d. barlokovÁ, j. ilavský danka barlokovÁ ján ilavskÝ ... · manganese and iron removal was...

D. BARLOKOVÁ, J. iLAVsKý

MODIFIED CLINOPTILOLITE IN THE REMOVAL OF IRON AND MANGANESE FROM WATER

KEY WORDS

• Treatment of water,• Removal of iron and manganese,• Natural materials (Klinopur Mn,

Greensand, Cullsorb M),• Modified Clinoptilolite,• Water analysis.

ABSTRACT

It is necessary to treat water intended for drinking purposes in many cases to meet the requirements of the Regulation of the Government of the Slovak Republic No. 496/2010 on Drinking Water. There is a tendency to look for technology with new, more efficient and cost-effective materials and technologies. The goal of this study is to compare activated natural zeolite known as clinoptilolite (rich deposits of clinoptilolite were found in the region of East Slovakia Region in the 1980s) with the imported Greensand and Cullsorb materials in the removal of iron and manganese from water. The results obtained from experiments carried out at WTP Kúty prove that Klinopur-Mn is suitable for the removal of iron and manganese from water and is comparable with the imported materials.

Danka BARLOKOVÁemail:[email protected]

Ján ILAVSKÝ email:[email protected]

Research field: methods of water treatment, naturalmaterials inwater treatment,water analysis, removalofcontaminantsfromwater

Address:DepartmentofSanitaryandEnvironmentalEngineering,FacultyofCivilEngineering,SlovakUniversityofTechnology,Radlinského11,81368Bratislava

Vol. XX, 2012, No. 3, 1 – 8

1. INTRODuCTION

In Slovakia there are anumber of groundwater resources. Largerresources are unevenly distributed throughout the territory;therefore, the water intended for drinking purposes is suppliedfromsmallerones.Inanevaluationofthequalityofwaterinsmallresources,more than 300 resourceswith higher concentrations ofiron, manganese, nitrates, ammonium ions, arsenic and antimonyhave been identified.This issue has been dealtwith by ateamofexpertsattheWaterResearchInstituteBratislava.Theydevelopedthecriteriaforwaterqualityaswellasothertechnicalandeconomicaspects of using awater resource for supplying the populationwith drinking water, since there are several regions with manymunicipalities without any connection to apublic water supplylocatedawayfromlargedistributionsystems[1].Inthecaseofgroundwaterusedfordrinkingpurposes,watertreatmentismostlyneededfortheremovalofironand/ormanganese.Concentrationsofdissolvedironandmanganeseareevaluatedeveryyearwithinthegroundwater monitoring done by the Slovak HydrometeorologicalInstitute(SHMU)forthewholeterritoryofSlovakia.

In 2009, there were approximately 5500 registered groundwaterresources,whichusedonaverage11045L/s(including8475.4L/sfor drinking water purposes). Of this amount 2632 l/shad to betreated,duetotheirhigherconcentrationofironandmanganese.According to the 2010 Reports on the Environment in Slovakia,theconcentrationofironexceededthe0.2mg/Llimitinmorethan18.9%ofthesamples,andtheconcentrationofmanganeseexceededthe0.05mg/Llimitinmorethan19.4%of396groundwatersamples(whichrepresent175basicmonitoringobjects).Theconcentrationof iron exceeded the 0.2 mg/L limit in more than 37.2% ofthe samples, and the concentration of manganese exceeded the0.05mg/L limit inmore than 40.1%of 698 groundwater samples(which represent 211 operational monitoring objects). The limitvaluesaredefinedunder theRegulationof theGovernmentof theSlovakRepublicNo.496/2010onDrinkingWater[2].In searching for suitablewater treatment technology, an emphasisis placed on new, more efficient and cost-effective methods andmaterialscomparedtothetechnologycurrentlyused.One of the newmethods is the removal of dissolved manganeseby using an oxidized film on the grains of afiltration medium.

2012 SLOVAK uNIVERSITY OF TECHNOLOGY 1

2 MODIFIED CLINOPTILOLITE IN THE REMOVAL OF IRON AND MANGANESE FROM WATER

2012/3 PAGES 1 — 8

Afilmisformedonthesurfaceofthefiltrationmediumbyaddingpotassium permanganate (not only KMnO4, but also other strongoxidizingagents).This filmservesasacatalystofoxidation– thegrainsofthefiltrationmediumarecoveredbymetaloxides.Insuchacase, this special filtration is the so-called “contact filtration” –filtrationbymanganesefilters.TheoxidationstateofthefilmoftheMnOx(s)mediumhasanimportantroleintheremovalofdissolvedmanganese. The efficiency of manganese removal is adirectfunctionoftheMnOx(s)concentrationanditsoxidizedstate.Filmswithdifferentabilitiestoremovedissolvedmanganesefromwaterareformedondifferentfiltrationmedia[3,4,5,6,7].

2. STuDY OBJECTIVE

Based on the present knowledge concerning this natural materialandworksdealingwith theremovalofdissolvedmanganesefromwater through oxidizing films on various filtration materials, wehave performed experiments with zeolite from Nižný Hrabovec,wherearichdepositofthismaterialislocated.TheobjectiveofthetechnologicaltrialsinthelocalityofKúty(awatertreatmentplant)wastoverifytheefficiencyofmanganeseandironremovalinwatertreatmentusingafiltrationmediumbasedonachemicallymodifiednatural zeolite (Klinopur-Mn).At the same time the efficiency ofmanganese and iron removal was compared with the importedGreensandandCullsorbM(USA)materials,whichareoftenusedabroad for dissolved manganese and iron removal from water insmall-scalewatertreatmentplants(smallwaterresources).

3. ExPERIMENTAL PART

The water treatment plant in Kúty is apart of the Senica groupofwater supply systems (Fig. 1).Thewater from twowellswithayieldof80L/sdoesnotmeettherequirementsofRegulationNo.496/2010onDrinkingWaterforiron,manganese,ammoniumions,and aggressive carbon dioxide.The technologicalwater treatmentprocess consists of aeration, adosage of calcium hydrate, slowmixing,filtrationanddisinfection.ThetechnologicalschemeoftheWTPKútyisshowninFig.2.Thefigure also indicates the location of the filter columns (samplingpoints)usedinourexperiments.Themethodologyfortheverificationofsuitablefiltrationmaterialsfor iron and manganese removal is based on their propertiesand possible technological applications in the water treatmentprocess.Thefollowingtechnologicalwatertreatmentmethodwasproposed:rawwater→filtrationandoxidation(backwashingandregeneration)

Raw water is passed through the filtration equipment, and theremoval of the Fe2+ andMn2+ ions is carried out directly in thefiltration column beds (the media). The following were used asfiltrationmaterials:• Greensand• CullsorbM• naturalactivatedzeolitewithMnO2(Klinopur-Mn)

The experiments were designed to optimize the filtration rate(contact timeof the rawwaterwith the filtermedia)andwashingandregeneratingthefiltermaterials(filterlengthcycles).Thequalityoftherawwater(FeandMncontent)andtreatedwaterat the outlet from the separate filtration columns was monitored

Fig. 2 Scheme of the technology of WTP Kúty and the location of the filter columns.

Fig. 1 Scheme of part of the Senica group water supply system.

Raw waterAeration

Rapid mixing

Ca(OH)2

Gentle mixingFiltration

Accumulation

Disinfection

Consumer

Sampling point No.1Experiment 1 Sampling point No.2

Experiment 2 Sampling point No.3Experiment 3

2012/3 PAGES 1 — 8

3MODIFIED CLINOPTILOLITE IN THE REMOVAL OF IRON AND MANGANESE FROM WATER

during the experiments. At the same time the amount of water(filtrationrate)attheoutletfromthecolumnswasmeasured.

3.1 Filtration Materials

Klinopur-Mn, which is produced in Slovakia, is activated zeolite–clinoptilolite(Tables1and2).Onthesurfaceofthegrainsthereis afactory-made film consisting of manganese oxides, whichenablesthismaterialtobeusedincontactfiltration.Thisfiltrationmaterial is much cheaper compared to imported materials fromtheUSA.Basedonexperiments(pilottests)performedbyexpertsfrom theDepartment of Sanitary and Environmental Engineeringat the Faculty of Civil Engineering of the Slovak University ofTechnologyinBratislava[8,9,10],itcanbestatedthatthesurfaceof clinoptilolite activated by manganese oxides is comparablewiththeimportedBirmmaterial,anditispossibletouseitfortheremovalofFeandMnfromwater.Clinoptilolite [(NaK)6(Al6Si30O72)⋅20H2O] is one of the mostfrequently used natural zeolites. At present it is also applied in

the water treatment process. Its sufficient mechanical resistance,chemicalstabilityandabrasionvalues(eveniftheyarecategorizedamongsoftmaterials)enableclinoptilolitetobeusedasafiltrationmaterial.ThebasicpropertiesofclinoptiloliteareshowninTable3. Greensand (imported from the USA) is aglauconitic mineralwithazeolite-typestructure.It isproducedfromglauconiticsand,which is activated by potassium permanganate (KMnO4). Theresultingproduct isagranulatedmaterialcoveredbyaMnO2filmon its surface and other higher oxides of manganese. It is usedfor the removal of iron, manganese and hydrogen sulphide fromwater.Dissolvedironandmanganeseareoxidizedandprecipitatedin contact with the higher oxides of manganese on the surfaceof Greensand. Undissolved iron and manganese are trapped inthe “greensand medium” and removed by backwash. After theexhaustion of its oxidizing capacity, the bed is regenerated usingaKMnO4 solution. The regeneration frequency depends on theamount of iron, manganese and oxygen in the water as well asthe filtersize.Werecognize tworegenerationprocesses, i.e.,withdiscontinuousorcontinuousregeneration.The pH value of water is an important factor influencing theefficiencyof filters. If thepH is lower than6.8, the efficiencyofgreensand is reduced.Theoperatingconditions forGreensandarelistedinTable4.Greensandhasbeenusedformorethan20yearsfortheremovalofFeandMnfromwater.Theadvantageisthatwaterwithalowoxygencontentdoesnothavetobepre-oxidized.Greensandcanbeusedincaseswithahighercontentofiron(over10mg/L)andmanganese.Itcanalsobeusedinindustry.Acontentoforganicsubstances,oilsandhydrogensulphideshasanadverseeffectonitsefficiency.

Tab. 1 Mineralogical analysis of the zeolite from the deposit at Nižný Hrabovec [11].

Mineral Content % Mineral Content %Clinoptilolite 84 Illite 4Cristobalite 8 Quartz traces

Feldspar 3-4Carbonateminerals

traces(<0.5)

Tab. 2 Chemical analysis of the clinoptilolite from the deposit at Nižný Hrabovec [11].

Compound Content% Compound Content%SiO2 66.4 MgO 0.56

Al2O3 12.2 Na2O 0.29K2O 3.33 MnO 0.02CaO 3.04 TiO2 0.15

Fe2O3 1.45 P2O5 0.02

Tab. 3 Basic properties of clinoptilolite.Clinoptilolite

Colour grey-green Effectivediameterofpores 0.4nmCompressivestrength 33MPa Absorbability 34–36%Specificgravity 2200–2440kg.m–3 Thermalstability do450°CApparentdensity 800–900kg.m–3 Stabilityagainstacids 79.50%

Tab. 4 Conditions of Greensand use.

Parameter Operating range ParameterOperating

range

pH 6.8to9.0Organicmatters

<5mg/L

Dissolvedoxygen

>15%ofFecontent

Oils ≈0mg/L

Fe2+/Mn2+ <15mg/L Temperature 5–30°CAlkalinity >2x(SO42

–Cl–) H2S <5mg/L


2012/3 PAGES 1 — 8

Cullsorb M (importedfromtheUSA) isanatural,highlyselectedmineral(greensand),lackinginadditivesandimpurities.Itisbasedonmanganese dioxide, which has an extremely high capacity forcatalyticoxidation.Itisspecificallyusedinfilteringplantsfortheremoval of iron,manganese and hydrogen sulfide by oxidation inwater.Thefiltercartridgerequiresperiodicorcontinuousregenerationoftheoxidizedreagent,eitherpotassiumpermanganateorair.The selected parameters of the filtration materials used in theexperimentsarelistedinTable6.

3.2 Water Treatment Model

Toverify the efficiencyof iron andmanganese removal from thewaterresourcesinthelocalityofWTPKúty,threefiltrationcolumnscontaining Greensand, Cullsorb M and Klinopur-Mn were used.The adsorption columns were made of glass. The parameters ofeachadsorptioncolumnareasfollows:diameter=5.0cm;height=2m;surface=19.635cm2;filtrationmediumheight110cm;andvolumeoffiltrationmedium2160[cm3].Thefiltrationequipmentis shown in Fig. 3.The figure shows asimple device that allowssplittingtheincomingwatereitherforwashingorfiltrationthroughavalvesystem.Thewaterwas supplied to filtration columns from threedifferentsitesfor the technologicalwater treatmentprocess.ThewaterforExperiment1(samplingpointNo.1)wastakenfromtheinletoftherawwatertothewatertreatmentplant.ThewaterforExperiment2(samplingpointNo.2)wastakenafteraerationofthewater,wherethe content of the oxygen in the water had increased. ThewaterforExperiment3 (samplingpointNo.3)was takenafter aerationand limedosing,where theoptimalconditions for the removalof

the iron and manganese (increased oxygen content and apH ofmorethan8)wereachieved.Table7showsthevaluesofthebasicparametersduringtheexperiments.

4. RESuLTS AND DISCuSSION

Themodeltestsandtheresultsoftheexperimentsaredividedintothreeparts:• forrawwaterfromwells,• forrawwaterafteraeration,• forrawwaterafteraerationandtheadditionoflime.

Tab. 5 Basic properties of Cullsorb M.Cullsorb M

Colour fromdarkbrowntoblackAspect granular,sphericorangularWatercontentat105°C<2% Manganese(asMn)>53%

Iron(asFe)<3.5%Manganesedioxide(asMnO2)>80%

Tab. 6 Filtration materials and some selected parameters. Material Clinoptilolite Cullsorb M Greensand Silica sandGrainsize[mm] 0.3–2.5 >0.4 0.25–0.8 0.7–2.0Specificgravity[g/cm3] 2.39 3.5–4.0 2.4–2.9 2.66Apparentdensity[g/cm3] 0.84 1.75–1.85 1.36 1.55Porosity[%] 64.8 – – 41.7Abrasion[%] 8.2 – – 0.57

Tab. 7 The basic parameters during the pilot test.

ParameterSampling point

No.1 No.2 No.3Fe(mg/L) 2.28–5.16 0.90–3.87 1.96–4.22Mn(mg/L) 0.82–1.12 0.816–1.092 0.198–0.524

pH 6.64–6.98 6.81–7.14 8.40–8.62Oxygen

(%saturation)6–7 59–60 56–57

Fig. 3 Filtration equipment – filtration columns.

2012/3 PAGES 1 — 8


Experiment 1

Raw water passed through the filtration columns in adownwarddirection.Theaveragefiltrationratewas6.23m/hfortheGreensand,5.98m/hfortheKlinopur-Mnand5.83m/hfortheCullsorbM.ThefiltrationconditionsareshowninTable8.Theresultsofremovingtheironandmanganesefromtherawwateraredocumented inFigs.4and5.Theyshow theconcentrationofmanganeseandironintherawwaterandthevaluesmeasuredaftertheypassedthroughthemonitoredfiltermaterials.Thefiguresalsoshow themanganese limitvalue (0.05mg/L)and respectively theironlimitvalue(0.2mg/L)fordrinkingwaterintheRegulationoftheGovernmentoftheSlovakRepublicNo.496/2010onDrinkingWater. The arrow represents the regeneration time of the filtermedia.Fig.4showsthatthequalityoftherawwater(lowpH–6.6to6.9,lowoxygencontent–6 to7%)hasaninfluenceontheefficiencyof the removal of the manganese and that the efficiency for themonitoredmaterialswasdifferent.Thebest resultswereachievedwithCullsorbM,whichevenafter260hoursofoperationdidnot

exceedthelimitvalueformanganese(0.05mg/L).It isafactthatCullsorbM is thematerialwith the highestMnO2 content on itssurface.TheGreensand exceeded the limit of 0.05mg/L after 20hours and the Klinopur-Mn after 42 hours of operation. Thosematerials had tobe regenerated (2.5%solutionofKMnO4).Aftertheregeneration,thecolumnswereoperatingagain,butforthistypeofwater,theirefficiencywastoolow.The Greensand and Klinopur released the manganese from theirsurfaces into thewater because of the pure quality of the treatedwater,thelowoxygencontentandthelowpHvalue.Fig.5shows thatall thematerialsareeffectivefor removing ironfromthewaterduringtheoperationofthefiltrationcolumnsanddidnotexceedthelimitvalueof0.20mg/L.

Experiment 2

Figs. 6 and 7 show the results of removing iron andmanganesefrom the raw water after aeration (sampling point No.2). Theconcentrationofmanganeseandironintherawwaterandthevaluesmeasuredafter theypassed throughthemonitoredfiltermaterials,

Tab. 8 Filtration conditions for the first sampling point.Parameter Greensand Klinopur CullsorbGrainsize[mm] 0.25–0.8 0.6–1.6 0.4–0.6Heightoffiltrationmedium[cm] 110 110 110Averagedischargethroughcolumn[mL/min] 204 195.75 190.83Averagefiltrationrate[m/h] 6.23 5.98 5.83Filtrationtotaltime[h] 260 260 260Totalvolumeofwaterflownthrough[m3] 3.182 3.054 2.977Averageresidencetimeincolumn[min] 10.587 11.034 11.318

Fig. 4 Course of removing the manganese from the water. Fig. 5 Course of removing the iron from the water.


2012/3 PAGES 1 — 8

contrasted with the manganese limit value (0.05 mg/L), andrespectivelythe ironlimitvalue(0.2mg/L)inthedrinkingwaterdefinedunderRegulationoftheGovernmentoftheSlovakRepublicNo.496/2010onDrinkingWaterandtheregenerationtimeforthefiltermedia,areillustrated.Fig.6showsthattheinfluenceofchangesinthequalityoftherawwater(pH6.8to7.2,theoxygencontentfrom56to57%saturation)fortheefficiencyofthemanganeseremovalfromthewaterthroughthe filtrationmaterials improved significantly.All threematerialsobtainedahighlevelofefficiencyofthemanganeseremovalfromthewater. In thecaseof theCullsorbMandGreensandmaterialsduringthe910hoursoftheoperationofthefiltrationprocess, thelimit value for manganese (0.05 mg/L) was not exceeded. It isnecessary tomodifyKlinopurMn by agradual backwashing andregenerationwithasolutionofKMnO4.Inthefirstfiltrationstepitexceededthelimitvalueof0.05mg/Lafter162hoursofoperation;in the second filter cycle the limit valuewas exceeded after 258hours,andthelimitvaluewasexceededinthethirdfiltercycleafter277hours.The filtration timewithout regenerationwasgraduallyextended. This means that the industrially activated clinoptilolite

(Klinopur-Mn) should be modified directly on-site in the watertreatmentplant.Thefiltercycleswillbeextended,andaftersometime,regenerationwillnotbeneeded.The filter media were backwashed continuously (approximatelyevery2to3days)(giventheamountofprecipitatedferrichydroxidecollected). Over time, as shown in Fig. 6, the concentration ofmanganeseinthetreatedwaterafterpassingthroughKlinopur-Mnexceeded the value of 0.05 mg/L; then the filter materials wereregeneratedwithasolutionofKMnO4(2.5%solution).Fig. 7 shows the course of removing the iron from thewater forsampling pointNo. 2 (after thewater aeration).The value of theironintherawwaterwasquitechanged,dependingonwhichwellwasusedforpumpingortheproductionofprecipitatedFe(OH)3,whichgraduallycloggedthesystem.Ingeneral,allthreematerialsremoved the iron effectively and, during the operation of thefiltration columnsdidnot exceed the limit valueof0.20mg/LasdefinedunderRegulationNo.496/2010onDrinkingWater.The filtration rates during the second experiment were lowercomparedtothefirstexperiment,whichwascausedbyprecipitationsofironaftertheoxidationandferrichydroxidecloggedthecolumns.

Tab. 9 Filtration conditions for the second sampling point.Parameter Greensand Klinopur CullsorbGrainsize[mm] 0.25–0.8 0.6–1.6 0.4–0.6Heightoffiltrationmedium[cm] 110 110 115Averagedischargethroughcolumn[mL/min] 191.1 167.5 185.2Averagefiltrationrate[m/h] 9.734 8.532 9.434Filtrationtotaltime[h] 5.84 5.12 5.66Totalvolumeofwaterflownthrough[m3] 910 910 910Averageresidencetimeincolumn[min] 10.435 9.148 10.113

Fig. 6 Course of removing the manganese from water. Fig. 7 Course of removing the iron from water.

2012/3 PAGES 1 — 8


Experiment 3

The results from removing the iron andmanganese from the rawwaterafteraerationand theadditionof limearebestdocumentedbyFigs.8and9,inwhichtheconcentrationofmanganeseandironin the rawwater and the values measured after passing throughthe monitored filter materials are shown. The figures also showthemanganese limit value (0.05mg/L), and respectively the ironlimit value (0.2 mg/L) in the drinking water as defined underRegulationNo.496/2010onDrinkingWater.Thearrowrepresentstheregenerationtimeofthefiltermedia.Fig.8showsthatthechangesinthequalityoftherawwater(pH8.4to8.6;anoxygencontentof59to60%saturation)hasanefficiencyin the removal of manganese from the water. The high removalefficiency of the manganese was achieved by all three materials–Cullsorb,GreensandandKlinopur-Mn.Evenafter802hoursofoperationofthefiltrationsystem,theydidnotexceedthevalueofthemanganese in the treatedwater limitvalueof0.05mg/L.Thefilter materials were backwashed continuously (approximatelyevery2to3days).Therewasnoneedtoregeneratethesematerials.

Fig. 9 shows the progress made in removing the iron from thewater for sampling point No.3 (after the water aeration and theadditionof lime).Thevalue of the iron in the rawwater is quitechanged, depending on the production of precipitated Fe(OH)3,whichgraduallycloggedthesystem.Ingeneral,allthreematerialsremoved the iron effectively and, during the operation of thefiltrationcolumns,didnotexceed the limitvalueof0.20mg/LasdefinedunderRegulationNo.496/2010onDrinkingWater.

5. CONCLuSION

The results obtained proved the possibility of usingKlinopur-Mninremovingironandmanganesefromwater(theso-calledcontactmanganese removal) and is comparable with the Greensand andCullsorbMmaterialsimportedfromabroad.Thematerialsobservedexhibitdifferentefficienciesofmanganeseremoval from water, since the quality of the treated water playamajor role (oxygen content and pH value). In the case of theremovaloftheironfromthewater,thequalityoftherawwateris

Tab. 10 Filtration conditions for sampling point No.3.Parameter Greensand Klinopur CullsorbGrainsize[mm] 0.25–0.8 0.6–1.6 0.4–0.6Heightoffiltrationmedium[cm] 110 110 115Averagedischargethroughcolumn[mL/min] 181.2 176.5 178.8Averagefiltrationrate[m/h] 5.54 5.39 5.46Filtrationtotaltime[h] 802 802 802Totalvolumeofwaterflownthrough[m3] 8.719 8.493 8.604Averageresidencetimeincolumn[min] 11.920 12.237 12.080

Fig. 8 Course of removing the manganese from water. Fig. 9 Course of removing the iron from water.


2012/3 PAGES 1 — 8

alimiting factor; all thematerials removed Fe from the water tobelowthelimitvalue(0.20mg/L).Therateoffiltration,backwashingtimeandintensity(self-carriagefiltermaterialduringthewashing)andthemethodofregenerationofthefiltermediawithKMnO4(a2.5%solutionofKMnO4)werealsomeasuredduringthepilotplantexperiments.The insertionofaerationand thepHadjustmentof the rawwaterbefore the filtrationcolumn to increase theefficiencyof the filtermediaprovideaneffectivetreatmentofthewaterasseenfromtheexperimentalresults.

ThetechnologyoftheremovalofFeandMnwithcontactfiltrationis often used for small water resources (the water treatment isdirectlyonthewaterresource).Basedonourexperiments,themostsuitablematerialforthewaterqualityandfiltrationconditionswasCullsorbM(containsover80%ofMnO2onitssurface).

Acknowledgements

ThetechnologicaltrialswereperformedwithintheAPVV-0379-07grantprojectandVEGA1/1243/12project.

REFERENCES

[1] Výročná správa VÚVH, Príloha č. 3: Zdravá pitná voda – súčasť potravinového reťazca, číslo projektu: RVT 27-42 (5060), WRI Annual Report, Annex 3: Healthy drinking water – part of the food chain, Project number: RVT 27-42 (5060),VÚVHBratislava,2002.

[2] Správa o stave životného prostredia Slovenskej republiky v roku 2009, Ministerstvo životného prostredia Slovenskej republiky, Slovenská agentúra životného prostredia, Report on the State of the Environment of the Slovak Republic in 2009, the Ministry of the Environment of the Slovak Republic, Slovak Environmental Agency,ISBN978-80-88833-53-6,p.308.

[3] Doula, Maria, K.:Removal of Mn2+ Ions from Drinking Water by Using Clinoptilolite and Clinoptilolite–Fe Oxide System.Water Research, Vol. 40, No. 17, October 2006, pp. 3167-3176.

[4] Knocke, W.R., et al.: Kinetics of Manganese and Iron Oxidation by Potassium Permanganate and Chlorine Dioxide. Jour.AWWA,Vol.6,1991,pp.80-87.

[5] Knocke, W.R., Hungate, R., Occiano, S.:Removal of Soluble Manganese by Oxide-Coated Filter Media: Sorption Rate and Removal Mechanism Issues. Jour.AWWA,Vol. 8, 1991, pp.64-69.

[6] Knocke, W.R., Hamon, J.R., Thompson, C.P.: Soluble Manganese Removal on Oxide-Coated Filter Media. Jour.AWWA,Vol.12,1988,pp.65-70.

[7] Merkle, P.B., Knocke, W.R, Gallagher, D.:Characterizing Filter Media Mineral Coatings.Jour.AWWA,Vol.12,1996,pp.62-73.

[8] Barloková, D., Ilavský, J.:Prírodné zeolity v úprave vody. Natural Zeolites in Water Treatment. Vodní hospodářství,Vol.6,2007,pp.213-215.

[9] Barloková, D., Ilavský, J.:Odstraňovanie železa a mangánu z malých vodných zdrojov. Removal of Iron and Manganese from Small Water Resources. SOVAK, ISSN 1210-3039,No.4,2009,pp.13-16.

[10] Barloková, D., Ilavský, J.:RemovalofIronandManganesefrom Water Using Filtration by Natural Materials. PolishJournalofEnvironmentalStudies,Vol.19,No.6,2010,1117-1122ISSN1230-1485.

[11] Reháková, M., Čuvanová, S., Gavaľová, Z., Rimár, J.: Využitie prírodného zeolitu typu klinoptilolitu v agrochémii a poľnohospodárstve. Utilization of Natural Zeolites of Type Clinoptilolit in Agrochemistry and Agriculturel. Chemickélisty97,2003,pp.260-263,ISSN1213-7103.

d. barlokovÁ, j. ilavský danka barlokovÁ ján ilavskÝ ... · manganese and iron removal was...

Documents