Water purification is the process in which contaminated, reclaimed, suspicious and/or dirty water undergoes various processes in order to make it suitable for reuse, drinking and/or irrigation. The term Water Purification consists of a wide range of treatment and purification methods ranging from simple water boiling, through biological water purification using organisms such as fish, plants and bacteria, to chemicals such as chlorine and iodine.
Increasing water pollution and overuse, along with the ongoing global water crisis and climate changes, have made water recycling an increasingly popular area of research and work in the past decade. With one out of six people lacking adequate access to clean drinking water, the necessity to find renewable and sustainable sources for drinking water has become more and more urgent over the years.
To accomodate this need for clean water for industrial, agricultural and domestic uses, many methods were developed in order to reclaim, treat and purify water and its sources. The developments and solutions differ between the source of pollution or the water source itself – for instance, well water purification has its own techniques – and new technologies are being developed every day.
Water Purification Methods
The treatment of water includes flocculation (the process of clarifying water) and sedimentation (allowing large particles to sink before pumping). These processes are usually followed by one or more purification methods.
Water purification methods can be divided into two areas: filtration and disinfection. Filtration consists of moving water through various screens and filters in order to remove unwanted particles and matter such as metals and nitrates. Disinfection addresses live organisms in the water, and it is acheived by using chemical or biological agents.
Sand is one of nature’s most effective water filters, and sand filters are frequently used in order to clear drinking water from various materials, usually with the assistance of activated carbon or anthracite coal filters which are more efficient at removing unwanted tastes and odours. In industrial water filtration water pressure is often used to filter water.
Filters can remove materials that did not dissolve in the water, but in order to remove dissolved matter it is necessary to use electrodeionization, Ion Exchange or ultrafiltration membranes. Toxic ions such as lead, arsenic and mercury require such techniques to be removed.
There are also biological filtration methods that use living organisms such as plants and bacteria in order to filter water from toxic ions and other unwanted matter.
Disinfectants are used in order to remove germs, bacteria and other organisms from drinking water. The most common water disinfectant is Chlorine (and its newer counterparts Chloramine and Chlorine Dioxide) which effectively destroys many biological agents in water.
Other disinfection methods include Ozone disinfection, Ultraviolet disinfection, Hydrogen peroxide disinfection, Fluoridation and more.