Water Chlorination System

Table 3.3.5-2 Partial FMEA for the Coolins Water Chlorination System...

Partial FMEA for the Cooling Water Chlorination System. 

LINE/VESSEL Cooling Water Chlorination System DATE December 22, 1992 PAGE of... 

DATE 1/4/93 PAGE 1 of 1 PLANT SYSTEM Cooling Water Chlorination System ITEM Pressure Check Valve REFERENCE ... 

This cruel experiment was unintentionally conducted in Peru in the 1980s. The result was a cholera epidemic affecting 300,000 people and causing 3,500 deaths. In the United States in 1994, problems in the water chlorination system of Milwaukee resulted in over a third of a million people being sickened by the protozoan, Cryptosporidium. Similarly, as discussed earlier in this book, the removal of DDT from Africa resulted in millions of deaths secondary to a resurgence of once-controlled malaria. The human trials have been done and, in retrospect, the benefit-to-risk ratio favors DDT and chlorine. Chlorine has not yet been banned. Why is there even any debate ... 

PERFORMING THE STUDY. A HAZOP Study focuses on specific points of a process called "study nodes," process sections, or operating steps. Depending on the experience of the study leader, the portion of a process included in a single study node can vary. In the most conservative studies, every line and vessel are considered separately. If the HAZOP study leader is experienced, he or she may elect to combine two or more lines into a single study node. For example, the cooling water chlorination system (Example Process 2) could be separated into three study nodes (chlorine supply to venturi, recirculation loop, and tower water basin), two study nodes (recirculation loop and tower water basin combined as a single study node), or one study node (the entire process). 

Figure 4.4. Example FTA for the Cooling Water Chlorination System. 66...

For the water-chlorine system above, a set of ten equations is required in order to solve for the ten unknowns just described. These equations are ... 

For the species in the water-chlorine system, the National Bureau of Standards (26) has tabulated the following values for the thermodynamic properties ... 

Impact of sunlight on stability. Sunlight, or more specifically ultraviolet light, rapidly reduces hypochlorous acid to non-biocidal chloride salt. On a sunny day nearly 100% of hypochlorous acid is destroyed in 2 hours (NSPI, 1995). Cyanuric acid is used in many recreational water chlorine systems as a UV stabilizer. Many US public health codes limit the cyanuric acid level to an upper limit of lOOmg/L. The present NSPI chemical... 

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