Role of pH in Biological Wastewater Treatment Processes

Abstract

pH is an important factor in wastewater treatment processes because of its influence on the process performance and efficiency. It plays an important role in both chemical and biological wastewater treatment systems. In the case of some chemical treatment processes, the pH of the influent is adjusted to the desired level by addition of appropriate chemicals. In biological wastewater treatment processes, although the adjustment of pH to an optimum level is not a means to achieve the stabilization of carbonaceous matter directly, the provision of such optimal pH conditions is conducive to the growth of microorganisms that are responsible for its stabilization. A buffer contains both an acid and a base, and can respond to the addition of either an acid or alkali, with a minimal change in pH. The major chemical equilibria, which are of significance in biological wastewater treatment systems include: carbonate, ammonia, sulfide, and chlorine.