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Georgia Journal of Science

Article Title

PRELIMINARY ASSESSMENT OF COMPOST QUALITY AND SAFETY AT GEORGIA COLLEGE**

Abstract

The Georgia College (GC) Green Fee Committee and Sustainability Council initiated a food recovery program with an industrial-grade composter in 2017 to decrease landfilled food waste on campus. Both pre- and post-consumer food waste from GC Dining Services is recovered, combined with untreated wood chips as a carbon source, processed through the in-vessel industrial composter, and then set out in windrows to mature. Our goal is to assess the quality and safety of the final compost product, to expand its applications both on- and off-campus. Understanding the chemical nature of the compost is vital to determining its overall nutrient level, which impacts how confidently we could apply the compost as a soil amendment for landscaping and gardening. During Fall 2020, we began sampling compost in the windrows. From August to October 2020, pH and nitrate levels were tracked weekly and assessed in situ via ion-specific electrodes. Both pH and nitrate concentrations provide reliable indicators of the overall nutrient availability and maturity of the compost. We expected the pH level to stabilize around 6.0-7.0, which is slightly acidic and ideal to ensure that nutrients are in their plant-available state. The nitrate levels were expected to increase as heterotrophic microorganisms respire carbon and nitrifying bacteria act on the available ammonium. To further investigate compost safety, we analyzed previously collected X-ray fluorescence data on total metal concentration, including heavy metals. We expect minimal heavy metal concentration since the compost inputs were obtained from a controlled source. All chemical data were compared using quality standards from the US Composting Council. We hope that continued research on our campus’s compost will help ensure the overall sustainability of the project over time.

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