Phoenix Area Office - Programs & Activities

Central Arizona Salinity Study (CASS)


Although, the mandate of CASS is complete with the finalization of the Phase II report, the CASS community continues to work on salinity related issues.

Managing salinity is required for the long term sustainability of central Arizona.  Over a million tons of salts are accumulating in the Phoenix Metropolitan area annually.  There are significant amounts of groundwater in central Arizona which already have total dissolved solids (TDS) concentrations which make the water non-potable.  In addition, effluent being produced at some of our waste water treatment plants has high concentrations of TDS.  At some of the Waste Water Treatment Plants (WWTP) the effluent is not suitable for the intended use. 

 There are three areas of salinity in which the CASS group will continue to study.

Public education on salinity issues is a key area.  To meet that need, CASS has formed a Public Education Sub-committee.   The first task of that Sub-committee was to create a made for TV video to get basic salinity information out to the public.  This video has had a large amount of exposure on public TV.   The sub-committee is investigating other venues to get the salinity message out.

Concentrate management is probably the most critical salinity challenge to be solved.   As the population grows, there will be an increase on the demand for water.  More communities will be using advanced water treatment techniques such as Reverse Osmosis to use impaired waters.  In an inland environment concentrate management can cause the construction and operation of an advanced water treatment facility to double in cost.   The concentrate from these processes must be disposed of in an economical and environmentally sound manner.  

Reclamation has sought and received additional funding for work in this area and is seeking to partner once again with SROG and other CASS members to find some concentrate management solutions.   

Two separate pilot projects are “in the works” which are being funded by Reclamation, City of Phoenix, City of Goodyear and SROG.    In Goodyear the Wetlands Pilot Project is exploring the possibility of using a wetland to treat brine.   Another Pilot Project, located in Scottsdale, will test a high tech solution seeking an economical Zero Liquid Discharge (ZLD) solution.

Improvements in concentrate management technologies are required for the large-scale desalination of brackish groundwater and impaired effluent in central Arizona to allow full utilization of our water resources.

Salinity control in the WWTP is the third area which CASS will be devoting some of its time and resources.  The focus now is on water softeners and the amount of salinity they add to the water system.  CASS is gathering information and exploring options on water softeners.

Arizona is working towards solving its salinity issues. 

Last Reviewed:
March 28, 2012

Joseph J. Billerbeck -

Last Updated: 6/25/15