Water Purification: Algae in Wastewater Oxidation Ponds

Waste stabilization ponds have been, for many years, a very common method of wastewater treatment, especially in warm climate areas. These are simple systems; the main advantage of which is the highly efficient destruction of pathogens. It is therefore recommended by the WHO as the process of choice in developing countries to protect human life with the limited resources and skills available. However, in developed countries due to the incomplete purification efficiency and the high consumption of land resources, these processes are gradually disappearing. Alga culture has attracted additional applications, for example, high-rate oxidation ponds, aimed at the exploitation of the high protein content of algae as fish and animal fodder, and for other purposes such as the recent pursuit for alternative biodiesel feedstocks. These applications, however, require high organic and nutrient loads, thereby contradicting the purpose of wastewater treatment. Other limitations such as uncontrolled environmental conditions, fluctuating growth of undesired algal species as well as harvesting difficulties have rendered these applications noneconomical.