Polymer Soil Treatment and Pathogen Transport
Hard
Can soil stop bacteria and viruses from reaching groundwater? Farmers sometimes spray wastewater on fields. Harmful microbes in that water could seep down to drinking water sources below.
This research tests how well Hawaiian agricultural soil filters out E. coli bacteria and MS-2 bacteriophage (a virus that infects bacteria). Packed soil columns receive a steady flow of contaminated water. Researchers measure what comes out the bottom.
The soil trapped virtually all bacteria and viruses. Even after 20 pore volumes of water passed through, no virus appeared in the output. The next step tests whether adding a polymer (PAM) changes these filtering abilities.
Hypothesis
The hypothesis is that polymer amendment of soils can reduce the transport of bacteria and viruses.
Method & Materials
You will conduct an initial screening of several polymers for their capacity to reduce erosion and enhance infiltration in several Hawaii soils. You will then conduct breakthrough experiments for bromide in packed sand columns under various degrees of water saturation. Finally, you will add a laboratory strain of Escherichia coli, sewage effluent, bacteriophage, and enterococcus bacteria to the leaching solution and monitor the transport of these organisms in polymer-amended agricultural soils.
You will need soils obtained from agricultural land on Oahu, a laboratory strain of Escherichia coli, sewage effluent, bacteriophage, and enterococcus bacteria, a leaching solution, and a high-molecular-weight polyacrylamide (PAM).
Results
The results of the experiments showed that the polymer worked well in preventing soil loss and enhancing infiltration. The bacteria and phage were significantly retained in the soil, with no breakthrough of either organism in the leachate.
Why do this project?
This science project is interesting and unique because it explores the effects of polymer soil treatment on subsurface virus and bacteria transport, which has not been investigated before.
Also Consider
Experiment variations to consider include testing different polymers and different soils, and testing the transport of other organisms such as fungi.
Full project details
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