Cryptosporidium: Implications for Variable Declining-rate Filtration

Price: £10  

The objectives of the work were to review the principles of variable declining rate (VDR) filtration and the implication for Cryptosporidium risk, in comparison with constant rate rfiltration, particularly in a UK context. Results are provided for a survey f UK water companies, which suggested that up to 50% of filters may operate with declining rate characteristics. Consideration of the mode of operation and review of the literature suggested that flow surges may be of lesser concern than for constant rate filters, and average turbidity should be no higher for VDR. However, the higher flowrate at the beginning of the run could increase the impact of the ripening period. This could be dealt with in the same way as for constant rate filters, for example by slow start or run to waste.



UKWIR Reference :- 00/DW/06/14Published Date :- 17/04/2002
Retail Price (£) :- 10ISBN :- 184057 201 9