3History:The independent study of the textile technology in Croatia started at the beginning of 1960 as a study at the Faculty of Technology in Zagrebfirst only textile chemical engineering, then later mechanical and clothing engineeringand at three independent colleges of textiles in Duga Resa, Varaždin and ZagrebIn 1991 the Institute of Textile and Clothing was organized as an independent Institution named Faculty of Textile Technology of the University of ZagrebZagreb, Croatia, June 7th, 2013.
4Departments: Department of Materials, Fibres and Textile Testing Department of Textile Design and ManagementDepartment of Clothing TechnologyDepartment of Textile and Clothing DesignDepartment of Fundamental Natural and Engineering SciencesDepartment of Textile Chemistry and EcologyDepartment of Applied ChemistryStudy in VaraždinCentre for Development and Transfer of Textile and Clothing Technologies and Fashion DesignZagreb, Croatia, June 7th, 2013.
5Wastewater of Textile Industry with an emphasis on laundries Tihana Dekanic, B.Sc.Zagreb, Croatia, June 7th, 2013.
61. INTRODUCTION The Textile industry: use high volume of water throughout its operationproduce large quantities of wastewatersis very diversebroad manufacturing sectormain pollution come from dyeing and finishing processes (require the input of a wide range of chemicals and dyestuffs – organic compounds of complex structure)Major pollutants are:high suspended solidsheatcolouracidity or alkalinityother soluble substancesZagreb, Croatia, June 7th, 2013.
72. FIBERS Classification of fibers: by TYPE by LENGTH by SIZE Zagreb, Croatia, June 7th, 2013.
8COTTON Features: soft fibers fiber – single elongated cell – twisted and ribbon like – wide inner hollow (lumen)90% cellulose, 6% moisture, other fats and impuritiesProperties:strengthdurabilityabsorbentcomfortableflexiblegood resistant to alkalispoor acid resistantpoor wrinkle resistanceZagreb, Croatia, June 7th, 2013.
9WOOLFeatures:fibre – irregular, roughly cylindrical, multi cellular structurethree basic layers: epidermis (outer layer), cortex (middle layer) and medulla (inner layer)Properties:absorbentlightweightversatilenaturally UV protectiondurable and elasticnon allergenicbiodegradableflame retardanteasy careZagreb, Croatia, June 7th, 2013.
10POLYESTER Features: smooth, straight, round cross sectionally rod-like shapeterm „polyester” – mostly refers to polyethylene terephalate (PET)Properties:high melting temperaturestronghydrophobicresistant to stretching and shrinkingresistant to most chemicalswrinkle resistantabrasion resistanteasily washedZagreb, Croatia, June 7th, 2013.
11visible changes of mechanical properties during washing and drying Cotton fibresbefore washingafter 6 washing cyclesafter 11 washing cyclesafter 50 washing cyclesvisible changes of mechanical properties during washing and drying
123. THE NATURE OF WATER Water: water molecule contains one oxygen and two hydrogen atoms connected by covalent bondsthree states of matter:solidliquidgascovers 71% of the Earth surface (96,5% in oceans,1,7% in ground water, 1,7% in glaciers and icecaps and 0,001% in the air)only 2,5% is fresh water and 98,8% of that water is in ice andgroundwaterless than 0,3% of all fresh water is in rivers, lakes and the atmosphereZagreb, Croatia, June 7th, 2013.
13Chemical and physical properties: is liquid at standard temperature and pressurepolar molecule with electrical dipole moment due to non linear structurehigh surface tensionhave cappilary actionuniversal solventlow electrical conductivitydensitythermal: specific heat and latent heatviscosityosmotic pressureoptical propertieselectrical properties: dielectric constant, electrical conductivityZagreb, Croatia, June 7th, 2013.
144. WATER QUALITY INDICATORS Absolutely pure water is never found in nature!According to Regulation on Water Classification, there are two groups of indicators of water quality:1st groups: mandatory indicators (physical and chemical parameters, oxygen demand, microbiological and biological indicators)2nd groups: metals, organic compounds, radioactivityZagreb, Croatia, June 7th, 2013.
151.1. Suspended matters 1.2. Turbidity 1.3. Colour PHYSICAL INDICATORS:1.1. Suspended mattersThis includes all matter suspended in water that is large enough to be retained on a filter with a given porosity.1.2. TurbidityMeasures the amount of suspended particles in water1.3. ColourThe color of a water sample can be reported as:Apparent color is the color of the whole water sample, and consists of color from both dissolved and suspended componentsTrue color is measured after filtering the water sample to remove all suspended materialsZagreb, Croatia, June 7th, 2013.
161.4. Transparency 1.5. Conductivity 1.6. Odour and taste PHYSICAL INDICATORS:1.4. TransparencyTransparency measures how far light can penetrate a body of water.1.5. ConductivityConductivity (k) is transmission speed of electrical charge through the material (mS/cm).In water is affected by the presence of inorganic dissolved solids such as chloride, sulfate, sodium, calcium and others.1.6. Odour and tasteWater odour can cause organic substances. Taste water could be indicators of changes in water sources or treatment process. Inorganic compounds such as magnesium, calcium, sodium, copper, iron, and zinc are generally detected by the taste of water.Zagreb, Croatia, June 7th, 2013.
17The stratification of a lake in the summer PHYSICAL INDICATORS:1.7. TemperatureNormal temperature: 22°C (limit value of wastewater temperature is 30°C)Sources: sunlight, thermal pollutionEffects: amount of oxygen that can dissolve, photosynthetic rate, metabolic rates change, senitivity to toxic wastes.Water temperature fluctuates seasonally, resulting in thermal stratification in deeper water.Wastewater: commonly higher; vary fromseason to season and with geographiclocationThe stratification of a lake in the summerZagreb, Croatia, June 7th, 2013.
182.1. Total dissolved solids CHEMICAL INDICATORS2.1. Total dissolved solidsTDS is a measure of the combined content of all organic and inorganic substances contained in a water in: molecular, ionized or micro-granular suspended form2.2. pHpH is measure of acidity in water (hydrogen ion concentration)pH = - log [ H+ ]1234567891011121314neutralacidalkalineZagreb, Croatia, June 7th, 2013.
19CHEMICAL INDICATORS 2.3. Alkalinity 2.4. Hardness Alkalinity is the quantitative capacity of water to neutralize an acid. Expressed in mg/l CaCO3. Wastewater is normally alkaline.2.4. HardnessCalcium and magnesium salt contentTemporary hardness - carbonates and bicarbonates, can be removed by boilingequilibrium: CaCO3 + CO2 + H2O ⇋ Ca2+ + 2HCO3−Permanent hardness - sulfates, chlorides, other anionsClassification of water by German HardnessZagreb, Croatia, June 7th, 2013.
202.5. Dissolved gases 2.6. Organic matters CHEMICAL INDICATORS2.5. Dissolved gasesPrime importance in considering the quality of water along with the other physical and chemical characteristics.Important gases dissolved in waters:oxygencarbon dioxidenitrogenammoniahydrogen sulfidesulfur dioxidechlorine etc.2.6. Organic mattersOrganic matter - organic material present in surface or ground water.Division to: biodegradable and non-biodegradable.Three major sources:the breakdown of naturally occurring organic materialscommercial and domestic chemical wasteschemical reactions that occur during water treatment and filtration processesZagreb, Croatia, June 7th, 2013.
21CHEMICAL INDICATORS 2.7. Nutrients 2.8. Metals Nutrients in wastewater:organic carbonnitrogenphosphoruspotassiumRequired for the primary production of organic matter2.8. MetalsMost of them are dissolved in water. Can cause public health or aesthetic problems (taste, odour, colour) if not removed.Can be divided into:non-toxic: arsenic, barium, cadmium, chromium, lead, mercury, silvertoxic: sodium, iron, manganese, aluminum, copper and zincZagreb, Croatia, June 7th, 2013.
222.9. BOD (Biochemical Oxygen Demand) CHEMICAL INDICATORS2.9. BOD (Biochemical Oxygen Demand)The amount of oxygen (mg O2/l) required by aerobic microorganisms to decompose the organic matter in a sample of water at 20°C.Measured after 5, 20 or 100 days (BOD5, BOD20 or BOD100).2.10. COD (Chemical Oxygen Demand)The amount of oxygen which is needed for the oxidation of all organic substances (biodegradable and non-biodegradable) in water (mg/l or g/m3).2.11. TOC (Total Organic Carbon)To characterize the dissolved and suspended organic matter in water.DOC (Dissolved Organic Carbon)To characterize only organic material that is actually dissolved, not suspended.Zagreb, Croatia, June 7th, 2013.
232.13. AOX (Adsorbable organic halogens) CHEMICAL INDICATORS2.13. AOX (Adsorbable organic halogens)The sum of parameters for water soluble "adsorbable organic halogens" in which 'A' stands for adsorbable, 'O' for organic and 'X' for the halogens chlorine, bromine and iodine.2.14. Otherfluorides (smaller amounts are good in preventing tooth decay)chlorides (give salty taste, can cause corrosion)sulfates (due to the dissolution of minerals can cause indigestion)cyanides (very dangerous, point to pollution waste water)radioactive substances (cause mutagenic changes, sterility, cancer)Zagreb, Croatia, June 7th, 2013.
243. BIOLOGICAL INDICATORS: Biological indicators (bioindicators) are organisms or communities of organisms, which reactions are observed representatively to evaluate a situation, giving clues for the condition of the whole ecosystem.Measurement:saprobic indexthe degree of biological productionmicrobiological indicators (coliform bacteria, E-coli, faecal streptococcus)the degree of toxicityZagreb, Croatia, June 7th, 2013.
25Surface water quality monitoring in Croatia 3. BIOLOGICAL INDICATORS:Surface water quality monitoring in Croatiacontinuous monitoring in Republic of Croatia started in the 1950’water quality monitoring is mainly based on physico-chemical parameterssince 2000 water quality assessment is significantly improvedsampling and assessment of water quality is done in accordance with Croatian (HRN) or International norms (ISO-EN) in authorized laboratoriesBiological surface water quality determinants being monitored according toWater Classification Act (“National Gazette” , NN 77/98) are:Saprobic index (Pantle – Buck),Extended Biotic Index andTrophy status (lakes)Bioindicator system that is currently in use in Croatia:Wegl (1983)Analysed communities:Benthic macroinvertebratesPeriphytonBiosestonHRIS - national bioindicator system (2005)Zagreb, Croatia, June 7th, 2013.
26INDICATORS AND MEASURES REFERENCE METHOD OF MEASUREMENT Croatia: the quality indicators of industrial wastewater discharged into the public sewage system or into surface watercourses and their limits are prescribed and explained in the Regulation on limit values and other hazardous substances in wastewaterINDICATORS AND MEASURESSURFACE WATERPUBLIC SEWER SYSTEMREFERENCE METHOD OF MEASUREMENTGENERAL INDICATORSpH6,5-9,06,5-9,5HRN ISO 10523:1998Temperature [ oC]3040DIN C4Deposited matters [ml/l]0,510DIN H9Suspended matters [mg/l]80(a)HRN ISO 11923:1998ORGANIC INDICATORSBOD5 [mgO2/l]-HRN EN :2004COD [mgO2/l ]200 (e)(d)HRN ISO 6060:2003 HRN ISO 15705:2003TOC [mgC/l]60 (c)HRN EN 1484:2002AOX [mg/l]HRN EN 1485:2002Surfactants, anionic and nononic [mg/l]1,0HRN EN 903:2002Mineral oils [mg/l]20HRN EN ISO :2002Parameters and Maximum Permissible Concentration (MPC) for laundry wastewater with applicable standardsZagreb, Croatia, June 7th, 2013.
27Zagreb, Croatia, June 7th, 2013. INORGANIC INDICATORS SURFACTANTS Sulphides dissolved S [mg/l]0,51,0HRN ISO 10530:1998 HRN ISO 13358:1998Sulphates SO4 [mg/l]Sulfites SO3 [mg/l]Free chlorine [mg Cl2/l]0,2HRN EN ISO7393-1:2001HRN EN ISO :2001HRN EN ISO :2001Total chlorine [Cl2mg/l]HRN EN ISO :2001Total phosphorus [mg P/l]-HRN ISO 6878Ammonium [mg N/l]5HRN ISO 5664:1998 HRN ISO :1998Total chromium Cr [mg/l]1,254,0HRN EN 1233HRN ISO 8288Chromium Cr6+ [mg/l]0,1HRN ISO 11083Ortophosphates [mg P/l]1-4Nitrites [mg/l]0,5-210HRN ISONitrates [mg/l]2-10HRN EN ISOAOX [mg/l]0,1-7,51HRN EN 1485SURFACTANTSTotal surfactant [mg/l]4-1020Σ surfactantsAnionic surfactant [mg/l]HRN EN 903ASTM DHRN EN ISOHRN ISO 2271Nonionic surfactant [mg/l]HRN ISO 2268HRN ISOCationic surfactant [mg/l]0,2-1,02HRN EN ISOHRN EN ISOASTMZagreb, Croatia, June 7th, 2013.
285. WASTEWATER OF TEXTILE INDUSTRY The common characteristics of textile wastewater are:high chemical oxygen demand (COD)high biological oxygen demand (BOD)high temperaturehigh pHsolid materialsphenol, sulphure and the colours caused by different dyesWastewater of textile industry are changeable in amount and composition.The 1st reason of pollutants: is the natural impurity in fibres.The 2nd reason: is the chemical materials that are used in processes. A huge amount of dye, carriers, chrome and its derivations and sulphur are found in wastewater.Zagreb, Croatia, June 7th, 2013.
29Textile industry is a very diverse sector in terms of raw materials, processes, products and equipment and has very complicated industrial chain.Main pollution came from dyeing and finishing processes. These processes require a wide range of chemicals and dyestuffs, which are generally organic compounds of complex structure.Because all of them are not contained in the final product, became waste and caused disposal problems.Besides its complex forms, textile wastewater creates problems due to their high volume. This industry takes place in the first ranks on account of water consumption.The other problem is that it produces wastewater in different forms and volumes since textile industry has many subdivisions.Zagreb, Croatia, June 7th, 2013.
30Major pollutants in textile wastewaters are high suspended solids, COD, heat, colour, acidity and other soluble substances.Substances which need to be removed from textile wastewater are mainly COD, BOD, nitrogen, heavy metals and dystuffs.ProcessEffluent compositionNatureSizingstarch, waxes, carboxymethil cellulose (CMC), polyvinyl alcohol (PVA), wetting agentshigh BOD, CODDesizingstarch, CMC, PVA, fats, waxes, pectinshigh BOD, COD, suspended solids, dissolved solidsBleachingsodium hypochlorite (NaClO), Cl2, NaOH, H2O2, acids, surfactants, NaSiO3, sodium phosphate, short cotton fibrehihg alkalinity,high suspended solidsMercerizingsodium hydroxide, cotton waxhigh pH, low BOD, high suspended solidsDyeingdystuffs, urea, reducing agents, oxidizing agents, acetic acid, detergents, wetting agentsstrongly coloured, high BOD,high dissolved solids,low suspended solids,heavy metalsPrintingpastes, urea, starches, gums, oils, binders, acids, thickeners, cross-linkers, reducing agents, alkalihighly coloured, high BOD,oily appearance,high suspended solids,slightly alkaline, low BODFinishingresins, waxes, chlorinated compounds, acetate, softeners, formaldehyde, PVAhigh alkalinity, high acidity, toxicity, high organic and inorganic suspended solidsLeather productionsulphite, chromium, synthetic tannins, biocides, lubricantstoxicity, high organic and inorganic suspended solids, odourTextile carefats, detergents, chlorine, active oxygenhigh BOD, high COD, high alkality,low suspended solids, toxicity, foamZagreb, Croatia, June 7th, 2013.
31LAUNDRIES AND WASTEWATER OF LAUNDRIES Washing is a complex process that is occurs in an aqueous meduim with the influence of four parameters:temperaturetimemechanicschemistryAll factors are important and need to be optimized in order to achieve a good results of washing.Particulary is important a hygienic aspects of quality control in the textile laundry from hospital, nursing homes, food and pharmaceutical industries, where is very important disinfection (thermal, chemical or chemo-thermal).Disinfection effect depends on temperature, concentration of disinfectants, time of action, the presence of microorganisms and the structure of the environment.Zagreb, Croatia, June 7th, 2013.
32Factors that influence on washing effects: 1. WATER -quantity -hardness (ratio Ca 2+/Mg2+)-purity, microbiological composition, content of heavy metals2.SOILING-the degree and type of soiling-interaction with components of detergent-composition and structure of textile materials3.TEXTILES- textiles (fabric, yarn..)- sweling Tg- finishing, coloration- charge (dimenzion, size..)- purpose, residuesZagreb, Croatia, June 7th, 2013.
33washing temperature (initial, heating, final temperature) washing time 4.WASHING MACHINEwashing temperature (initial, heating, final temperature)washing timemechanics of laundering (rotation speed, reversible rotation and drum diameter), volume, volume baths, weight and dimensions of textiles, fabrics/friction, foam), washing program (prewash, main wash and rinse)5.DETERGENTActive componentsanionic surfactantnonionic surfactantsoapcationic surfactantInorganic componentsalkalies (silikates, Na2CO3)phosphates (sodium triphosphate)zeolites (sodium aluminosilicate)chemical bleaches (sodium perborate, sodium percarbonate)stabilizer (magnesium silicate)Zagreb, Croatia, June 7th, 2013.
34laundering is an energy intensive process Organic componentscobuilders (NTA, citrates…)polycarboxylic acid polymersoptical brighetenerssolvents (alcohols)enzymes (protease, amylase, lipase, cellulase, mananaze)activators of chemical bleaches (EDTA and NOBS)graying inhibitors (carboxymethyl cellulose, hydroxyethyl cellulose, special polymers (SRP), fragrance)Generally:laundering is an energy intensive processmore than 90% of energy for washing is used to heat the water - thus low temperature washing should be a great energy saverhowever an important factor to consider is that reducing the washing temperature decreases the degree of disinfection and increases the possibility of cross-infection of textiles washed in the same loadZagreb, Croatia, June 7th, 2013.
35ANALYSIS AFTER RINSING preparation of technological water (ion exchangers: synthetic resins and ion exchange)REQUIREMENTSWater hardness (°dH)Iron content (mg/l) 0,1Copper content (mg/l) 0,05Manganese content (mg/l) 0,03The total number of microorganisms (CFU/ml)Water-rinse100Prewash1000ANALYSIS AFTER RINSINGorganic incrustation(%) 1inorganic incrustation(%)pH6,5-8,3Anionic surfactant (g/g) 200Nonionic surfactant (g/g) 400Zagreb, Croatia, June 7th, 2013.
36Wastewater due to the pollution source An important criteria at industrial laundry are hygienic conditions, especially in the case of hospital laundry and laundry from food industry.It is referring to the disinfection of all work areas, vehicles, auxiliary devices (transport truck), employees and equipment.Wastewater due to the pollution sourceNORMAL LAUNDRYHOSPITAL LAUNDRYWORKING CLOTHESCLEANING CLOTHESCOD (mg O2/l)tohydrocarbons (mg/l)0 - 10-to 30000Surfactant (mg/l)to 300AOX (mg/l)0 - 40 - 120-36to 50Copper (mg/l)0 - 0,40 - 0,21-7to 100Lead (mg/l)0 - 0,10,7-2,8Zagreb, Croatia, June 7th, 2013.
376. PURIFICATION OF TEXTILE WASTEWATERS When wastewater (effluent) discharged into a river body such as lake, river or sea, a number of process occur which cause loss of organismsIt is necessary to treat effluent or waste before discharging in water bodyThe types of water treatment are regularly used to:improve water qualityremove microorganismsreduce the level of toxic substancesThe treatment procedure are generally divided into three groups:PRIMARY TREATMENT (mechanical treatment)SECONDARY TREATMENT (biological treatment)TERTIARY TREATMENT (advanced biological or chemical treatment)Zagreb, Croatia, June 7th, 2013.
38PRIMARY TREATMENT - mechanical treatment suspended solids and floating material is removedphysical and/or chemical treatmentSedimentation:the suspended and colloidal impurities are separated in sedimentation tank by gravitationthe main principle: allow water to rest or flow at a very slow velocity - heavier particles settle down due to gravitysettling of particles depend on velocity of flow, size, shape and specific gravity of particles and viscosity of liquidthe velocity of water decreased by increasing the length of flowZagreb, Croatia, June 7th, 2013.
39PRIMARY TREATMENT - mechanical treatment Coagulation/Floculattion:sedimentation is not sufficient to remove all the suspended mattercoagulation is used to remove colloidal particles from watercoagulation - process in which certain chemical agent is mixed with water then colloidal and suspended particles are agglomerated and form insoluble metal hydroxide known as flockscoagulation: is the destabilization of colloidal particles brought about by the addition of a chemical reagent called as coagulantfloculattion: is the agglomeration of particles into microfloc and after into bulky floccules which can be settledthe factors which can promote the coagulation-flocculation are:the velocity gradientthe timethe pHZagreb, Croatia, June 7th, 2013.
40PRIMARY TREATMENT - mechanical treatment Filtration:to remove colloidal and suspended matter remaining after sedimentationthe water pass through thick layer of sand or porous material which retain coarse impurities on its surface and in poresdoes not remove dissolved solidsas filtration media may be used:quartz sandsilica sandanthracite coalgarnetmagnetite and other materialsZagreb, Croatia, June 7th, 2013.
41SECONDARY TREATMENT - biological treatment microorganism play important role for the treatment of effluentmicroorganism decompose the organic wasteclassified into AEROBIC and ANAEROBIC treatmentAEROBIC TREATMENT:carried out by microorganism in the presence of oxygenbased on principle autopurificationANAEROBIC TREATMENT:carried out by aerobes in the absence of oxygenZagreb, Croatia, June 7th, 2013.
42Major differences in aerobic and anaerobic treatment ParameterAerobic treatmentAnaerobic TreatmentProcess principlemicrobial reactions take place in the presence of molecular/free oxygenreactions product are carbon dioxide, water and excess biomassmicrobial reactions take place in the absence of molecular/free oxygenreactions products are carbon dioxide, methane and excess biomassApplicationsWastewater with low to medium organic impurities (COD<1000 ppm) and for wastewater that are difficult to biodegradable e.g. municipial sewage, refinery wastewater etc.Wastewater with medium to high organic impurities (COD>1000 ppm) and easily biodegradable wastewater e.g. from food and baverage wastewater rich in starch/sugar/alcoholReaction kineticsRelatively fastRelatively slowNet sludge yieldRelatively highRelatively low (generally one fifth to one tenth of aerobic treatment process)Post treatmentTypically direct discharge or filtration/ disinfectionInvariably followed by aerobic treatmentFoot-PrintRelatively largeRelatively small and compactCapital investmentRelatively low with pay backExample technologiesActivated sludge e.g. etended aeration, MBR, fixed film processes etc.Continuously stirred tank reactor/digester, upflow anaerobic sludge blanket etc.Zagreb, Croatia, June 7th, 2013.
43Activated sludge process AerobicActivated sludge processmost versatile biological oxidation processtreatment of waste water contain dissolved solid, collides, rough solid and organic mattersewage from sedimentation tank enter into aeration tankactive sludge is mixed for about 4 to 8 hoursthe microorganisms oxidize organic matter in the presence of abundant quantity of oxygen in the aeration tanksewage is settle in secondary sedimentation tanksome portion of activated sludge is recalculated into the aeration tankcontain a large number of aerobic bacteria and other microorganismsZagreb, Croatia, June 7th, 2013.
44Trickling filters (TF) - biotowers AerobicTrickling filters (TF) - biotowersare used to remove organic matter from wastewateran aerobic treatment systemenable organic material in the wastewater to be adsorbed by a population of microorganisms (aerobic, anaerobic, and facultative bacteria; fungi; algae; and protozoa) attached to the medium as a biological film or slime layerthe wastewater flows over the medium - microorganisms form a film - the organic material is degraded by the aerobic microorganisms in the outer part of the layerlayer thickens through microbial growth - oxygen cannot penetrate the medium face - anaerobic organisms develop - biological film continues to grow - microorganisms near thesurface lose their ability to cling to the medium - a portion of the slime layer falls off the filter (so-called sloughing)sloughed solids are picked up and transported to a clarifier for removal from the wastewaterZagreb, Croatia, June 7th, 2013.
45Aerobic Advantages and disadvantages of Trickling filters (biotowers) Zagreb, Croatia, June 7th, 2013.
46AerobicAerated pond - lagoonwastewater is purified by action of algae and aerobic bacteriaorganic matter are decomposed by bacteria and are consumed by algaeoxygen is released during the process of photosynthesisaerobic bacteria get O2 from atmosphere and convert the organic matter present in CO2 which is again taken by algae during the process of photosynthesisZagreb, Croatia, June 7th, 2013.
47Anaerobic treatmentbiological agents are used to remove the contaminant from water in the absence of oxygenbiological agents include microorganisms which break down biodegradable material present in sludge after it is filtered from polluted water (so-called anaerobic digestion)huge sealed tanksmicroorganisms breakdown the sludge and convert it to organic acids, carbon dioxide, hydrogen and ammoniain the later stages the sludge remains are converted to biogas by methanogenbiological anaerobic treatment is a very low energy processideal for treating wastewater which is high in soluble BOD and/or CODZagreb, Croatia, June 7th, 2013.
48Bioremediation types of bioremediation: In situ – at the site process that uses microorganisms, fungi, green plants or their enzymes to return the natural environment altered by contaminants to its original conditiontypes of bioremediation:In situ – at the siteEx situ – away from the siteadvantages:low costminimal site disruptionsimultaneous treatment of contaminated water and soilminimal exposure of public and site personneldisadvantages:time consumingseasonal variationproblematic addition of additivesZagreb, Croatia, June 7th, 2013.
49- advanced biological or chemical treatment TERTIARY TREATMENT- advanced biological or chemical treatmentto decrease the content of nitrogen and phosphorous compound in the effluentDisinfectionWater is disinfected to kill any pathogens which pass through the filters and to provide a residual dose of disinfectant to kill or inactivate potentially harmful microorganisms in the storage and distribution systemsChlorine disinfectionthe most common disinfection methodchlorine – a strong oxidant - rapidly kills many harmful microorganisms danger of a release toxic gases - problem is avoided by the use of sodium hypochloriteZagreb, Croatia, June 7th, 2013.
50Advanced Oxidation Processes (AOPs) Chlorine dioxide disinfectiona faster acting disinfectant than elemental chlorinechlorine dioxide is supplied as an aqueous solution and added to water to avoid gas handling problemsa powerful disinfectant, excellent for removing odours, destroys organic matter, viruses and sporesvery explosive so cannot be storedAdvanced Oxidation Processes (AOPs)the aim of these methods is to mineralize the pollutants, i.e., to convert them entirely to CO2, H2O, and mineral acids such as HClmost AOPs are ambient-temperature processesgeneration of significant amounts of the hydroxyl free radical (OH.) – in aqueous solution is a very effective oxidizing agentthe hydroxyl radical can initiate the oxidation of a molecule – by extraction of hydrogen atom, or addition to one atom of a multiple bond, or extract an electron from an anionZagreb, Croatia, June 7th, 2013.
51Fenton process From AOPs the most common are: Fenton process Ozone oxidationOxidation by UV raysFenton processbased on oxidation by Fenton regaens, which is an oxidative mixture of hydrogen peroxide and Fe2+ ionseffectiveness depends on the pH, temperature and the ratio of the amount of Fe2 + ions and hydrogen peroxideAdvantages: no formation of chlorinated organic by-products, both reactants are relatively inexpensive, simple to use and non-toxicZagreb, Croatia, June 7th, 2013.
52Ozone oxidation Oxidation by UV rays Ozone: strong oxidizing agent, unstable to store (has to be made as it isused)it is produced by passing an electrical discharge through air which is then bubbled through the waterpowerful oxidizing agent which is toxic to most waterborne organismssome of the advantages include the production of fewer dangerous by-products (in comparison to chlorination) and the lack of taste and odour produced by ozonisationOxidation by UV raysvery effective at inactivating cystsUV lights disinfection effectiveness decreases as turbidity increasesthe water is passed through banks of cylindrical,quartz-jacketed fluorescent bulbsdisadvantages: some dissolved materials (iron and some organic compounds) can absorb the light, expensiveZagreb, Croatia, June 7th, 2013.
53Other water purification – MEMBRANE PROCESS Common membrane processes include:microfiltration (MF)ultrafiltration (UF)nanofiltrationreverse osmosis (RO)Water can be purified of most contaminant ions, molecules, and small particles, including viruses and bacteria, by passing it through a membrane in which the individual holes, called pores, are of uniform and microscopic sizethe pore size of the membrane must be smaller than the contaminant sizeZagreb, Croatia, June 7th, 2013.
54REVERSE OSMOSIS or HYPERFILTRATION membrane separation processes can be define as procedures which divide the input current (feed liquid) into two streams:permeate (the part of the input current who ispassed through the membrane)retentate (concentrate) part of the input currentretained by membraneREVERSE OSMOSIS or HYPERFILTRATIONwater is forced under high pressure to pass through the pores in a semipermeable membrane, composed of an organic polymeric material such as cellulose acetate or triacetate or a polyamideonly water (and other molecules of its small size) can pass through the pores, the liquid on the other side of the membrane is purified waterZagreb, Croatia, June 7th, 2013.
55MEMBRANE BIOREACTOR - MBR Is an improvement of the conventional activated sludge processes, where the traditional secondary clarifier is replaced by a membrane unit for the separation of treated water from the mixed solution in the bioreactorMembrane Bioreactor (MBR) Technology is based on Biological Treatment followed by membrane separation.Advantage:the high-quality of the purified waterincreased volume efficiencystops the pathogenic microorganisms and other pollutantsenables the growth nitrifying bacteriaability to work on high-organic pollutionbiomass growth is significantly reducedDisadvantage:membrane foulingZagreb, Croatia, June 7th, 2013.
56TYPES / MODULES of membranes: plate-and-frametubularspiral-woundhollow-fiberZagreb, Croatia, June 7th, 2013.
58CONCLUSIONSprior to discharge of industrial water into the drainage system they need to be purifiedmethod of treatment depends on the technological process where are produces wastewaterthe newest and the best effects of water purification achieved by a combination of purification processesmodified the process with the task of reducing the quantity of wastewaterre-use of purified wastewaterZagreb, Croatia, June 7th, 2013.
59Regarding to laundry: Sources of pollution: from the raw water (salts) detergents (surfactants – tenzides; phosphates, silicates)dirt from clothes (fiber clothing, colour, fat, oil)temperatureImportant:physical treatment (membrane procesess)biological treatmentcombination of procesessZagreb, Croatia, June 7th, 2013.
60Thank you for your attention! Zagreb, Croatia, June 7th, 2013.