What is the minimum pH level for lime stabilization after the first 2 hours?

The minimum pH level for lime stabilization after the first 2 hours is indeed 11.5. During the lime stabilization process, elevating the pH to this level is crucial because it effectively inactivates pathogens and enhances the dewaterability of the sludge.

At a pH of 11.5, lime reacts with the sludge, increasing the available hydroxide ions, which facilitate the coagulation and flocculation of suspended solids. This helps in achieving a significant reduction in harmful pathogens and a safer end product. Furthermore, maintaining this pH level is important for optimizing the chemical reactions that occur during stabilization to ensure that the material meets regulatory and safety standards.

Lime stabilization is a widely used method in wastewater treatment for reducing the volume of sludge and improving its handling. If the pH were to be lower than 11.5, the efficiency of pathogen reduction and stabilization would decrease, potentially compromising the safety and effectiveness of the treatment process.