Reduce the environmental impacts of rainbow trout ponds effluent by Biofloc technology Running title: Biofloc and the reduced impacts of effluent

Rainbow trout is the main spices in aquaculture production of Iran، which its effluent، containing organic materials، could alter natural situation of the ecosystem. Biofloc production could reduce the impacts of aquaculture effluent into the environment. In this study the Biofloc production was evaluate to reduce contamination of effluent to the natural resources. Four treatments each with triplicate were designed as control، molasses، sugar and equal combination of molasses and sugar. Two hundred grams of rainbow trout waste materials with six litters of ponds effluent transferred into the glass cone. Then the cones located in a place with constant temperature (25 C) and continue aeration. After measuring the content of rainbow trout waste nitrogen the desired of carbohydrate calculated and added into the cones، respectively. Study was continued for 72 hours and during this time the nitrogen compounds of different treatments with the pH were measured and recorded daily. Results showed final form of nitrogen in control was nitrate and its level significantly (P<0. 05) was higher than the other groups. Also، results indicated that in other groups the nitrate was absorbed by microorganisms and changed to Biofloc. We concluded that in Biofloc technology environmental contamination impacts of aquaculture effluent could reduce efficient by conversion of nitrogen compounds to Biofloc