Algal polymorphism in high rate wastewater treatment ponds

In the past as well as today there have been two conflicting opinions as to whether changes in the algal species in water bodies indicate polymorphism or the development of separate species. Similar changes were also found in High Rade Algae Pond (HRAP) used for wastewater treatment, effluent reclamation and protein production. To critically examine both opinions, samples of HRAP effluent were taken and the algal species identified and measured continuously, using conventional methods. Two main algal species were identified. These remained stable during all four monitoring sessions over a three-year period. The external changes observed in the algae were a reflection of controlled periods of organic loading and the conditions under which the pond was operated, such as retention time (a dependant of radiation), ambient temperature, effluent depth and aeration methods.