The City of Phoenix conducted the Lake Pleasant Water Quality and Testing Study
Project to assess the viability of various advanced treatment processes to meet anticipated
drinking water regulations. Lake Pleasant is a man-made storage facility that stores
Colorado River Water delivered via the Central Arizona Project (CAP) Canal. The water
from the lake is released during the summer season to meet the peak water demands of
the Phoenix Metropolitan area. Many water treatment facilities are being served by the
CAP Canal and Lake Pleasant, including the City of Phoenix' existing Union Hills Water
Treatment Plant (UHWTP) and the proposed Lake Pleasant WTP.
The City conducted pilot and demonstration scale testing of various processes such as
conventional treatment, microfiltration (MF), ultrafiltration (UF), granular activated
carbon, nanofiltration, ballasted flocculation, and several preoxidants. These unit
processes were configured in alternative treatment trains to optimize removal of turbidity,
pathogens, disinfection byproduct (DBP) precursors, and taste and odor compounds.
The project will include potential stress testing of the treatment processes with simulated
high algae and/or high turbidity raw water, during periods of lake releases. A significant component of this testing program was the assessment of residuals handling
systems to treat waste streams from these various water treatment processes. Membrane
treatment options were evaluated as a possible alternative to commonly used residual
treatment processes like clarification. The membrane treatment residual treatment options
evaluated include ultrafiltration of the decant stream obtained after settling of the
microfiltration backwash residual stream. The recovered water from this process can be
recycled without risking microbial contamination. Another innovative process that was
evaluated was the treatment of microfiltration backwash using tubular UF membranes
operated in hybrid mode. It was found that the hybrid mode operation of the UF system
allows the backwash to be directly sent to the membrane without any settling, resulting in
cost savings. This is compared to treatment of MF backwash by settling and subsequent
treatment of the decant through a hollow fiber UF system.
Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 660 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 13 |
| Published : | 11/01/2002 |
