Aluminium formate was prepared and its coagulation performance regarding different fractions of natural organic matter (NOM) was investigated. Aluminium sulphate was used as the reference coagulant. The raw water used was collected from the River Oulujoki. The fractional composition of the water and the seasonal variation of the composition was also studied. For comparison, lake water from one source was also used. The NOM was fractionated into hydrophobic, transphilic and hydrophilic fractions. Aluminium formate was found to be able to remove the hydrophobic fraction the most readily. The removal of the transphilic and hydrophilic fraction was found to be less effective and also more sensitive to the coagulation pH than the hydrophobic fraction with both of the tested coagulants. Similar results were observed with aluminium sulphate. Aluminium formate was thus found to be a potential alternative in the removal of NOM to traditional aluminium coagulants, which can be harmful to process equipment. (C) 2013 Elsevier B.V. All rights reserved.