Evaluation of the Efficiency of a Combination Media Filter in the Removal of Nonpoint Source Pollution

Abstract

Stormwater runoff is a major source of nonpoint source pollution, contributing 22-40% of the total pollution load in 4 major rivers, which has a significant impact on aquatic ecosystems. The criteria for installation of nonpoint pollution abatement facilities in Korea focuses on the removal of suspended solids. Since the load of dissolved phosphorus and heavy metals in stormwater runoff is increasing, it is necessary to develop a method to reduce dissolved materials as well. In this study, the efficiency of using clay granule, zeolite, blast furnace, and basic oxygen furnace slag (from laband pilot-scale experiments) to remove SS, phosphorus, and heavy metals from surface waters was evaluated. Among the four types of filter media, the removal performance of clay granule for SS and basic oxygen furnace slag for phosphorus and heavy metals was excellent. As a result, the clay granule and basic oxygen furnace slag were selected as the filter media. In the pilot column test, 89.5% of SS, 77.6% of phosphorus, 87.3% of Zn, and 67.5% of Cu was removed, indicating stable removal efficiency, with a head loss of 3.8 cm. It satisfied the nonpoint pollution abatement facility installation criteria of functioning at a linear velocity 20 m/h. The clay granule and basic oxygen slag filter would be a useful addition to a nonpoint pollution abatement facility.