The Relationship Between Algae and Microbial Communities Found in Treated Wastewater

The concentration of nutrients in treated wastewater is not adequately regulated by current wastewater treatments, causing increased levels of nitrogen and phosphorus in water systems. Excessive nutrients stimulate plant overgrowth in aquatic systems, resulting in plant decomposition and lower oxygen levels. The adoption of an experimental tertiary wastewater treatment employing algal phytoremediation has been suggested as one possibility to mitigate the effects of nutrient pollution in water. In collaboration with the Metropolitan Water Reclamation District of Greater Chicago and Gross-Wen Technologies, we are growing algae on vertical belt systems that rotate through wastewater tanks. The three systems used at the facility include a 10-foot vertical conveyor belt, a raceway pond equipt with a paddle wheel, and a series of four 6-foot vertical converter belts. To understand the relationship between algae and the microbial communities found in treated wastewater, samples of water were analyzed using Biolog EcoPlates. The utilized organic substrates in EcoPlates will assist in understanding the functions of the microbial community. Color development on EcoPlates was analyzed with a spectrophotometer to determine use of thirty-one organic substrates by microbes. A Principal Component Analysis indicated that there were differences in utilization of carbon substrates by the microbial community based on the algal system used. There was higher overall functional diversity and utilization of organic substrates such as Hydroxybutyric Acid, D-Galactonic Acid, and Phenylethylamine, in the 10-foot system when compared to the raceway pond and series 4 system. Determining the use of carbon substrates by microbes can help us further understand the symbiotic relationships between algae and the microbial community in wastewater treatment systems