Suitability of coagulation for treatment of groundwater

Coexistence of organic substances and iron in groundwater causes that a specified part of iron exists as ferro-organic connections taking a form of colloids, or dissolved complexes, and water can be characterized for its increased colour intensity and turbidity. Successful treatment of such water generates technological problems and is practically impossible by means of traditional groundwater treatment processes. Laboratory tests showed, that the effectiveness of treatment of groundwater with a high amount of organic substances and total iron depended on the kind of oxidizing agent, the kind and dose of coagulant, and the time of sedimentation. The effectiveness of the sedimentation process increased with the time of the process, and its results depended most on the method of oxidizing Fe(II). From among the oxidizing agents used before the coagulation process the best results in terms of a decrease in colour, turbidity, the concentration of manganese and organic substances were obtained in the case of oxidization with potassium permanganate, and as far as the effectiveness of removing total iron was concerned oxidizing with dissolved oxygen. Among the coagulants types under analysis (sulphate (VI) of aluminum, polialuminum chloride (PAX XL-60), the best results in removing ferric compounds and organic contamination, and which also ensured the colour as well as the turbidity, were guaranteed by polialuminum chloride. In order to remove manganese and the amounts of total iron, residual aluminum in excess over the standards amounts and in order to decrease turbidity it was necessary to adopt the process of filtration by the filter bed