In the mid-to-late 1800s, chlorine had been used sporadically to help control waterborne illnesses and pollutants in drinking water. This also prompted utilities across the world to begin large-scale filtration of water supplies and wastewater treatment. However, back then filtration alone was inadequate to reduce widespread illnesses and disinfection with chlorination virtually eliminating waterborne epidemics, increasing life expectancy by 50 per cent.

Conventional water and wastewater treatment facilities use various disinfection processes at the head of the treatment work with the aim of not creating chlorine byproducts, thereafter chlorine is applied to the effluent or finished water product to maintain a residual throughout the water distribution system. With increasing water pollution and stringent environmental regulations, it is becoming more difficult to achieve all of the requirements for safe Water and Wastewater disinfection with one treatment alone. Today, more and more people use sodium calcium hypochlorite.

A solid tablet, calcium hypochlorite is typically 60 per cent available chlorine delivered via a dilution tank or tablet feed system whereby the calcium hypochlorite is dissolved into solution then dosed with a metering pump. It is commonly used in swimming pools. Because calcium hypochlorite is expensive per pound of chlorine and is difficult to accurately dose when it is occasionally used for water and wastewater treatment, it is typical for smaller remote plants or treatment works where other methods of chlorine feed are not feasible.

With a well-defined water and wastewater treatment process goals and experience, knowledgeable partners working together, developing the most effective, simple and budget-conscious water and wastewater disinfection plan should be a simple, sustainable and economical process.