Severn Trent wins Chinese nuclear plant contract

This part of the project will treat 22,000 m3/d of wastewater.

Water recirculated in industrial cooling towers tends to absorb ammonia and organic nitrogen compounds from the air. Because chlorine dioxide does not react with ammonia, it is effective in eliminating algae and slime growth in cooling towers without interim reactions with ammonia. The result is reduced dosage and fewer tower clean-up cycles.

The Capital Controls T70G4000 chlorine dioxide generator is an all-liquid, all-vacuum system. The gas produced is always in solution and any loss of vacuum automatically shuts the system down, preventing reagent or solution leaks. The generator uses commercially available 25% sodium chlorite and 32% hydrochloric acid to produce a product yield greater than 95%.

The vacuum is produced by means of an integrally mounted ejector. The ejector draws the concentrated chlorine dioxide solution into the motive water of the ejector and pumps it to the treatment process. The system can be operated manually or automatically. Automatic control is achieved with a three-ported precision control valve that maintains the proper ratio of reagents throughout the entire flow range of the generator. The reagent flow rates are indicated by means of precision variable area flow meters.