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Scaling up?

Discussion in 'General Discussion' started by David - WI, Jan 9, 2016.

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  1. David - WI

    David - WI New Member

    I was really beyond excited when I found this site and started reading here and around the internet about algae scrubbers... but was shocked at the tiny amount of waste processed per square foot of scrubber.

    Is there anything that "changes" when you scale these things up? Let's say I needed to handle 500# of feed per day? I know there are some "industrial" size systems cleaning up the everglades and Suwanee river; but I don't have anywhere near that kind of space for algae scrubbers.

    Over the course of two days I went from "saved" to "cursed again" when I actually started to run the numbers.
  2. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    It all depends on the construction of the scrubber. The rule of thumb of 12 sq in of screen / cube of food fed /day is generic. You can, IMO, push that by efficient design. However this has not really been bench-tested, nor have any of the "modern" algae scrubber designs. Nor have refugiums for that matter, and there are only a handful of formal data sets for just about every other filtration system.

    Factors that one can optimize are things like:

    Lighting (type, intensity, duration, distance, etc)
    Screen (dimensions, material, roughness)
    Flow (rate, even-ness)
    Chamber (enclosed vs free-air, dimensions, etc)

    Constructing the unit with a 3D growth chamber is, IMO, one of the major factors that increases capacity. But that doesn't mean you can take an open-air screen and enclose it any old way, making it so the growth can "pile up" is what creates the 3D growth effect.

    Also, the capacity scale is probably not linear. Just guessing here but it makes sense that as you get larger and larger, there is probably some kind of point where capacity per unit area starts to increase due to the effects of things like adjacent growth and even light distribution.

    I have more thoughts on this as well, getting ready to board a plane so I might follow up with those later.
  3. David - WI

    David - WI New Member

    Thank you for the reply.
    Somehow I would need about a 10x increase in "efficiency" in order to even try it. :(
  4. vereecjw

    vereecjw New Member

    Is the limitations for you space, operating costs, or something else?

    If it is operating costs, I would look to use solar light.

    If it is space, you can look at increasing the cooling efficiency for led heat sinks using chemical coolants piped through the heatsinks. This would let you stack and pack scrubbers. Cleaning could be tough.

    500 lbs of food @ 0.1 Oz / 12 inch screen comes out to:

    500 × 16 / .1 = 80000 12 inch screens
    960000 square inches (double sided not likely solar)
    Call it 7000 square feet. Add a depth of 3 inches and you hit 1750 cubic feet.

    Now that seems like a lot, until we ask, what are you feeding 500 lbs a day?

    That comes to 10 dolphins.
    Assuming you are housing a pod of dolphins, a 1750 cubic ft commitment doesn't seem unreasonable.
    This doesn't include room for access, but you get the idea.

    Also, I wanted to look at this so I could get to the final question,

    Can you please post pics of whatever is getting 500 lbs of food a day? That sounds epic
    Turbo likes this.
  5. David - WI

    David - WI New Member

    It's really not "epic"... it's going to be about 30,000 yellow perch; indoor "aquaponics" and space a problem.

    Operating cost for the algae scrubber isn't really the issue, we'll already have about 20,000 watts of lights and 25hp worth of pumps & compressors running 24/7.

    The main thing, I guess, is that I don't think we don't have or need anywhere near the flow it would take to run these algae scrubbers (we have about 900 gpm that we could use, but don't need to use it all). The "side stream"" that we could most easily use would total about 250 gpm.

    The one thing that ends up way out of balance in aquaponics is nitrogen. I don't have enough space to grow all the plants it would take to use up all of the nitrogen; and if I did we would be short of other nutrients. But, I have it worked out now.

    The algae scrubber seemed like the "miracle" solution but I'm going to end up with anaerobic denitrification which won't require any additional lighting or flow.

    I appreciate the info but I\it's not going to work for us.
  6. vereecjw

    vereecjw New Member

    That makes much more sense now.

    Good luck!
  7. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    lol that cracks me up

    Seriously though @David - WI how much are you actually planning on feeding every day? Is it really 500#?

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