AWWA MTC53720

The City of Ashland, Wisconsin is constructing a new 2.0 million gallons per day (mgd) microfiltration watertreatment plant. The existing slow sand filtration system, built between 1896 and 1913, has nopretreatment prior to the filters. The filters have difficulty meeting the finished water turbiditylimit of 1.0 NTU when the source water turbidity exceeds 5 - 10 NTU. The WisconsinDepartment of Natural Resources is also concerned with the vulnerability of the filters tocontamination and a potential breakthrough of a chlorine-resistant pathogen, such asCryptosporidium. In addition to the water quality concerns, the existing plant has severaloperational difficulties. Without a backwash system, the 100-year-old filters are cleaned in alabor-intensive sand washing procedure and the 50-year-old vacuum-primed high lift pumps aredifficult to maintain. In 1993, the City investigated alternatives for improving or replacing theexisting plant. After evaluating other treatment options, the City selected a new treatment plantusing microfiltration technology. Construction began in August 2000, and the plant is expectedto be brought on-line in May, 2001. The total project cost is estimated at $2.6 million, and theestimated annual costs are $223,000. Includes 4 references, tables.

Product Details

Edition:

Vol. - No.

Published:

05/01/2001

Number of Pages:

18

File Size:

1 file , 120 KB