Design calculation of Cascade Aerator || Water treatment plant calculation
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- เผยแพร่เมื่อ 25 ม.ค. 2025
- This Video is about the design and calculation of cascade aerator which is generally used in water and wastewater treatment plants for removal of odor gases, iron, excess carbon dioxide (CO2), H2S and CH4 by mixing the air into water.
Cascade aerators consist of a series of steps that allow water to fall in thin layers from one level to another where aeration is accomplished in the splash zones and The exposure time of air to water is increased by increasing the number of steps. And area-volume ratio could be improved by adding baffles to produce turbulence but the major operating problems include corrosion and slime and algae buildup.
Circular and RECTANGULAR ARE two main configurations, which are generally used.
Aeration equipment is used to intensively mix air and water so as to facilitate the transfer of gases into or out of the water.
So, Cascade aerator is used
For intensively mixing of air in water: It is necessary for surface water where the natural oxygen content was depleted due to the presence of large amounts of organic substances.
For removal of dissolved iron and manganese because Iron and manganese are oxidized and form nearly insoluble hydroxide sludges. They can be removed in a settling tank or by means of a coarse filter.
And cascade aerator is also used Removal of excess carbon dioxide (CO2) to prevent corrosion of metal and concrete surfaces.
And Reduction of H2S, CH4, and VOC and other volatile compounds that produce objectionable taste and-odor and ALSO USED FOR temperature reduction.
So, for detailed calculation please watch the above video.
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Dear All - One correction required in slide indicating Design criteria of cascade aerator. The area (indicated as 'surface overflow rate') to be provided should read as 0.015 to 0.045 m2/m3/HR and not per second. Author to also note please. For reference, you can see CPHEEO manual for Water Treatment or any standard Water Treatment handbook.
Yes, it is a typing mistake, but I can't change it now due to technical issues of youtube policy. Apology for unit writing mistake, sometimes because of the mistakes I have come to know that who have watched complete video, thanks for watching my videos and pointing our very important point.
Also in your table water velocity for the center pipe is 0.6 - 1.0 m2/s. But you used 1.2 m2/s. Diameter of the Cascade aerator is 1.6m is not correct and should be 1.5m is correct (Solve the equation correctly). You are totally wrong in this aerator steps calculation. In the 1st table you mentioned step width should be between 300-600mm and after your calculation step 50mm 2" which is two narrow. 1st you decide/select the width of the step a value between 300-600. Then subtract the radios of the shaft from the radios from the aerator and divide the step width then you get the number of steps. then you decide the height of the step within a value between 150-300mm. You may get a maximum of 2 to 3 steps for this kind of flow. Your decision to have 200mm around the shaft is too much and according to your calculation please draw scale drawing to see how it looks. Your collection canal is also wrong and over design, please kindly note that water volume divides half, half into both sides and you need to consider only half of the flow rate for sizing the canal. It appears to me you are too young to publish this kind of video without consulting one who is very conversant with the subject, You may mislead the others.
Thank for your information. can you forward rectangular cascade aerator calculations.
Thank you for the video. It is very informative. Can you tell how I can design my aerator for specific dissolved oxygen concentration? For example, I need 0.14 mg/l oxygen to oxidize 1 mg/l iron. For 10 mg/l iron, I need 1.4 mg/l DO. How can I ensure I am achieving this DO concentration wit this method?
Nice one..
First of all, thanks a lot for the information. Second, the area of the pipe, indicated as "Area of discharge pipe", should be calculated by dividing the Q over V to be 0.0116 and not 0.01667... All the best,
Thanks for the informative video. Do you know how much these processs typically cost?
how to calculate the velocity of the channel (0.6 m/s) is it the standard? also for discharge velocity of the water (1.2 m/s)?
Yes, the given value is standard for gravity flow. You can find the same in detail in METCALF EDDY (Author) book of water and wastewater treatment.
@@MeenuJainLalitpur please could you mention the velocity of water in pipes under gravity flow with slope 2%...
Please substantiate an acceptable reference
@@MeenuJainLalitpur Dear madam, could you mind, if you share me this book pleas?
Sorry I have hard copy.
How to compute BOD across a small 4 step aerator for residential waste water
Cascade aerator is used in water treatment plant instead of wastewater treatment plant, and this unit is basically used for residual iron removal, maintaining Dissolved oxygen level and odor removal of incoming water (River or any local water body). This unit is not used for BOD removal.
I would recommend to read water supply manual CPHEEO 1999.
Please suggest book for absolute design
Metcalf Eddy, wastewater engineering
nice vedio.i want to download it.
How to calculate volume of launder
thank you so much
Please share the knowledge.
Also in your table water velocity for the center pipe is 0.6 - 1.0 m2/s. But you used 1.2 m2/s. Diameter of the Cascade aerator is 1.6m is not correct and should be 1.5m is correct (Solve the equation correctly). You are totally wrong in this aerator steps calculation. In the 1st table you mentioned step width should be between 300-600mm and after your calculation step 50mm 2" which is two narrow. 1st you decide/select the width of the step a value between 300-600. Then subtract the radios of the shaft from the radios from the aerator and divide the step width then you get the number of steps. then you decide the height of the step within a value between 150-300mm. You may get a maximum of 2 to 3 steps for this kind of flow. Your decision to have 200mm around the shaft is too much and according to your calculation please draw scale drawing to see how it looks. Your collection canal is also wrong and over design, please kindly note that water volume divides half, half into both sides and you need to consider only half of the flow rate for sizing the canal. It appears to me you are too young to publish this kind of video without consulting one who is very conversant with the subject, You may mislead the others.
stop hating u b4stard
ur wrong nerd
stop hating please, this video is actually VERY informative for the majority of the viewers.
My purpose was not to focus on numbers, I was mainly focusing on telling the methods of calculations. I am really glad that you watched video completely and tried the calculations by yourself. My purpose of posting the video is done.
@@MeenuJainLalitpurI urge you to reconsider and correct the video you’ve posted. In engineering, numbers are just as crucial as the methodology, and it's essential to present accurate information. I have over 35 years of experience in this field, and I respectfully disagree with your approach.
Please correct the inaccuracies and repost the video to avoid misleading others.