Three Problems, One Solution Arsenic, Iron, and Manganese Present Treatment Challenges

Abstract

This article discusses a problem at the Hilltown Township (Pennsylvania) Water and Sewer Authority with naturally occurring arsenic in its groundwater. The article describes how the township tested an iron‐based adsorption treatment technology as part of the U.S. Environmental Protection Agency's Environmental Technology Verification Program. The program verifies the performance of innovative technologies that can improve protection of human health and the environment. The article discusses the testing process, along with test results, and the installation of a 300 gpm arsenic removal system at the utility as the solution for the arsenic problem. The system uses three‐stage adsorber vessel treatment technology in which the pretreatment system removes iron and manganese before water enters an adsorber containing ferric‐oxide media for arsenic removal. The pretreatment system allowed the township to address its needs for reducing iron, manganese, and arsenic at the same time. As media capture iron and manganese, system pressure begins to climb, and backwashing is performed based on pressure differential. The system is backwashed every 3‐4 weeks. More frequent backwashing is required when the system operates 24 hr/day in the summer.