College

College of Engineering and Polymer Science

Date of Last Revision

2022-04-28 08:26:36

Major

Civil Engineering

Honors Course

4300:497

Number of Credits

3

Degree Name

Bachelor of Science

Date of Expected Graduation

Spring 2022

Abstract

The primary objective of this research was to determine whether concrete slag acquired from building debris in a disaster can be utilized to remove pathogens biochemically through changes in pH or physically through filtration. Direct Plate Enumeration testing was completed for different water samples to compare the general activity of bacterial growth as an indication of pathogenic potential. Throughout each experiment, the pH of different water samples was monitored and consistently indicated that water samples in contact with concrete pieces (concrete water samples) would exhibit a higher pH than samples with no exposure to concrete (control water samples). Compared to water samples with no concrete exposure, the average pH of water filtered through concrete pieces was found to be 22% higher and the average pH of standing water exposed to concrete for 1 day was found to be 25-27% higher. However, this elevated pH did not always translate into a clear decrease in the growth of bacteria colonies. For standing water experiments, the concentrations of colony forming units (CFU) from water samples did not exhibit an explicit trend separating those samples that were in contact with concrete compared to those that were not. Colony growth was higher in control samples when the concrete in water was given sufficient time to raise the water pH, but the reverse was true when the concrete water was plated before substantially affecting the pH. Specifically, the average colony concentration after 2 days of incubation was 84% larger for samples plated immediately after concrete exposure compared to water that was not exposed to concrete, but the concentration was 82% smaller for samples plated 1 day after concrete exposure. When water was filtered through a bucket of concrete aggregate, a more marked difference in bacterial activity was apparent, as the concentrations of samples filtered through concrete aggregate were consistently lower than control samples. Given a 2-day incubation time, the colony concentrations of the control samples were 60% and 58% higher than samples filtered through concrete pieces 10 and 20 times, respectively. Thus, although this research indicated that bacterial growth can be temporarily inhibited through concrete media filtration, further experimentation should be completed to confirm and expand upon the limits of this disaster treatment application.

Research Sponsor

Dr. Teresa Cutright

First Reader

Dr. Nariman Mahabadi

Second Reader

Dr. Christopher Miller

Honors Faculty Advisor

Dr. Ping Yi

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