By: Zakeyah Alsharif
In medical devices reprocessing, water is used almost during all of the steps. Starting from pre-cleaning to sterilization. Therefore, it is important to use high quality water; very pure water. The Association for the Advancement of Medical Instrumentation’s (AAMI) TIR34 Water for the reprocessing of medical devices, defines water quality as the descriptor of the levels of various impurities present in water. So, based on the impurities found on the water we can determine the quality of the water. Water with high concentration of impurities consider poor water and water with low concentration of impurities consider high quality water.
AAMI TIR34:
2014 introduces two categories of water quality available for instrument reprocessing: Utility water and Critical water. Utility water often referred to as tap water, is used mainly for flushing, washing, and rinsing. Not all tap water is acceptable for sterile processing. It can be used after analyzing it by an expert. Critical water is extensively treated, usually by a multistep treatment process that may include softening, deionization, reverse osmosis, and distillation.
The key factor in water treatment is knowing your water, and based on the contents you can install the proper treatment system. Each treatment is targeting a specific impurities. For example if the water contain excess of iron, you need to use the iron filter system.
There are many well-known treatment system that is used to purify water. Distillation is the traditional method of purifying water. It simply done by heating the water to converting it to a gaseous form and then cool it down to return to the liquid form. By performing the distillation, microorganisms like bacteria, viruses, protozoan cysts will be removed.
The other methodology of treating the water is softening. To fairly understand softening, we need to know what is hard water. In simple, hard water is water that has high mineral content. So, soft water means water that contains low concentrations of ions and in particular is low in ions of calcium and magnesium. A water softener is an ion exchanger. It is not a water filter.
The most famous technology for treating water is reverse osmosis (RO). In this method, a large majority of impurities will be removed from water by pushing the water under pressure through a semi-permeable membrane. Reverse osmosis water will be free from most microorganisms and impurities. It is better to soften the water before using the RO system because the hardness of the water will cause scaling of the membrane and the filter will be changed frequently which will be expensive.
There are other treatment systems that can be used to treat water like deionization which is used to get rid of ionized minerals and salts. Also, the sand filter is used to remove large particles from the water. Another filter is the activated carbon filter which can remove the taste, the odor, and some organic content from the water.
At the end here is how the water treatment system is installed in one CSSD in a well-known hospital in Jeddah. First, the impure water is filled in a tank. Then, it will go through the sand filter, iron filter, carbon filter, and then it will go through the softening system. At that point, it will be followed by the deionization system. Before we can use the pure water in the CSSD, the water finally will go through the RO system.
