Which substance can be added to a sour digester as a remedial measure?

In the context of addressing acidity in a sour digester, the addition of lime or soda ash serves as an effective remedial measure. These substances are alkaline materials, which means they can neutralize acidic conditions within the digester. When the pH is low, indicative of a sour condition, introducing lime (calcium hydroxide) or soda ash (sodium carbonate) raises the pH, thus helping to restore a more favorable environment for the microbial activity that is critical for the digestion process. This adjustment supports the stabilization of the digestion of organic matter, ultimately enhancing the efficiency of the treatment process.

Calcium carbonate, while also an alkaline substance, has a slower reaction time compared to lime or soda ash and may not be as effective in rapidly correcting sour conditions. Chlorine bleach is a strong oxidizing agent and not suitable for managing pH or acidity levels in digesters, as it could harm beneficial microorganisms. Hydrogen peroxide, being a strong oxidizer, is likewise not intended for pH adjustment and could negatively impact the digestive process if introduced into the system. Therefore, lime or soda ash stands out as the most appropriate choice for stabilizing the sour digester.