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BOD modeling in sewerGems

Hi to all,

1.in my project, I'm going to model quality of sewerage. I change active numerical solver from implicit to explicit and insert BOD local inflow for several manholes. after running the model, none of analyse on quality doesn't  accomplish in model and BOD out not be represented. why does it occur?

2.for modeling BOD when we have data as person (50 gr/day), what process we must be do for modeling BOD in sewerGems?

Thanks in advance.

A.Ghasemi

MS in Civil engineering- Environmental engineering

  • Hello Amir,

    Do you mean that you are not getting results for BOD after modeling that using Explicit solver?

    If that is the case then , could you please upload a copy of your model for our review?

    There are two options for sharing your model files on  Communities. If you would like the files to be visible to other members, compress the files into a zip file and upload them as an attachment using the ‘Advanced Reply editor’ before posting. If your data is confidential, you can follow the instructions in the link below to send it to us via Bentley Sharefile. Files uploaded to Sharefile can only be viewed by Bentley.

    communities.bentley.com/.../7079.be-communities-secure-file-upload

    If you send the model, please post here so we know it is available.

     

    About your second question,

    • First, you should get the BOD data converted into say mg/L , as required by SewerGEMS.
    • As you have data per person, if you know the population that contributes to each manhole or to each ward which you could later distribute into manholes of that area.

    So if you know population that contributes to each manhole you can multiply that population with BOD per person, and you could get BOD loading at manholes.

     

    Regards,

    Sushma. 

    Regards,

    Sushma Choure

    Bentley Technical Suppport

  • thanks for your following.
    we have bod per person, Density, area and we can make thiessen polygon for manholes. in this condition how can I model bod?
  • Hello Amir,

    Could you send us a copy of your model? That will be useful in looking into this for you. There are two options for sharing your model files on Communities. If you would like the files to be visible to other members, compress the files into a zip file and upload them as an attachment using the ‘Advanced Reply editor’ before posting. If your data is confidential, you can follow the instructions in the link below to send it to us via Bentley Sharefile. Files uploaded to Sharefile can only be viewed by Bentley.

    communities.bentley.com/.../7079.be-communities-secure-file-upload

    If you send the model, please post here so we know it is available.

    Regards,
    Scott
  • Hello Amir,

    Just to be sure - are you saying that you have a polygon shapefile in which each polygon has an area and a population density, or just the area and population density of the entire study area? For the former, one idea is to use Loadbuilder (Tools > Loadbuilder) > Population/land use data > Load Estimation by Population. Create and select a Thiessen polygon as the service area layer, select your shapefile as the "population layer", select the population density field, then in the table at the bottom, enter your "bod per person". If your model already had other loading on your manholes, you may need to set up a unique Pattern to assign to the loads, so you can later filter out the "real" loads.

    After the Loadbuilder run has completed, either go through each manhole, open the Sanitary Load Collection and copy/paste the base load value to the BOD field, or use Modelbuilder to Sync out/in with a spreadsheet. Meaning, set up a blank spreadsheet with column headers for manhole label, base load, load type and Pattern. Connect to the spreadsheet with Modelbuilder, using "Manhole, Sanitary Loads" as the Table Type, mapping the label as the key field, the base load coumn to the Base Flow field, the Load Type column to the "Load Definition (label)" field and the Pattern column to the "pattern (label)" field. At the end of the Modelbuilder run, choose "no" when asked if you want to build the model. Then, back in the Modelbuilder manager, select the connection you just configured and click the Sync Out button at the top. This will export the information to the spreadsheet. If you had "real" loads already in the model, open the spreadsheet and delete all the rows related to those real loads. If you used a unique pattern in Loadbuilder then this should be easy.

    Now, set up another Modelbuilder connection to the same spreadsheet, this time using the "Manhole" table type, mapping Label as the key field and mapping the Base Load column to the BOD field. This will import the "loads' from Loadbuilder into the BOD field. Lastly, you'll need to delete the loads from the model. You can do this in the Sanitary Load Control Center (tools menu). Filter by pattern if needed, select the rows, then delete.


    Regarding hydrogen sulfide modeling in general: you can read more about it in the help and in the below article:

    http://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/16217.what-s-new-in-sewergems-and-civilstorm-v8i-selectseries-4

    You can also watch the below Webinar:

    http://pages.info.bentley.com/video-details/?video=CO_VID_OCT22&videoDBID=2de5febb-f911-4358-92a8-b6358c7e6564

    Make sure you have the calculation option "Run Hydrogen Sulfide Analysis" set to "true".


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

  •  Shapefile conclude several field with different population density such as above picture.

    When it used load builder, only we can use unit as L/capita/day but unit of BOD it used gr/capita/day, how can gr/capita/day change to L/capita/day???

    other loading mean quantity of sewer?  how does quality parameter (flow) add to quantity parameter(BOD)??

    I can’t filter out the "real" loads and don’t know about it. How can I do it?

    What you said first paragraph doesn’t accomplish the modeling of BOD? Why do we do paragraph 2& 3?

    Can you say easier for my understanding to fulfill the model?

    Best Regards.