oconn5,
I agree with the previous posting - that you need to precise your question more. If you could post some idea of what you are attempting to do and/or learn - it will help in directing you to the right kind of or books.
A great resource is Metcalf&Eddy. It provides a pretty comprehensive overview of sludges and related treatment processes. There's also a book by Viessman and Hammer (Water Supply and Pollution Control) - in this, you'll find some basic overview of WTP and WWTP treatment schemes. This may help you to understand more in detail where sludges come from and in what quantities.
Hope that helps.