Empirical models for chlorine dissipation in drinking water distribution systems have
been developed as a function of pipe material and water quality. Polyvinyl chloride (PVC), galvanized steel,
unlined cast iron and lined ductile iron pipes were taken from actual distribution systems
and used to build eighteen pilot distribution systems (PDSs), which received finished
water. Operation of the pilot distribution systems simulated normal operation
circumstances. Hydraulic retention time was regulated using pumps to 5 days. Free
chlorine and monochloramines were used in the study. The PDSs were monitored for
time, temperature, pH, and total organic carbon. Separate models for free and total
chlorine decay were developed.
First-order kinetic models accurately described free and combined chlorine decay. Rate
constants were dependent on pipe material, UV-254 and temperature. Rate constants
were developed by material and free and total chlorine using non-linear regression. Free
and combined chlorine decay was similar in PVC and lined ductile iron pipes, and was
significantly less rapid than in galvanized and unlined cast iron pipes. Hence, surface
reactions with the aqueous phase disinfectant were more significant than disinfectant
reactions with the aqueous phase solutes. Sensitivity analyses indicated that disinfectant
residuals required by regulation were difficult to achieve in summertime conditions for
unlined metallic pipes. Includes 14 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.7 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 20 |
| Published : | 06/17/2004 |
