Any pond, natural or artificial, receiving raw or partially treated sewage or waste, in which stabilization occurs through sunlight, air and microorganisms. Waste Stabilization Ponds (WSP), are also known by the name of oxidation ponds or lagoons. They act as holding basins for secondary wastewater treatment, Here organic matter is decomposed naturally, i.e. biologically. In WSP waste is stabilized and pathogens reduced through the action of bacteria and algae. The process aims to convert organic content of the effluent to more stable forms.