The concern in mitigating the negative impact generated by the discharge of nutrients in the receiving water body is a challenge for the sustainable development of Brazilian fish farms. Thus, the purpose of this study was to evaluate the water quality and environmental impact caused by trout farming system effluent with focus on discharge of phosphorus. Sampling was performed on a weekly basis in triplicate from September to November 2010. Sample sites were distributed according to the water flow: upstream from trout farming system, water supply, effluent, artificial wetland, mixing zone and downstream (60 m from effluent). In the field, pH, conductivity, dissolved oxygen, water temperature and turbidity were measured. In laboratory, nitrogen and phosphorus series, chlorophyll a, total solids suspended and their organic and inorganic fractions were analyzed. For the good growth of trout in production system, the abiotic factors described in the water quality monitoring demonstrated acceptable values. Environmentally, after passing through the production system and artificial wetland, there was an increase in concentrations of total phosphorus, total nitrogen, orthophosphate, ammonium, chlorophyll a, total solids suspended and their organic and inorganic fractions (P < 0.05). These results are related with the quality of feed, feeding management and the inefficiency of the artificial wetland. Therefore, it is necessary to use best quality feed to meet the nutritional requirements of trout, maintaining an optimal feed conversion and reducing pollution generated by effluent.
 Virtual Library of Sao Paulo State (2007) Geography of Sao Paulo State. (in Portuguese)
 Ministry of Fisheries and Aquaculture (2012) Fisheries and Aquaculture Statistical Bulletin-Brazil 2010. (in Portuguese)
 Sindilariu, P.D., Brinker, A. and Reiter, R. (2009) Factors Influencing the Efficiency of Constructed Wetlands Used for the Treatment of Intensive Trout Farm Effluent. Ecological Engineering, 35, 711-722.
 Amirkolaie, A.K. (2011) Reduction in the Environmental Impact of Waste Discharge by Fish Farms through Feed and Feeding. Reviews in Aquaculture, 3, 19-26.
 Noroozrajabi, A., Ghorbani, R., Abdi, O. and Nabavi, E. (2013) The Impact of Rainbow Trout Farm Effluents on Water Physicochemical Properties of Daryasar Stream. World Journal of Fish and Marine Sciences, 5, 342-346.
 Pulatsu, S., Rad, F., Koksal, G., Aydin, F., Benli, A.C.K. and Topcu, A. (2004) The Impact of Rainbow Trout Farm Effluents on Water Quality of Karasu Stream, Turkey.Turkish Journal of Fisheries and Aquatic Sciences, 4, 9-15.
 Teixeira, E.A., Crepaldi, D.V., Faria, P.M.C., Ribeiro, L.P., Melo, D.C., Euler, A.C.C. and Saliba, E.O.S. (2006) Replacement of Fishmeal in Feeds for Fish. Revista Brasileira de Reproducao Animal, 30, 118-125. (in Portuguese)
 Piedrahita, R.H. (2003) Reducing the Potential Environmental Impact of Tank Aquaculture Effluents through Intensification and Recirculation. Aquaculture, 226, 35-44.
 Boaventura, R., Pedro, A.M., Coimbra, J. and Lencastre, E. (1997) Trout Farm Effluents: Characterization and Impact on the Receiving Streams.Environmental Pollution, 95, 379-387.
 Cao, L., Wang, W., Yang, Y., Yang, C., Yuan, Z., Xiong, S. and Diana, J. (2007) Environmental Impact of Aquaculture and Countermeasures to Aquaculture Pollution in China.Environmental Science and Pollution Research, 14, 452-462.
 Kocer, M.A.T., Kanyilmaz, M., Yilayaz, A. and Sevgili, H. (2013) Waste Loading Into a Regulated Stream from Land-Based Trout Farms. Aquaculture Environment Interactions, 3, 187-195.
 Yalcuk, A., Pakdil, N.B. and Kanturer, O. (2014) Investigation of the Effects of Fish Farms in Bolu (Turkey) on Aquatic Pollution. International Journal of Agricultural and Food Research, 3, 1-13.
 Valderrama, J.C. (1981) The Simultaneous Analysis of Total Nitrogen and Total Phosphorus in Natural Waters. Marine Chemistry, 10, 109-122.
 APHA, AWWA and WPCF (2005) Standard Methods for the Examination of Water and Wastewater. 21st Edition, American Public Health Association, American Water Works Association and Water Pollution Control Federation, Washington DC.
 Teixeira, C., Tundisi, J. and Kutner, M.B. (1965) Plankton Studies in a Mangrove Environment II: The Standing-Stock and some Ecological Factors. Boletim do Instituto Oceanográfico, 14, 13-41.
 Sartory, D.P. and Grobbelaar, J.U. (1984) Extraction of Chlorophyll a from Freshwater Phytoplankton for Spectrophotometric Analysis. Hydrobiologia, 114, 177-187.
 Brazil (2005) CONAMA Resolution No. 357 of March of 2005. Official Gazette of the Federative Republic of Brazil, Brasília. (in Portuguese)
 Bartoli, M., Nizzoli, D., Longhi, D., Laini, A. and Viaroli, P. (2007) Impact of a Trout Farm on the Water Quality of an Apennine Creek from Daily Budgets of Nutrients.Chemistry and Ecology, 23, 1-11.
 Union of Industries of Animal Nutrition (2011) (in Portuguese)
 Miller, D. and Semmens, K. (2002) Waste Management in Aquaculture. West Virginia University, Publication No.. AQ02-1.
 Bergheim, A. and Cripps, S.J. (1998) Effluent Management: Overview of the European Experience. Proceedings of the 2nd International Conference on Recirculating Aquaculture, Roanoke, 16-19 July 1998, 233-244.
 MacMillan, J.R., Huddleston, T., Woolley, M. and Forthergill, K. (2003) Best Management Practice Development to Minimize Environmental Impact from Large Flow through Trout Farms. Aquaculture, 296, 91-99.
 Dalsgaard, J. and Pedersen, P.B. (2011) Solid and Suspended/Dissolved Waste (N, P, O) from Rainbow Trout (Oncorhynchus mykiss). Aquaculture, 313, 92-99.
 Brinker, A., Koppe, W. and Rosch, R. (2005) Optimizing Trout Farm Effluent Treatment by Stabilizing Trout Feces: A Field Trial. North American Journal of Aquaculture, 67, 244-258.