Investigating the effect of BIODROF systems based on algae-bacterial biofilm for removing COD and TOC from domestic wastewater

Along with the development of urbanization over the past century, water consumption in urban areas rose sharply. Produce large amounts of waste in cities around the world on the one hand, and restricted access to freshwater resources, on the other, increase the requirement to regard for recycling of domestic wastewater. Especially in the Middle East region, that has an arid and semiarid climate. A major problem in urban wastewater purification treatment systems using conventional is chemical oxygen demand and high organic carbon content in the effluent, which creates environmental restrictions for the reuse of treated wastewater. So today, the use of algae in the biological treatment of wastewater is considered as a global strategy. In the present study, for the first time, we evaluated the performance of a BIODROF system that in this system the algal biofilm is added to its bacterial part for decrease COD and TOC content in domestic wastewater. In this regard, a biological treatment system was designed, that consists of four sectors including oil separator, Sediment Retention part, suspended solids trap and BIODROF system as part of the fourth. After inoculation system with algae-bacterial biofilm, municipal wastewater for biological treatment process was added to the system. The results of the testing period of 9 days showed a higher removal efficiency of COD and TOC compared to similar studies at the same time. The uptake efficiency for COD and TOC was at least up to 95% and 92% of their initial concentration respectively. Finally, we can say that the symbiosis of algae and bacteria with favorable conditions for gas exchange in BIODROF system, could be a good reason for the better performance of our system compared to similar systems.