How to Remove Cryptosporidium from Water?

Cryptosporidiosis is a diarrheal disease disease caused by the tiny parasite Cryptosporidium. Cryptosporidium can live in the guts of several mammals, including humans. It is shaped like egg-like cells, called oocysts, is 4-6 micron in diameter, can survive long-term outside the body, and can be transmitted directly from person to person through contact with carrier animals or ingestion of contaminated water or food. 

Outbreaks of Cryptosporidiosis are found worldwide and can be found anywhere that is contaminated by animal or human waste, such as lakes, streams and reservoirs. Therefore, it is necessary to monitor the quality of water, especially its Cryptosporidium content, and at the same time select a suitable water treatment process to effectively remove Cryptosporidium.

Then how could we remove Cryptosporidium effectively from water? Let's check out the below methods:

1. Drinking Water Disinfection

Cryptosporidiosis outbreaks due to urban drinking water contamination. Bactericidal doses of bleaching powder(5% NaOCl) are ineffective against Cryptosporidium oocysts and can survive exposure for several hours. Although increasing doses can kill oocysts, the doses of chlorine dioxide by-products chlorite and chlorate are also corresponding increase. Ozone is effective for the inactivation of oocysts, but it also requires high doses, and there are side effects after use, that is, ozone has a strong oxidizing ability, which can decompose organic matter in water into nutrients for bacteria in water, and stimulate bacterial growth. Some bacteria are pathogenic, especially in immunocompromised people.

2. Absolute Filtration with Membrane Pleated Filters

The mechanism of removing Cryptosporidium oocysts by filtration can be summarized as: a. The sieving effect of membrane pores; b. Adsorbed on particles in water, then removed by membrane; c. Adsorbed on the surface of the filter membrane; d. Filter cake removal on membrane surface. If Cryptosporidium oocysts are between 4 and 6 micron in size, they may deform and pass a retention filter with a retention threshold greater than or equal to 3 micron. Therefore, to effectively retain these parasites, it is recommended to select a filter system with a cut-off threshold less than or equal to 1 micron.

Hongtek APC Series Pleated Filter Cartridges are tailor-made filtration products for intercepting Cryptosporidium and Giardia intestinalis in water, which can effectively reduce the risk of Cryptosporidium infection.

The APC pleated filter element adopts a progressive pp polypropylene pleated filter membrane, which has strong dirt holding capacity and ensures an absolute retention rate of more than 99.98% at 1 micron (ß >5000), greatly increases the interception efficiency of Cryptosporidium oocysts. The depth filtration mechanism of the APC pleated filter cartridge provides excellent oocyst retention and high throughput, making it widely used in the food, beverage, mineral water and other bottled beverage water treatment industries.

3. UV Oxidation Method

The reason why UV disinfection is used to replace traditional chemical disinfection methods is mainly because UV disinfection is a physical disinfection method, without adding any chemicals to the water, and without producing disinfection by-products. And it has been proved by experiments that UV is a kind of high-efficiency sterilant, which can effectively inactivate microorganisms that are difficult to be effective by chemical agents. 

The disinfection and sterilization of water by ultraviolet rays is mainly through the radiation of ultraviolet rays to microorganisms. The nucleic acid in the organism absorbs the light energy of ultraviolet rays, which damages and destroys the function of the nucleic acid, and kills the microorganisms, thereby achieving the purpose of disinfection. The economics of UV disinfection are even more pronounced when higher inactivation rates are required under poor water quality conditions.