AWWA MTC69762

The City of Camarillo, California is implementing a groundwater desalination facility tobetter utilize groundwater from an aquifer with continuing degradation in waterquality. The city's wells have been increasing in total dissolved solids (TDS), chlorides, and sulfates, which willrequire desalination, but have also been increasing in iron and manganese,causing complications in selection of a desalination process. The city has been pilot testing various alternatives for iron and manganese control aheadof reverse osmosis, looking at methods of oxidation and filtration during a twelve monthpilot study. Aeration plus media filtration was found to be an effective method forremoval of iron, while not impacting the dissolved manganese, which is less likely tofoul the reverse osmosis (RO) membranes. While iron oxidation through aeration is generally thought tobe a rapid process, organic complexation of iron has slowed the oxidation process, suchthat complete oxidation of iron was not seen within a 37 minute pre-filtration contacttank. Membrane filtration and conventional media filtration were both tested todetermine whether membrane filters could provide better removal of oxidized iron.However, it was found that the depth filtration achieved in conventional media filtersenhanced both the oxidation and removal of iron, making it a more effectivepretreatment process for reverse osmosis at this facility.This paper presents the impact of contact time, dissolved oxygen level, pH, andcatalyzing agents on the complete oxidation and removal of iron ahead of reverseosmosis. Includes 4 references, table, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2009

Number of Pages:

14

File Size:

1 file , 1.1 MB