Case Study of a Marine Filter Curtain System for Coliform Reduction at a Public Beach

Abstract

A floating marine filter curtain system (boom) was placed around a tidal beach on Long Island Sound to reduce coliform levels following storm events. Coliform data were collected inside and outside the boom over a three-year period. The results showed a 93% reduction in total coliforms and a 73% reduction in fecal coliforms, based on a comparison of the medians. Exceedences of the applicable water quality standards were reduced by 98% for total coliforms, and 81% for fecal coliforms. The method by which the boom actually reduces bacteria levels is thought to be a combination of filtration of solids, and the alteration of hydraulic conditions at the beach.