Mineral and lime addition are the principal methods for in-plant removal of phosphorous from wastewater. Lime (Calcium Hydroxide) removes phosphorous through the chemical precipitation of hydroxyapatite. There are no soluble side products from using lime, and it also can be effective to remove oil, grease and scum while being non-corrosive.
In waste treatment lime controls the environment needed for the growth of pathogens in biosolids and converts sludge into a usable product. It also helps to destroy biological waste odors.
Lime can be added in a single-stage or two-stage treatment at either the primary or secondary stage. Lime slurry is pumped into the wastewater to obtain the correct pH, then mixed and passed into flocculation and settling units.
Lime slurry however, is one of the most difficult products to handle due to its abrasiveness, and high solids content. It can wreak havoc on wearing metallic parts and rip through rotors, stators and seals of other pump types causing a maintenance nightmare.
With peristaltic pumps the slurry is secured and only in contact with the hose - maintenance is a breeze.