AWWA EDC52027

New Disinfectants/Disinfection Byproducts regulations promulgated December 16,1998 are expected to have significant impacts on existing cold lime softening(CLS) plants in Florida. Because of the high levels of natural organic matter(NOM) typically present in Florida's groundwater and the need to providesoftening to reduce hardness to acceptable levels, many utilities are planningthe construction of new membrane treatment facilities at tremendous cost. Theexisting CLS plants represent substantial capital investments that will not beutilized by the membrane technology. This study investigates enhanced softening,and the required modifications to the CLS process to improve NOM removal andreduce disinfection byproducts. Bench and full-scale test results from two southFlorida utilities are presented, effectively demonstrating that the CLS processcan be adjusted to meet the new regulatory challenges. Full-scale test resultsfor enhanced softening and simultaneous coagulation and softening are presented,using accelators operating at flows from 20 to 40 million gallons per day.Disinfection byproduct data presented includes actual distribution system totalorganic carbon, trihalomethanes and haloacetic acids. The implications ofenhanced CLS residuals management are also discussed. During the full-scaletesting, Langlier Index data was collected to insure that the processmodifications would produce a stable finished water. Includes 5 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

01/01/1999

Number of Pages:

20

File Size:

1 file , 610 KB