AWWA JAW57848

It is well known that increased turbidity in drinking water has a negative effect on an ultraviolet (UV) disinfection system. Current published research supports the use of UV disinfection after filtration only when turbitidy is 1 ntu and lower. For drinking water with elevated levels of turbidity from 1 to 10 ntu and beyond, the effectiveness of UV light for disinfection is not well understood. The authors studied the effects of elevated turbidity on the transmission of UV light, as well as on UV reactor design and operation. Their conclusions provide evidence that UV light disinfection can be implemented into systems with elevated turbidity of up to 10 ntu, such as before filtration and for unfiltered systems. Especially when used for large, unfiltered systems, this technique will provide cost-effective water disinfection. The authors also offer information about how to account for the effects of elevated turbidity by properly measuring unfiltered UV absorbance, which is a key water quality parameter for UV reactor design and operation. Includes 32 references, tables, figures.