Effects of Copper Nanoparticles on a Microbial Community in a Model Septic System
Authors:Timothy Chow, Alicia Taylor
Mentor:Sharon Walker, Associate Professor of Chemical and Environmental Enginering, University of California, Riverside
Nanoparticles are found in many consumer goods such as foods and cosmetics and are a raising concern due to the uncertain effects on the environment and human health. With 20% of American households disposing waste through an onsite septic system, it is likely that nanoparticles may enter this treatment process, with the potential to alter the function of the septic system and the microbial community inside of the system. This can lead to a disruption of function within the septic system, causing groundwater contamination and improper biodegradation of waste in the septic system. Nanoparticles may have greater reactivity with microbial communities due to their small surface area to volume ratio and copper has long been known to be toxic to microorganisms. This study will determine the effects of micro Cu, nano Cu, and Cu(OH)2 nanoparticles on a model septic tank and its microbial community. Evaluations of the microbial community and water quality parameters will be analyzed to detect changes between the microbial community structure, septic tank function, and nanoparticle characteristics. Over the course of the experiments for micro Cu, the conductivity increased within the system while experiencing decreases in electrophoretic mobility (EPM) and total cell concentration. Similar to micro Cu, nano Cu also experiences a decrease in EPM. Cu(OH)2 data is expected to have similar effects on the microbial community when compared to the micro and nano Cu particles. The system experienced minor increases in alkalinity when dosed with micro Cu, and Cu(OH)2. With changes seen in the water quality and microbial characteristic, maintaining the function of the septic system and the health of the microbial communities within the septic system are critical not only for proper sanitation, but also necessary for environmental health.