The oxygenic photogranule for wastewater treatment process

Abstract

Wastewater treatment is an energy-intensive process. During secondary wastewater treatment, unwanted characteristics like Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) etc. are reduced to permissible levels with the help of bacteria as this is a microbe driven process. A novel method of cultivating Oxygenic Photo Granules (OPGs) which are natural aggregates predominantly consisting of cyanobacteria from the activated sludge and using it to treat the wastewater in the secondary treatment is under development. After the primary treatment, OPGs help to substitute the high energy-consuming aeration equipment which deems the secondary process more sustainable. Cultivation of OPGs is influenced by many factors including the intensity of light used during cultivation, the concentration of sludge etc. Manipulating these factors, we can cultivate OPGs in the most efficient way possible. The objective of this work is the optimization of the time constraints for developing OPG samples, then analyze the energy saving of this process at a pilot scale. OPGs substitute the aeration equipment in the secondary treatment process, and they are mix evenly with the wastewater to be treated in a sequential batch reactor. Upon continuous stirring followed by settling and decanting, the wastewater is treated and analyzed. Utilization of OPGs in wastewater treatment not only saves energy but is also efficient than the conventional method, thereby making this process a more economical option.