Lime Stabilization

In this process, lime is added to untreated sludge to raise the pH to 12 or higher. The high pH environment inhibits the survival of micro-organisms, and thus eliminates the risk of sludge putrefaction and odour creation. Hydrated lime (Ca (OH)₂) and quicklime (CaO) are most commonly used for lime stabilization. Lime is added either prior to dewatering (lime pre-treatment) or after dewatering (lime post-treatment).