Moses

I have simulated my model and got DO and C(S_O) in last tank (anoxic tank) in the series is less than 0. The anoxic tank is preceded by aerobic tanks in the series. I didn't change any influent parameters defaults values. I'm wondering the Kla value for two aerobic tanks are 0 and the last tank is 0 as well. The assumed y_S values for PI controller in two consecutive aerobic tanks are 2 and 1 mg/l and I assumed: K_P =-1000, T_I=0.1d, u0=0, umin=0 and umax=1000. Am I right for my assumption or where should i dwell on to improve my simulation results?
Thanks
Regards
Moses

Thanks for your help. Its now working better but a bit slow (1 day simulation takes 2 minutes). Whatever pop ups after simulation, i will come back to you.
Regards
Moses

I have encountered several problems in my simulation results. Please find the attached influent fractionation model and message log details. I tried to check the model if the anticipated sludge and oxygen concentration in the aeration tanks is correct  but I didn't succeed. Can you please advice me where I make a mistake.
Please note that I didn't have TSS influent flow data and there is hanging outgoing variable (X_TSS), I didn't know what to do with it.
Regards
Moses

Hello,

I would like to facilitate my model with a bypass control system by which a certain amount of the inflow (above a given value) should bypass the WWTP directly to the recipient while the rest continues through the treatment process. I wonder what kind of controller I shall use in order to set up the system?  How I shall modify the parameters? In other words how can I bypass the excess flow?

I am modelling an activated sludge WWTP with phosphorus removal (ASM2d).

Regards,
Moses

Dear Enrico
Thanks.
Regards
Moses

Hi
I'm wondering on how to copy the a block from plant layout to the ms-word. I tried to copy the screen from the layout and paste it to ms-word but the quality is not good. Can you please show me the alternative way of copying it to get a better quality structure?
Regards
Moses

Thanks Enrico
Much appreciated
Moses

Dear Enrico and Youri

I have connected timer and buffer tank (u1 to Q_pump) and then I connect buffer tank to sand filter (pumping Energy to backwash). Am I right for what I have done?
There is parameters at the timer (T1, T2, u11 and u12). how can I set this parameters?. I'm also wondering on how to include variables in that flow scheme to get on/off backwashing?
Regards
Moses

Dear Enrico and Youri
Thanks for your assistance. I have succeeded all except sand filter part.
There is group operational parameter 'backwash' which is unit less. which value should I put there? my backwash pump capacity is 0.33 m3/s.

I want to start operate backwash once the sand filter is clogged. what equation should I use based on sand filter parameters and how to incorporate it in the model?

Thanks
Moses

Dear MikebyDHI

I’m using ASM2d to model WWTP with the aim of evaluating the influence of stormwater contribution

Primary Clarifier

I dragged primary clarifier (PST_1) from separation block library, there is only Q_flow (m3/d) box to fill in the value. I was expecting to find boxes for area or volume to fill in values as well. Is there something wrong I have done in selecting primary clarifier?

Aeration basins

I want to control SRT with the aim of achieving sufficient nitrification. Oxygen level should be controlled by ammonium feedback and set point should vary between 1 to 2mg/l. I have read all your previous comment to Tanya but I have two aerated zones which I represented them in the model as two different tanks in series. How should I do it?

Sand Filter

The sand filter is aimed to remove P by using Fe compound. The sand filter has parameters such as area (A), height (m) and backwash. The backwash box has no unit while data I have for backwash flow rate has unit in m3/s. What should I do to make sure that the model recognize the backwash flow unit?

Also, I want to manipulate filtered flow and unfiltered flow. The variable I have are Q_backwash, Q_In, Q_out_filtered, Q_out_unfiltered,  X_backwash, X_In,  X_out_Filtered, X_out_unfiltered and H.  I have read your comment to Hjrey but the equation does not include particulate (X). I want to include on/off function i.e. when Q_out_filtered flow is zero the Q_backwash pump should start and when it stop the flow should start passing through the sand filter. How can I do it by using my variable parameters?

Thanks in Advance.
Moses