Efficiency of Plant Nasturtium aquaticum for Biological Ramoval of the Nutrients of Rainbow Trout Pond Wastewater

 In this study, an indoor fish farm was selected to assess the biological treatment of the waste effluents. The purification lagoon surface was completely grown by target species, Nasturtium aquaticum. Six stations were selected as the water source, the farm outlet, the starting point of outlet water to the lagoon and three next other sampling stations. The averages of many chemical parameters of the stations water were compared and their trends were analyzed. The dissolved oxygen values exhibited the most fluctuations and greatest impact on the biological or chemical process of waste water. The values change of the other parameters at the stations were not great. Nitrate values did not significantly decrease after the farm outlet, which could be due to the relatively high nitrate content of the source, and so the lack of nitrogen absorption ability by the plants. The nitrite content in the experimental lagoon was decreased, but was affected by the ambient oxygen concentration (recorded in the stations). The results showed that measured ammonia values of the other stations of the lagoon were lower than its output concentration at the outlet station because of the influence of plant mass purification. The rate of ammonia reduction in the lagoon appears to have been influenced by the reduction in ambient dissolved oxygen at the latest station. The greater efficiency of the lagoon in the control and reduction of ammonia can be explained by the ability of ammonia to be absorbed by the N. aquaticum species relative to other nutrients.