Chlorine Dioxide (Clo2: A Case Study

• the type of disinfectant used ,say for considering case of disinfection by chlorine dioxide (ClO2) substantial amount of chlorite (ClO2 -) is formed which acts as a precursor or product.(Bull ,1982)
• the disinfection dose,
• the residual disinfection involved,
• nature and conditions of disinfection
• temperature, and pH,
• reaction time,
• nature of source water
• the constituents of water (organic as well as inorganic ), and
• most importantly the concentrations and properties of naturally present organic matter (NOM)in the water.
Thus ,the amount of organic precursors including the algal load in the drinking water to be treated , water temperature and pH, the amount and type of chemical disinfectants, and the stage in the process

It is a yellow, volatile and oily liquid ,which has low viscosity. It is hydrophilic as well as lipophilic thus making its impact on health much more. NDMA is light sensitive, especially UV and undergoes fast photolytic degradation.The mechanism of NDMA formation is related to the reaction of secondary amines with nitrite, wherein NO+ plays a particular role. Tertiary amines do not react with nitrite. Secondary amines on reacting forms appropriate nitrosoamines (Andrzejewski et al,2005) But with primary amines, the reaction led to the formation of ammonia, with NDMA as intermediate

Much of the mutagenicity of the DBPs is related to the compound 3-chloro-4-(dichloromethyl)-5-hy-droxy-2(5H)-furanone (MX) (Kargalioglu et al., 2002). In Massachusetts studies suggest that levels of MX may be considerably higher than previously reported in the United States or Europe (up to 80 ng/l) (Wright et al., 2002). MX was originally identified in pulp-mill effluent ; and later from chlorinated drinking water from a number of samples taken around the world(Richardson