1. Pasteurization

The purified water in storage and distribution system is heated to 80℃ ,that called “pasteurization”,then circulate for 1-2hours under this temperature to finish disinfection of pure water storage and distribution system . Pasteurization only heat purified water ,no other,so more safety .The quantity of purified water is related to heating time and consumption of steam ,so the water quantity need to be controlled before heating . If the water quantity is too much ,the heating time and consumption of steam is more big,more cost;If the water quantity is little ,when the purified water is heating ,it is easy to cause cavitation of circulating pump to damage seal of pump . There are two disinfection method for pasteurization ,one is tank jacket heating and other is heating exchanger , due to the time is long for tank jacket heating ,poor temperature uniformity , so the heating exchange is common method. The control of pasteurization is only temperature control , so simple control ,conveniently test ,high accuracy, stable disinfection effect.The pasteurization need industrial steam , and the time of process is about 4 hours .

2.Ozone Disinfection

Ozone disinfection is started in CHINA in recent years. O3 is a colorless broad-spectrum bactericide,which has strong inactivation effect on bacteria ,bacterial spores,viruses ,fungi ,etc., and its solubility in water is relatively high, so it has good disinfection effect in purified water system .O3 is a strong oxidant,which can destroy non-metals in system, and it is bad for air and person if it leak. The half-life of O3 is relativity short ,easy to decompose, There are more higher requirement for Ozone equipment and detection. The price of Zone generator( water electrolysis method ) and instrumentation is expensive,and also need to add UV for O3 removal ,add ozone exhaust gas destroyer at the exhaust port ,even install automatic valve at used points (Interlock with ozone detector to prevent water containing ozone from entering the point of use and causing harm to the environment and human body), the cost will be added .At present,There are two method of producing O3 ,one is discharge method and water electrolysis method . the discharge method is relatively low (brought into the air ),which can cause a certain impact on the system .It is used in a small enterprises in China. The water analysis method is usually recognized in local and foreign country . The purified water is as the raw water ,no outer contamination, but the cost of equipment is expensive . Popularizing rate is low .