Abstract: A multi-stage filtering and treatment apparatus comprising a minimum of three stages, wherein the first stage comprises a container for separation of large scale aggregate or particulate matter from the washout slurry, the second stage comprises a container for separation of small scale aggregate or particular matter from the washout slurry, and the third stage comprises a container for separation of suspended particles and fines from the washout slurry and adjustment of the pH as needed. Each such stage comprises a pass-though container that temporarily retains the washout liquid before allowing passage of liquid from one stage container to the next and then out of the apparatus altogether.