Print Email Facebook Twitter Removal of both dissolved and particulate iron from groundwater Title Removal of both dissolved and particulate iron from groundwater Author Teunissen, K. Abrahamse, A. Leijssen, H. Rietveld, L. Van Dijk, H. Faculty Civil Engineering and Geosciences Date 2008-06-05 Abstract Iron is the primary source for discolouration problems in the drinking water distribution system. The removal of iron from groundwater is a common treatment step in the production of drinking water. Even when clear water meets the drinking water standards, the water quality in the distribution system can deteriorate due to settling of iron (hydroxide) particles or post-treatment flocculation of dissolved iron. Therefore it is important to remove dissolved and particulate iron to a large extent. This paper describes the study towards the current iron removal processes and experimental work towards improving removal of dissolved and particulate iron. The study was carried out at groundwater treatment plant Harderbroek, consisting of aeration, rapid sand filtration and tower aeration. The research contains two parts: 1) a particle fingerprint of the treatment, resulting in a quantification of particles breaking through the rapid sand filtration. 2) Small column experiments on the oxidation and filterability of iron. The fingerprint showed that operational events such as switching on/off of filters and backwashing have a significant impact on the volume concentration of particles breaking through the filter. A frequency plot of the different size ranges of particles indicates that mainly the filterability of the middle size ranges (2–7 ?m) of particles was influenced by switching a filter on/off. A backwash event mainly affects the bigger particle size ranges. The column experiments showed that in the cascade effluent the majority of the iron is dissolved iron(II), indicating that the oxidation of iron(II) to iron(III) is the rate determining step at Harderbroek, which is limited by pH. Dosing caustic soda resulted in a significant increase of the oxidation rate and improved the removal of iron(II) in the column. Crushed limestone filtration gave promising results, but the contact time applied was too short to completely oxidize iron(II). Subject OA-Fund TU Delft To reference this document use: http://resolver.tudelft.nl/uuid:51ecb58e-b357-46d0-ace6-4fd5cfc02b46 Publisher Delft University of Technology Source Drink. Water Eng. Sci. Discuss., 1, 87-115, 2008 Part of collection Institutional Repository Document type journal article Rights © Author(s) 2008. This work is distributed Files PDF dwesd-1-87-2008.pdf 802.06 KB Close viewer /islandora/object/uuid:51ecb58e-b357-46d0-ace6-4fd5cfc02b46/datastream/OBJ/view