This was dramatically improved, to over 90%, by dosing polyaluminium chloride. Without coagulation removal rates in a single pass of a medium-rate filter were about 50%. Research at Swansea University for PWTAG in 2004 demonstrated the importance of coagulation in filtering out Cryptosporidium oocysts. But sand filters are very limited in their ability to remove Cryptosporidium. Backgroundįiltration through a porous medium such as a sand bed is an efficient and cost effective means of reducing water turbidity. This note clarifies the application and dosing rates for the various different grades of polyaluminium chloride being sold in the UK. The resulting floc is then trapped on the filter. Like all coagulants PAC works by extracting and then clumping together dissolved, colloidal and suspended matter. Continuous coagulation with polyaluminium chloride has long been recommended by PWTAG – especially in the light of the threat from Crytposporidium.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |