Evaluation of Oxidants Products as Disinfectants Seeking Reuse of Refinery Wastewater

Wastewater reuse from municipal and industrial effluents is a very emerging alternative to obtain water resources and is becoming increasingly important in many areas around the world. Water scarcity, local regulation and environmental impact are driving many industries to reuse the large volume of produced effluent. Disinfection is an essential component of many wastewater reuse treatment station (WRTS) of refinery that has as objective to inactivate or destroy pathogen organisms. Although the most common method of wastewater disinfection is chlorination, the potential toxicity of chlorination by-products generated in reaction with organic matter present in reuse water makes this process less attractive. The essential foundation for successful implementation of such WRTS is the capability of producing water of a desired quality that guarantee protecting worker health and the environment and the industry demands. In order to cope with the large fluctuations of wastewater quality generated by refinery and considering cost-effective operation of the system, studies based in the evaluating oxidizing disinfectants alternative to chlorine were conducted. The activities of commercial disinfectant with active bases in performic acid, peracetic acid, hydrogen peroxide and chlorine dioxide were evaluated against total aerobic heterotrophic bacteria (THB) and total coliform (TC) in laboratory scale to replace chlorine. Performic acid, chlorine dioxide and peracetic acid exhibited an excellent activity against TC. However, none of the products presented effectiveness for the reduction of THB in the conditions of contact time and concentrations used. The technical evaluation showed favorable economic application of performic acid. Currently, studies are being conducted with continuous application of performic acid for disinfection of effluent in the WRTS of refinery.