AWWA MTC61085

During the course of planning for and designing of four water treatment facilitiesfor the Seminole Tribe of Florida, disposal of the membrane reject water and other treatmentsidestream flows became an issue, due to extremely rigorous requirementspertaining to environmental impacts. The plants for the four reservations, havecapacities ranging from 0.10 to 1.0 million gallons per day (mgd). Source watercomes from wells at each site, and membrane purification results inconcentration of dissolved constituents in the reject flows to between 4 and 5times their original strength, depending on recovery. This stream, as well as theinitial startup well purge stream (to reduce and stabilize SDI) contained highlevels of hardness, minerals and miscellaneous dissolved and suspendedcomponents. These waste streams required disposal, and were originally to beprocessed through the wastewater treatment facilities (WWTF). However, anabsence of nutrient value, combined with the strength of dissolved constituentswould impose an unacceptable hydraulic and inert material load on the WWTFs,and another alternative was sought.The following alternatives were evaluated:surface water (point) discharge;land application as spray or percolation;subsurface disposal by deepwell injection;ocean outfall; and,co-disposal with treated wastewater effluent.Alternative evaluation included discussions with various regulatory agenciesconcerning permitting viability, relative economic impact on overall project costsand long term risks. The alternatives each had advantages and liabilities thatwere evaluated before the final recommendation was made to the Seminole Tribe. Variations on land application were eventually selected at three of the foursites, and the final site is still being evaluated.

Product Details

Edition:

Vol. - No.

Published:

03/01/2005

Number of Pages:

4

File Size:

1 file , 260 KB