Microbial pathogens are the biggest public health threat faced by most drinking water supplies and one of the most important is Cryptosporidium. These parasites call humans and cattle home and are spread via faecal matter. While investing in this crypto can't make you a millionaire, it can prevent a Cryptosporidosis outbreak. Cryptosporidosis is a gastrointestinal illness that is caused by ingested Cryptosporidium parasites burrowing into the intestinal walls. Because of the risk presented by Cryptosporidium and the lack of a routine method for detecting them, a multi-barrier approach is essential.
Much like the crypto buzz, Cryptosporidium just won't go away. These parasites are poorly treated by chlorine and able to live in the environment for months. As a result of this, it's better to keep these guys out of water than to remove them once they're there.
Human and animal waste present the greatest risk for waterway contamination. There is only one recorded drinking water caused Cryptosporidosis outbreak in Australia which was due to a sewage overflow. Maintaining appropriate sewage and waste management within catchments is essential for public safety. This can involve consideration of not just public and domestic services but also recreational activities in waterways. Animal husbandry is another significant source of this pathogen.
Where a Cryptosporidium risk exists in a drinking water supply, it either needs to be removed through catchment management practices or factored into the treatment process. Conventional water treatment is often not enough to manage this risk, because the normal chlorine disinfectant is ineffective. This pathogen can be physically removed through filtration, but often a second barrier is also needed. A common choice for this is Ultra Violet (UV) light disinfection.
The parasite is transmitted through oocysts, which are 4-6µm in diameter and 99.99% can be removed by a well run filtration system. Well run means achieving a post-filter turbidity of less than 0.15NTU. Proper operation, maintenance and monitoring of filtration systems is essential to achieve the performance required for effective Cryptosporidium removal.
It has been shown that UV disinfection is effective for treating Cryptosporidium and this method is becoming increasingly popular. To maximise protozoa inactivation, UV units must be carefully operated to ensure the energy dose is consistent and at an effective level.
Critical control points outlined in water quality management plans are used to ensure treatment is operating appropriately for safe drinking water quality.