First, did you report total nitrogen and phosphorous or is it phosphate and ammonia concentrations? In it is the first case you have a problem with enough nutrients for biomass formation.

I have reported Nitrogen as N and phosphorus as P in the problem.

According to your assumptions, what steps do you foresee?

Do you have 5 mg/L phosphate-P or total phosphate?

Total

There are currently no single method to remove the specified contaminants. However, considering their low volume of ammonia and high organics concentrations a bio-reactor with embedded film made of activated carbons will be necessary for the treatment.

The very high carbon to nutrients ratio will be a challenge for your bioreactor. It can help to use a biofilm system. A biogas proces for the first stage and to treat the sludge could help with the low nitrogen level.

You could try to run a pilot treatment with a biofilm reactor to see if you can get more of the COD degraded than the BOD analysis indicate.

Henrik Rasmus Andersen, he has to carry out a pilot test to determine the feasibility of the proposed choice of a biofilm reactor will be pretty expensive. I think that is what Ali Haseli is considering here the cost without sacrificing efficiency. We can recycle the sludge for further treatment or reconvert the same for energy generation. I will refer to this troubleshooting to @Bruno Peeter.

Ali Haseli, It is unusual to have such high C:N ratio. I like to know the main industries that contribute. Did you consider inhibitory substances? Salt?

@Prosper. I don't know anyone who can afford to build a large treatment plant without pilot test. Did you ever do that on your own projects?

Prof. Henrik, he is definitely needs to verify via experimentation.

Hi dear Henrik Rasmus Andersen and Prosper Ovuoraye

It is assumed that there is an industrial town in the warm region, and the effluent of this industrial town has these characteristics.

What type of anaerobic reactor and how many reactors do you consider for it?

Do you have a suitable process for sludge management or biogas production?

How and how many of these reactors do you place?

How about the aerobic system? What process and how many do you assume?

It is not possible to conduct pilot tests in the laboratory due to the change in the nature of the effluent, but in general, please consider the specifications given in the question.

This is a challenging question.

dear Henrik Rasmus Andersen and Prosper Ovuoraye

please consider the appropriate and necessary assumptions to solve this question.

Ali Haseli , In the absence of further information the design cannot be very detailed. It is very dangerous to build a plant based on so few parameters determined. I urge you to repeat the analysis of total nitrogen and phosphor.

My suggestion remains the same as I suggested in my first answer. The main driver for the design is that the C:N ration is extremely high at about 400. If you were to make a traditional active sludge plant with about 10 d SRT as one would do for a high BOD wastewater in warm weather you would have to spend a lot on dosing nitrogen to get the treatment to work.

I would start with a anaerobic stage which removes a lot of carbon (as CO2 and CH4) without loss of nitrogen and very little biomass formation. I would then make a IFAS system to degrade as much COD as possible.

You should have a digestor for the sludge, mainly in order to mineralize as much sludge as possible in order to return the N and P to the water treatment process, but also because it should be economic to make methane given the high BOD concentration, temperature and volume of water that are to be treated.

Ok, thanks dr.@Henrik Rasmus Andersen

But I think it is better to start with anaerobic reactor.

An important question is, what type of anaerobic reactor do you choose to treat this wastewater? (AnFBR, UASB, EGSB, ABR, AnRBC, AF, Down flow, Up flow and..., Which do you prefer and why?)

And in what order do you place the anaerobic reactors?

How many numbers do you put?

How is the flowchart?

Ali Haseli

If we assume that the BOD figure you provided is correct, then the BOD/COD ratio seems to indicate that about 28% of the COD would be recalcitrant to (aerobic) biodegradation resulting in about 72% biodegradable COD (bCOD). This relatively high recalcitrant fraction may be due to mineral oil and other soluble and solid organic compounds from industries. Although you didn't mention other characteristics of the water. Could you clarify which kind of characteristic contaminants, that would contribute most to organic wastewater load? Please also confirm the wastewater temperature range. If I assume that at least there are coarse solids (by screens), grit/sand (by trap), free fat, oil and grease (FOG), and settleable/floatable solids (by settler/DAF) could be removed and that the wastewater temperature would be at least 25°C, then a high-rate anaerobic digestion (HRAD) would be recommended as the main bio-treatment. In this HRAD stage will convert up to 99% of the biodegradable fraction of the COD (bCOD) after minimal pretreatment (as indicated) to biomethane using a process with the latest up-flow reactor(s). It would probably need 2 (two) reactors operating in parallel (pending further data and operating temperature). If necessary (depending on final effluent requirements), a polishing stage using (advanced) aerobic biotreatment such as (AS) could be added. The ratio of nutrients (nitrogen and phosphorus) to bCOD would definitely be far too low for classic main aerobic bio-treatment but could be sufficient for an HRAD producing about 10 times less waste bio-sludge. The organic solids (without free oil) from the pretreatment could be digested by the waste biosludge from the HRAD stage and converted to biomethane as well as using classic or advanced anaerobic digestion (AD).

If you could you clarify another kind of characteristic contaminant that would contribute most to organic wastewater load and also confirm the wastewater temperature range? This will help to provide a better understanding of you challenge and probably the right possible recommendation can be made.

There are plenty of online tools available concenrned to design of wastewater treatment facilities. My suggestion is, first you decide what mode of treatment you can afford/follow by observing local pollution prevention norms and, obviously, the level of treatment required means would reuse of treated water or not? Another, but most important thing is budget available for the treatment, operation and maintenance. However, if you going to design a reactor for lab-scale studies, forget about aforementioned and go for hit and trial by follow any highly cited free-available (open access) literature/book. My, recommendation according to your provided influent data is MBBR. A suggestion for reliable open access literature/book is IWA journals.