Biopellet / biomedia in one!

[pooootiqe]

Printed some PHA (biopellet material) parts reminiscent of K1 fluidized bed media ;) will check if they tumble well in a reactor.

 

[Lasse]

reminiscent of K1

The secret with K1 is that the density of the plastic is only little. little bit higher than water and they give a rather effective area. I do not know your plastics density but the effective area is much. much lesser than for K1. The tinny holes will be overgrown and you will miss the internal area.

Sincerely Lasse

 

[pooootiqe]

The secret with K1 is that the density of the plastic is only little. little bit higher than water and they give a rather effective area. I do not know your plastics density but the effective area is much. much lesser than for K1. The tinny holes will be overgrown and you will miss the internal area.

Sincerely Lasse

You’re right lasse! PHA is much denser than water, more like 1.2g/cm3. It does not tumble well (still tumbles however in an Innovative Marine Minimax media reactor).

Regarding surface area, is it to do with k1’s material as well ( is it microporous?) or is it simply the geometry? I can try to follow k1s geometry to a tee, but PHA seems to expand during printing and even with a 0.2 nozzle I doubt it would be close to K1’s plastic thickness.

 

[Lasse]

Regarding surface area, is it to do with k1’s material as well ( is it microporous?) or is it simply the geometry? I can try to follow k1s geometry to a tee, but PHA seems to expand during printing and even with a 0.2 nozzle I doubt it would be close to K1’s plastic thickness.

I´ll try to explain what I´m thinking is one of the most misunderstood and biggest myths regarding the surface area of a filter media.

Sellers often talk about the enormously large surface areas that their fantastic filter media have. Then they often emphasize all the micropores in the filter material - what they forget to mention is that as soon as a bacterial film builds up, they are clogged and of little interest, especially for oxygen-demanding processes.

K1 was originally developed to be a moving and oxygenated bed for BOD reduction and nitrification. Their spoke wheel design maximizes the surface area and minimizes overgrowth, which means that the holes between the spokes do not become clogged. Today they are also often used in slowly stirred anoxic filters for denitrification - even then the K1 is more efficient than your design because more anoxic sludge (bacteria) gets stuck inside and where denitrification takes place.

Today there are further different filter materials developed by the Norwegian company Kaldnes Miljøteknologi AS, (in parentheses - the K in Kx stands for Kaldnes). Of these, their latest K5 is perhaps the best in my experience - both for BOD reduction/nitrification and oxygen-free denitrification. It may be easier for you to print as it should be.

​

IMO - in order to function optimal you need to have a buoyancy rather near the original because if you use it for BOD reduction and nitrification it needs to move rather fast and in a way there the biofilm will go away if it get to thick.

Sincerely Lasse

 

[pooootiqe]

I´ll try to explain what I´m thinking is one of the most misunderstood and biggest myths regarding the surface area of a filter media.

Sellers often talk about the enormously large surface areas that their fantastic filter media have. Then they often emphasize all the micropores in the filter material - what they forget to mention is that as soon as a bacterial film builds up, they are clogged and of little interest, especially for oxygen-demanding processes.

K1 was originally developed to be a moving and oxygenated bed for BOD reduction and nitrification. Their spoke wheel design maximizes the surface area and minimizes overgrowth, which means that the holes between the spokes do not become clogged. Today they are also often used in slowly stirred anoxic filters for denitrification - even then the K1 is more efficient than your design because more anoxic sludge (bacteria) gets stuck inside and where denitrification takes place.

Today there are further different filter materials developed by the Norwegian company Kaldnes Miljøteknologi AS, (in parentheses - the K in Kx stands for Kaldnes). Of these, their latest K5 is perhaps the best in my experience - both for BOD reduction/nitrification and oxygen-free denitrification. It may be easier for you to print as it should be.

​

IMO - in order to function optimal you need to have a buoyancy rather near the original because if you use it for BOD reduction and nitrification it needs to move rather fast and in a way there the biofilm will go away if it get to thick.

Sincerely Lasse

Thank you lasse, for sharing the knowledge! I’m not sure if there’s a 3D printing filament that’s close to HDPE (or is it PP?) as being neutrally buoyant. Maybe a mixture of PLA and light-weight PLA would work but at that point might as well pay for Kaldness media!

Just curious, do you employ k5 in home aquaria or commercial facilities? Gonna need a large vessel to tumble k5s in a home aquarium!

 

[Lasse]

Just curious, do you employ k5 in home aquaria or commercial facilities? Gonna need a large vessel to tumble k5s in a home aquarium!

We used both K1 and K5 in an recirculated catfish farm back in the days. The filter canisters was 1 cubic meter (1000 L) and in the aerated ones - it was the perfect storm

Sincerely Lasse

 

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That K5 does look hard to print, even with a 0.2 nozzle.