The Influence of Aeration and Type of Coagulant on Effectiveness in Removing Pollutants from Groundwater in the Process of Coagulation

The subject of research was groundwater from Quaternary formations with high concentration of total iron, increased colour and turbidity, and an increased amount of organic substances and manganese. Successful purification of such water creates technological problems and is practically impossible to achieve by applying traditional groundwater treatment processes. One of the ways recommended for intensifying the removal of iron that occurs in the form of stable iron-organic compounds is the application of the coagulation process. The paper discusses the effectiveness of coagulation with iron(III) sulphate and with two aluminium coagulants: aluminium sulphate and polyaluminium chloride in purifying groundwater without aeration and groundwater aerated for 15 minutes. The aeration of water increased the removal rate of iron and pollutants causing colour and turbidity, but it decreased effectiveness in removing organic substances. The efficiency in purifying water increased as the dose of coagulants increased, and the most effective was polyaluminium chloride. The least effective in removing iron compounds and organic substances, and at the same time in decreasing the intensity of the colour of the water, was iron(III) sulphate.