Alum/Al2(SO4)3 Powder

What is Alum and How Does it Work?

Alum (aluminum sulfate) is a nontoxic liquid that is commonly used in water treatment plants to clarify drinking water. It’s use in lakes began in the early 1970’s and is used to reduce the amount
of phosphorus in the water. Lower amounts of phosphorus lead to lower amounts of algae and the symptoms associated with poor water quality. Alum is most often used to control phosphorus release from the lake bottom sediments (internal loading). Research has shown that even when external sources of phosphorus from the surrounding watershed are lowered, the internal cycling can continue to support significant nuisance algal blooms.

Alum is applied to lakes using specialized equipment and barges that ensure the precise placement of the material in the lake. On contact with the water, the liquid alum forms a fluffy aluminum hydroxide precipitate called floc. Aluminum hydroxide (the principle ingredient of common antacids such as Maalox) binds with the phosphorus to form an aluminum phosphate compound. The compound is insoluble in water and the bound phosphorus can no longer be used to fuel the algae. As the floc settles, phosphorus and particles are removed from the water column leaving the lake noticeably clearer. The floc then forms a thin layer on the bottom that binds the phosphorus as it leaches out of the bottom sediments during internal loading events. The floc layer keeps the phosphorus from entering the overlying water and makes it unavailable to the algae. The result is a reduction in the frequency and intensity of nuisance algal boom, rather than the total elimination of all algae.

Aluminium Sulphate finds application in various water treatment processes, including:

1. Raw Water Treatment: Aluminium Sulphate is utilised for the treatment of raw water, whether intended for potable water supply or industrial process water. It aids in the removal of impurities, suspended solids, and contaminants, ensuring water meets the required quality standards.
2. Wastewater and Sludge Treatment: Aluminium Sulphate plays a crucial role in wastewater treatment and sludge management at wastewater treatment plants. It aids in the removal of pollutants, organic matter, and suspended solids, facilitating the purification and safe disposal of wastewater.