Water treatment is one of the most important parts of every public health program. Contaminated water spreads disease more quickly than any other substance, and a good water treatment program can prevent all of that danger. Since clean water is so vital for human health, governments and medical organizations have put a massive amount of work into finding new water treatment technologies. They can make the difference between sickness and health, so everyone should try to have a basic understanding of them.
Filtration technology is the oldest form of water purification. It’s also very reliable, and most water is filtered in addition to undergoing other treatments. Many individuals who rely on private water treatment depend on it exclusively, and it can significantly reduce the risk of waterborne disease even in the absence of other methods. It is most useful when treating rain or river water, since those sources tend to lack the chemical contaminants which can get through a filter.
Water filters work by allowing water to flow through a material that has many small gaps in it. The gaps are big enough to allow the water to pass through, but small enough to trap most contaminants. In some cases, the gaps can even be small enough to trap bacteria and parasites. Filters come in many different types, including ceramics, charcoal, and even sand, all of which can be useful in different contexts.
Biocides are a special type of additive which exist to destroy living things inside the water, such as bacteria and algae. Most of them are chemicals, but some of them are living microorganisms in their own right.
Biocides are most often used in an industrial context, because they can easily target specific organisms without otherwise impacting the water. That limits their utility in contexts where all contaminants need to be destroyed, but they are a cheap and effective way to deal with a single organism or group thereof, such as those that cause corrosion in underwater metal.
Water treatment plants can make use of a variety of other additives, which are usually chemicals. In most cases, they kill bacteria and other microorganisms that are too small to eliminate through filtrations. In other cases, they can adjust the properties of the water, such as its pH value, to make it more useful for a specific goal. Some additives, such as fluoride, are used due to their medical benefits.
Distillation is rare because it requires a lot of energy, but it can completely purify water without relying on additives. Water is placed in a still and heated until it evaporates. The vapor is collected in another chamber and cooled until it condenses back into liquid form. This leaves behind every contaminant that has a higher boiling point that the water, which is most of them. If there are any with a lower boiling point, they can be evaporated and collected in the same way to get them out of the water.