DIY self cleaning mesh/sieve

[JHKOI]

I have a 40-60 m3 pond that is spring fed/very high water table year roundwater that needs an overhaul in terms of filtering.

I been thinking a lot about whether an RDF is the way to go but I wonder if it wouldnt be equally effective (and quite cheaper) to use a 200 micron mesh that would be backflushed on a timer via some nozzles on the underside of the mesh.

I did find some self cleaning concepts online but they all flush the mesh from the same side as the water from the pond/pump, and not from underneath. I cannot figure out why as I think it would prevent cloging a lot more.

As the pond is spring fed I am not concerned with the pond's water level as the waste water will go back into the water table/pond.

Has anyone tried any concept like this? Any reason why it wouldn't work?

If anyone is interested I can dwelve more into how the pond is built AS IS.

[coolwon]

A hand drawing might assist in visualizing what you have in mind.

How do you wash the filter out against the flow of water coming in?

How do you divert the dirty water back into the water table pond?

Mechanically on a timed stepper motor?

[JHKOI]

I was thinking of something like I draw "below" (sorry for the bad drawing skills ahah). I would be building on the ideias found on these links:

https://www.youtube.com/watch?v=t3zXhPYUfyc

https://www.youtube.com/watch?v=OTo8YCeh4jU

https://www.youtube.com/watch?v=zMie5Xngmck&t=316s






The pressure pump would be activated on a timer, multiple times a day, for a brief period of time (probably a wifi outlet could do the trick).

Given what I already have, I think that I would only need to figure out the best mesh for the job, get the underwater pressure pump, a plastic box for the sieve system, the nozzles and the timer.

I don't think that the backwash process would require halting the normal operation of the sieve and that only a minimal amount of water should be needed to clean the sieve but that would have to be tested.

[JHKOI]

Something like this:





The idea would be to use a pressure pump to backflush the mesh while the filter is in operation. The other implementations I saw use nozzles on the same direction as the water flow from the filter but I reckon it would be more effective if the mesh was sprayed from below.

Any inconvenience with this sort of design?

[JHKOI]

I was thinking of something like this. I would have a pressure pump drawing filter water from below the mesh and backwashing the mesh with some nozzles/sprinklers.

The pressure pump would be activated on a timer, probably a wifi outlet for finer control. The dirty water would just be used to water a flower bed right next to the pond. The water will permeate into the pond effectively filtered.

Am I crazy or would something like this be doable? Any suggestion would be greatly appreciated.

[coolwon]

In a drum filter,I see the dirt carried or washed away with the nozzle water into the

drain pan below and on into the garden.

With the drawing I see the water being bounced and partially washed into the gutter.

I do see the fine filter media assisting in transporting the dirt into the gutter.

Extra feed water fed from the spray supply, could be fed into the end of the gutter to

assist in carrying the accumulated moist dirt away to the garden.

I do not see the present drawing being as efficient as a drum without some tweaking.

My description is my interpretation of the drawing.

[JHKOI]

Thanks for the feedback.

I'll do some tweaking and revert with some solutions. I get your point but I guess that the waste could have an extra nozzle as you point out. Most of my doubts now are about whether the pressure pump below will have enough force to overcome the incoming flow and dislodge anything that is clogging the mesh.

I also thought about using a fine filter sock at the waste drain to retain most of the water inside the system but I am struggling to reconcile that with the idea of an overflow in case the mesh clogs and/or the cleaning process stops working.

Perhaps the drainage channel could have 2 filter socks to be cleaned periodically and the overflow could be a pipe a couple of inches above that.

I don't expect the system to be as effective as an RDF but if it ends up being 70% effective, fully automatic and built at a 1/10 of the cost, I'd be pretty happy.

[JHKOI]

Hello all,

a pump failure meant it took me longer to build a first prototype but here it is at last.






I still need to test it long run and do some adjustments to the way water flows but so for so good. The water is filtered and all the solids are retained by the mesh.

Now I need to think about how to best do a plant pond (where the water falls into) in such a way that most nutrients are removed by plant uptake.

I'll keep you posted on the trial.

Cheers

[aquaholic]

Any updates or general comments after longer use? Especially around automated cleaning? Hopefully you now have something satisfactory? Biofilm buildup makes mesh size smaller over time.

Most higher end seives use wedge wire to screen and these are easier to hose clean.