Testing and implementation of an advanced wastewater reclamation and recycling system in a major petrochemical plant

This paper describes a major water reclamation project utilizing a membrane -based advanced treatment system to recover organic wastewater treatment sy stem (OWWTS) effluent and cooling tower blowdown (CTB) for reuse in a large petrochemical plant in the Far East. The treatment process train includes chemical oxidation, dual media filtration (DMF), granular activated carbon (GAC) adsorption, ultrafiltration (UF), ultraviolet (UV) disinfection, reve rse osmosis (RO), and degasification. The reclaimed pure water, which has a conductivity <240 <mu>S/cm, is used as makeup water for the plant's ion ex change deionization (DI) system. Using this water for DI system makeup save s more than 80% of the expensive DI system regeneration cost and drasticall y reduces water purchase cost and wastewater discharge fees, The treatment system was tested on a pilot-scale (110 m(3)/d) basis for nearly 18 months. Various flux rates for UF/RC and accelerated biofouling tests for the holl ow-fiber UF membranes were conducted. With excellent pretreatment, the thin film composite polyamide RO membranes were relatively clean and non-foulin g after more than 2,000 hours of operation without chemical cleaning. A tot al overall water recovery of 73.6% was achieved consistently in the pilot p lant, A full-scale plant treating an influent blended flow of 9,000 m(3)/d and recovering 6,600 m(3)/d of pure water has been constructed at the petro chemical plant. System startup and commissioning are expected to be complet ed in September 1999. The treatment system may be expandable by 50% with mi nimal facility addition in the future.