As H₂S gas is very toxic, corrosive and hazardous in nature and the plant has a dynamic hold up of 200 Te H₂S, extreme care has been taken in the design of the plant, selection of equipment and materials, adhering to stringent fabrication procedures and codes. The exchange process operates at about 20 atm. pressure and at a temperature of 30 to 120 Deg.C. while the vacuum distillation plant works at a pressure of 100 mm Hg absolute. The isotopic exchange reaction which is the heart of the technology is carried out with the aid of specially designed efficient trays. The H₂S gas required for the process is manufactured in a separate unit at the plant premises by the chemical reaction between sodium sulphide and sulphuric acid. Very elaborate and sensitive H₂S detection instrumentation is provided not only in the plant but also in the surrounding areas to monitor the environment.