Treatment of Rendering Plant Wastewater with Ozone to Reduce Biochemical Oxygen Demand, Chemical Oxygen Demand, Color, Malodor Emissions and Bacterial Content

Title: Treatment of Rendering Plant Wastewater with Ozone to Reduce Biochemical Oxygen Demand, Chemical Oxygen Demand, Color, Malodor Emissions and Bacterial Content

Principle Investigator: Annel K. Greene and John K. Duke

Year: 2000

Objective: To treat rendering plant wastewater with ozone to reduce biochemical oxygen demand, chemical oxygen demand, color, malodor emissions and bacterial content.

Lay Summary/Industry Summary: Ozone holds promise as a pre-treatment method for wastewater remediation. Ozone treatment causes progressive oxidation of organic compounds until ultimately carbon dioxide. As the second most powerful oxidizing agent known, ozone has the potential to oxidize any compound to carbon dioxide given sufficient concentration and time. Ozone is generated on-site with ozonator devices. There are no hazardous storage concerns, however, ozone is toxic upon extended exposure. But just as we have learned in the food industry to manage toxic chlorine sanitizing compounds, so can we learn to safely manage ozone. Ozone destruct units (ultraviolet light or heat) are available. Another more simplistic approach to ozone management involves proper ventilation.

Future issues to be addressed include cost efficiency, how far to ozonate and how to prevent foam formation. It is hypothesized that rendering plants would not want to ozonate wastewater to complete clarity due to time and energy concerns. However, a partial treatment with ozone can degrade many of more recalcitrant molecules in wastewater thereby allowing quicker degradation by other chemical or microbiological means. Our experience with ozonation of wastewater indicates that there can be great batch-to-batch variability. This variability can be attributed to variability in the concentration and composition of the waste stream. Additionally, depending on the ozonator design, ozone output may decrease with time. Ozone detection meters (ORP meters) are useful in monitoring ozone output. In the experience of this laboratory, ozonator manufacturing companies vary greatly in knowledge and quality of equipment. The industry has undergone a rapid transformation in the past few years. A number of companies have come and gone (including the manufacturer of the ozonator used in this experiment). A list of companies with which we have had success is available upon request.

Scientific Abstract: Not included