Dairy Plus Co in Thailand
has replaced its chlorinebased
disinfection system
with medium pressure UV
technology from Hanovia.

The company decided to
reduce high levels of chlorine
dosage throughout the
process because it was deemed
ineffective at removing all
microorganisms, particularly
in the rainy season. It was
also producing an after-taste.

Water to the plant is from
two sources: city water and
deep well water. Chlorine is
only dosed at the raw water
feed level, after the clarifier
for pre-chlorination and then
some low concentration
dosing after the softener.
“The incoming city water
in particular has a high
microbial contact – often as
much as 20,000cfu/ml in the
rainy season,” says Ying Xu,
Hanovia’s Asia-Pacific sales
manager. “At these times,
high chlorine doses of even
8ppm were still resulting in
microbial concentrations of
over 6000cfu/ml.”
Five Hanovia UV systems
are now installed at the plant
– four on duty and one
standby. They remove microorganisms
without any
problems of after-taste or reinfection.

Each UV system
treats up to 130m3/h of water.