A water quality model of a distribution system provides
an alternative to extensive grab sampling of chlorine
residuals and disinfection byproduct concentrations,
but the accuracy of such models depends on the
input of a chlorine-decay rate relationship and the
specific rate constant for reaction with pipe-wall material.
This has proven difficult to quantify in currently
available distribution system modeling software. Unlike
small coupons of pipe material that are used in other
bench-scale tests of chlorine-decay rate, the pipe section
reactor (PSR) proposed in this article uses an undisturbed
section of the actual pipe material filled with
test water and a variable-speed stirrer blade to simulate
a range of water velocities.
Results are given for chlorine-decay rate tests on old
cast-iron pipe and new ductile-iron pipe. With further
testing of the PSR, rate models and rate constants will be
available for use in water quality models to replace empirical
approaches. This should improve the accuracy of chlorine
residual predictions, with less reliance on field calibration.
Accurate predictions of chlorine residual throughout
the distribution system are essential to determine where
low residuals exist and thus to comply with the Stage 2
Disinfectants/Disinfection Byproducts Rule.
Includes 19 references, tables, figures.
| Edition : | Vol. 97 - No. 1 |
| File Size : | 1
file
, 200 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 12 |
| Published : | 01/01/2005 |
