Phytoplankton role in waste water treatment by stabilization ponds system

ABSTRACT

In developing countries, oxidation pond system is considered now as a valid means of wastewater treatment, and the effluent can be reused for fish aquaculture or on agricultural land for crop irrigation. Since oxidation ponds require large areas, land should be available at low cost. This could be applied successfully in aired areas affected by water shortage and protein deficiencies. Maturation pond showed their best performance during spring season and at lower detention times in summer and autumn. It was noticed that high temperature, high intensity of light and longer detention times decreased the efficiency of the pond instead of increasing it as a result of the formation of algal mats on the surface. Although algae produce an additional organic load during hot seasons, yet their merits are as follows [1] They constitute valuable source of oxygen in facultative and maturation ponds, leading to an acceleration in the aerobic degradation of organic compounds. [2] They remove appreciable amounts of nitrogen and phosphorus from the final effluent. [3] They play an important role in raising the pH which acts as a bactericidal factor. [4] Finally, algae serve as food source for the fish Tilapia nilotica in the aquacultural pond. Phytoplankton diversity was found to maintain high values in the maturation ponds confirming successful performance of the system in wastewater treatment