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Zagreb, Croatia, June 7 th, 2013. History History : The independent study of the textile technology in Croatia started at the beginning of 1960 as a.

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Presentation on theme: "Zagreb, Croatia, June 7 th, 2013. History History : The independent study of the textile technology in Croatia started at the beginning of 1960 as a."— Presentation transcript:


2 Zagreb, Croatia, June 7 th, 2013.

3 History History : The independent study of the textile technology in Croatia started at the beginning of 1960 as a study at the Faculty of Technology in Zagreb first only textile chemical engineering, then later mechanical and clothing engineering and at three independent colleges of textiles in Duga Resa, Varaždin and Zagreb In 1991 the Institute of Textile and Clothing was organized as an independent Institution named Faculty of Textile Technology of the University of Zagreb

4 Zagreb, Croatia, June 7 th, Departments Departments: Department of Materials, Fibres and Textile Testing Department of Textile Design and Management Department of Clothing Technology Department of Textile and Clothing Design Department of Fundamental Natural and Engineering Sciences Department of Textile Chemistry and Ecology Department of Applied Chemistry Study in Varaždin Centre for Development and Transfer of Textile and Clothing Technologies and Fashion Design

5 Zagreb, Croatia, June 7 th, Tihana Dekanic, B.Sc.

6 Zagreb, Croatia, June 7 th, The Textile industry: use high volume of water throughout its operation produce large quantities of wastewaters is very diverse broad manufacturing sector main 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 solids heat colour acidity or alkalinity other soluble substances

7 Zagreb, Croatia, June 7 th, Classification of fibers: by TYPE by LENGTH by SIZE

8 Zagreb, Croatia, June 7 th, Properties: strength durability absorbent comfortable flexible good resistant to alkalis poor acid resistant poor wrinkle resistance Features: soft fibers fiber – single elongated cell – twisted and ribbon like – wide inner hollow (lumen) 90% cellulose, 6% moisture, other fats and impurities

9 Zagreb, Croatia, June 7 th, Properties: absorbent lightweight versatile naturally UV protection durable and elastic non allergenic biodegradable flame retardant easy care Features: fibre – irregular, roughly cylindrical, multi cellular structure three basic layers: epidermis (outer layer), cortex (middle layer) and medulla (inner layer)

10 Zagreb, Croatia, June 7 th, Properties: high melting temperature strong hydrophobic resistant to stretching and shrinking resistant to most chemicals wrinkle resistant abrasion resistant easily washed Features: smooth, straight, round cross sectionally rod-like shape term polyester – mostly refers to polyethylene terephalate (PET)

11 Cotton fibres before washing after 11 washing cycles after 6 washing cycles after 50 washing cycles visible changes of mechanical properties during washing and drying

12 Zagreb, Croatia, June 7 th, Water: water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds three states of matter: solid liquid gas covers 71% of the Earth surface (96,5% in oceans, 1,7% in ground water, 1,7% in glaciers and ice caps and 0,001% in the air) only 2,5% is fresh water and 98,8% of that water is in ice and groundwater less than 0,3% of all fresh water is in rivers, lakes and the atmosphere

13 Zagreb, Croatia, June 7 th, Chemical and physical properties: is liquid at standard temperature and pressure polar molecule with electrical dipole moment due to non linear structure high surface tension have cappilary action universal solvent low electrical conductivity density thermal: specific heat and latent heat viscosity osmotic pressure optical properties electrical properties: dielectric constant, electrical conductivity

14 Zagreb, Croatia, June 7 th, Absolutely pure water is never found in nature! According to Regulation on Water Classification, there are two groups of indicators of water quality: 1 st groups: mandatory indicators (physical and chemical parameters, oxygen demand, microbiological and biological indicators) 2 nd groups: metals, organic compounds, radioactivity

15 Zagreb, Croatia, June 7 th, PHYSICAL INDICATORS: 1.1. Suspended matters This includes all matter suspended in water that is large enough to be retained on a filter with a given porosity Turbidity Measures the amount of suspended particles in water 1.3. Colour The 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 components True color is measured after filtering the water sample to remove all suspended materials

16 Zagreb, Croatia, June 7 th, PHYSICAL INDICATORS: 1.4. Transparency Transparency measures how far light can penetrate a body of water Conductivity Conductivity ( ) 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 Odour and taste Water 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.

17 Zagreb, Croatia, June 7 th, PHYSICAL INDICATORS: 1.7. Temperature Normal temperature: 22°C ( limit value of wastewater temperature is 30°C) Sources: sunlight, thermal pollution Effects: 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 from season to season and with geographic location The stratification of a lake in the summer

18 Zagreb, Croatia, June 7 th, CHEMICAL INDICATORS 2.1. Total dissolved solids TDS is a measure of the combined content of all organic and inorganic substances contained in a water in: molecular, ionized or micro- granular suspended form 2.2. pH pH is measure of acidity in water (hydrogen ion concentration) pH = - log [ H + ] acidalkaline neutral

19 Zagreb, Croatia, June 7 th, CHEMICAL INDICATORS 2.3. Alkalinity Alkalinity is the quantitative capacity of water to neutralize an acid. Expressed in mg/l CaCO 3. Wastewater is normally alkaline Hardness Calcium and magnesium salt content Temporary hardness - carbonates and bicarbonates, can be removed by boiling equilibrium: CaCO 3 + CO 2 + H 2 O Ca HCO 3 Permanent hardness - sulfates, chlorides, other anions Classification of water by German Hardness

20 Zagreb, Croatia, June 7 th, CHEMICAL INDICATORS 2.5. Dissolved gases Prime importance in considering the quality of water along with the other physical and chemical characteristics. Important gases dissolved in waters: oxygen carbon dioxide nitrogen ammonia hydrogen sulfide sulfur dioxide chlorine etc Organic matters Organic matter - organic material present in surface or ground water. Division to: biodegradable and non-biodegradable. Three major sources: the breakdown of naturally occurring organic materials commercial and domestic chemical wastes chemical reactions that occur during water treatment and filtration processes

21 Zagreb, Croatia, June 7 th, CHEMICAL INDICATORS 2.7. Nutrients Nutrients in wastewater: organic carbon nitrogen phosphorus potassium Required for the primary production of organic matter 2.8. Metals Most 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, silver toxic: sodium, iron, manganese, aluminum, copper and zinc

22 Zagreb, Croatia, June 7 th, CHEMICAL INDICATORS 2.9. BOD (Biochemical Oxygen Demand) The amount of oxygen (mg O 2 /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 (BOD 5, BOD 20 or BOD 100 ) 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/m 3 ) 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.

23 Zagreb, Croatia, June 7 th, CHEMICAL INDICATORS 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 Other fluorides (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)

24 Zagreb, Croatia, June 7 th, 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 index the degree of biological production microbiological indicators (coliform bacteria, E-coli, faecal streptococcus) the degree of toxicity

25 Zagreb, Croatia, June 7 th, BIOLOGICAL INDICATORS: Biological surface water quality determinants being monitored according to Water Classification Act (National Gazette, NN 77/98) are: Saprobic index (Pantle – Buck), Extended Biotic Index and Trophy status (lakes) Bioindicator system that is currently in use in Croatia: Wegl (1983) Analysed communities: Benthic macroinvertebrates Periphyton Bioseston HRIS - national bioindicator system (2005) Surface water quality monitoring in Croatia continuous monitoring in Republic of Croatia started in the 1950 water quality monitoring is mainly based on physico-chemical parameters since 2000 water quality assessment is significantly improved sampling and assessment of water quality is done in accordance with Croatian (HRN) or International norms (ISO-EN) in authorized laboratories

26 Zagreb, Croatia, June 7 th, 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 wastewater INDICATORS AND MEASURES SURFACE WATER PUBLIC SEWER SYSTEM REFERENCE METHOD OF MEASUREMENT GENERAL INDICATORS pH6,5-9,06,5-9,5HRN ISO 10523:1998 Temperature [ o C]3040DIN C4 Deposited matters [ml/l]0,510DIN H9 Suspended matters [mg/l]80(a)HRN ISO 11923:1998 ORGANIC INDICATORS BOD 5 [mgO 2 /l]30-HRN EN :2004 COD [mgO 2 /l ]200 (e)(d) HRN ISO 6060:2003 HRN ISO 15705:2003 TOC [mgC/l]60 (c)(d)HRN EN 1484:2002 AOX [mg/l]0,5 HRN EN 1485:2002 Surfactants, anionic and nononic [mg/l]1,0(a)HRN EN 903:2002 Mineral oils [mg/l]1020HRN EN ISO :2002 Parameters and Maximum Permissible Concentration (MPC) for laundry wastewater with applicable standards

27 Zagreb, Croatia, June 7 th, INORGANIC INDICATORS Sulphides dissolved S [mg/l]0,51,0 HRN ISO 10530:1998 HRN ISO 13358:1998 Sulphates SO 4 [mg/l] Sulfites SO 3 [mg/l] Free chlorine [mg Cl 2 /l]0,20,5 HRN EN ISO7393-1:2001 HRN EN ISO :2001 HRN EN ISO :2001 Total chlorine [Cl 2 mg/l]0,51,0 HRN EN ISO :2001 HRN EN ISO :2001 HRN EN ISO :2001 Total phosphorus [mg P/l]1,0-HRN ISO 6878 Ammonium [mg N/l]5 HRN ISO 5664:1998 HRN ISO :1998 Total chromium Cr [mg/l]1,254,0 HRN EN 1233 HRN ISO 8288 Chromium Cr 6+ [mg/l]0,10,2HRN ISO Ortophosphates [mg P/l]1-4-HRN ISO 6878 Nitrites [mg/l]0,5-210HRN ISO Nitrates [mg/l]2-10-HRN EN ISO AOX [mg/l]0,1-7,51HRN EN 1485 SURFACTANTS Total surfactant [mg/l]4-1020Σ surfactants Anionic surfactant [mg/l]1-410 HRN EN 903 ASTM D HRN EN ISO HRN ISO 2271 Nonionic surfactant [mg/l]1-410 HRN ISO 2268 HRN ISO Cationic surfactant [mg/l]0,2-1,02 HRN EN ISO HRN EN ISO ASTM

28 Zagreb, Croatia, June 7 th, The common characteristics of textile wastewater are: high chemical oxygen demand (COD) high biological oxygen demand (BOD) high temperature high pH solid materials phenol, sulphure and the colours caused by different dyes Wastewater of textile industry are changeable in amount and composition. The 1 st reason of pollutants: is the natural impurity in fibres. The 2 nd 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.

29 Zagreb, Croatia, June 7 th, Textile 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.

30 Zagreb, Croatia, June 7 th, Major 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 compositionNature Sizing starch, waxes, carboxymethil cellulose (CMC), polyvinyl alcohol (PVA), wetting agents high BOD, COD Desizing starch, CMC, PVA, fats, waxes, pectins high BOD, COD, suspended solids, dissolved solids Bleaching sodium hypochlorite (NaClO), Cl 2, NaOH, H 2 O 2, acids, surfactants, NaSiO 3, sodium phosphate, short cotton fibre hihg alkalinity, high suspended solids Mercerizing sodium hydroxide, cotton wax high pH, low BOD, high suspended solids Dyeing dystuffs, urea, reducing agents, oxidizing agents, acetic acid, detergents, wetting agents strongly coloured, high BOD, high dissolved solids, low suspended solids, heavy metals Printing pastes, urea, starches, gums, oils, binders, acids, thickeners, cross-linkers, reducing agents, alkali highly coloured, high BOD, oily appearance, high suspended solids, slightly alkaline, low BOD Finishing resins, waxes, chlorinated compounds, acetate, softeners, formaldehyde, PVA high alkalinity, high acidity, toxicity, high organic and inorganic suspended solids Leather production sulphite, chromium, synthetic tannins, biocides, lubricants toxicity, high organic and inorganic suspended solids, odour Textile care fats, detergents, chlorine, active oxygen high BOD, high COD, high alkality, low suspended solids, toxicity, foam

31 Zagreb, Croatia, June 7 th, Washing is a complex process that is occurs in an aqueous meduim with the influence of four parameters: temperature time mechanics chemistry All 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.

32 Zagreb, Croatia, June 7 th, Factors that influence on washing effects: 1.WATER -quantity -hardness (ratio Ca 2+ /Mg 2+ ) -purity, microbiological composition, content of heavy metals 2.SOILING -the degree and type of soiling -interaction with components of detergent -composition and structure of textile materials 3.TEXTILES - textiles (fabric, yarn..) - sweling Tg - finishing, coloration - charge (dimenzion, size..) - purpose, residues

33 Zagreb, Croatia, June 7 th, WASHING MACHINE washing temperature (initial, heating, final temperature) washing time mechanics 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.DETERGENT Active components anionic surfactant nonionic surfactant soap cationic surfactant Inorganic components alkalies (silikates, Na 2 CO 3 ) phosphates (sodium triphosphate) zeolites (sodium aluminosilicate) chemical bleaches (sodium perborate, sodium percarbonate) stabilizer (magnesium silicate)

34 Zagreb, Croatia, June 7 th, Organic components cobuilders (NTA, citrates…) polycarboxylic acid polymers optical brigheteners solvents (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 process more than 90% of energy for washing is used to heat the water - thus low temperature washing should be a great energy saver however 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 load

35 Zagreb, Croatia, June 7 th, preparation of technological water ( ion exchangers: synthetic resins and ion exchange) REQUIREMENTS Water hardness (°dH)0 Iron content (mg/l) 0,1 Copper content (mg/l) 0,05 Manganese content (mg/l) 0,03 The total number of microorganisms (CFU/ml)Water-rinse 100 Prewash 1000 ANALYSIS AFTER RINSING organic incrustation(%) 1 inorganic incrustation(%) 1 pH6,5-8,3 Anionic surfactant ( g/g) 200 Nonionic surfactant ( g/g) 400

36 Zagreb, Croatia, June 7 th, Wastewater due to the pollution source NORMAL LAUNDRY HOSPITAL LAUNDRY WORKING CLOTHES CLEANING CLOTHES COD (mg O 2 /l) to hydrocarbons (mg/l) to Surfactant (mg/l) to 300 AOX (mg/l) to 50 Copper (mg/l)0 - 0,40 - 0,21-7to 100 Lead (mg/l)0 - 0,20 - 0,10,7-2,8to 100 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.

37 Zagreb, Croatia, June 7 th, When wastewater (effluent) discharged into a river body such as lake, river or sea, a number of process occur which cause loss of organisms It is necessary to treat effluent or waste before discharging in water body The types of water treatment are regularly used to: improve water quality remove microorganisms reduce the level of toxic substances The treatment procedure are generally divided into three groups: PRIMARY TREATMENT ( mechanical treatment ) SECONDARY TREATMENT ( biological treatment ) TERTIARY TREATMENT ( advanced biological or chemical treatment )

38 Zagreb, Croatia, June 7 th, PRIMARY TREATMENT - mechanical treatment suspended solids and floating material is removed physical and/or chemical treatment Sedimentation: the suspended and colloidal impurities are separated in sedimentation tank by gravitation the main principle: allow water to rest or flow at a very slow velocity - heavier particles settle down due to gravity settling of particles depend on velocity of flow, size, shape and specific gravity of particles and viscosity of liquid the velocity of water decreased by increasing the length of flow

39 Zagreb, Croatia, June 7 th, PRIMARY TREATMENT - mechanical treatment Coagulation/Floculattion: sedimentation is not sufficient to remove all the suspended matter coagulation is used to remove colloidal particles from water coagulation - process in which certain chemical agent is mixed with water then colloidal and suspended particles are agglomerated and form insoluble metal hydroxide known as flocks coagulation: is the destabilization of colloidal particles brought about by the addition of a chemical reagent called as coagulant floculattion: is the agglomeration of particles into microfloc and after into bulky floccules which can be settled the factors which can promote the coagulation-flocculation are: the velocity gradient the timet he pH

40 Zagreb, Croatia, June 7 th, PRIMARY TREATMENT - mechanical treatment Filtration: to remove colloidal and suspended matter remaining after sedimentation the water pass through thick layer of sand or porous material which retain coarse impurities on its surface and in pores does not remove dissolved solids as filtration media may be used: quartz sand silica sand anthracite coal garnet magnetite and other materials

41 Zagreb, Croatia, June 7 th, SECONDARY TREATMENT - biological treatment microorganism play important role for the treatment of effluent microorganism decompose the organic waste classified into AEROBIC and ANAEROBIC treatment AEROBIC TREATMENT: carried out by microorganism in the presence of oxygen based on principle autopurification ANAEROBIC TREATMENT: carried out by aerobes in the absence of oxygen

42 Zagreb, Croatia, June 7 th, Major differences in aerobic and anaerobic treatment ParameterAerobic treatmentAnaerobic Treatment Process principle microbial reactions take place in the presence of molecular/free oxygen reactions product are carbon dioxide, water and excess biomass microbial reactions take place in the absence of molecular/free oxygen reactions products are carbon dioxide, methane and excess biomass Applications Wastewater 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/alcohol Reaction kinetics Relatively fastRelatively slow Net sludge yield Relatively high Relatively low (generally one fifth to one tenth of aerobic treatment process) Post treatment Typically direct discharge or filtration/ disinfection Invariably followed by aerobic treatment Foot-Print Relatively largeRelatively small and compact Capital investment Relatively highRelatively low with pay back Example technologies Activated sludge e.g. etended aeration, MBR, fixed film processes etc. Continuously stirred tank reactor/digester, upflow anaerobic sludge blanket etc.

43 Zagreb, Croatia, June 7 th, Aerobic Activated sludge process most versatile biological oxidation process treatment of waste water contain dissolved solid, collides, rough solid and organic matter sewage from sedimentation tank enter into aeration tank active sludge is mixed for about 4 to 8 hours the microorganisms oxidize organic matter in the presence of abundant quantity of oxygen in the aeration tank sewage is settle in secondary sedimentation tank some portion of activated sludge is recalculated into the aeration tank contain a large number of aerobic bacteria and other microorganisms

44 Zagreb, Croatia, June 7 th, Aerobic Trickling filters (TF) - biotowers are used to remove organic matter from wastewater an aerobic treatment system enable 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 layer the wastewater flows over the medium - microorganisms form a film - the organic material is degraded by the aerobic microorganisms in the outer part of the layer layer thickens through microbial growth - oxygen cannot penetrate the medium face - anaerobic organisms develop - biological film continues to grow - microorganisms near the sloughed solids are picked up and transported to a clarifier for removal from the wastewater surface lose their ability to cling to the medium - a portion of the slime layer falls off the filter (so-called sloughing)

45 Zagreb, Croatia, June 7 th, Aerobic Advantages and disadvantages of Trickling filters (biotowers)

46 Zagreb, Croatia, June 7 th, Aerobic Aerated pond - lagoon wastewater is purified by action of algae and aerobic bacteria organic matter are decomposed by bacteria and are consumed by algae oxygen is released during the process of photosynthesis aerobic bacteria get O 2 from atmosphere and convert the organic matter present in CO 2 which is again taken by algae during the process of photosynthesis

47 Zagreb, Croatia, June 7 th, biological agents are used to remove the contaminant from water in the absence of oxygen biological agents include microorganisms which break down biodegradable material present in sludge after it is filtered from polluted water (so-called anaerobic digestion) huge sealed tanks Anaerobic treatment microorganisms breakdown the sludge and convert it to organic acids, carbon dioxide, hydrogen and ammonia in the later stages the sludge remains are converted to biogas by methanogen biological anaerobic treatment is a very low energy process ideal for treating wastewater which is high in soluble BOD and/or COD

48 Zagreb, Croatia, June 7 th, Bioremediation process that uses microorganisms, fungi, green plants or their enzymes to return the natural environment altered by contaminants to its original condition types of bioremediation: In situ – at the site Ex situ – away from the site advantages: low cost minimal site disruption simultaneous treatment of contaminated water and soil minimal exposure of public and site personnel disadvantages: time consuming seasonal variation problematic addition of additives

49 Zagreb, Croatia, June 7 th, TERTIARY TREATMENT - advanced biological or chemical treatment to decrease the content of nitrogen and phosphorous compound in the effluent Disinfection Water 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 systems Chlorine disinfection the most common disinfection method chlorine – a strong oxidant - rapidly kills many harmful microorganisms danger of a release toxic gases - problem is avoided by the use of sodium hypochlorite

50 Zagreb, Croatia, June 7 th, Chlorine dioxide disinfection a faster acting disinfectant than elemental chlorine chlorine dioxide is supplied as an aqueous solution and added to water to avoid gas handling problems a powerful disinfectant, excellent for removing odours, destroys organic matter, viruses and spores very explosive so cannot be stored Advanced Oxidation Processes (AOPs) the aim of these methods is to mineralize the pollutants, i.e., to convert them entirely to CO 2, H 2 O, and mineral acids such as HCl most AOPs are ambient-temperature processes generation of significant amounts of the hydroxyl free radical (OH. ) – in aqueous solution is a very effective oxidizing agent the 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 anion

51 Zagreb, Croatia, June 7 th, Fenton process based on oxidation by Fenton regaens, which is an oxidative mixture of hydrogen peroxide and Fe 2+ ions effectiveness depends on the pH, temperature and the ratio of the amount of Fe 2 + ions and hydrogen peroxide Advantages: no formation of chlorinated organic by-products, both reactants are relatively inexpensive, simple to use and non-toxic From AOPs the most common are: Fenton process Ozone oxidation Oxidation by UV rays

52 Zagreb, Croatia, June 7 th, Ozone oxidation 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 water powerful oxidizing agent which is toxic to most waterborne organisms some of the advantages include the production of fewer dangerous by- products (in comparison to chlorination) and the lack of taste and odour produced by ozonisation Oxidation by UV rays very effective at inactivating cysts UV lights disinfection effectiveness decreases as turbidity increases the water is passed through banks of cylindrical,quartz-jacketed fluorescent bulbs disadvantages: some dissolved materials (iron and some organic compounds) can absorb the light, expensive

53 Zagreb, Croatia, June 7 th, Other water purification – MEMBRANE PROCESS Common membrane processes include: microfiltration (MF) ultrafiltration (UF) nanofiltration reverse 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 size the pore size of the membrane must be smaller than the contaminant size

54 Zagreb, Croatia, June 7 th, 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 is passed through the membrane) retentate (concentrate) part of the input current retained by membrane REVERSE OSMOSIS or HYPERFILTRATION water 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 polyamide only water (and other molecules of its small size) can pass through the pores, the liquid on the other side of the membrane is purified water

55 Zagreb, Croatia, June 7 th, MEMBRANE 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 bioreactor Membrane Bioreactor (MBR) Technology is based on Biological Treatment followed by membrane separation. Advantage: the high-quality of the purified water increased volume efficiency stops the pathogenic microorganisms and other pollutants enables the growth nitrifying bacteria ability to work on high-organic pollution biomass growth is significantly reduced Disadvantage: membrane fouling

56 Zagreb, Croatia, June 7 th, TYPES / MODULES of membranes: plate-and-frame tubular spiral-wound hollow-fiber


58 Zagreb, Croatia, June 7 th, prior to discharge of industrial water into the drainage system they need to be purified method of treatment depends on the technological process where are produces wastewater the newest and the best effects of water purification achieved by a combination of purification processes modified the process with the task of reducing the quantity of wastewater re-use of purified wastewater

59 Zagreb, Croatia, June 7 th, Sources of pollution: from the raw water (salts) detergents (surfactants – tenzides; phosphates, silicates) dirt from clothes (fiber clothing, colour, fat, oil) temperature Important: physical treatment (membrane procesess) biological treatment combination of procesess Regarding to laundry:

60 Zagreb, Croatia, June 7 th, 2013.

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