Biosolids are primarily organic materials produced during wastewater treatment which may be put to beneficial use. These materials are rich in nitrogen and phosphorus, as well as other valuable micronutrients. Under prevailing United States Environmental Protection Agency (USEPA) standards for the use and disposal of sewage sludge, wastewater solids need to be processed through stabilization prior to the same being used for beneficial purposes.
Stabilization helps facilitate (i) reduction of potential for odor generation, (ii) destruction of disease-causing organisms, and (iii) decrease the material's vector attraction potential. Addition of alkaline materials is one method of stabilization intended to raise the pH level to make conditions unfavorable for the growth of organisms (such as pathogens).