WillsC

Had a go at building a RDF filter

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I was not real happy with the radial filter so figured I would try to build a Rotating drum filter.  They are not very hard to make but I admit it is a bit of "redneck engineering".

 

post-4451-0-36562100-1462652113_thumb.jppost-4451-0-87697800-1462652125_thumb.jppost-4451-0-85986800-1462652144_thumb.jppost-4451-0-51758500-1462652146_thumb.jp

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They are not very hard to make but I admit it is a bit of "redneck engineering".

 

Are you going to add brushes to the outside for nitrifying bacteria?

 

Redneck engineering is that the same as if your Dad walks with his 3 rd grade son to school, because they are both in the same grade? Then that's being a Redneck.

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 Hi,

 

I was not real happy with the radial filter so figured I would try to build a Rotating drum filter.  They are not very hard to make but I admit it is a bit of "redneck engineering".

 

attachicon.gif!cid_Resized_20160504_151315.jpgattachicon.gif!cid_Resized_20160505_173149.jpgattachicon.gif!cid_Resized_20160506_132943.jpgattachicon.gif!cid_Resized_20160506_133131.jpg

 

The radial flow separator is generally very effective....and far less trouble to make than the RDF.  What was your specific concern?

 

Gary

Edited by Gary Donaldson (see edit history)

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Are you going to add brushes to the outside for nitrifying bacteria?

 

Redneck engineering is that the same as if your Dad walks with his 3 rd grade son to school, because they are both in the same grade? Then that's being a Redneck.

 

No brushes.  There is a tote fluidized bed filter for the bacteria. 

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So this system filters what exactly or just oxygenate the water for fish ? Can sand be used to help filter in this type of RDF?

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 Hi,

 

 

The radial flow separator is generally very effective....and far less trouble to make than the RDF.  What was your specific concern?

 

Gary

Gary,

 

Maybe I should not have said "not real happy" as it worked just fine.   The issue I had is that the sediment is not out of the system in the radial, it is in the bottom but it still is in the system. With the RDF it is gone, and fully automatic.   Yes the RDF is harder to make but it isn't that hard.  

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So this system filters what exactly or just oxygenate the water for fish ? Can sand be used to help filter in this type of RDF?

 

It filters all of the water, anything over 80 microns is removed.  The only way out of that barrel is through the screen or out the waste line. 

 

Here this may help, it is what I based it off of.  The drawing is not mine.  

 

post-4451-0-45148400-1462658109_thumb.jp

Edited by WillsC (see edit history)

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Is pressure also applied by pumps to speed water flow or filtration? Pictures aren't doing enough justice guess I will look up more info. But RDF reminds me of waterwheels a little 😀

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Mike,

 

Sorry,  more details.  The water coming back from 14 IBC totes enters the 4" PVC at the front.  That 4" pvc is also the shaft the barrel spins on (on toilet flanges that have had the inside diameter increased on a lathe).  The water enters the barrel through 3 2.5" holes cut in the bottom of the pipe.  Once the water enters the barrel it goes out through the very fine screen but all the debris and fish waste stays in the barrel.  Eventually the screen starts to clog up and the water can't get out of the barrel.  The water is still flowing out of that tote the barrel is in to the bio filter then the sump and pump so as the water level in the filter tote drops it triggers a solenoid to open which allows water to come out of the spray bar (house pressure well water).  At the same time the motor comes on that turns the drum.  As the drum turns the dirty screen is washed off in to a trough inside the barrel and that waste leaves by the 4" PVC to the back.  The T in the middle is blocked by a plug.  As the screen is cleaned the water can once again flow through the screen so the water level rises and shuts off the solenoid and turning motor.  It only runs about 20 seconds an hour but being fully automatic if there is more load it comes on more often....less load it comes on less often.   

Edited by WillsC (see edit history)
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I forgot to mention......also in the front of the barrel there is also a 3" toilet flange that is also thinned so a 3" pvc fits in it tightly and extends out almost to the wall of the tote and is capped off. Also on that short length of pipe is a 3" Coupler but it too has been hollowed out so it slides freely on the 3" pipe.  The purpose is that eventually (waiting on the 3" uniseal to arrive)...on the tote there will be a 3" uniseal and a short pipe inside and outside the tote and a cap.  So you turn the barrel to align the pipe off the barrel and the pipe in the tote.  Slide the hollowed out coupler so it joins the two pipes temporarily.  Remove the cap and the water gushes out of the barrel into a container.  Doing this will flush out any fry or young fish that have made their way in to the filter.   

 

The fish inside the filter are fine as even when the water level in the tote drops due to the screen clogging it never gets under 4" deep inside the barrel.  That was our idea, well a friends and I thought it was a brilliant addition.

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Nice so the filter system is somewhat fish safe too. Like overall design definitely waterwheel like wonder if you can do something with that could save on energy. I believe that most waterwheels generate power by rotation of the wheel in water is connected by chain normally and the chain rotates a generator the creates power to be used later.

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A couple more pictures that might help.  

 

 

Close up of the front with the two hollowed out toilet flanges

 

post-4451-0-68117500-1462662926_thumb.jp

 

 

The metal around the barrel and what connects the barrel together end to end is wiggle wire track.  It is the structural support as well as what the fabric attaches to by adding wiggle wire.  The track on the end also acts as the track for the belt to ride on. 

 

 

post-4451-0-11502700-1462662928_thumb.jp

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Nice so the filter system is somewhat fish safe too. Like overall design definitely waterwheel like wonder if you can do something with that could save on energy. I believe that most waterwheels generate power by rotation of the wheel in water is connected by chain normally and the chain rotates a generator the creates power to be used later.

 

Well this has a very tiny motor to power it, can even use solar and a battery The barrel spins very very freely on the toilet flanges.  You can run it on a timer also to come on every say 8 hours for 30 seconds.  It all just depends on the load of fish you have.  Commercial made units like it are pricey..$3,000-$7,000 dollars and I have maybe $300 in it total.

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Well one thing I save is pvc and drums so maybe making something similar would benifit. Like how it can run on solar and battery. What would the benifits of running duel RDFs in one system?

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Well one thing I save is pvc and drums so maybe making something similar would benifit. Like how it can run on solar and battery. What would the benifits of running duel RDFs in one system?

 

Im not sure if there is any advantage to running dual RDF's except perhaps redundancy in case of a failure.  I will have two RDF's because the way the tanks are arranged it was just easier for me and the other RDF will filter 11 more totes but just one the size I built is more than enough to run all 25 totes I will have with fish in them.   

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Nice, inventive RDF you have there.     

 Thanks:)   On the next one I am going to change the cross supports from under the rim of the barrel to on top but other than that I am very happy with how it turned out.

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Can RDFs be used in other systems like to purify water for drinking or in stock growing systems because of how safe and how potential well it can clean water? Maybe if rotation was increased also would the oxygen level of the cleaned water?

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Mike,

 

I think your questions are beyond me friend.......but I doubt it.  The size of items in water that might hurt you like bacteria or the like would pass through a 80 micron screen like a BB going through a tennis court net......no effect at all.

 

For filtration for the fish you don't want the filter spinning fast as all that would lead to is breaking the waste up in to smaller pieces that could go through the 80 micron screen or could make the waste be soluble in that water.  This device would not be a good aerator, it is a filter.  The koi people use it a lot as it leads to very clear water.  I can notice the difference in my water after just a few days of running.  Over time the mesh builds up a bio-film on it which will make the pore size even finer.  When it gets to the point the filter is cycling too often the bio film can be removed easily but up to a point I think the bio-film is a good not bad thing.  It is basically a time saver as it cleans itself and removes the bio-load from the water.   The water will flow out and to a barrel with a sump and is then stored in a tote as I want that nutrient rich water as a fertilizer for my plants (own a fig nursery).  

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Nice to know koi water can be cleaned so well with RDFs 😀

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Gary,

 

Maybe I should not have said "not real happy" as it worked just fine.   The issue I had is that the sediment is not out of the system in the radial, it is in the bottom but it still is in the system. With the RDF it is gone, and fully automatic.   Yes the RDF is harder to make but it isn't that hard.  

 

When I recall the nature of your fig set up, it all makes perfect sense.  

 

A cost effective RDF for backyarders and small-scale commercial operators has been something of a holy grail......and I love your integration of the captured solids with your fig tree operation.  This is what integrated aquaculture is really about.

 

Great work, mate.

 

Gary

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Gary, 

 

Thanks for the words of support.  It really is not a hard build and I think the only tool needed that most probably don't have is a lathe for thinning out the toilet flanges.  The commercial systems I looked at for ideas I think over complicate the system and add a LOT of unneeded cost.  

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Gary, 

 

Thanks for the words of support.  It really is not a hard build and I think the only tool needed that most probably don't have is a lathe for thinning out the toilet flanges.  The commercial systems I looked at for ideas I think over complicate the system and add a LOT of unneeded cost.  

 

Nice build. Try to operate it with a maximum water level between in and outside of 10 cm.

 

The real test is going to be reliability, good commercial units will run for years with little maintenance.

 

An alternative on building it like you did is by using parts from an old frontloading washing machine: pick out a model with a belt drive and a stainless steel drum. you can use the housing of the drum, and the level sensors and selenoids too, and if you use mains water (pressure) for the backwash you even can avoid a pressure pump.

 

As for complicated thus expensive units. If you ever worked with a Hydrotec or Faivre drum you know where the money is: typical very heavy high grade stainless steel made with very small tolerances. I have a little faivre drum at home 60 cm diameter and 60 cm deep; weight of the drum alone is more then 35 kg (estimate based on the struckle I had to re-assemble it); result 0 flex in the construction. They also come with high quality multistage Grundfos pressure pumps. Now you don't buy these drums under $10,000 and I have some doubts on the cheaper "commercial" units as used by the koi people.

 

I came acrross a number of locally made commercial drumfilters (Australia) and they all seems to underpreform in the long run.

 

In RAS aquaculture drums are used to remove suspended solids and linked nutrients out of the water body as fast as possible, main benifits are low level of suspended solids and low water exchange (exchange rate is typical set by nitrate levels). Obvious depending on set-up, but in most aquaponic systems the instand removal of the bulk of the nutrients isn't required or desirable and thus the typical aquaculture configuration (for RAS) might be not optimal for an aquaponic system.

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I was not real happy with the radial filter so figured I would try to build a Rotating drum filter.  They are not very hard to make but I admit it is a bit of "redneck engineering".

 

attachicon.gif!cid_Resized_20160504_151315.jpgattachicon.gif!cid_Resized_20160505_173149.jpgattachicon.gif!cid_Resized_20160506_132943.jpgattachicon.gif!cid_Resized_20160506_133131.jpg

 

If it works I don't call that redneck at all.  And if it works just as well as an expensive purchased system I call that a victory of ingenuity and savings at the same time. 

 

I've actually built things that not only saved me money, but worked better than something purchased! I call that a win/win! 

Edited by Cecil (see edit history)

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Nice build. Try to operate it with a maximum water level between in and outside of 10 cm.

 

The real test is going to be reliability, good commercial units will run for years with little maintenance.

 

An alternative on building it like you did is by using parts from an old frontloading washing machine: pick out a model with a belt drive and a stainless steel drum. you can use the housing of the drum, and the level sensors and selenoids too, and if you use mains water (pressure) for the backwash you even can avoid a pressure pump.

 

As for complicated thus expensive units. If you ever worked with a Hydrotec or Faivre drum you know where the money is: typical very heavy high grade stainless steel made with very small tolerances. I have a little faivre drum at home 60 cm diameter and 60 cm deep; weight of the drum alone is more then 35 kg (estimate based on the struckle I had to re-assemble it); result 0 flex in the construction. They also come with high quality multistage Grundfos pressure pumps. Now you don't buy these drums under $10,000 and I have some doubts on the cheaper "commercial" units as used by the koi people.

 

I came acrross a number of locally made commercial drumfilters (Australia) and they all seems to underpreform in the long run.

 

In RAS aquaculture drums are used to remove suspended solids and linked nutrients out of the water body as fast as possible, main benifits are low level of suspended solids and low water exchange (exchange rate is typical set by nitrate levels). Obvious depending on set-up, but in most aquaponic systems the instand removal of the bulk of the nutrients isn't required or desirable and thus the typical aquaculture configuration (for RAS) might be not optimal for an aquaponic system.

Phri,

 

Good morning.

 

As to reliability as you say time will tell but it is a very simple design.......I do not see where a failure could occur.  The drum spins slowly and yes I have seen some of the commercial units that spin much faster but I see that as no advantage and as you know with speed comes more chance of a failure.  With water as the bearings there is no wear parts and even if something did fail how bad could it possibly be?    The sprayers work on pressure from the well, same as my home and it cleans the screen completely so see no need for an additional pressure pump.  Granted the spray heads use more water that those that would be higher pressure.  I am not concerned with conserving the water as it is all captured and used anyway.  If I wanted to minimize the waste water the addition of a booster pump for a lower flow higher PSI heads would be a good decision. 

 

 

I am curious where you think a failure could occur?  I just do not see many weak spots.  The only point of failure I could determine was IF the water level in the IBC tote fell due to a failure in the solenoid to trigger or a motor failures the drum would get VERY heavy as the water in the tote dropped but I solved that by making 3 of the screen panels breakaway and the screen would come out of the wiggle wire at that point and release the load of water. 

 

Yes in aquaculture you really do not want to filter out all of the fertilizer, I understand that but my set up is for aquaculture.  I have a fig nursery with 500 or so varieties but they are not in this loop other than the in ground plants benefiting from the fish water.  

Edited by WillsC (see edit history)
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