Moving Bed filter air placement.

[jobney]

I'm using a 20 gallon Rubbermaid Brute tote for a Moving bed filter. If making my own airline for churning via a 1/2 inch PVC pipe with holes drilled in it I can think of two configurations. A rectangle for sides up center down flow, or a plus + for center up sides down flow. (a third would be an "H" shape.)

I already have a bunch of 1/2 inch elbows, a T, and some pipe from an old undone project so I was thinking of doing the rectangle loop. Any objections?

[tpilk]

Hi Jobney,

No objections to your idea...actually a question for you:

I have just about everything to build my moving bed filter. I was at a shop which specialized in pond accessories, particulalry fountain stuff. I saw some practical sized rings, rectangles, etc. designed for water spray patterns. I was thinking they might make good preformed air pattern designs to be placed on the bottom of the filter. They're quite inexpensive - are you familiar with these? Any thoughts on driving media with one?

Chip

[GaryD]

.....or you could just use a Sweetwater-style airstone.

A moving bed bio-filter will look like nothing much.....until the media becomes conditioned. Initially, the media floats but, over time, bio-film attaches to it.....to the point where it sinks down into the water.

When it reaches this point, the slightest movement of the water will stir the media. The desirable end in a moving bed bio-reactor is to have the media moving in what I'd describe as a gentle simmering action.

The principal failing in my MBBR's is that I have the media boiling a bit hard.....and that shears off the bio-film long before it should......so the nitrifying performance of the bio-filter is less than it should be.

This gentle stirring action will happen......below the massed media near the surface.....long before you can see it. One day, you'll front up to your MBBR and the whole thing will be spinning along beautifully......and the media will be a dark brown colour.

Once you get a handle on them, MBBR's are the ultimate bio-filter......and the best place for them is in.....or alongside.......the sump.

Gary

[Earthan Group]

All good ideas. Keep in mind that the bacteria will require oxygen so if you can use a medium pore stone diffuser or similar the better your bio filter will respond. You can use a ring of small tube with small holes in it around the bottom of the filter and it will work. The nexus uses this principle however it is one of the limiting factors in the nexus design. Up to you how you want to move the media, but best to use the filter as a place to also aerate the water and gass off some CO2 and the finer bubbles created by an airstone or aeration tube will improve the filters performance.

[tpilk]

Sorry to busy up your thread Jobney...

I don't currently use a sump, though that may be something I need to consider as the system develops. I am looking to replace my barrel filter with two filters, a pond-style brush filter and a K1 media filter. I've been looking at several ideas and have it down to two basic thoughts: the first would be to build the brush and bio filters in plastic totes linked together. The second idea would be to use something like a 5 gal water cooler bottle properly filled with K1, drilled and plumbed for water flow and air driving up from the bottom. There are many smaller aquarium versions of this - I'm thinking larger scale. This bottle would live inside my 1500L FT.

With my crude plumbing, I am a bit limited today. My pump has plenty of reserve (10,000L/hr) so I'd just need to add a circuit to manage proper flow for the filters if I go with the boxes. On the other hand, I do like the performance of the bottle design - the lift created by the air column creates a nice water flow through the filter. Aeration is good as well. The downside is that I don't like that it takes up valuable FT space.

Any thoughts on either idea?

Cheers

[jobney]

I've seen the bottle MBF you've mentioned and thought of the same thing with the 5 gallon water cooler jugs.. I'm not using K1 media but Kaldnes says "50 litres of K1 media will handle up to 0.25kg of food per day."

Linked plastic totes are exactly how I'm building mine. From the swirl filter it will go into the first tote that is a brush filter, then the moving bed filter, then a sump with the pump in it. The first two are linked and then an overflow pipe into the sump tote so that only the level in the sump changes. I'm using 20 gallon Rubbermaid brute totes as they are heavy duty and are guaranteed food safe. They also have nice snap on lids that will stay put.

If you lay the brushes down a little you can get the lid on and you don't need to build a hanging rack.

I originality had planed on the media being in the sump but then saw the benefit of having the two filters always be a the same water level so I've added a third tote for a stand alone sump. This picture is the old setup. Now I can place a heater in the sump with the pump. Note I only needed 16 brushes not 20 like in the drawing.

Sorry to busy up your thread Jobney...

I don't currently use a sump, though that may be something I need to consider as the system develops. I am looking to replace my barrel filter with two filters, a pond-style brush filter and a K1 media filter. I've been looking at several ideas and have it down to two basic thoughts: the first would be to build the brush and bio filters in plastic totes linked together. The second idea would be to use something like a 5 gal water cooler bottle properly filled with K1, drilled and plumbed for water flow and air driving up from the bottom. There are many smaller aquarium versions of this - I'm thinking larger scale. This bottle would live inside my 1500L FT.

With my crude plumbing, I am a bit limited today. My pump has plenty of reserve (10,000L/hr) so I'd just need to add a circuit to manage proper flow for the filters if I go with the boxes. On the other hand, I do like the performance of the bottle design - the lift created by the air column creates a nice water flow through the filter. Aeration is good as well. The downside is that I don't like that it takes up valuable FT space.

Any thoughts on either idea?

Cheers

[Pugo]

Well, I am still using two medium air stones in my system, but I think it is due to my media ratio. But still it is working great. I will play with it today and see it I can get it down to one stone, but as I have so much air any way, and the extra air does help with oxygenation of the water.

[jobney]

If it's a food grade plastic and you can plumb it into your system airtight it should work. You may have to drill out the holes if they prove too small. They will also want to float so you would need to hold them down with something. If I need to drill each hole larger I might as well just use the DIY PVC or regular air stone. Like Gary and I've said elsewhere. The media will float for a while and not move well until it is conditioned to the system. So you won't have the instant gratification. Everything I've seen points to it being very hard to screw up.

Why use an air stone when I can do it the hard way.

Hi Jobney,

No objections to your idea...actually a question for you:

I have just about everything to build my moving bed filter. I was at a shop which specialized in pond accessories, particulalry fountain stuff. I saw some practical sized rings, rectangles, etc. designed for water spray patterns. I was thinking they might make good preformed air pattern designs to be placed on the bottom of the filter. They're quite inexpensive - are you familiar with these? Any thoughts on driving media with one?

Chip

[tpilk]

Hi Jobney,

Your graphics are awesome - sure makes it easy to visualize the project....

So, would you remove the swirl filter with the brush filter in place? I think for my needs it would be redundant, but I'm using GB's and have additional pads in the GB's for solids. I'd like to have the right amount of filtration without bulking up the area...if possible. That said, if the two compliment each other...

I've gone round and round on the brush design. It's not rocket science, but the brushes aren't cheap when the cutting begins.....

I started with a standpipe on the intake side, then water would travel through three rows of verticle 4" brushes, then pass through one or two rows of horizontally places brushes to the output at gravity feed. Now I'm thinking of just packing the tote full of brushes in verticle rows till the tote is full. I'd just cut the brushes to length and as my tote sides have no taper, all would sit snug in the tote without a rack system. To clean, just pull them out, wash the brushes and re-pack. I bought some decent quality, less expensive brushes locally - was a little hesitant to cut those expensive brushes till I figured out exactly what I'm going to do.

Regardless of the K1 filter design, the brush filter will happen. I really appreciate the input from all.

Chip

[Pugo]

Well,my design for my brush filter was only to place brushes at the top have of the barrel, I couldn't bring myself to cut them down. So I used them as a packed media solids filter. So far it has worked great and see no reason to cut them.

I know I have way more MBBR in my barrel than I should have, and that is the reason I have to have two air stones, to run it but the media seems to move smoothly. So it is OK.