Ferrous trichloride is a reddish-brown, liquid, highly corrosive substance with an active ingredient based on trivalent iron and a concentration of about 12% Fe3 +, which is used mainly in the treatment of industrial water for coagulation and hence reducing levels of COD, BOD5, Undissolved and extractable substances, and removal of phosphorus and ammonium. The advantage of the offered product is its successful action in terms of wastewater treatment containing nutrients (nutrients), the release of which into the environment poses great risks to human health. Under other conditions, Nitrogen and Phosphorus can be treated only in a separate stage of the treatment plants (which leads to an increase in investment and operating costs), in the case of using iron chloride, the quality of treated water is significantly reduced due to its addition. higher efficiency is achieved in their removal. Other advantages of the product that should be emphasized are the fact that with its optimal dosage it is possible to adjust the degree of load on the biological stage of the treatment process (to reduce downtime - to increase the capacity of the installation), as well as the fact that its use reduces the amount of air consumed for aeration in the biological stage, which leads to a reduction in energy consumption in the biological stage of purification.