of Zeovit. I figure I'll just about fill it with bio-balls. I'd consider another substrate if anyone has a better idea. The key being that I do not want to replace it every 6 weeks or so.

 

[philbo32]

Why don't you just try recharging it?

 

[reefgeezer]

Why don't you just try recharging it?

How does that work?

 

[recife111]

I was told that zeolite is used in bacterial filtration systems like FaunaMarin because the zeolite attracts some types of bacteria due to the iron in it.
Maybe explains why they recommend to use it to increase bacterial numbers.

 

[solos2]

Re: Zeolites

From my experience using the NPBP reactor, oxygen isn't a major issue. I had a power outage for 4 hours once and there was no problem with the reactor once power is restored.

However I had problem with bacteria growth that clogged the sponge thus the reactor output, so I tend to think the ability to dislodge bacteria film (ie water flow) is more important than available oxygen. Unless you overdose carbon otherwise oxygen shouldn't be a problem.

That's why I'd think a fluidized sand filter with medium flow would work with the carbon source bacteria.


Sent from my iPhone using Tapatalk

 

[reefgeezer]

For discussion's sake, consider my thoughts when planning this project...

One of zeolite's observable benefits is better water clarity. I can guess that the increased clarity is due to the capture of organics and particulates on the surface thus producing the biofilm. I can also imagine that the friction created in the fluidized bed would keep the biofilm from developing or greatly reduce it.

I also theorize that most of the N & P reduction work is really done by the free floating bacteria in the water column that is removed by the skimmer. Although I don't understand the mechanism, I think that the reactor is more of a place where bacteria is cultured and the biofilm is concentrated. Like every other surface in the tank, it also performs ammonia/nitrite reduction.

All that being said, IMO, the fluidized bed might not be enough of an improvement over just bio-balls or some other immobile substrate in the reactor to justify the complication.

 

[MavG]

Perhaps Having 2 reactors in Tandem would be a better approach.

The first reactor is being fluidized with a water pump, or air pump, or both (like a moving bed filter used in wastewater) to control biofilm thickness and clean the Zeolite.

(as i believe the main objective of fluidizing the media that is being discussed is to free up the surface area of the zeolite again for Ion exchange, rather than bacterial colonization)

and the second Reactor can be plunged, aerated, pumped water through at a higher rate only on a periodical basis to remove biofilm.

I would think you would need to make two modifications however:

1. you would have to use a smaller media if using a fluidized approach in order to be able to "tumble" it effectively to get the desired result, this may not be all bad however as incresed surface area will increase the ion exchange rate.

2. you would have to plunge the second "static" reactor more often, as the biofilm "abrasion" from the first reactor would almost definitely clog the second static reactor/media much faster.

I suppose you could run them the other way around as well, running the fluidized reactor after the static reactor and running the outlet near your skimmer to harvest off the abrased biofilm from the fluization process?

you could also run them completely independantly as well i suppose, and just run the outlet of fluized reactor directly into the skimmer, as the rate of biofilm abrasion off of the zeolite would undoubtedly be much higher.

As the main "proposed or theoretical" purpose of a fluidized zeolite reactor is simply to renew or clean the media in order to make more site re-available for ion exchange i would think it could be run independantly to the normal static reactor, as well as being able to be tumbled wuite aggressively in relation to a normal fluid bed or moving bed biofilter.

MavG

 

[solos2]

I agree with you that most of the N/P reduction is done by free floating bacteria and then skimmed out.

As for the biofilm, from my observation, it's more than just organics and particulates captured by the zeolites. Prior to using NPBP reactor, I had Rowaphos in the same reactor and I used 3mm thick coarse sponge on both side of the reactor. It took over 3 weeks before it's 30% clogged.

However, after switching to NPBP, and reduced the thickness of the sponge from 3mm to 1mm, it was 95% clogged in just 3 days, TWICE.

I've checked all the water parameters and they're fine, there was nothing dying in the tank and I didn't just overfeed by 600%. So the sudden increase in biomass that clogged the sponge had got to do with the rapid growth of carbon source utilizing bacteria.

I also understand that zeolite is capable of capturing organics and particulates, however, using GAC alone can also achieve the similar results.

So my question is however, what differentiate GAC from zeolite and why the daily pumping is needed.

I tend to think that the rapid growth of carbon source tend to clog up all the surface area of any bacteria housing media, GAC or zeolite, in a relatively short period of time.

For GAC, it's the norm that we replace them every 2-3 weeks, so it doesn't matter if the surface area is all clogged up. According to the ZEOvit guide, the replacement time interval is somewhere from 6-12 weeks, that's almost 4 times longer than GAC, therefore it's very likely that all surface area will be clogged in half that time without the daily pumping.

So IMO in terms of the ability to capture organics and particulates, and house bacteria, using GAC in a reactor really should have the same effect as using zeolites, but using GAC in a fluidized reactor may produce lots of fine charcoal powder from the grinding action, so it may not be the best media.

You could also use bio-balls as the media but without the daily pumping I think it'll be very likely they'll then into a furball in a matter of weeks, clogged by the bacteria.

Therefore I tend to think that using fine grain coral sand as the media (along with GAC in mesh bag) would be a better media. The constant motion of water should keep the surface area relatively clean, as long as the water flow isn't too great, and it should produce the same results as using zeolite.

 

[reefgeezer]

I use GAC in a reactor but it is not a 100% active design and is fed by my skimmer. I'm going to change that to make a 100% active GAC reactor supplied by my return pump.

I don't quite understand the goal of using the fluidized bed. Guess I'm a little more of a moron than usual this morning. Is the fluidized bed used for ammonia and nitrite control only and is the GAC reactor then used for cultivation of carbon based bio-mass?

I appreciate these discussions. Thanks.