Algae Scrubber Advanced

[acroman]

What are some of the bennifets of the 'dump style' that you are aware of? I know Inland aquatics in Terre Haute has a patent on one of those large dump styles that they use for a large system. The guy I spoke with mentioned that the air contact during that dump was 'key'

IIRC the line of logic is that it improves air contact, which increases gas transfer. The added benefit is that it also keeps itself clean, and free (relatively) of algae types that will coat and inhibit growth of the turf algae.

I also think that when submerged (and the turf algae fibers are oriented perpendicular to the screen surface) the available surface area for photoreception is increased. This is opposed to the waterfall design (where the fibers are oriented relatively parallel to the screen surface) which can cause shading, and reduces the available surface area for growth.

Also, turf algae grows really well in tidal areas and rocks near the water line, so i figure I'm kind of simulating that

 

[Floyd R Turbo]

The dump style is inherently inferior to the waterfall style. Filtration only happens when water is passing across the algae. This only happens in the dump scrubber when the bucket is dumping, because of the boundary layer issue. So a vertical scrubber is not filtering when the chamber is full or filling with water for the same reason that a horizontal scrubber is not filtering when it is filling with water.

The submerged screen of a UAS work because of the bubbles which defeat the problem of the boundary layer in a submerged screen, as well as turnover rate of the water. A stagnant pool of water will not grow algae very well.

Turf in tidal areas does grow, but there is also wave action and turbulence.

turf/dump bucket scrubbers are more geared towards the growth of true turf algae. vertical waterfall scrubbers are geared towards GHA which grows faster, filters better, and moves around easier so that shading is less of an issue. Also I never refer to waterfall scrubbers as turf scrubbers or ATSs because they don't grow turf algae, at least not preferentially (I scrub that stuff off with a stiff brush).

 

[scolley]

turf/dump bucket scrubbers are more geared towards the growth of true turf algae. vertical waterfall scrubbers are geared towards GHA which grows faster, filters better, and moves around easier so that shading is less of an issue. Also I never refer to waterfall scrubbers as turf scrubbers or ATSs because they don't grow turf algae, at least not preferentially (I scrub that stuff off with a stiff brush).

Cool! When you spend enough time lurking, you can actually learn something.

Thanks for that lesson Floyd! You punched my "learn something" ticket for today. :thumbsup:

 

[acroman]

turf/dump bucket scrubbers are more geared towards the growth of true turf algae. vertical waterfall scrubbers are geared towards GHA which grows faster, filters better, and moves around easier so that shading is less of an issue. Also I never refer to waterfall scrubbers as turf scrubbers or ATSs because they don't grow turf algae, at least not preferentially (I scrub that stuff off with a stiff brush).

Good info -

So my hybrid that is mostly waterfall, but sometimes submerged should grow GHA then, NOT true turf algae

 

[_shorty_]

With the waterfall running during the dump part, I don't think you'd get that air/CO2 exchange. It might help with the second bennifet, though, about maybe keeping the slimy GHA inhibiting growth washed off. I assume only experience will truly tell. Maybe you could run an air bubbler from underneath so that the lower/filled area will have the CO2 exchange of the UAS style. That would at least reduce the bicarbonate usage typical to the waterfall style scrubber.

IME - you'll also need a way of cleaning the inside of the acrylic or glass too - so think about what you'll use for that. Hard to tell the actual size of everything from the video.

 

[herring_fish]

I don't have much to comment about the design. It looks cool and we will just have to see how it works and what it produces. Good luck.

I did want to clear up some of the misconceptions around the ideas behind the dump bucket concept. This my give us a better context, in which we can view this design.

Also, turf algae grows really well in tidal areas and rocks near the water line, so i figure I'm kind of simulating that

The main idea of the dump, in bump buckets is the turbulence! Of course, that is only one leg of a three legged stool. One leg is strong lighting of good quality. A second is adequate surface area and the quality of it. The third is water turbulence which also includes proper water flow.

The original inventor of the ATS made a lot of fuss over the need for turbulence, sighting many many studies that show that it can change efficiency by 50%. Good scrubbing action helps keep individual strands of algae separated from each other and then additionally brakes down surface tension. This helps respiration because much more water actually comes into contact with any given number of algae cells.

A secondary benefit of wave action and strands moving around in a randomize fashion is light flashing and shading. We have all seen the shimmering lights that are caused by an undulating water surface. This focuses light many times as stronger than normal and these focused spots move around very quickly. This is followed by lower than normal light levels of light. Moving strands can provide short periods of solar shading as well.

Algae just so happens to like this and it can be demonstrated in several objective ways. Studies, starting in the 1930's began to show that algal grow can be much higher with less total light. They started with strobe lighting that was cause by a spinning wheel with a hole cut in it. Subsequent studies found that between 1 to 10, to 4 to 10 ratios (light on to light off) worked best. Pulsing can reduce light saturation, often loosely referred to as photo inhibition. This was shown to be useful on all kinds of plant organisms, simple and complex, turfs and trees. That being said, phyto algae growers are using LED flashing to increase production.

I have flooded my AtS bin and everytime my sheet gets soaked it yellows my water a little. Not sure if you will have this issue

Any yellowing is caused by the roots dying from shading; they turn a wheat color which looks yellow in the water.

When you have root damage and then flush it out, you might get yellowing but if damage doesn't occur, you don't get yellowing. I have never seen that in my tank.

There are many studies that were done on injecting CO2 directly into the feed water but I haven't read much about the plusses and minuses of intermittent direct air contact with algae strands but a dump bucket alternates between exposed and submerged. I set mine to dump about every 30 seconds. When the dump happens, the velocity of the water is quite high and then it transitions to a highly chaotic state followed by a rest stage before dumping again. This turbulence and fast flow flushed out the area of all detritus.

My dump bucket never grew short turf algae. It started growing hair algae and then converted to the long Easter basket cellophane like algae that is preferred. Turbulence at the water line in some places is so strong that it rips the "GHA" off but both kind of algae will grow best in the right amount of turbulence. By the way, Dr. Adey's assertion was that turf algae, grown under the proper conditions, is the fastest growing algae around. I personally like the translucent GHA because I can simply reach in and grab a hand full or two.

Now a big down side of a dump bucket is that it is hard to build and there normally is a splashing sound. This sound can be minimized through design but I like it. My old tank had the wedge styled design on the top of the tank. For my new outfit, I raise the bucket up a foot to make the splash stronger. I find it soothing like being at the ocean. Others may hate it.

Another issue with my wedge is that, although you don't have a pane of glass between the lights and the algae, this is a one sided screen design. This means that on a 130 gallon main tank, this is 4 foot long tray, 6 inches wide and 3 inches deep. Add the lighting and it is 6 inches tall. That is a big package. It can be under the tank but it is still an odd shape and big.

The design presented in the video is interesting because it mixes several styles. You might get the worst of all of the features or you might get the best of them. I have a few guesses but only your results matter. I think that you will like what you get.
Please keep us posted.

 

[Floyd R Turbo]

herring, thank you very much for the information! Also I like your use of the term "light saturation" in lieu of "photoinhibition"...going to adopt that from now on

 

[_shorty_]

Ca reactor effluent into waterfall scrubber

Ca reactor effluent into waterfall scrubber

Okay - so I have my new ATS design online as of this week, and my brand new screen is starting to grow. I am also starting to piece together a Ca reactor as cheaply as I can find parts. I got a used reactor this past weekend, and have leads on CO2 tank - and am thinking Arduino and shields as a controller to control pH as well as everything else on my system. All that is beside the point of my actual question:

I plan to run the effluent of the Ca reactor directly into the waterfal style scrubber. In theory these two pieces (in my mind) are perfect compliments to each other.

I supply my scrubber via a dedicated pump. The pump currently elbows into the horizontal slotted pipe that supplies the screen. I am thinking that I might be able to add a 'T' instead of this elbow in order to run a vertical pipe or tubing high enough so that I can drip in my effluent into it without water spraying all over the place.

Any input on:
1) how much the low pH concentrated CO2 water negates the tendency for waterfall scrubbers to absorb bicarbonate out of the water? Anyone with experience in how much % wise maybe that it helps? I'm guessing that it all depends on pH of reactor vs flow of effluent vs flow through scrubber... but any input on what to expect would be great.

2) best way to feed effluent into scrubber? Does my proposed method seem feasible? Any guesses on how high I will have to go with my vertical pipe/tubing from the T? Any better suggestions than what I propose?

Does anyone think it would be bennificial to be able to seal/easy-connect/easy-disconnect the effluent to my vertical pipe/tube for less CO2 escape? - or the pressure might be too much for my effluent, changing the flow rate from what I think I'm outputting?

Any other considerations or advice?

 

[Floyd R Turbo]

There was quite a bit of discussion on the algae scrubber site about this. Google "CO2 Turbo" (no relation) and take a read.

Basically the answer is yes, if you feed the screen highly aerated water, it not only decreases or stops bicarbonate uptake, it also grows greener, apparently. This is one of the reasons why I started recommending to people to put their scrubber pump right next to the effluent of their skimmer, but CA reactor effluent should work well too.

There is also a thread that discussed the possibility of photosynthetically induced phosphate precipitation in the high pH environment of the algae scrubber screen. A few of use have noticed that algae harvests have these odd chunks of what looks like aragonite sand in the algal mat, and it's been theorized that this is precipitate of some kind.

 

[_shorty_]

There was quite a bit of discussion on the algae scrubber site about this. Google "CO2 Turbo" (no relation) and take a read.

Basically the answer is yes, if you feed the screen highly aerated water, it not only decreases or stops bicarbonate uptake, it also grows greener, apparently. This is one of the reasons why I started recommending to people to put their scrubber pump right next to the effluent of their skimmer, but CA reactor effluent should work well too.

Thank you. I'll google that and take a read.

There is also a thread that discussed the possibility of photosynthetically induced phosphate precipitation in the high pH environment of the algae scrubber screen. A few of use have noticed that algae harvests have these odd chunks of what looks like aragonite sand in the algal mat, and it's been theorized that this is precipitate of some kind.

very interesting.. If that is the case, does the introduction of the low pH or highly areated water theoretically contribute to that phosphate precipitation some how?

 

[Floyd R Turbo]

Well it's kind of over my head at this point. I just haven't had the time to delve into the details and understand it...

 

[acroman]

There was quite a bit of discussion on the algae scrubber site about this. Google "CO2 Turbo" (no relation) and take a read.

Basically the answer is yes, if you feed the screen highly aerated water, it not only decreases or stops bicarbonate uptake, it also grows greener, apparently. This is one of the reasons why I started recommending to people to put their scrubber pump right next to the effluent of their skimmer, but CA reactor effluent should work well too.

There is also a thread that discussed the possibility of photosynthetically induced phosphate precipitation in the high pH environment of the algae scrubber screen. A few of use have noticed that algae harvests have these odd chunks of what looks like aragonite sand in the algal mat, and it's been theorized that this is precipitate of some kind.

Algae preferentially take up CO2 vs -CO3 (less costly to process.)

That's why freshwater planted tanks (sometimes) use a CO2 bubbler. Also the reason why CO2 is commonly injected into microalgae cultures... it allows for a much denser culture.

This is sort of like with nutrient uptake. Most plants can (and readily will) utilize N as NO3. However, it costs the plant less energy to utilize NH3/NH4, so if both NH3 and NO3 are present, the plant will preferentially take up the NH4 before switching to NO3 absorption.

Photo-induced precipitation? hmmm.... this could be interesting if we could figure out a way to harness it... I'm thinking a laser-beam reactor sounds epic! :lol:

 

[_shorty_]

Well it's kind of over my head at this point. I just haven't had the time to delve into the details and understand it...

I found what you were talking about. Kind of interesting. I think this idea of Ca effluent into scrubber would counter the pH from getting high enough for this precipitation to occur. Not sure how you would control, or even really measure the pH in the screen for testing of this theory, though. Seems it would be a delicate balance to get right, to be able to make PO4 precipitation happen as well as good algal growth for N removal without depleating bicarbonates and or anything else that may be precipitating along with the phosphates... I think I'll stick with my idea and test it until more information and testing is available behind this theory. I will definitely follow his progress, though. Thanks for bringing it up!


for anyone else, I google'd: Photosynthetically Induced Phosphate Precipitation

edit: Oh - just found a whole different thread on it as well. much more info in there. I'll keep reading.

 

[Brummie]

Hi Floyd, Shorty and everyone else. Sorry different username, same avatar. I stopped Co2 dosing as I believed it was causing a slimy growth in the pipeslot. So I started Diffusing Co2 directly into a screened skimmer, to get it to grow in their instead. This didn't work. Since then, various tests and reading has led me to certain conclusions;
1) thick algae screens, underlit can be consumers of organic material.
2) thin highly lit screens are producers of organics.
3) these organics become a carbon source akin to carbon dosing and can be used in a similar nutrient removal to VSV dosing, ie skimmed out.
4) yellowing of the water can be caused by these organics (dying algae is the same stuff that algae exudes daily)
5) maintaining the pH of the treated water at 8.2 or below seems to prevent precipitation of ALK,cal etc.
6) increasing the pH of the treated water (by stopping aeration, to precipitate phos for example) reduces the algae growth rate.
7) aerating the screen creates acceptable gas exchange, when a skimmer is not used.

Always open to differing opinion

 

[SantaMonica]

Yellowing is caused by dead "wheat like" growth; wheat is already yellowish colored, and thus makes the water yellow.

Glucose, vitamins, amino's etc. from live algae is colorless.

Algal particles from broken algae, similar to phyto, are usually green or brown because they are just smaller pieces of the larger algae growths.

 

[Brummie]

Well, that's not right. What about systems that have a yellowing (most) that haven't got an algae filtration. You'll find algae screens that are light limited actually are organic consumers.

 

[SantaMonica]

Several things can yellow. But a green-growing screen won't.

No, the algae on screen does not consume organics. If you mean dino's, they only grow the first day or two, and even then they are populating based on the newly available light, meaning they are acting as photoautotrophs and not hetero. They would not have grown with the light off, which hetero's can do. And only hetero's consume organic carbon.

 

[Brummie]

It is clear from the experiments presented here that when concentrations of small, labile organic nitrogen compounds are sufficiently high, organic nitrogen has the potential to contribute a significant quantity of N to the overall N demand of estuarine macroalgae. The kinetic uptake parameters for urea and the various amino acids vary substantially between compounds, suggesting variable uptake mechanisms. The difference in uptake rates between species denotes that the importance of organic compounds may vary substantially between species of macroalgae, and may signify different adaptive strategies

http://www.vcrlter.virginia.edu/thesis/A_C_Tyler_Dissertation.pdf
page 141

Our data suggests that neutral amino acids may have the highest uptake rates in macroalgae, and that the potential for uptake is not necessarily proportional to the relative concentration of these amino acids in the environment (Chapter 3). The maximum uptake rate of amino acid N varies substantially between different types of amino acids, ranging from 0.1 to greater than 5 µmol g dw-1 h-1. We measured the highest maximum uptake rates for the two aliphatic neutral amino acids glycine and leucine; the lowest rate was also measured for an aliphatic neutral amino acid, aminobutyrate. Serine, an aliphatic hydroxy amino acid, was intermediate and the two acidic amino acids, aspartic and glutamic acids, had the lowest rates. As described further below, even among chemically similar molecules the mechanism for uptake appears to vary. Amino acid uptake rates for U. lactuca were higher than G. tikvahiae for all amino acids, as they were for urea

page 159/160

In an effort to assess the rate of organic P conversion or capture within an ATSâ„¢, HydroMentia conducted studies in which water samples were taken at intervals down an active floway at the S-154 MAPS facility. Noted in Figure 10 are these trends. From this data, it appears that organic P removal equals, and typically exceeds ortho P removal within the ATSâ„¢. The implication is that organic P hydrolysis, which generates ortho P, is occurring at a rate equal to or greater than ortho P uptake or precipitation. This provides strong indication that enzymatic activity is extensive within the ATSâ„¢. As this particular floway is harvested once weekly, it also appears that the enzyme-producing organisms are sustained on the actively managed floway. It is of course necessary to recognize that perhaps not all of the organic P removal may be associated with enzymatic activity, as particulate capture could also be involved. However, if there were no hydrolysis of organic P, it would be expected that ortho-P, not being replenished, would be reduced noticeably down the floway. This is not the case however, providing support to the probability that enzymatic activity is prevalent

http://www.hydromentia.com/Products.../2004_Stewart-Algal-Turf-Scrubber-History.pdf

macroalgae are capable of utilizing many forms of dissolved nitrogen, even at low concentrations, but that there are distinct species-specific differences in organic nitrogen uptake kinetics. These differences may dictate the competitive dominance of individual species under conditions of variable inorganic and organic nitrogen supply

page 181 (same reference)

 

[Brummie]

The yellowing;

http://www.sciencedirect.com/science/article/pii/S0272771409002935

The link I'm using wont let me copy and paste the abstract sorry. There's probably more like this if you google "Chromophoric Dissolved Organic Matter algae"

There is some better news though. It may be possible to destroy this yellowing by oxidising it on the screen by putting a uv light source on the screen, aided by the supersaturation of oxygen produced by the algae. I don't think anyone has tried this yet though.

 

[Floyd R Turbo]

Garf I'm not sure what is going on with your posts, but drop the url tag and just post as a direct link, as far as the QUOTE code not working I am not sure what to tell you, it should be, maybe you're pasting in extra BB code?