965 resultados para Water treatment plants


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In many industries, such as petroleum production, and the petrochemical, metal, food and cosmetics industries, wastewaters containing an emulsion of oil in water are often produced. The emulsions consist of water (up to 90%), oils (mineral, animal, vegetable and synthetic), surfactants and other contaminates. In view of its toxic nature and its deleterious effects on the surrounding environment (soil, water) such wastewater needs to be treated before release into natural water ways. Membrane-based processes have successfully been applied in industrial applications and are considered as possible candidates for the treatment of oily wastewaters. Easy operation, lower cost, and in some cases, the ability to reduce contaminants below existing pollution limits are the main advantages of these systems. The main drawback of membranes is flux decline due tofouling and concentration polarisation. The complexity of oil-containing systems demands complementary studies on issues related to the mitigation of fouling and concentration polarisation in membranebased ultrafiltration. In this thesis the effect of different operating conditions (factors) on ultrafiltration of oily water is studied. Important factors are normally correlated and, therefore, their effect should be studied simultaneously. This work uses a novel approach to study different operating conditions, like pressure, flow velocity, and temperature, and solution properties, like oil concentration (cutting oil, diesel, kerosene), pH, and salt concentration (CaCl2 and NaCl)) in the ultrafiltration of oily water, simultaneously and in a systematic way using an experimental design approach. A hypothesis is developed to describe the interaction between the oil drops, salt and the membrane surface. The optimum conditions for ultrafiltration and the contribution of each factor in the ultrafiltration of oily water are evaluated. It is found that the effect on permeate flux of the various factors studied strongly depended on the type of oil, the type of membrane and the amount of salts. The thesis demonstrates that a system containing oil is very complex, and that fouling and flux decline can be observed even at very low pressures. This means that only the weak form of the critical flux exists for such systems. The cleaning of the fouled membranes and the influence of different parameters (flow velocity, temperature, time, pressure, and chemical concentration (SDS, NaOH)) were evaluated in this study. It was observed that fouling, and consequently cleaning, behaved differently for the studied membranes. Of the membranes studied, the membrane with the lowest propensity for fouling and the most easily cleaned was the regenerated cellulose membrane (C100H). In order to get more information about the interaction between the membrane and the components of the emulsion, a streaming potential study was performed on the membrane. The experiments were carried out at different pH and oil concentration. It was seen that oily water changed the surface charge of the membrane significantly. The surface charge and the streaming potential during different stages of filtration were measured and analysed being a new method for fouling of oil in this thesis. The surface charge varied in different stages of filtration. It was found that the surface charge of a cleaned membrane was not the same as initially; however, the permeability was equal to that of a virgin membrane. The effect of filtration mode was studied by performing the filtration in both cross-flow and deadend mode. The effect of salt on performance was considered in both studies. It was found that salt decreased the permeate flux even at low concentration. To test the effect of hydrophilicity change, the commercial membranes used in this thesis were modified by grafting (PNIPAAm) on their surfaces. A new technique (corona treatment) was used for this modification. The effect of modification on permeate flux and retention was evaluated. The modified membranes changed their pore size around 33oC resulting in different retention and permeability. The obtained results in this thesis can be applied to optimise the operation of a membrane plant under normal or shock conditions or to modify the process such that it becomes more efficient or effective.

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The project "Water and Environment"for the improvement of educational practices in the aquatic environment, is a research project led by four members of the Research Group of Physical Education at the University of Vic (GREF) experts in water activities. The aim is to train the technicians who teach swimming during school hours. The training is based on improving water treatment practices and competence to face a contradictory scene where clubs develop educational content and where schools transfer to clubs part of its educational activity to contribute significantly and positively to water activities fitting the educational curriculum.

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The nutrient load to the Gulf of Finland has started to increase as a result of the strong economic recovery in agriculture and livestock farming in the Leningrad region. Also sludge produced from municipal wastewater treatment plant of the Leningrad region causes the great impact on the environment, but still the main options for its treatment is disposal on the sludge beds or Landfills. The aim of this study was to evaluate the implementation of possible joint treatment methods of manure form livestock and poultry enterprises and sewage sludge produced from municipal wastewater treatment plants in the Leningrad region. The study is based on published data. The most attention was put on the anaerobic digestion and incineration methods. The manure and sewage sludge generation for the whole Leningrad region and energy potential produced from their treatment were estimated. The calculations showed that total amount of sewage sludge generation is 1 348 000 t/a calculated on wet matter and manure generation is 3 445 000 t/a calculated on wet matter. The potential heat release from anaerobic digestion process and incineration process is 4 880 000 GJ/a and 5 950 000 GJ/a, respectively. Furthermore, the work gives the overview of the general Russian and Finnish legislation concerning manure and sewage sludge treatment. In the Gatchina district it was chosen the WWTP and livestock and poultry enterprises for evaluation of the centralized treatment plant implementation based on anaerobic digestion and incineration methods. The electricity and heat power of plant based on biogas combustion process is 4.3 MW and 7.8 MW, respectively. The electricity and heat power of plant based on manure and sewage sludge incineration process is 3.0 MW and 6.1 MW, respectively.

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Diplomityön tavoitteena oli tutkia biokaasulaitoksen rejektivesien ominaisuuksiin vaikuttavia tekijöitä ja rejektiveden esikäsittelyn tarpeellisuutta. Lisäksi tavoitteena oli tarkastella Kouvolaan suunnitteilla olevan Kymen Bioenergia Oy:n biokaasulaitoksen rejektivesien vaikutusta Kouvolan Veden Mäkikylän jätevedenpuhdistamolla. Biokaasulaitoksen rejektivedet ovat yhdyskuntajätevesiin verrattuna selvästi konsentroituneempia. Jätevedenpuhdistamoilla erityisesti rejektiveden korkea typpipitoisuus aiheuttaa lisäkuormitusta. Suomessa toiminnassa oleville biokaasulaitoksille tehdyn kyselytutkimuksen tulosten perusteella rejektiveden typpipitoisuuteen vaikuttaa syötteen typpipitoisuus sekä mädätysjäännöksen kuivauksen tehokkuus. Rejektiveden kiintoainepitoisuudella on puolestaan vaikutusta biologiseen hapenkulutukseen ja välillisesti myös rejektiveden kemialliseen hapenkulutukseen. Rejektivesien jätevedenpuhdistamoilla aiheuttamaa kuormitusta on mahdollista vähentää esikäsittelemällä rejektivedet joko biologisella tai fysikaalis-kemiallisella puhdistusmenetelmällä. Kyselytutkimus kuitenkin osoitti, että rejektivesien esikäsittelyssä ei aina päästä puhdistustavoitteeseen. Jätevedenkäsittelyn sijaan rejektivesiä on mahdollista käyttää lannoitteena, mikäli biokaasulaitoksen syöte ei sisällä jätevedenpuhdistamon lietteitä. Myös Kouvolan Veden Mäkikylän puhdistamolla biokaasulaitoksen rejektivedet tulevat lisäämään merkittävästi tulovirtaaman typpikuormaa. Typpikuorman lisäys edellyttää ilmastusaltaassa ilmastuksen tehostamista sekä kalkin syöttömäärän lisäämistä, jotta jäteveden happipitoisuus ja pH pysyvät typenpoistoreaktioille suotuisina. Lisäksi tulovirtaamasta puolet tullaan ohjaamaan esiselkeyttimen ohi, jotta ilmastusaltaassa on orgaanista ainetta typenpoistoon riittävästi. Mäkikylän puhdistamon typenpoistokapasiteettia on mahdollista kasvattaa lisähiilen syötöllä. Mikäli biokaasulaitoksen kapasiteettilisäyksen jälkeen rejektivesien typpikuoma ylittää lisähiilellä saavutetun lisäkapasiteetin, on rejektivedet esikäsiteltävä.

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Original sludge from wastewater treatment plants (WWTPs) usually has a poor dewaterability. Conventionally, mechanical dewatering methods are used to increase the dry solids (DS) content of the sludge. However, sludge dewatering is an important economic factor in the operation of WWTPs, high water content in the final sludge cake is commonly related to an increase in transport and disposal costs. Electro‐dewatering could be a potential technique to reduce the water content of the final sludge cake, but the parameters affecting the performance of electro‐dewatering and the quality of the resulting sludge cake, as well as removed water, are not sufficiently well known. In this research, non‐pressure and pressure‐driven experiments were set up to investigate the effect of various parameters and experimental strategies on electro‐dewatering. Migration behaviour of organic compounds and metals was also studied. Application of electrical field significantly improved the dewatering performance in comparison to experiments without electric field. Electro‐dewatering increased the DS content of the sludge from 15% to 40 % in non‐pressure applications and from 8% to 41% in pressure‐driven applications. DS contents were significantly higher than typically obtained with mechanical dewatering techniques in wastewater treatment plant. The better performance of the pressure‐driven dewatering was associated to a higher current density at the beginning and higher electric field strength later on in the experiments. The applied voltage was one of the major parameters affecting dewatering time, water removal rate and DS content of the sludge cake. By decreasing the sludge loading rate, higher electrical field strength was established between the electrodes, which has a positive effect on an increase in DS content of the final sludge cake. However interrupted voltage application had anegative impact on dewatering in this study, probably because the off‐times were too long. Other factors affecting dewatering performance were associated to the original sludge characteristics and sludge conditioning. Anaerobic digestion of the sludge with high pH buffering capacity, polymer addition and freeze/thaw conditioning had a positive impact on dewatering. The impact of pH on electro‐dewatering was related to the surface charge of the particles measured as zeta‐potential. One of the differences between electro‐dewatering and mechanical dewatering technologies is that electro‐dewatering actively removes ionic compounds from the sludge. In this study, dissolution and migration of organic compounds (such as shortchain fatty acids), macro metals (Na, K, Ca, Mg, Fe) and trace metals (Ni, Mn, Zn, Cr) was investigated. The migration of the metals depended on the fractionation and electrical field strength. These compounds may have both negative and positive impacts on the reuse and recycling of the sludge and removed water. Based on the experimental results of this study, electro‐dewatering process can be optimized in terms of dewatering time, desired DS content, power consumption and chemical usage.

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Phosphorus and nitrogen cause eutrophication of water bodies, causing severe damage to the ecosystem. Eutrophication of the waters causes oxygen depletion, which in turn increases fish mortality, releasing toxins in waters. The released toxins can cause damage to animals and humans, which is the reason in many countries to set emission limits for waste water. Nutrients exist naturally, but due to human activities there is high nutrient leaching to water bodies. Human activity is one of the main reasons to the eutrophication. The aim of this thesis was to estimate the suitability of different water treatment options for Yara Finland’s fertilizer plant’s process waters in Siilinjärvi. The fertilizer plant process waters are high concentrate and especially nitrogen concentrations are high, which bring challenge to the treatment. At the theoretical part was investigated conventional and as well advanced wastewater treatment methods like reverse osmosis, adsorption and ion exchange. Beside different treatment methods corporate environmental requirements, responsibility and strategies were researched. At the empirical part of the thesis the goal was to find out possibil-ities to intensify the efficiency of purification at lamella clarifier with chemical precipitation. In addition possibility to use already existing chemical purifying plant for process waters was estimated. As a result of the research Yara has a possibility to intensify lamella clarifier’s action by addi-tion of calcium hydroxide and thus to obtain the phosphorus and fluorine to precipitate out of the water. But in practice this would be too expensive. It is possible to eliminate nitrogen compounds by adsorption or ammonia stripping, both methods requires additional testing. It is possible to process waters in chemical purifying plant, if ammonium nitrogen has been reduced before. Reverse osmosis is possible to exploit for the phosphoric acid plant’s waters.

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This study aimed to evaluate the effect of Moringa oleifera Lam extract on the removal of total solids (TS), total suspended solids (TSS) and chemical oxygen demand (COD), in different filter media for treating wastewater of dairy cattle breeding (DCW). The moringa seed extract was obtained by grinding 50 g of seeds in one liter of distilled water and, after passing the solution through a quantitative paper filter of 25 microns, 60 mL of the extract were added to wastewater from cattle breeding before the filtration process in organic filters made of thin coal, bamboo leaves, eucalyptus leaves, gliricidia branches and sawdust. This was followed by the completely randomized experimental design, adopting a factorial of 5 x 2. Aliquots of filtered effluent were collected and the total solids (TS) concentrations, total suspended solids (TSS) and chemical oxygen demand (COD) were determined. It was found that the increase in the efficiency of removal of COD and total solids can be attributed to the coagulating power of the moringa seed extract, wherein the filter medium with bamboo leaves presented the best performance, showing potential for use as alternative filter material in the primary treatment of DCW.

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Irrigation plays an important role for grape’s yield as well as on its quality for winemaking. Thus, the effects of deficit irrigation strategies on yield and quality of wine grapes cv. Syrah were evaluated in Petrolina, State of Pernambuco, Brazil. Evaluations were carried out throughout the second and third growing seasons, which were from November 2010 to February 2011 (rainy season) and from May to September 2011 (dry season), respectively. Vines were drip irrigated and the experimental design was completely randomized with three treatments and four replications. The treatments were full irrigation (FI), performed according crop evapotranspiration; regulated deficit irrigation (RDI), in which irrigation was interrupted in phenological growth stage of bunch closure, but was occasionally performed according soil water monitoring of the root zone; and deficit irrigation (DI), when irrigation was interrupted from bunch closure to harvesting. Differences on leaf water content among treatments were observed in both growing seasons and RDI and DI treatment plants presented moderate water stress. The number of bunches did not differ among treatments in both growing seasons; however, bunch weight per plant, average bunch weight and soluble solid content were higher in FI treatment during the dry season. Deficit irrigation strategies promoted water saving.

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ABSTRACT Water and sewage treatment plants (STP and WTP) generate as byproduct a significant amount of sludge with environment harmful elements. Sending to landfills or depositing on the ground or rivers are respectively expensive and dangerous alternatives. In this scenario, the use of this waste in paving processes is a promising alternative for disposal thereof. In this study, we focused on characterizing sludge and evaluating its use in paving, which showed satisfactory results for use in base and sub-base floors.

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Tässä raportissa tarkastellaan Saaristomeren ja Ahvenmaan merialueen kuormitusta ja tilaa ja niissä viime vuosikymmeninä tapahtuneita muutoksia vuosiin 2008 ja 2009 saakka. Pääpaino on ravinnekuormituksessa ja veden laadussa, mutta mukana on taustatietoa ja muun muassa katsaus kalakannoista. Saaristomeren ja Ahvenanmaan merialueen tila on heikentynyt huomattavasti viimeisten vuosikymmenten aikana. Erityisesti fosforin ja a-klorofyllin määrät ovat kasvaneet ja näkösyvyys pienenentynyt. Viimeisen kymmenen vuoden aikana pintaveden fosforipitoisuuden kasvu on laantunut suurimmassa osassa aluetta, mutta pohjanläheisessä vesikerroksessa ja talvella fosforipitoisuus on jatkanut kasvuaan monin paikoin viime vuosiin asti. Myös a-klorofyllin määrä on lisääntynyt ulko- ja välisaaristossa 2000-luvullakin. Viime vuosina klorofyllipitoisuuden kasvu on kuitenkin laantunut tai pitoisuus laskenut varsinkin rannikonläheisissä vesissä. Merialueen suurin paikallinen ravinnekuormittaja on maatalous, mutta varsinkin typpeä tulee runsaasti myös ilmalaskeumana. Sisäinen kuormitus ja virtausten mukana Suomenlahdelta ja muualta Itämereltä tulevat ravinteet heikentävät niin ikään merialueen tilaa. Muita ravinnelähteitä ovat mm. haja-asutus, jätevedenpuhdistamot ja kalankasvatus. Ahvenanmaan merialueelle ravinteita tulee enemmän muualta kuin Ahvenanmaalta. Hajakuormituksessa on tapahtunut viime vuosikymmeninä selviä vuodenaikaisia muutoksia. Vuosina 1990 – 2009 jokien mereen tuoma ravinne- ja kiintoainekuormitus on ollut talvisin ja syksyisin selvästi suurempaa kuin vuosina 1970 – 1989. Talviaikaisen kuormituksen lisääntyminen johtuu aiempaa lauhemmista talvista, ja antaa viitteitä ilmastonmuutoksen mukanaan tuomista muutoksista. Vaikka Saaristomeren ja Ahvenanmaan merialueen tilassa on ollut viime aikoina nähtävissä myönteisiäkin merkkejä, on niiden tila edelleen huolestuttava. Ainoa keino merialueen tilan parantamiseksi on kuormituksen huomattava vähentäminen. Vähentäminen koskee niin paikallisia ravinnelähteitä, erityisesti maataloutta, kuin muualta Itämereltä virtausten mukana tulevia ravinteita ja ilmalaskeumaa.

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Thousands of tons of pharmaceuticals are consumed yearly worldwide. Due to the continuous and increasing consumption and their incomplete elimination in wastewater treatment plants (WWTP), pharmaceuticals and their metabolites can be detected in receiving waters, although at low concentrations (ng to low μg/L). As bioactive molecules the presence of pharmaceuticals in the aquatic environment must be considered potentially hazardous for the aquatic organisms. In this thesis, the biotransformation and excretion of pharmaceuticals in fish was studied. The main biotransformation pathways of three anti‐inflammatory drugs, diclofenac, naproxen and ibuprofen, in rainbow trout were glucuronidation and taurine conjugation of the parent compounds and their phase I metabolites. The same metabolites were present in fish bile in aquatic exposures as in fish dosed with intraperitoneal injection. Higher bioconcentration factor in bile (BCFbile) was found for ibuprofen when compared to diclofenac and naproxen. Laboratory exposure studies were followed by a study of uptake of pharmaceuticals in a wild fish population living in lake contaminated with WWTP effluents. Of the analyzed 17 pharmaceuticals and six phase I metabolites, only diclofenac, naproxen and ibuprofen was present in bream and roach bile. It was shown, that diclofenac, naproxen and ibuprofen excreted by the liver can be found in rainbow trout and in two native fish species living in the receiving waters. In the bream and roach bile, the concentrations of diclofenac, naproxen and ibuprofen were roughly 1000 times higher than those found in the lake water, while in the laboratory exposures, the bioconcentration of the compounds and their metabolites in rainbow trout bile were at the same level as in wild fish or an order of magnitude higher. Thus, the parent compounds and their metabolites in fish bile can be used as a reliable biomarker to monitor the exposure of fish to environmental pharmaceuticals present in water receiving discharges from WWTPs.

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Interest in water treatment by electrochemical methods has grown in recent years. Electrochemical oxidation has been applied particularly successfully to degrade different organic pollutants and disinfect drinking water. This study summarizes the effectiveness of the electrochemical oxidation technique in inactivating different primary biofilm forming paper mill bacteria as well as sulphide and organic material in pulp and paper mill wastewater in laboratory scale batch experiments. Three different electrodes, borondoped diamond (BDD), mixed metal oxide (MMO) and PbO2, were employed as anodes. The impact on inactivation efficiency of parameters such as current density and initial pH or chloride concentration of synthetic paper machine water was studied. The electrochemical behaviour of the electrodes was investigated by cyclic voltammetry with MMO, BDD and PbO2 electrodes in synthetic paper mill water as also with MMO and stainless steel electrodes with biocides. Some suggestions on the formation of different oxidants and oxidation mechanisms were also presented during the treatment. Aerobic paper mill bacteria species (Deinococcus geothermalis, Pseudoxanthomonas taiwanensis and Meiothermus silvanus) were inactivated effectively (>2 log) at MMO electrodes by current density of 50 mA/cm2 and the time taken three minutes. Increasing current density and initial chloride concentration of paper mill water increased the inactivation rate of Deinococcus geothermalis. The inactivation order of different bacteria species was Meiothermus silvanus > Pseudoxanthomonas taiwanensis > Deinococcus geothermalis. It was observed that inactivation was mainly due to the electrochemically generated chlorine/hypochlorite from chloride present in the water and also residual disinfection by chlorine/hypochlorite occurred. In real paper mill effluent treatment sulphide oxidation was effective with all the different initial concentrations (almost 100% reduction, current density 42.9 mA/cm2) and also anaerobic bacteria inactivation was observed (almost 90% reduction by chloride concentration of 164 mg/L and current density of 42.9 mA/cm2 in five minutes). Organic material removal was not as effective when comparing with other tested techniques, probably due to the relatively low treatment times. Cyclic voltammograms in synthetic paper mill water with stainless steel electrode showed that H2O2 could be degraded to radicals during the cathodic runs. This emphasises strong potential of combined electrochemical treatment with this biocide in bacteria inactivation in paper mill environments.

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Käänteisosmoosisuodatusta käytetään erityisesti teollisuuden jätevesien loppupuhdistuksessa. Suodatuksen ongelmana on kalvojen likaantuminen ja tukkiutuminen. Tässä työssä on aiempia tutkimuksia hyväksikäyttäen tutkittu käänteisosmoosiin tulevan veden esikäsittelemistä niin, että kalvojen likaantumiselta vältyttäisiin. Menetelmien vertailussa on käytetty erilaisia veden laadusta kertovia parametreja. Ongelmallisimmiksi aineksiksi huomattiin orgaaninen aines ja jotkin veteen liuenneet ionit. Kiintoaineen erottaminen ei ole ollut suuri ongelma, sillä sen saa poistettua tavallisesti käytetyillä rakeissuodatuksella, laskeutuksella, flotaatiolla ja kalvosuodatuksella. Orgaanista ainesta on saatu erotettua erityisesti hapettamalla, aktiivilieteprosessilla ja biologisella aktiivihiilisuodattimella. Mikro- ja ultrasuodatusta käytetään usein juuri ennen käänteisosmoosia poistamaan erityisesti kolloidista materiaalia ja joitain liuenneita ioneja. Flokkien muodostaminen koagulaatiossa ja flokkulaatiossa parantaa lähes kaikkien menetelmien toimivuutta selvästi. Veden puhdistuksessa käytetyt kemikaalit voivat myös liika-annosteltuina liata kalvoja. Vesien pitoisuuksissa eri ainesten osalta on huomattavia eroja, joten puhdistettava vesi on hyvä analysoida etukäteen parhaiden käsittelymenetelmien valitsemiseksi.

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The study evaluates the potential application of chemical substances, obtained from biogas plants` by-products. Through the anaerobic digestion process with biogas the large amount of digestate is produced. This digestate mainly consists on the organic matter with the high concentration of nutrients such as nitrogen and phosphorus. During ammonia stripping and phosphorus precipitation the products- ammonia water, ammonium sulfate, ammonium nitrate, ferrous phosphate, aluminum phosphate, calcium phosphate and struvite can be recovered. These chemicals have potential application in different industrial sectors. According to Finnish market and chemicals properties, the most perspective industrial applications were determined. Based on the data, obtained through the literature review and market study, the ammonia water was recognized as a most perspective recovered substances. According to interview provided among Finnish companies, ammonia water is used for flue gas treatment in SNCR technology. This application has a large scale in the framework of Finnish industrial sectors. As well nitrogen with phosphorous can be used as a source of nutrients in the biological wastewater treatment plants of paper mills.

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The acid mining drainage is considered the most significant environmental pollution problem around the world for the extensive formation acidic leachates containing heavy metals. Adsorption is widely used methods in water treatment due to it easy operation and the availability of a wide variety of commercial adsorbent (low cost). The primary goal of this thesis was to investigate the efficiency of neutralizing agents, CaCO3 and CaSiO3, and metal adsorption materials with unmodified limestone from Company Nordkalk Oy. In addition to this, the side materials of limestone mining were tested for iron adsorption from acidic model solution. This study was executed at Lappeenranta University of Technology, Finland. The work utilised fixed-bed adsorption column as the main equipment and large fluidized column. Atomic absorption spectroscopy (AAS) and x-ray diffraction (XRD) was used to determine ferric removal and the composition of material respectively. The results suggest a high potential for the studied materials to be used a low cost adsorbents in acid mine drainage treatment. From the two studied adsorbents, the FS material was more suitable than the Gotland material. Based on the findings, it is recommended that further studies might include detailed analysis of Gotland materials.