"The overall study results revealed that the CHLOR-FLOC system was not adequate to physically remove, or to provide adequate chemical disinfection of, Cryptosporidium oocysts to the required level of 99.9 percent reduction. Water, Purification, CHLOR-FLOC tablets, Micro-organisms, Cryptosporidium, Klebseilla, Echovirus, Latex beads, Protozoan cysts, Bacteria, Disinfection, Coagulation." Source: oai.dtic.mil

Purifying water can be done through a variety of methods, like using a filter, treating with chemicals, or boiling. Water should be purified whenever you have reason to believe that it could be contaminated. Typically, this is necessary if you are camping in the wilderness or your home water source has been compromised. Whatever the reason, purifying water will remove any sediments and contaminants, as well as kill any germs, so that you can enjoy clean water without worrying about getting sick.
We were looking for to replace an RO unit that was many years old and were impressed with iSpring's RO / UV / Ph / multi-filter options, with the More-Is-Better paradigm. Patience is required for the multipart installation because the directions are vague. We also had to run a GFCI receptacle for the UV. The UV does warm the water a bit but we remedied this by running an additional line to the fridge for cold water and ice. The system was flushed a half dozen time over two days. The initial glass was cloudy but that cleared to show some carbon from that particular filter. The water taste great and we highly recommend this drinking water system.
One of the first steps in most conventional water purification processes is the addition of chemicals to assist in the removal of particles suspended in water. Particles can be inorganic such as clay and silt or organic such as algae, bacteria, viruses, protozoa and natural organic matter. Inorganic and organic particles contribute to the turbidity and color of water.
These survival tips can help you avoid becoming just another statistic. Accidents are the leading cause of death among U.S. men 18 to 50 years old, accounting for 37,000 of the roughly 148,000 annual fatalities. Some instances of unintentional death, to use the official term, are unavoidable—wrong place, wrong time—but most aren't. Staying alive requires recognizing danger, feeling fear, and reacting. "We interpret external cues through our subconscious fear centers very quickly," says Harvard University's David Ropeik, author of How Risky Is It, Really? Trouble is, even smart, sober, experienced men can fail to register signals of an imminent threat. Here we present 20 easy-to-miss risks, and how to avoid or survive them.
Use water purification and disinfection tablets. Water purification tablets are made of either chlorine dioxide or iodine and kill bacteria and viruses in water. To use these tablets, fill a pitcher or jar with water and add enough tablets to treat the water. One tablet typically treats 1 quart (1 L) of water. These tablets generally need anywhere from 30 minutes to four hours to work.[4]
This water filtration system has 7 stages of treatment, including an 11-watt UV light to zap any microorganisms that may be lurking in well water. While this isn’t usually a major concern for homeowners on municipal water, the conditions of a well sometimes harbor bacteria and microorganisms that could pass through your plumbing and into your glass. A UV sterilizer is an efficient, effective way to eliminate this risk and have more peace of mind when drinking well water.
Ultraviolet light (UV) is very effective at inactivating cysts, in low turbidity water. UV light's disinfection effectiveness decreases as turbidity increases, a result of the absorption, scattering, and shadowing caused by the suspended solids. The main disadvantage to the use of UV radiation is that, like ozone treatment, it leaves no residual disinfectant in the water; therefore, it is sometimes necessary to add a residual disinfectant after the primary disinfection process. This is often done through the addition of chloramines, discussed above as a primary disinfectant. When used in this manner, chloramines provide an effective residual disinfectant with very few of the negative effects of chlorination.

The addition of inorganic coagulants such as aluminum sulfate (or alum) or iron (III) salts such as iron(III) chloride cause several simultaneous chemical and physical interactions on and among the particles. Within seconds, negative charges on the particles are neutralized by inorganic coagulants. Also within seconds, metal hydroxide precipitates of the iron and aluminium ions begin to form. These precipitates combine into larger particles under natural processes such as Brownian motion and through induced mixing which is sometimes referred to as flocculation. Amorphous metal hydroxides are known as "floc". Large, amorphous aluminum and iron (III) hydroxides adsorb and enmesh particles in suspension and facilitate the removal of particles by subsequent processes of sedimentation and filtration.[6]:8.2–8.3