ABSTRACT
Traditional ponds, lakes and lagoons as natural algal photobioreactors are the most attractive and economic options for wastewater treatment and help in remediation functioning as stabilization ponds, facultative lagoons, oxidation ponds, high rate algal ponds. The pond system has been followed globally and can be seen operational in Mediterranean and southern European nations, especially in suburbs comprising of facultative and maturation ponds as in Algeria, Egypt, Greece, Morocco and Tunisia. Facultative system usually provides all dynamic environments such as an aerobic environment in the top predominated by algal communities heterotrophic bacteria; an anaerobic environment at the pond bottom and the middle depth regions that has transient aerobic to anoxic nature, which allows both aerobic and anaerobic bacteria to thrive. Economic viability of treatment systems depends on the location and quantum aspects. Globally, there is great deal of difference in the human resource and commodity/infrastructure availability that sets the labor and the materials cost.
