55. Dahej Petrochemical Complex Effluent Treatment and Advanced Water Reclamation Plant, Case Study India

The following chapter describes the refinery water reclamation plant (WRP) built by VA Tech WABAG in Dahej, India. The WRP, which was commissioned by Reliance Industries Limited, is an excellent example of industrial used water management and reuse. Owing to the growing scarcity of water in the region, a special focus was placed on the reutilization of the treated streams. The WRP is based on the segregated treatment concept, which foresees the categorization of the effluents from differing petrochemical processes by their COD and other contaminant content, and their subsequent targeted treatment. For example, the effluents with a high-COD content resulting from the production of polyethylene terephthalate (PET) and purified terephthalic acid (PTA) are treated via an upflow, anaerobic sludge blanket, followed by a heavy metal removal system, membrane bioreactor, and ion exchange (IX). Similarly, high-COD streams with additional oil content such as oily and sanitary used water undergo flotation via DAF and extensive biological treatment. By contrast, the low-COD effluents are treated with a dual media filter and ultrafiltration. A final reverse osmosis (RO) unit desalinates the diverse streams, and the high-quality permeate is reused for the production of boiler make-up. Different treatment by-products such as RO brines or IX regeneration wastes are safely disposed of into a sea outfall. The WRP also encompasses a common sludge handling facility that deals with the hazardous material from various treatment units. The technologies presented are interlinked to other chapters, thereby providing comprehensive explanations of the treatment system presented.