Document Type

Thesis - Open Access

Award Date

2019

Degree Name

Master of Science (MS)

Department / School

Civil and Environmental Engineering

First Advisor

Guanghui Hua

Keywords

Adsorption, E.coli, Intermittent flow, NOM, Steel chips filter, Stormwater

Abstract

Media filtration has received increasing attention as an effective technology that can facilitate the removal of particles and dissolved pollutions in the stormwater. However, most traditional media filtration systems are generally ineffective in removing bacteria, causing pollution of groundwater and receiving surface water. In this study, recycled steel chips were evaluated as low-cost filter materials for bacterial removal from stormwater. Laboratory column experiments were conducted to evaluate the impact of steel chips particle size, flow rate, initial E.coli concentration, pH, natural organic matter (NOM), steady and intermittent flow on E.coli removal. The results showed that E.coli removal decreased from 99.4% to 58.1% with increasing steel chip size from 0.5-1.0 mm to 4.0-8.0 mm. The E.coli removal efficiency of 1.0-2.0 mm steel chips varied between 86.5% to 99.2% and was not greatly affected by variations of infiltration rate, influent bacteria concentration, and pH. The competitive adsorption of co-loading NOM can inhibit E.coli adsorption by up to 80.5%. Intermittent flow can lower E.coli adsorption to 54.3% at the beginning of the flow event and gradually increased to 83.2% with the increase of time. The result also showed that less than 0.4% adsorbed E.coli (total adsorbed E.coli=6.7×109 MPN) were desorbed in different conditions (flow rate, NOM). Steel chips also showed high E. coli removal capacity when treating real stormwater. Overall, the results suggest that steel chips are an efficient E.coli adsorption material that can potentially be used for stormwater treatment under a wide range of field conditions.

Library of Congress Subject Headings

0Runoff -- Purification -- Filtration.
Water -- Purification -- Microbial removal.
Escherichia coli.
Water quality management.
Steel -- Recycling.

Format

application/pdf

Number of Pages

69

Publisher

South Dakota State University

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Rights Statement

In Copyright