About Cryptosporidium

• Cryptosporidium is a protozoa that causes a diarrheal illness called cryptosporidiosis

• The parasite is transmitted by cysts that, if ingested, can result in an infection

• Infection is typically short-term, but can cause severe illness

Once a person is infected, the parasites proliferate in the intestine and in some cases the respiratory tract. The infection can last more than two weeks and even longer for immunodeficient individuals.

In 1993, more than 100 people died and over 400,000 developed gastrointestinal illnesses as a result of a Cryptosporidium outbreak in the drinking water supply of Milwaukee, Wisconsin.

After the Milwaukee outbreak, many water treatment plants installed UV in order to meet the USEPA Long Term 2 Enhanced Surface Water Treatment Rule, since Cryptosporidium treatment was required.

UV Treatment as a Cryptosporidium Barrier

Cryptosporidium is resistant to chlorine, but has been shown to be effectively inactivated with UV treatment. Relative to other treatment technologies, such as ozone and membrane filtration, UV offers a cost-effective solution for Cryptosporidium inactivation.

See the USEPA UV Disinfection Guidance Manual for more information.

About Giardia

• Giardia is a protozoan cyst that is protected by an outer shell and is one of the most common waterborne parasites

• Although Giardia is often referred to as a camping or backpacking-related concern (beaver fever), it can also be found in swimming pools, hot tubs, and contaminated drinking water

• It causes the diarrheal illness known as giardiasis – signs and symptoms from a Giardia infection can last two to six weeks

UV Treatment as a Giardia Barrier

Traditional methods of chlorine-based water treatment require relatively high concentrations and contact times to eliminate Giardia, a situation that is further exacerbated by cold water conditions.

UV treatment can inactivate Giardia at relatively low doses.

Where the design of chlorine-based systems is governed by highly chlorine resistant organisms like Giardia, UV offers a cost-effective treatment alternative. In this type of application, UV can form part of a by-product reduction strategy. Furthermore, a UV treatment system’s small footprint can also provide significant cost and space savings compared to the design and construction of a chlorine contact chamber expansion.