Green Sand Filter Plant Posted on April 12, 2016December 21, 2023 by Weston & Sampson (A) Construction of Green Sand Filter Plant Weston & Sampson performed construction on the Avon Water Treatment Plant, including the construction of a new green sand filter plant to remove iron and manganese. BACK Looking for assistance with your Construction project? How can we help? Posted in Construction, Treatment Facilities and tagged Avon, MA.