NATURAL WATER DEFERRIZATION BY DEEP AERATION METHOD

Abstract

Natural water, both groundwater and surface water, is characterized by high hardness, content of iron and partly manganese, and also dissolved gases. However, prolonged consumption of water with high content of iron compounds can cause the accumulation of its colloidal form in the liver and lead to its destruction. Therefore, water deferrization is an important step in water treatment. Therefore, the purpose of the study is to choose an effective device for water processing and deferrization, and to define optimal conditions of work. The main unit is a horizontal absorber with bucket dispersant. This is a hollow cylindrical device with a diameter of 0.5 m and a length of 0.33 m. The study is conducted with a simulator that contains Fe2+ (mg/dm3): 13.2; 20.6; 30.2; 40.8 and 50.2. When working with low content of iron compounds (from 10 to 20 mg/dm3), 50 % of it can be removed in 30-50 seconds and 100 % – in 2 minutes. The duration of the complete extraction of iron compounds increases significantly with an increase in concentration of Fe2+ and can reach up to 10 minutes (СFe2+ ≥ 40 mg/dm3). Nevertheless, two regions of the process can be observed for all concentrations. The first region is characterized by a sharp decrease in the concentration of iron compounds, namely, oxidation at high speed, and in the second region, these processes are slower. Fictitious oxidation flow rate of Fe2+ to Fe3+ in this region decreases with an increase in iron compounds concentrations and ranges from 9,15 to 5.75 g/m3·min. The oxygen that dissolves in water reacts immediately. In the second region, the concentration of Fe2+ ions is lower, so the probability of their collision and interaction decreases, and the process slows down. This is evident from the fictitious values of the process speed as they are reduced from 4.0 to 0.51 g/m3 ·min for all concentrations. The watering density between the volumes of liquid and gas phases positively affects the process of deferrization of water containing up to 40 mg/dm3 of iron compounds. In this case, the speed of the process increases. Increase in concentration of iron compounds over 40 mg/dm3 slows down the process and affects the quality of water purification. Thus, the absorber with horizontal bucket dispersants can be used for deep aeration and effective purification of natural water from iron compounds.