Recycling of refinery and petrochemical effluents employing advanced multi-barrier systems

The Indian Oil Corporation Ltd. Panipat had to build two water reclamation plants as a response to the demands of the environmental authorities. The plants, which treat secondary refinery and various refinery/petrochemical process effluents, were commissioned in 2006 and 2010 respectively. Advanced multi-barrier systems (including ultrafiltration and reverse osmosis) have been employed in order to meet the stringent quality requirements for the recycling of boiler make-up water. Excellent results with regard to the removal of the major parameters such as total dissolved solids (TDS) and silica have been accomplished, e.g. silica is mainly removed by RO (from 11.6 mg/L in the UF outlet to 0.09 mg/L in the RO permeate (99.2% removal)) and is then reduced further to 0.007 mg/L (7 μg/L; total removal 99.94%) in the mixed bed ion exchanger (20 μg/L is the specified limit for boiler make-up water in various power plant guidelines). Both UF process units have shown relatively good performance. The older UF has been in operation for more than five years with still acceptable permeability values and a relatively low number of fibre breakages.