Hi,
From a wheelie bin cleaners point of view.......
Most operators and certainly the ones that like to stay within the laws have the following:
Waste Carriers Licence - Allows the carriage of waste
You will also gain authority from the local water company in your area to dispose of waste water into a designated waste water drain, which is a foul drain basically although it does depend on each individual water authority.
I believe that as long as you tell them where you are using they are usually okay, basically they can trace back any problems to you if you use it.
Not sure if the same applies to the initial question but my local authority office was fantastic its just finding the right person.
Good Luck