AWWA QTC98291

There has been concern about the effectiveness of filtration plants in providing a robust barrier to particulate material in the low micron size range (2 to 5um). The filter ripening period has been identified as a key issue with respect to the passage of particulate material into drinking water supplies. This material may include floc, bacteria, and microorganisms such as Giardia and Cryptosporidium. The effects at pilot scale of the use of differing start up strategies in reducing the magnitude of numbers of particles passed during the filter ripening period have been reported previously. Reductions of up to 65% were observed. That pilot work evaluated two strategies namely slow start and delayed start. North West Water (NWW) has now evaluated both of these strategies at full scale on a number of its water treatment plants including rapid gravity and pressure filters. It was found that both strategies provided significant reductions in the total amount of particulate material passed into drinking water supply. This can be achieved without incurring significant cost. Adoption of an optimised filter start up procedure can be regarded as good operational practice.

Product Details

Published:

01/01/1998

ISBN(s):

0898679796

Number of Pages:

10

File Size:

1 file , 89 KB