Effects of Shrimp feeding on the Increasing of Nitrogen and Phosphorus in white Shrimp Penaeus vannamei ponds

Shrimp farming activities can lead to increase organic and inorganic matters in the aquatic environment and environmental degradation. According to information obtained from the cultivation of the white shrimp Penaeus vannamei in a closed system, only about 31% of nitrogen and 15% of phosphorus Entered by feeding, are absorbed by shrimp and the rests are stored in sediment or dissolved in water. In a 1 hectare pool with a production rate of 3 tons per hectare and a FCR of 1.67, the nitrogen and phosphorus inputs to this pool will be about 283 and 39 kilograms respectively, which only about 88 kg of nitrogen and 6 kg of phosphorus absorb by shrimps and The rest enters the environment. One of the methods of bio-refinery treatment of shrimp farms effluents ,is the transfer of these effluents into a quarantine pond before entering into the natural environment and using biological filters. The waste water is treated step-by-step by various groups of aquatic animals, such as filter feeders (bivalves and barnacles), deposit feeders (polychaete worms and sea cucumbers) and aquatic plants.