[en] The Heavy Water Plant at Hazira is based on monothermal ammonia-hydrogen exchange process. The plant is built in two stream for isotopic exchange and enrichment with common facilities for interconnections with fertilizer plant, synthesis unit, amide preparation, utilities and final product, identical to HWP, Thal unit. This plant is built after incorporating some of the improvement effected from operating experiences gained from Baroda, Tuticorin and Thal plants. Plant erection was completed without a single casualty/mishap well within the time schedule and commissioning was completed within six months from charging of synthesis gas and ammonia in the plant. A few modifications of minor/major nature have been incorporated both in the design and during the course of operation. Some procedural changes have also been adopted for flexibility of operation, improved productivity and energy conservation. (author). 2 figs