Green Sand Filter Plant Posted on April 12, 2016December 21, 2023 by Weston & Sampson (A) Construction of Green Sand Filter PlantWeston & 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.