I have a project there we use this combination in a pilot system for hospital wastewater, MERMISS2.

Veolia has several full scale systems on municipal wastewater that use this combination both for MBBR and combined systems with suspended and attached biomass (IFAS/HYBAS) there the sludge concentration is likely op to 1000 mg/L.

https://www.researchgate.net/project/MERMISS2?_esc=profileProjectCards&_sg=AtdsscSbXOx2rFxZwfUYqLwepFM9QWFQH6HImUgOP1yGZg92cAXINs7QI4IzVJ3B03RQywrNVwh854NsDGo1kQ

http://www.etec-sales.com/pdf/Kruger%20-%20AnoxKaldnes-%20MBBR%EF%80%A2IFAS.pdf

http://technomaps.veoliawatertechnologies.com/mbbr/en/?bu=doc

Dear Henrik, Thank you very much for the information. MBBR technology is generally used for small to medium size wastewater treatment plants (around 20,000 m3/day). I can understand Disc filter is a promising replacement of clarifiers. I am working on a project of WWTP which capacity is more than 100,000 m3/day.  For large plants maintenance of several disc filters can be a big issue (back washing, removing solids etc.). Do you have any suggestion for using Disc Filter for large plants of MBBR and or attached growth type (having effluent SS around 1000 mg/l)? If you know any reference please let me know.  best regards, Lalit

Dear Lalit if you have 1000 mg/l of TSS you will need quite and open Discfilter say 80 micro meter otherwise your hydraulic capacity will be very low. This will though influence your effluent quality. In generally it will be optimistic to hope for more than 90% TSS removal meaning that you effluent will have more than 100 mg TSS/ wich is most likly not accepable. The Veolia project I know of my self you are closer to 500 mg TSS/l than to 1000 mg/l. 1000 mg/l seems though also a very high value to me more realsitic valuue in Municipal use 200 - 500 mg/l wich allow tighter panel and hence also better effluent quality.

I had assumed SS concentration of around 1000 mg/l in the overflow (before the clarifier) from the MBBR. I think around 500 mg/l SS in the overflow from the attached growth process in general would be a better estimate.

As said before, I am working on a large WWTP (capacity more than 100,000 m3/day) based on Fixed Film Attached Growth process. I assume MLSS in suspension in the aeration tank would be maintained at 500 mg/l and in the overflow(effluent) I expect the same amount i.e. 500 mg/l SS. The effluent standard will not allow SS of more than 50 mg/l in the effluent before discharging it in the environment.

In view of above situationI have following queries:

From your point of view, will it be useful to provide coagulation using polymer and settling device before the effluent entered into the disc filter? It will allow reduced load on this disc filter. But, the process will require more space and there is cost to it (capex and O&M). 

My second question is:

Can Disc Filter be a sustainable and long term option for a large WWTP (kind of process on which I am working)?

If you choose a Discfilter with 40 micron opening and dose polymer before the filter it will be realistic to achieve 50 mg TSS/l with 500 mg/l comming in.

I can suggest to conact Hydrotech (Veolia) for a qoute on this.

Having now made promotion for my competitors, I will have also to recomend considering the FLUOPUR from WABAG as MBBR system.

 Thank you very much for sharing your useful experience on Disc Filter. In the last I would be very much thankful to you for your overall evaluation & suggestion for applying disc filter for a large scale fixed film kind process (more than 100,000 m3/day) where SS carryover in the effluent is expected to be around/below 500 mg/l (300-500 mg/l).

In case of large scale WWTP, a number of disc filters would be required. Each stream/line of the treatment system would have several Disc Filters. Is it okay to operate and maintain such large number of Disc filters? Is there any need of providing the standby disc filters? If yes, how many standby disc filters (out of under operation disc filters) should be provided in each treatment stream?

Dosing of polymer would be necessary before filter: It would add to extra space (for coagulation & settling) and also it will add to cost of chemicals.

Considering the above issues, what is your suggestion in favor of the Disc Filters to high rate clarifier (like that of Veolia’s). I am sure I will consider your MBBR when my project is get matured. 

For this size of plant and that high TSS to be honest I would consider Lamella settlers this will most likely give a more compact solution since for the Disc filter the limiting factor will be the TSS load and not the Hydraulics. Lamella clarifier will be more compact, but you mus tbe careful with the sludge treatment and not rely on taking out more than 1.5 - 2 % TSS. You will though need to dose both Coagulant and Polymer, but with lower dosing.

Thank you for your valuable point of view. We should consider the Disc Filter still a Technology on Development to replace the clarifier of MBBR or any kind of attached growth process where SS carryover in the effluent is likely to be in the range 300-500 mg/l. As for tertiary treatment (where SS carryover is less than 50 mg/l), Disc filter is very promising.

Agree

Thank you very much for your valuable time and exchanging your experience. 

I have initiated discussions on my idea for doing a study and research. Please give your valuable suggestions to help me in the research.

Subject: Hanging-Curtain kind of long life membrane with both the surface with different characteristics

I have following situation. 

1) It is a membrane hanging curtain type system. 

2)    Air-side surface of the membrane should allow growth of fungal kind biomass and water-side surface of the membrane should be hydrophobic.

3)    Membrane should allow transfer of nutrients (N, P) and carbon source from water-side surface to air-side surface for limited growth of fungus.

3)    Membrane should also allow diffusion of oxygen (generated from the fungal activity) to water side of the surface to keep the inner side of water layer in aerobic condition.

4)    Framed all side Membrane would be kept in hanging position where on one side nutrient rich water will be flowing/spreading across its width slowly from top to bottom under gravity and other side of membrane would be exposed to air. 

I want to know the material of membrane/type of membrane meeting approximately above conditions. The membrane should have life of about 10 years (at least more than 5 years). I am okay for cheap membrane or expensive kind of membrane for my study and research. 

Hi, As my colleague Kim has answered at high SS i.e. above 300 mg/l you would need to use two steps with disc filter. First step course filtermedia (say 400 micron) and polish in a second step with say 10 - 40 micron. I would if SS is closer to 1000 mg/l go for flotation followed by disc filter 10 micron, which also would be a compact installation. You could also consider Actiflo as first step with Disc filter for final polishing.

Ran across this answer and found the discussion very useful. I am looking at the other end of the spectrum. In small plants say 100m3/Day. Can 130micron Disc filters replace primary clarifiers or lamella settlers for raw sewage applications? I am evaluating use of such filtered sewage for irrigation particularly for growing bamboo etc Christina Sund Kim Helleshoej Soerensen

130 um will probably be to fine and will most probably give very low Hydraulic Capacity. 200 - 300 um will more likely be in the correct range.