Algae-Based Biofilm Productivity and Treatment of Dairy Wastewater: Effects of Temperature and Organic Carbon Concentration

Production of dairy and associated products is a source of millions of gallons of wastewater every year. Water used in cleaning feeding stalls as well as the liquid component of the animal waste are two of the major volumetric components of this wastewater. This water is nutrient rich, often limiting the viability as a land applied fertilizer. However, these same nutrients could be used as an inexpensive feedstock for the cultivation of algae, which can then be used to produce downstream products including animal feed and aquaculture. As part of this study, algal biomass was cultivated on dairy wastewater from the Utah State University Caine Dairy. A Rotating Algal Biofilm Reactor (RABR) system was used to grow the biomass. The RABR is a biofilm technology designed and developed at Utah State University and has been applied to the treatment of municipal wastewater. In this study, the RABR was adapted for use in a dairy wastewater stream. The RABR was operated at temperatures ranging from 7-27 °C, and organic carbon levels in the wastewater ranged from 300-1200 mg/L of Total Organic Carbon (TOC). Areal algal biofilm growth rates were calculated, and statistical analysis showed that both increasing temperature and levels of organic carbon contributed to an increase in biomass growth and an increase in nutrient removal. Equations were then developed using a linearization method and corresponding constants and equations were generated that can be used to evaluate algal biomass productivity and nutrient removal rates in future experiments and designs for dairy wastewater

Algae-based biofilm productivity utilizing dairy wastewater: effects of temperature and organic carbon concentration

Photograph Illus. 6.4