Fluidized Sand Filter using Airlift

Rob Nash asked me why I was doing this, I started to explain my reasons for looking outside of conventional aquaponic methods.  While writing I came full circle and saw that he was right.   It comes down to adding more media beds.  
Ive been saying its all about the Nitrates and began to see that as my primary goal.  I kinda got off track from the real goal which is to provide Nitrates to as much high density growing space as possible.
Ive got to quit thinking like an aquarium owner and more like a farmer.

But Ill keep this post available because the mistakes I make are something others might be able to learn from.
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Im still playing around with ideas for a fluidized sand filter.  I would really like it to run on airlift.

Heres a concept drawing.   I have done some small scale experimenting, and Im feeling like these concepts shown here may not work.  Joeys videos below demonstrate a proven system using both an air pump and a water pump.

* Further design has taken me away from Airlift Pumps and static bio filters, and into Moving Bed Filtration using an impeller pump. 

This idea may be a starting point for design, but my recent tests have shown that fluidization would be difficult to achieve as shown. 

Uaru Joey has a couple very good videos. 

Starting at 17:45 Joey talks about the amount of K-1 and other helpful specifications

Starting at 17:45 Joey talks about the amount of K-1 and other helpful specifications 

Here is a low cost filter I made as an experiment. 

Ill keep you updated.  Id like to hear suggestion.
CLICK HERE for my Moving Bed Media experiments

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Gravel Bio Filter

Here is a concept drawing of a bio filter which filters from the bottom up
I have used this is the type of filter for many years without problems.

A spray nozzle is angled on the bottom of the power wash tube which is connected to a garden hose to stir up the waste.
The 2" inlet also serves as a waste drain.
A tee with either a diverter valve or two separate valves allows switching from normal operating to backwash mode.

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This page continues to get a lot of Google hits, so I have added this drawing to demonstrate how the bio-filter in my pond was built.

The gravel media is suspended above an open space.  I did this by building a cement block cistern on top of a 6" concrete slab.  The blocks were laid dry and then filled with concrete.  Inside I laid 1-1/2"x8"x16" paver bricks on edge to create a shelf for the PVC tubes to rest on.

The PVC tubes are 1" pipe and contain a piece of 5/8" rebar to give them the strength to support the gravel.  The ends are capped to prevent the rebar from rusting. Yes it takes a lot of these pipes laid side by side. Over the top of these PVC tubes I placed a piece of PVC fencing material to further support the gravel.

There is a drain and an inlet pipe placed at the bottom.  Both are mortared in place as is the outlet near the top.  Then to prevent leaks I coated the entire inside surface with Thoroseal .

I have also built small filters inside of plastic olive barrels as depicted in the drawing at the top of this page.  The gravel is supported by a PVC cage.  Ill let you use your imagination rather than attempt to draw that.

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 Another idea I have is to plumb the spill tube down to the bottom and bring the inlet to the top.  Dirty water is filtered down through the gravel.  A mesh on top of the gravel would facilitate cleaning

This would facilitate cleaning.  A mesh could be laid on top of the gravel and periodically rinsed off

SketchUp Link

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Aquaponics Self cleaning swirl filter revisited

One of the many people named Anonymous took the time to comment on my self cleaning swirl filter, so I thought Id revisit the topic with some thoughts Ive been having.

For the last few weeks Ive been thinking of getting some more fish.

And Ive also been thinking about developing the self cleaning swirl filter a little more.

My original design was to tap off a small amount of clean water for NFT tubes employing the self cleaning filter to keep the roots from collecting solids and blocking the NFT tubes. In the end I got around that by just taking my water from the sump, where there were no solids, but that required a better pump to get water to the top of the tubes. .


If this were ever to be implemented as a system to remove solids from a system rather than returning them to the grow beds it would need some adjustment.

Its easy to set up a container so that it is right at the point of tripping a siphon, but will never actually get there unless someone suddenly dumps water into it. With this in mind, one option I thought of  when I was playing with this idea, was to use a deer scarer...

http://en.wikipedia.org/wiki/Shishi-odoshi

Set a dripping tap, so it slowly filled a deer scarer. The deer scarer should tip only once or twice a day, and should dump the same amount of water that the self cleaning swirl filter takes from the system each time its triggered.

Im going to build a deer scarer, and see how it works, then see if it really would take care of dosing the self cleaning filter with the correct amount of water to make it do its thing.

You can see my previous work on my self cleaning swirl filter here.

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Is Water Flushed From A Filter Better

Ive often heard people say water flushed from a filter is better for your plants. 
I wondered how true that is.  Is It higher in Nitrate?
Heres the test.

Its higher in some trace elements, but dont count on it for Nitrate.

The problem with dumping this on your terra-garden  is that this nutrients are lost from the aquaponic system.

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Water Storage and the BioSand Filter

825 gallon rain water catchment system
I live in the US, in arguably the richest county in the US, per capita (Fairfax, VA).

Even so, there are times when no amount of money can make potable water come out of my tap. System flaws (e.g., water main ruptures), acts of God (e.g., hurricanes), or acts of man (e.g., sabotage) can all mess with the availability and/or quality of my water.

Not cool. Thirst, dysentery, and cholera are nasty things.

Im loving the magnitude of water storage possible with common 55-gallon drums and PVC pipe or hose and hose fittings.

But if I had an infinite supply of water, Id still have to purify it.

I have my solar oven, with a water pasteruization indicator (WAPI), a little vial filled with soy wax. You put it in a container of water with the wax side up - come back after a day in the sun, and if the wax has melted and re-coalesced at the bottom, you know the water was at 200 degrees Fahrenheit for at least 10 minutes and has been pasteurized.

But I think Ive come across something even better: The BioSand Filter. One of these babies can produce 5-15 gallons of clean water in an hour. Here are two videos: a funny one that doesnt really explain the physics/biology of the thing, and an earnest Christian charity one that does a great job of explaining all the details you need to understand:

BioSand Filter - Cute video (light on detail)

BioSand Filter - Earnest Christian video
Wikipedia has a nice article on the BioFilter, and theres a website called BioSandFilter.org that gives details regarding who, how, and what, for those of you who like those kinds of details.

Enjoy!

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My Spin Filter

I have to admit this did not work as well as I had hoped.  But Im sharing my triumphs as well as my failures so that others can also learn from what Im doing.

It will be interesting to see how well this spin filter works when I add the fish.  While its not exactly as I had  hoped I believe it will make a significant difference.

UPDATE 12/23/2012
As the fish grew and the demand increased it became apparent that this was only marginally useful as a settling tank.  Maybe a better design would be more effective.

Below are links to two short videos that show the currents and settling of Koi food

Test with floating Koi food

Test with sinking Koi Food

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Stirling engines Slow motion balloon power piston

I made a few adjustments to my little tin can Stirling engine. It now spins twice as fast, at a rate of around 210rpm. Not that that means much because the more flame you put under it the faster it goes. But its around twice as fast as it was originally. Quite a success as far as bettering a terribly inefficient Stirling engine goes.

If you ask me.

The main adjustment I made was to replace the two sections of shaft that make contact with the supports. The original shafts and bearing surfaces were made of galvanised fencing wire.

I replaced them with a thinner grade of stainless wire. Actually its welding wire, and is the same stuff I use whenever I mention stainless wire in the construction of my fishing lures or anything else on the blog.

Pictured here in this uncomfortably framed, but interestingly red image, is the new wire, the old wire, and a match.

The thin stainless wire makes a huge difference. It even runs without the 8g counter weight now.

The counter-weight is there to mirror the weight of the displacer, so without it, the power piston has to lift all that weight on its own.



With the counter-weight and a minimum sized flame, it can now tick along as slowly as only 32 rpm.

Stately.

To run as slowly as 32 rpm, I found it also needed a small drop of very light lubricant (fishing reel/sewing machine oil). But its important to note that the shaft for the displacer - the one that goes through the small hole in the can, should not be oiled. The oil burns, and leaves a sticky residue which will stop the engine.  As seen by the improvement by the slight reduction in friction, the smallest extra friction will kill these little engines. Use graphite, or just leave it with nothing.

If you did lubricate the displacer shaft, its also possible that oil or Vaseline could get into the displacer container, and being flammable, might eventually find its way to igniting if everything was just right.

Everything is very rarely just right, and a Stirling engine is a very safe thing to make and use because there are no pressurised containers. The making involves some sharp bits of tin can, and should probably not be built by kids, but as a finished item, its as safe as any small candle is, so probably qualifies as relatively child friendly.

Lets say... As child friendly as a birthday cake.

Anyway, it looks like this in slow motion (sorry for the poor picture quality)...

[edit from the future - Opps, for some reason the video wasnt dropped into place.] Here it is...




Even more stately.

Its currently clunking away on my desk, running at around 60rpm on these two little flames, and has been doing so for an hour. One flame is about the size a birthday candle, and the other is around half the size of a birthday candle.

My point is it isnt using much heat compared to the last version.





I find its sounds...

oddly soothing.



K-chunk K-chunk



120 Things in 20 years thinks that if ever I disappear, it might be because Im off on a Stirling engined bike trip around Australia... in slow motion.

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