AWWA WQTC64171

The City of Scottsdale (City) plans to expand the Central Arizona Project (CAP)Water Treatment Plant (WTP) by adding 30 MGD for a net total production of 80MGD. As part of the treatment process selection and conceptual design for the30 MGD expansion, a detailed evaluation of the various alternatives wasconducted. A workshop-based approach was used to identify thirteenconfigurations, short-list to four alternatives, and select a treatment process train.Ultimately, a side-stream treatment (referred to as Plant III) consisting of highrate clarification and membrane filtration (MF) was selected as the mostappropriate process configuration for the plant expansion. Initially, dissolved airflotation (DAF) was selected as the high-rate clarification; however, during thepilot testing, the clarification technology was expanded to also include sandballasted flocculation (SBF).A five-month pilot study was conducted at the CAP WTP to evaluate theperformance of clarification and membrane filtration technologies and to establishoperating parameters for the design of the proposed 30 MGD plant. Theclarification technologies tested consisted of two DAF systems and sandballasted flocculation (SBF). Note that the SBF was introduced later in the pilottesting program and was only tested for approximately one month. Fivemembrane manufacturers submitted their Statement of Qualifications (SOQ) forparticipation in the pilot program. After review of the SOQs, three membranesystems were selected for the pilot testing. The entire pilot project was divided into two phases.Phase I consisted of optimization of operating parameters followed bylong-term operation of the DAF and membrane units. After the completionof the initial optimization phase, the DAF systems operated in a nearsteady-state mode to minimize the variations in the water quality feedingthe membranes systems. The MF units participated in two consecutiveflux confirmation tests with a chemical clean performed between the twotests.Phase II was the extended pilot period to test the DAF and SBF unitsunder ambient and artificially elevated turbidity conditions. Includes tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2006

Number of Pages:

18

File Size:

1 file , 1.2 MB