Sodium bicarbonate is an ideal pH and alkalinity control agent for wastewater treatment. It provides a reserve buffering ability to help prevent upsets in the operating systems of secondary treatment plants that depend on microorganisms to digest organic wastes and control odor.
Acids produced in the waste breakdown process, along with other conditions prevalent in treatment plants tend to lower pH. This alters the biological balance, and can result in bulking sludge, digester upset and the “rotten egg” or hydrogen sulfide odor that usually means trouble and expense for the plant.
Because sodium bicarbonate is buffered, it cannot cause the pH overrun that harsh alkaline chemicals like lime, caustic soda and ammonia can. It can be slug-fed or added continuously to digesters at the operator’s discretion.
In aerobic digestion systems, the optimum feed point is the return sludge line, or at the head of the aeration basin. Since low loading takes place at most wastewater treatment plants during the night, sodium bicarbonate is added in the late afternoon or early evening for best results.
With anaerobic systems, it is recommended that product be applied in the wet well or scum pit on the sludge line leading to the digester. Sodium bicarbonate should be fed in a manner that promotes maximum distribution throughout the digester.