Coagulation is a somewhat simple chemical process that involves bringing insoluble materials together by manipulating the charges of particles, by adding iron or aluminum salts, such as aluminum sulfate or ferric sulfate, to a wastewater stream. The primary purpose of using a coagulant besides removing vary fine particles from suspension is that this process results also in less turbidity of the water, i.e. clearer water.
With coagulants’ positive charge, the negatively charged particles in the water are neutralized. This causes the suspended solids in the water to bind together into larger flocs. These larger flocs begin to settle at the base of the water supply. The larger the size of the particles, the quicker the floc settles.
Coagulation helps to remove a number of different pollutants that cause your water to become dirty or toxic, including:
- Organic compounds and certain dissolved organic materials, commonly referred to as Natural Organic Matter (NOM) or Dissolved Organic Carbon (DOC)
- Suspended inorganic precipitates like iron and some metals
- Certain viruses and bacteria
Through coagulation, industrial water supplies are put into the perfect chemical state for easy mechanical filtration. Once the flocs settle at the bottom of your clarifier, equipment like a filter press can then take those larger clumps of aggregated particles and remove them, delivering clean water back into your system.
When used together, coagulants, clarifiers and filter presses offer maximum water reclamation of over 95 percent. With so little water actually discharged with the solids, you can create a nearly closed-loop process.
