A recent news article has warned of cryptosporidium parasites in pool water. Another article warns of the same problem. These microbes cannot be removed or killed effectively by the use of chlorine. Ozone is effective but requires high concentrations of the chemical to kill cryptosporidium and the system must be designed specifically for that purpose.
There is an alternative that neither of these articles mentions. Slow sand filtration is the most effective way to actually remove cryptosporiduim from water.
“Of the technologies available to the drinking water industry, membrane processes (forms of micro- and ultra-filtration) appear to provide the most significant levels of Cryptosporidium removal. Conventional treatment practices appear capable of meeting 2-log removals in most of the cases studied to date. Although direct filtration and in-line filtration may be expected to be less effective than conventional treatment, this has not yet been demonstrated in a conclusive manner. Alternative technologies such as diatomaceous earth filtration and slow sand filtration appear capable of achieving comparable, if not better, levels of Cryptosporidium removal than conventional treatment. A comparison of removal efficiencies of some bench-, pilot-, and full-scale water treatment processes is presented in Table 3 below.”
Slow sand filters do not use chemicals to filter water. They use naturally occurring beneficial non-toxic bacteria that actually eat cryptosporidium microbes and all other dangerous micobes. A slow sand filter is actually a small wetland that purifies water naturally. These filters are inexpensive and require very little maintenance and no added chemicals. They are totally sustainable. This entire blog is about slow sand filtration. Why aren’t these people using them?
and here (see page 2 of the document) greater than 99.9 percent removal (removal not just killing – ozone or chlorine only kill the microbe)