The amount of cold water fish culture in the country in 2013 was 126,000 tons, which reached 182,601 tons in 2018. This production in Central Province was 2022 tons in 2013, which increased to 6069 tons in 2018. The most important goals of mechanization in aquaculture are to reduce the share of production costs and improve profitability, reduce production risk, observe health and prevent diseases, and observe environmental aspects in production. Improving the quality of farm wastewater and proper nutritional management ultimately lead to productivity. This research was conducted with the aim of investigating the efficiency of mechanization on the quality of wastewater in the dual-purpose farms for raising rainbow trout in Markazi Province. 5 cities with high production capacity and more pools were selected. The selection of farms from each city was done and studied in cooperation and according to the opinion of the provincial fisheries. For this purpose, the experts were sent to the introduced farms and after receiving some information from the province's fisheries and aquatic management, other required information in the form of a questionnaire regarding the existing and active mechanization equipment and technologies used and actual production in the farm, how to treat wastewater the exit, the presence of a disinfection basin at the entrance of all the entrances completed. Some physical and chemical factors of water such as temperature, pH, dissolved oxygen, nitrite, nitrate, ammonium, ammonia, alkalinity, total hardness, electrical conductivity, total dissolved solids and total suspended solids were investigated. The type and flow rate of the water source was also determined. Although the water factors of most of the studied farms were acceptable for raising rainbow trout, various variables such as the amount of production, quantity and quality of food, health management, density, fish weight, how and amount of washing ponds, output and discharge Improper pools, failure to use a siphon between two outlets, failure to implement fishing patterns, improper siphonage and drainage can be effective in farm performance and disrupt the balance of physical and chemical factors of water and the efficiency of mechanized devices and challenge the equipment used in farms.
Keywords: Mechanization, Agricultural dual-purpose fields, Rainbow trout, Agricultural effluent quality, Markazi Province