AWWA SP250157

This paper discusses different methods of pretreatment for a nanofiltration or membrane softening system which utilized a highly fouling surface water for raw water supply. The methods of pretreatment discussed are conventional, granular activated carbon (GAC), alum coagulation-settling-dual media filtration, and microfiltration. Conventional membrane pretreatment is defined as scaling control by acid or antiscalent addition and prefiltration with a five to twenty micron filter. Sulfuric acid addition was used to control scaling in all systems. Conventional pretreatment is used following all the other pretreatment schemes presented in this article. For example, the order of unit operations for the system utilizing GAC pretreatment would be GAC, acid addition, five micron prefiltration and nanofiltration. The same order was utilized for the systems using alum coagulation settled sand filtered (ACSSF) and MF pretreatment.

Product Details

Published:

01/01/1991

ISBN(s):

0898675758

Number of Pages:

12

File Size:

1 file , 2.7 MB