The Upper Trinity Regional Water District is planning for a new plant in the metropolitan Dallas
area. The raw water source for the new facility will be Chapman Lake. Conventional treatment
with ozonation was evaluated to address water quality challenges, which included episodic
occurrences of objectionable taste and odors, variable turbidity with spikes up to 200 NTU, and
occasionally elevated concentrations of iron and manganese. Ozone demand of the raw water
was high (in the range of 6 to 15 mg/L) and therefore, ozone disinfection of the raw water was
found to be cost prohibitive. Ozonation of settled water (at the optimum alum dose for turbidity
removal) had much lower ozone demands (2 to 5 mg/L). Formation of BDOC during ozonation
for 1-log Cryptosporidium inactivation was substantial, and biologically active filters with an
extended empty bed contact time (ie. greater than 10 minutes) may be required to produce a
biologically stable effluent. Bromate formation during ozonation of the settled water was low to
moderate. In subsequent testing, the percent removal of 2-MIB and geosmin were found to be
essentially constant for a given ozone dose. It was concluded that during episodes of elevated
T&O, higher ozone dosages or an advanced oxidation process, such as peroxone (ozone plus
hydrogen peroxide) would be required to provide an aesthetically acceptable water.
Includes 3 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 340 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 14 |
| Published : | 11/01/2002 |
