What is scullage water (bottom line)?
Think he may mean Sullage Water.
Sullage Water is waste water from household sinks, showers, and baths, but not waste liquid or excreta from toilets.
Sullage Water https://www.google.co.uk/webhp?sourceid=chrome-instant&rlz=1C1DSGL_enGB426GB426&ion=1&espv=2&ie=UTF-8#q=What+is+sullage+water
by cyngast moderator
Scullage seems to be an older term for sullage. I found a reference to it in a book from 1849 that referred to scullage water as being from the scullery, where pots, pans, and dishes were washed up. https://books.google.com/books?id=C1ihlhCIapIC&pg=PA24&lpg=PA24&dq=scullage+water&source=bl&ots=x8mpltuMtH&sig=nYS8quRFQu09SeUucIyuyhE4W2s&hl=en&sa=X&ved=0ahUKEwjB9Omdo5jTAhVIz2MKHRJbAYAQ6AEIIzAD#v=onepage&q=scullage water&f=false
That makes sense with its use on this diary page with the reference to grease traps.