Manganese is typically found in all water supplies in the United States. Manganese concentrations are usually higher in water obtained from groundwater sources or resei:voir hypolinutlons. This is because manganese is more soluble in the reducing conditions normally found in these waters. Although manganese is not known to cause any health related problems, the secondary drinking water MCL for manganese is 0.05 mg/L. This standard was set to eliminate aesthetic problems associated with manganese bearing waters. In this study continuous-flow filters were operated in both pre-oxidative (oxidized Mn applied to filters) and auto-oxidative (soluble Mn applied) modes. The oxidants used were dllorine (HOCl/OCl⁻) , potassium permanganate (KMnO₄), chlorine dioxide (ClO₂), and ozone (O₃). Other experimental parameters included: filter media type - manganese coated or non-coated, filter loading rate --2 to 5 gpm/f², operating pH -- pH 6 to pH 9, and temperature --5 to 25℃. The most important experimental parameter was whether or not the filter media had a prior oxidized coating of manganese. If this was the case the filter produced an effluent concentration of manganese below the MCL under all pre-oxidative conditions and under auto-oxidative conditions when the pH was above neutral. Increased flow rate through the filter caused deeper penetration of manganese into the filter bed. This should not prove to cause an effluent breakthrough problem for filter depths typically used in water treatment plants. Temperature and pH effected the reaction rate of manganese oxidation in both the pre- and auto-oxidative modes. In most cases th.is did not effect the effluent quality from manganese coated filter media. However, when non-coated media was used and no oxidant was added, a decrease in pH or temperature usually adversely effected effluent quality. / M.S.

This study was conducted to examine the kinetics of manganese sorption on oxide-coated filter media. Initial experimentation confirmed the findings of other investigators, the Mn²⁺ sorption capacity of oxide-coated media increases as solution pH increases. Further study revealed that uptake rate kinetics could be described by first order kinetics and also increased with increasing solution pH. The addition of free chlorine (HOCl) to solution greatly enhanced Mn²⁺ uptake rate kinetics. Later studies indicated that the oxide coating had very little impact on the physical properties of the media tested. Actual data from a water treatment plant filter confirmed laboratory experimental results by showing that sorption of soluble manganese does indeed occur on oxide-coated filters. The water treatment plant data also suggested that the sorption kinetics were relatively rapid, again upholding laboratory findings. Results from the manganese kinetics and sorption experiments were combined to formulate a theoretical model which would predict manganese breakthrough in a filter, given a known set of loading parameters. Preliminary use of the model indicated that oxide-coated filters could sorb significant quantities of soluble manganese before detectible levels of manganese appear in the effluent. / Master of Science

This project determined the thermodynamic potentials for various reactions between reduced manganese (Mn²), manganese oxide (MnO₂(s)), chlorine dioxide (Cl0₂), and potassium permanganate (KMnO₄). Based on these findings, laboratory analyses were performed to determine if these reactions would occur under simulated water treatment plant conditions. In addition, a speciation procedure was developed to quantify the various species of manganese and chlorine dioxide present in a single sample. The reactions and the speciation procedure were evaluated at TOC concentrations ranging from < 1.0 mg/L to 5.0 mg/L and at pH 6.0 and 8.0. The speciation procedure yielded a reliable measure of Mn², insoluble manganese, and Mn⁺⁷; however, the Mn⁺⁷ evaluation could be disrupted by the presence of free chlorine. The determination of Cl0₂ and Cl0₂- concentrations was also possible; however, the C10₂- concentration was subject to error. The laboratory analyses revealed that Cl0₂ was unable to oxidize either Mn² or MnO₂(s) to Mn⁺⁷ under any of the thermodynamically favored conditions. Both KMn0₄ and Cl0₂ selectively oxidized reduced organic material before reducing the concentration of Mn². When C10₂ and KMnO₄ were added simultaneously, the ClO2 reacted preferentially with the reduced materials. Only after the Cl0₂ concentration was exhausted did the MnO₂⁻ begin to oxidize the reduced species. / Master of Science

The removal mechanisms of soluble manganese [Mn (1l)] through mixed-media filters were investigated. Experimentation was directed toward the continuous supply of an oxidant during column filter studies. Free chlorine (HOCl, OC1â ) was chosen to increase soluble manganese removal efficiency because chlorine is readily available and inexpensive. Filter media from four different water treatment plants were used in this study. Continuous-flow filter columns were operated in the presence and absence of 2.0 milligrams per Liter (mg/ L) free chlorine. Maintaining constant influent manganese concentrations of 1.0 mg/L and flow rates of 2.5 gallons per minute per foot squared (gpm/ft2), the operational pH values of 6-6.2, 7.8 and 8.8 were investigated. Results indicate that a continuous feed of free chlorine (2 mg/L) applied to the filter columns could increase manganese (II) removal efficiency. However, the amount and oxidation state of the MnOx(S) surface coating initially on the media and the influent pH had major influences upon the uptake of soluble manganese. From numerous Mn (II) uptake studies with different media and varying pH conditions, oxide-coated filter media continuously regenerated with free chlorine could result in increased soluble manganese removal through adsorption upon the MnOx(s) surface coating and subsequent oxidation directly on the media surface. The relationships of manganese removal and chlorine consumed were also explored. To further investigate the mechanisms of free chlorine oxidation for the removal of reduced manganese, pH 5.0 backtitrations were conducted following exhaustion of the filter media. The exposure of such low pll conditions to columns operated in the presence and absence of HOCI would ascertain if oxidation of the adsorbed Mn²⁺ was always occurring, regardless of an oxidant feed. Results indicated that in the absence of HOCI, the mechanisms for manganese removal on oxide-coated filter media were adsorption only. With the additional of HOCI, the adsorbed Mn²⁺ is oxidized directly on the surface of the media, thereby, continuously regenerating the surface oxide coating. Additional work was begun to ascertain if free chlorine could be used as a viable alternative to potassium permanganate (KMnO₄) regeneration of oxide-coated filter media. Preliminary findings indicate from column cycling experiments that free chlorine could be used to regenerate oxide-coated filter media prior to backwashing. / Master of Science

This study deals with a reconstruction of the water treatment plant. The First chapter gives a brief overview of iron and manganese common removal methods. The next chapter looks at technical condition evaluation of urban water networks and presents a new methodology TEA Water developed by Brno University of Technology, module TEAT-Water Treatment Plants in particular. Following chapters describes local water distribution system and current condition of the water treatment plant. The main aim of this thesis is to choose the best suitable technologies for water treatment in order to reduce high operating expenses, especially energy consumption and to reduce volume of backwash water.

Manganese is a problem at the Ni River Water Treatment Plant in Spotsylvania County, Virginia. The Ni River Reservoir (the water source) is a eutrophic reservoir. In the summer, the dissolved oxygen decreases to near or zero at depths greater than two meters. As a result, soluble manganese increases to levels of nearly 6.0 mg/L at the bottom. It is released from the sediments under anaerobic conditions. Total organic carbon levels ranging from 4.0 to 7.25 mg/L were noted with increasing depth. Plant profiles were developed to indicate the performance of the sedimentation and filtration units in reducing manganese concentration. Essentially, all the particulate manganese was removed by sedimentation, and some removal of soluble manganese was evident. The filters removed additional soluble manganese. Soluble manganese removal probably was due to the adsorption of manganese on solid manganese dioxide in the sludge blanket and on the filter media with subsequent further oxidation. Ozone was effective at a dose of approximately 5 mg/L. Chlorine and chlorine dioxide were marginally effective as pretreatments at dosages of 5 and 2 rng/L, respectively. Potassium permanganate proved effective at dosages of 0.5 to 0.625 mg/L (1.5 to 1.9 times the theoretical requirement). Aeration proved effective in reducing levels of approximately 0.1 mg/L to below the secondary maximum contaminant level (0.05 mg/L) and, in addition, somewhat effective in reducing a concentration of nearly 2 mg/L by 31 percent. Aeration appears to be a viable means of reducing the anaerobic conditions in the reservoir that lead to the high soluble manganese concentrations. / M.S.

[pt] Metais quando presentes em concentrações elevadas podem causar danos não só a saúde do homem como também ao meio ambiente, o metal na condição de contaminante abordado neste estudo foi o manganês sendo este importante à vida, mas ao mesmo tempo considerado um contaminante. Sua presença em águas não se dá somente pela ação do homem, podendo este ser encontrado naturalmente em concentrações de até 10 mg/L, embora raramente essa concentração exceda 1 mg/L. Os agentes responsáveis por essa concentração natural de manganês são minerais provenientes do solo e subsolo contendo manganês em sua estrutura. O trabalho desenvolvido estudou a remoção de manganês (II) em sua forma precipitada utilizando-se da adição de determinadas substâncias: Oxigênio, Peróxido de Hidrogênio, Hipoclorito de Sódio, Hipoclorito de Sódio e Peróxido de Hidrogênio, SO2 e Oxigênio, SO2 e Peróxido de Hidrogênio, Carbonato de Sódio e por fim Ácido de Caro, para identificar dentre estes processos um com maior eficiência na remoção de águas e efluentes na sua forma precipitada. Os resultados foram obtidos a partir do tratamento de uma solução sintética com concentração inicial de 10 mg/L de manganês (II), cujo objetivo foi desenvolver caminhos para que este pudesse ser removido na sua forma precipitada e também para enquadramento deste efluente na legislação brasileira (CONAMA número 430/2011), que estabelece concentração máxima de 1,0 mg/L de manganês (II) em águas de Classes 1 e 2. Os ensaios foram realizados em pH 6, 7, 8, 9 e 10 e com utilização dos oxidantes em dosagens com excesso de 100 por cento e 300 por cento. Dentre os testes realizados, os testes com a utilização de Hipoclorito de Sódio, Hipoclorito de Sódio e Peróxido de Hidrogênio, SO2 e Ar, SO2 e Peróxido de Hidrogênio, Carbonato de Sódio e Ácido de Caro apresentaram eficiência na remoção de Manganês (II), atingindo-se concentrações finais de manganês inferiores à 0,01 mg/L em alguns casos. Verificou-se também grande dependência do pH para precipitação, essa ocorrendo em grande parte somente em valores de pH superiores a 7. / [en] Dissolved metals when present in elevated concentrations can cause damage not only to man s health but also to the environment. The metal in the condition of contaminant to be addressed in this study is the manganese which, although being important to life, is also considered a contaminant. Its presence in the water is not only a consequence of man s actions, it being able to be found naturally in concentrations of up to 10 mg/L, although this concentration rarely exceeds 1 mg/L. The agents responsible for this natural concentration of manganese are minerals from the soil and the underground containing manganese in its structure. The work developed studied the removal of manganese (II) in its precipitated form using the addition of determinated substances, such as: Oxygen, Hydrogen Peroxide, Sodium Hypochlorite, Sodium Hypochlorite and Hydrogen Peroxide, SO2 and Air, SO2 and Hydrogen Peroxide, Sodium Carbonate and finally Caro s Acid, to identify among these processes one with more efficiency in the removal of manganese from waters and effluents in its precipitated form. The results discussed were obtained from the treatment of a synthetic solution with initial concentration of 10 mg/L of manganese (II), whose objective was to develop paths so it could be removed in its precipitated form and also for the framework of the effluent in the Brazilian legislation (CONAMA number 430/2011), that establishes maximum concentration of 1 mg/L of manganese (II). The experiments were performed in pH 6, 7, 8, 9 and 10 and with utilization of the oxidants in stoichiometric dosages with excess of 100 per cent and 300 per cent. Among the tests performed, the tests with the use of Sodium Hypochlorite, Sodium Hypochlorite and Hydrogen Peroxide, SO2 e Air, SO2 and Hydrogen Peroxide, Sodium Carbonate and Caro s Acid presented efficiency in the removal of Manganese (II), reaching final concentrations of manganese inferior to 0,01 mg/L in some cases. Great dependency on the pH to precipitation was verified, this happening in great part only in elevated values of pH, these values being superior to 7. It can also be verified in some cases that the concentration of the chemical reagent utilized can have influence over the precipitation of Manganese.