The Environmental Protection Agency has approved a new
flocculation process that effectively filters
cryptosporidium out of pool water.
Research conducted at Auburn University in Auburn, Ala.,
and by Jeff Williams, Ph.D., at HaloSource in Redmond,
Wash., found that cryptosporidium can be trapped
in a sand filter without reintroducing it into the
The application uses a positively charged, water-soluble
polymer to catch crypto (which is negatively
charged) and form it into a larger clump. A second
application then stabilizes the clump and prevents it from
unraveling and filtering out of the sand bed. The two-step
process flocculates particles down to 0.5 microns.
Crypto is between 4 and 6 microns.
The application does not destroy the pathogen, but
because the process creates a stable flocculated clump, it
can be removed through backwashing. Studies conducted at
Auburn University show a 99.9 percent reduction of
crypto when applying the flocculent process.
The process also has proven effective in trapping
chloroforms, algae, oils and organic matter as well. It
therefore works to prevent water turbidity. With space
between particles in a sand filter at approximately 50
microns, most cannot effectively trap crypto and
other pathogens because of their small size.
Crypto is particularly worrisome to facility
operators because it takes nearly seven days to be
destroyed by chlorine due to its tough outer shell.
According to Williams, this is the first flocculation
process that effectively traps crypto, and
recently was given approval by the EPA. ?This is a
monumental breakthrough for public recreational water
facilities to improve quality and reduce risk,?
said Williams, chief technology officer of the health
sciences company that focuses on specialty polymers and
their use in water treatment.
He said the application provides another layer of
protection against crypto along with proper pH
balance, chlorine levels and use of UV.
Cryptosporidium is a parasite that causes
vomiting, diarrhea, fever, weight loss and other symptoms.
It can be spread through fecal matter introduced into a
recreational water setting.