Assessment of accidental refinery wastewater discharge: a case study

The physicochemical qualities of an accidental discharge of refinery liquid waste, water, and soil sediment of that effluent-receiving water body (canal) were investigated. Analyses of the discharge, qualities of water, and sediment of the canal showed high parametric concentrations. Investigations revealed that the discharge took place form the spent caustic that was generated from the caustic wash tower of Fluidized Catalytic Cracker of the refinery. A simple but realistic model was suggested for the remediation of sediments of the canal with an estimated cost of about US $1.86 million. Recommendations were made to prevent such discharges and to revise thoroughly the Indian effluent discharge standards in force for petroleum oil refinery. Subsequently, revised standards were notified under Indian guidelines. Interestingly, cyanide besides many other parameters was introduced into these standards. Furthermore, Volatile Organic Compound (VOC) was also stipulated as an emission parameter from the waste water treatment plants. Concentration- and mass-based standards thus promulgated were stricter than the existing standards.