Passive Screens versus Intake Structures

Question

What are the main pros and cons for both intake systems to lean forward any of them when designing abstraction of raw water? From the environmental point of view, suction velocity at the intake structure can be set up in such a way to minimize impingement.
My first thought is that passive screens would skip the requirement to install coarse and fine screens and also serve as intake structure, two in a row and therefore a more budget friendly solution.
Regarding cleaning and chlorination, also these are requirements for regular intake structures, therefore in my opinion always passive screens are a better option.
Regards

Steve Oxtoby · Answer

I have installed a few of both types in my time. With the passive screens they usually need to have a good depth at the intake (typically 2 times diameter). Often the solution is to divide into smaller units but this increases cost. With the passive screens the screenings stay in the water and so there is not a need to dispose of them. The water requirements of fish return and the pressures usually demanded means that this incurs a significant energy cost.

Kurt Rasmussen, P.Eng. · Answer

We have installed many many intakes over the years but the most effective and environmentally compliant method is to install a fish return system.  we also have installed air-blast systems around the actual screen to be able to clean it off regularly from algae growth or other blockages.  lastly the intake velocity is designed according the Canada Transportation and Canadian Fisheries standards to minimize the amount of fish to be "sucked" into the intake.  But if fish do find their way in, the fish return system is designed to return the fish back to their natural environment with minimal harm to the fish.

Michael Kohls · Answer

Dear Mr. Daniel Cañadas García,
to be able to send the requested Information, please send me your email address.
Regards
Michael Kohls (michael.kohls@taprogge.de)

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