Water treatment is carried out by several methods depending on the quality of the water to be cleaned and the quality demanded of the end product. Most methods include a separation step where the impurities are removed from the water-phase as a firm substance. Such separation may be sedimentation, flotation or filtration. To form a mud which can be easily removed from the water, it is often appropriate and necessary to add flocculents; Protanal® alginates are being used at an increasing rate as such flocculents. Alginates have the advantage of being natural, non-toxic polymers, and furthermore are approved by FAO/WHO as an additive in the food industry. The main areas for alginates in water cleaning are drinking and waste water.