Long-term behavior of syntrophic algal-bacterial biomass in a pilot-scale raceway pond treating domestic wastewater

The growing need for environmentally friendly wastewater treatment technology has prompted researchers to look into natural alternatives. Among these, algal-bacterial systems have received attention for their capacity to combine biological treatment and biomass production. This study focuses on the use of algal-bacterial flocculent biomass for wastewater treatment in a 400 L pilot-scale raceway pond, with a focus on its potential as a sustainable option for lowering environmental impacts. The synergistic interactions between algae and bacteria in the consortia improve nutrient removal from wastewater, while also providing biomass for future use. The aim was to develop a high-concentration flocculent algal-bacteria biomass. The raceway system was placed in a greenhouse with water temperature 32±8^oC for about 230 days. The pilot-scale experiment evaluates treatment efficiency of domestic wastewater in a batch mode procedure.  The removal of chemical oxygen demand, ammonia, nitrate, and total phosphorus was over 95%.  The biomass concentration stabilized at about 4 g/L after 70 days of operation. The implementation of algal-bacteria flocculent processes for the treatment of domestic or source-separated domestic wastewater shows great promise as a low-cost, sustainable, and efficient solution.