A、Whether the water is clean enough. B、If it can be used in all types of weather. C、If it will lead to less visitors. D、Whether

It is barely half a century since parts of the Thames were declared "biologically dead" because the river was so dirty. But with the water now cleaner than at any time in living memory, entrepreneurs want to build a ￡ 10 million open-air swimming pool in the middle of the Thames in Central London.
     (19) Purification specialists from Germany—which has the highest water cleanliness standard in Europe— have designed a system which the scheme’s backers say will ensure that bathing is safe for visitors of all ages. (20) Health concerns have been raised about the project because of sewage overflows during heavy rain and the unpleasant experience of comedian David Walliams during a 140-mile charity swim in 2011. But experts from German firm Polyplan, which has built natural swimming pools all over Europe, have come up with a solution. Tim Evans, director of British firm Gartenart, which is working on the project, said the water will be "as clean as anything you would find in a mountain lake".
     (21) The open air swimming pool will have changing rooms, a 130ft slope leading from the shore to the water, a plunge pool and a children’s paddling area, while a 4ft-high glass partition will protect swimmers from waves caused by river traffic. (22) Chris Romer-Lee, of Studio Octopi—the London architects behind the scheme—said he hoped an initial ￡ 300,000 to cover consultancy costs and other fees, which would be raised by crowd-funding, where members of the public can contribute to community schemes. If planning permission is granted, the pool could open late next year.
19. What can be learned about Germany?
20. What do people concern about the project?
21. What is the function of the glass partition?
22. Where is the money of the project likely to come from?