Types of Bacteria Inactivated by Medium‑Pressure UV Disinfector

Medium-pressure UV delivers a broad spectrum of 180-400 nm. It damages microbial DNA and RNA, effectively inactivating Gram-positive and Gram-negative bacteria. With sufficient UV dose, the inactivation rate can reach 99.9%-99.99 prcent.

Gram-negative Bacteria   Most common in swimming pools

Legionella pneumophila

Pseudomonas aeruginosa

Escherichia coli

Klebsiella pneumoniae

Salmonella spp.

Shigella spp.

Vibrio cholerae, Vibrio parahaemolyticus

Gram-positive Bacteria

Staphylococcus aureus

Enterococcus faecalis, Enterococcus faecium    indicator bacteria for NSF/ANSI 50 pool standard

Streptococcus spp.

Bacillus spp.  bacterial spores, require higher UV dosage 

Other Important Pathogens

Viruses  Adenovirus, Norovirus, Rotavirus, Hepatitis A virus Chlorine-resistant protozoa   Cryptosporidium parvum, Giardia lambliaAlgae   Cyanobacteria, green algae

Important Notes

Medium-pressure UV acts as secondary disinfection. Residual chlorine must still be maintained in pool water, since UV provides no persistent residual biocidal effect.

Disinfection performance depends on UV dose, UV transmittance of water and hydraulic retention time. Turbid water significantly reduces UV efficiency.

Broad-spectrum advantage: compared with LPHO UV, MPUV inhibits microbial photoreactivation and reduces the risk of bacterial repair and regrowth.