Effect of Organic Substances on the Efficiency of Fe(Ii) to Fe(Iii) Oxidation and Removal of Iron Compounds from Groundwater in the Sedimentation Process (original) (raw)
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Molecules, 2020
Due to the coexistence of organic matter and iron in groundwater, a certain part of the iron is present as iron-organic complexes in the form of colloids and/or dissolved complexes. The study was conducted to evaluate the impact of the type of oxidizing agent: O2, Cl2, H2O2, or KMnO4, on the efficiency of the oxidation and removal of iron compounds from three groundwaters with significantly different contents and types of organic substances among which humic and fulvic acids occurred. This study shows that after the aeration and the oxidation with Cl2 and H2O2, the increasing content of dissolved hydrophilic organic substances containing aromatic rings in the raw water reduced the effectiveness of Fe(II) oxidation and the effectiveness of iron removal during the sedimentation process. This regularity was not found only when KMnO4 was used as the oxidant. After oxidation with H2O2, the highest number of organo-iron complexes and an increased concentration of dissolved organic carbon ...
Civil and Environmental Engineering Reports, 2017
The article presents the results of studies concerning the impact of the method of Fe(II) ion oxidisation (dissolved oxygen and potassium manganate (VII)) on the effectiveness of coagulation in the removal of iron and manganese from groundwater with an increased content of organic substances. The efficiencies of two coagulants were compared: aluminium sulphate (VI) and polyaluminium chloride (Flokor 1.2A). Among the used methods of iron (II) oxidisation, the best effects have been achieved by potassium manganate (VII) because one of the oxidation products was manganese oxide (IV) precipitating from water. Better results in purifying the water were obtained with the use of a prehydrolysed coagulant Flokor 1.2 A than aluminium sulphate (VI).
Removal of Iron and Organic Substances from Groundwater in an Alkaline Medium
Journal of Environmental Engineering and Landscape Management, 2019
The article discusses the effectiveness of alkalinisation with calcium hydroxide or sodium hydroxide in the treatment of groundwater from Quaternary formations with an increased content of total iron (up to 6.82 mgFe/dm3) and organic substances (TOC up to 5.60 mgC/dm3). The aim of the research was to determine the effectiveness of the groundwater treatment, in particular, the removal of iron and organic substances in the sorption process and co-precipitation with calcium carbonate and magnesium hydroxide. The correction of the reaction was carried out with aqueous solutions of calcium hydroxide and sodium hydroxide in the pH range from 8.5 to 10.5. As the pH of the water increased, the efficiency of its treatment increased. The treatment results depended on the type of alkalizing reagent, especially in the case of removal of organic substances, reduction of colour and organic substances fixed in iron-organic complexes. Higher suitability of calcium hydroxide than sodium hydroxide in...
Techniques for Reducing Iron (Fe) Content in Groundwater: an Article Review
Journal of Islamic Pharmacy, 2021
Iron is a chemical element that is found in almost every place on earth, including in well water or groundwater. Iron can be suspended in water with organic substances or inorganic solids in the form of ferrous cations (Fe2+) and ferries (Fe3+). The presence of iron that exceeds the threshold can cause detrimental effects such as corrosion of the piping, the color of the water turns brown, smells bad, and can cause health problems. The iron content in groundwater can be reduced so that it can be used as water that is fit for consumption or use in everyday life. This study aims to determine several types of techniques used to reduce iron in groundwater or well water through literature studies. Techniques covered include filtration, aeration, adsorption, coagulation, electrocoagulation, and cascade aerators. The results showed that the greatest reduction in efficiency was found in the combination type of adsorption technique and filtration technique by more than 99.1%, then followed b...
Impact of dissolved organic carbon on the removal of iron during water treatment
Water Research, 1992
Ahutraet-The fate of iron complexed by various organic compounds was investigated as a function of both oxidative and coagulation removal methods. Organic compounds evaluated included humic and fulvic acids, tannic acid and oxalic acid. Oxidants evaluated were potassium permanganate, chlorine dioxide and free chlorine. Both laboratory-scale and field monitoring studies were undertaken. Selected samples were analyzed for DOC molecular weight to evaluate how changes in this parameter affected the eificiency of soluble iron removal by either oxidation or alum coagulation. Higher molecular weight DOC sources (e.g. humic and tannic acids) resulted in a high degree of ferrous iron complexation. Such complexation rendered the iron stable a m~inst the addition of each of the oxidants considered. Potassium permanganate was found to be the most effective oxidant of the three investigated. Free chlorine and chlorine dioxide were ineffective for iron removal for all DOC sources except oxalate. Alum coagulation under pH 6.06.3 conditions was very effective for promoting iron removal when the iron was complexed by high molecular weight DOC compounds.
2007
Technological testing of underground waters collected in four localities in the Podkarpackie province and characterized by various physicochemical and chemical parameters is presented. In order to determine the optimum methods of pollutant removal, a number of unit processes were tested. In addition to traditional methods (aeration and filtration through sand bed), the catalytic masses proved to be effective for removing iron and manganese. In the case of water of low hardness, its al-kalization with calcium appears to be a favourable process. The water of excessive hardness was softened by means of sodium hydroxide and in ion exchange process. The process of ion exchange on nitrate-selective anion exchanger appeared to be an effective way of removing nitrate ions.
MATEC Web of Conferences, 2018
Experiments are done for different combinations of Fe+2 and Mn+2 concentrations. The obtained results show that Potassium Permanganate (PP) gives good results in iron and manganese removal. By using PP dose near to half of the theoretically required one, it can remove up to 100 % and 90 % of iron and manganese, respectively over different tested concentrations at pH=7.0. Increasing rate of filtration influences the Mn+2 removal process obviously. Sedimentation is required when combined concentrations of iron and manganese are greater than 5.0 ppm to reduce filter rapid clogging. Using conventional treatment with adding alum, flocculation, sedimentation and filtration can remove up to 97% and 18% of iron and manganese, respectively. Using PP in addition to alum enhances manganese removal but decreases iron removal. However, using alum with increasing pH to 10 leads to 100 % and 95 % of Fe +2 and Mn +2 removal and increases filter working period.
Removal of iron and manganese from groundwater by oxidation and microfiltration
Desalination, 2000
Iron and manganese can be removed from groundwater by a process which combines oxidation and microfiltration (MF), especially when the concentrations of these metals are high and variable. The present experimental work focused on the MF of iron and manganese oxide suspensions in order to study the effects of the operating variables (tangential flow rate, pressure, metal feed concentrations) on permeate quality and permeation flux decline, i.e., membrane fouling. Artificial and natural groundwaters in which iron and manganese were previously oxidized were used to perform laboratory-scale MF experiments. The results show that the oxide particles, with sizes ranging from 1.5 to 5~m, were efficiently microfiltered even at high concentrations. Within the experimental limits, the effect of operating pressure appeared to be much more significant than the those of tangential flow rate and feed concentration. A relatively high and constant permeation rate of 0.5 m/h was obtained at a pressure below 10 kPa, whereas rapid permeation flux declines were observed at higher pressure. Both artificial and natural groundwaters always exhibited very similar behavior.
Aqua, 2015
In groundwater treatment, after aeration, iron(II) is precipitated in rapid sand filtration (RSF) by homogeneous, heterogeneous and biological oxidation. The contribution of homogeneous iron(II) oxidation may be calculated from equations and constants available in the literature. Heterogeneous iron(II) oxidation produces hydrous ferric oxides coated filter sand, resulting in a growing filter bed height, from which the contribution of heterogeneous iron(II) oxidation may be estimated. The complement is contributed by biological iron(II) oxidation. At present this contribution may also be estimated by Gallionella spp. counts by quantitative real-time polymerase chain reaction. Based on field data of drinking water treatment plants from the Netherlands and Belgium, it appears that at pH ≈ 7.5 biological iron(II) oxidation is the main iron(II) removal process. At higher pH homogeneous iron(II) oxidation becomes dominant, while at lower pH heterogeneous iron(II) oxidation delivers a relevant contribution. The distribution of these oxidation processes is influenced by RSF operation such as presence of supernatant water, wet or dry (trickle) filtration, oxygen concentration, filter velocity, etc. Experience shows that the distribution between these three iron(II) oxidation processes may change over time. These results are important for RSF operation, iron sludge production, and fields like chemical well clogging.
Removal of Iron and Manganese from Water using filtration by natural materials
Groundwater is the most common resource of drinking water in Slovakia (83.9 percent of the population is supplied with drinking water from ground resources). In localities without a quality drinking water resource (groundwater), the surface water is used for this purpose or water from an other locality is supplied through long-distance distribution systems [1]. In 2006 there were 5,507 groundwater resources registered in Slovakia. On average, the amount of 11.665 l·s -1 was used (8.836 l·s -1 for water supply), including 2.63 l·s -1 that is required to be treated. The treatment is mostly related to undesirable concentrations of iron and manganese. According to the 2006 Report on the Environment in Slovakia, the concentration of iron exceeded the limit 0.2 mg·l -1 in more than 36.5 % of samples, and the concentration of manganese exceeded the limit 0.05 mg·l -1 in more than 40.1% of groundwater samples. The limit values are defined under the Regulation of the Government of Slovak Republic No. 354/2006 specifying the requirements on water intended for human consumption and quality of water intended for human consumption [2].