HRP920640A2 - Treatment of waste waters containing vinyl acetate - Google Patents

Description

Oblast tehnike iz koje je pronalazak The technical field from which the invention originated

Pronalazak je iz područja kemije i to zaštite životne sredine (tehnologije obrade otpadnih voda). Po međunarodnoj klasifikaciji pronalazak se ubraja u razred C02F 1 /00. The invention is from the field of chemistry and environmental protection (wastewater treatment technology). According to the international classification, the invention is included in class C02F 1 /00.

Tehnički problem Technical problem

Pronalaskom pod nazivom "Postupak za pročišćavanje otpadnih voda od vinilacetata", omogućuje se pročišćavanje otpadnih voda sa sadržajem vinilacetata. Postupkom se omogućuje pročišćavanje otpadnih voda od vinilacetata u efikasnosti > 99 % računato na koncentraciju u influentu". Postupak je naročito primjenljiv kod industrija sa nižim (< 100 m /dan) protocima otpadnih voda, odnosno kod diskontinuiranih protoka otpadnih voda. The invention entitled "Procedure for the purification of waste water from vinyl acetate" enables the purification of waste water containing vinyl acetate. The process enables the purification of vinyl acetate waste water with an efficiency of > 99% calculated on the concentration in the influent". The process is particularly applicable in industries with lower (< 100 m/day) waste water flows, that is, with discontinuous waste water flows.

Stanje tehnike State of the art

Vinilacetat predstavlja u kemijskoj industriji veoma često korištenu kemikaliju, prvenstveno kod proizvodnje ljepila i sličnih vezivnih sredstava, odnosno kod proizvodnje njegovih polimernih produkata. Takvi se proizvodi proizvode reaktorskom tehnikom, najčešće pod povišenim pritiskom, uz dodatak različitih aditiva, u šaržnim uslovima. Nakon sinteze produkta,reaktor za sintezu se isprazni i ispire sa vodom. Ovisno o tome da li se kod ispiranja koriste viško ili niskotlačne pumpe, količina otpadne vode može varirati od 5 do 100 m /šarži. Količina otpadne vode također naravno ovisi i o veličini odnosno kapacitetu reaktora. Vinyl acetate is a very frequently used chemical in the chemical industry, primarily in the production of adhesives and similar binders, i.e. in the production of its polymer products. Such products are produced using reactor technology, usually under elevated pressure, with the addition of various additives, in batch conditions. After product synthesis, the synthesis reactor is emptied and rinsed with water. Depending on whether high-pressure or low-pressure pumps are used for flushing, the amount of waste water can vary from 5 to 100 m/batch. The amount of waste water also naturally depends on the size or capacity of the reactor.

Po svom kemijskom sastavu takve otpadne vode sadrže djelomično polimerizirani vinilacetat, neizreagirani vinil acetat, a kao nečistoće može sadržavati i neizreagirane katalizatore, biocide i slične kemikalije koje se koriste kod sintetiziranja različitih produkata polimerizacijom vinilacetata. According to its chemical composition, such wastewater contains partially polymerized vinyl acetate, unreacted vinyl acetate, and as impurities it may also contain unreacted catalysts, biocides and similar chemicals used in the synthesis of various products by polymerizing vinyl acetate.

Otpadnu vodu koja sadrži topive i netopive organske i druge komponente moguće je čistiti primarnim obradama otpadnih voda iza kojih slijede sekundarne obrade otpadnih voda, a po potrebi i tercijarne. Pod primarnim obradama otpadnih voda podrazumijevamo one kojima se otpadna voda priprema za obradu sekundarnim postupcima. Sekundarni postupci obrada otpadnih voda predstavljaju isključivo biološke metode obrade otpadnih voda dok se tercijarnim obradama otpadnih voda podrazumijeva niz tehnologija obrada otpadnih voda kojima se polira kvaliteta efluenta sekundarnih obrada. Kod visokih protoka otpadnih voda (veličina protoka od 10 do 100000 metara kubnih na sat) sekundarne obrade otpadnih voda predstavljaj) i tehnološko-tehnički i ekonomski najprihvatljivije oblike tretmana otpadnih voda. Pritom primarne obrade otpadnih voda igraju jedino funkciju pripreme otpadne vode da bi se one mogle dovoljno kvalitetno obraditi sekundarnim obradama otpadnih voda. Tercijarne obrade otpadnih voda predstavljaju takve oblike obrada otpadnih voda kojima se polira efluent sekundarnih obrada (npr. pješčanim filterima, reversnim osmozama itd.) u cilju da se otpadna voda što bolje pročisti za ponovnu upotrebu u energetskim postrojenjima (npr. kao make-up vodu rashladnih sistema ili kao make-up vodu kotlova). Međutim veća upotreba tercijarnih obrada otpadnih voda u praksi će se početi primjenjivati po prognozama tek u devedesetim godinama iz razloga što je danas cijena ulazne vode u neki industrijski objekt još uvijek niža od jedinične cijene tercijarno pročišćene otpadne vode. Iz tog razloga premda su tercijarne obrade otpadnih voda, tehnološko-tehnički razrađeni postupci, njihova primjena nije još velika . Wastewater containing soluble and insoluble organic and other components can be cleaned by primary wastewater treatment followed by secondary wastewater treatment and, if necessary, tertiary treatment. By primary wastewater treatment we mean those by which wastewater is prepared for treatment by secondary procedures. Secondary wastewater treatment procedures represent exclusively biological methods of wastewater treatment, while tertiary wastewater treatment refers to a series of wastewater treatment technologies that polish the quality of secondary treatment effluents. In the case of high flows of waste water (flow rate from 10 to 100,000 cubic meters per hour), secondary treatment of waste water is presented) and the most technologically and economically acceptable forms of waste water treatment. At the same time, the primary treatment of waste water plays only the function of preparing waste water so that it can be treated with sufficient quality by secondary treatment of waste water. Tertiary wastewater treatment represents such forms of wastewater treatment that polish the effluent of secondary treatments (e.g. sand filters, reverse osmosis, etc.) in order to purify the wastewater as best as possible for reuse in energy plants (e.g. as make-up water cooling systems or as boiler make-up water). However, the greater use of tertiary wastewater treatment in practice will begin to be applied, according to forecasts, only in the 1990s, due to the fact that today the price of water entering an industrial facility is still lower than the unit price of tertiary treated wastewater. For this reason, although the tertiary treatment of waste water is a technologically and technically developed procedure, its application is not yet widespread.

U posljednje vrijeme sa primjećuje pojava kombinacija tehnoloških rješenja gdje se kombiniraju elementi sekundarne i tercijarne obrade otpadnih voda, odnosno gdje se kombiniraju elementi primarne i tercijarne obrade otpadnih voda. Tipični primjeri takvih oblika obrada otpadnih voda predstavljaju PACT proces (kombinacija sekundarne i tercijarne obrade otpadnih voda) koji o čemu se detaljniji podaci mogu naći u literaturi: Lately, the appearance of combinations of technological solutions has been noticed, where elements of secondary and tertiary treatment of waste water are combined, that is, where elements of primary and tertiary treatment of waste water are combined. Typical examples of such forms of wastewater treatment are the PACT process (combination of secondary and tertiary wastewater treatment), which more detailed information can be found in the literature:

U.S. 3.904.518. odnosno Kerry L.Sublette - WATER RESEARCH vol. 16 (1982 )str . 1075-1082. Što se tiče povezanosti primarnih i tercijarnih obrada vrlo dobar prikaz svih mogućih kombinacija obrada otpadnih voda (uključujući i PACT proces) mogu se pronaći u Eckenfelder W.W.-CHEMICAL ENGINEERING (1985)Sep.2.str.60-74. LOUSE. 3,904,518. or Kerry L. Sublette - WATER RESEARCH vol. 16 (1982) p. 1075-1082. Regarding the connection of primary and tertiary treatments, a very good presentation of all possible combinations of wastewater treatments (including the PACT process) can be found in Eckenfelder W.W.-CHEMICAL ENGINEERING (1985) Sep.2.pp.60-74.

U literaturi su opisani postupci i uređaji za pročišćavanje otpadnih voda od polivinilacetata i vinilacetata i ti postupci odnosno uređaji predstavljaju najčešće kombinacije primarnih i sekundarnih obrada otpadnih voda (npr. kombinacija flokulacije i aerobne biološke obrade sa aktivnim muljem) odnosno primarne i tercijarne obrade otpadnih voda (npr. kombinacija flokulacije i adsorpcije na aktivnom ugljenu). Takve su kombinacije vrlo logične iz razloga što vode od ispiranja reaktora od vinilaacetata sadrže pored neizreagiranog vinilacetata (koji je topiv u vodi) i polivinilacetat (koji nije topiv u vodi već je emulgiran u vodi). Da se pročisti takva voda potrebno ju je najprije predtretirati, (gdje se odstranjuje neizreagirani vinilacetat), a nakon toga dopunsko obraditi bilo aerobnom biološkom obradom bilo adsorpcijom na aktivnom ugljenu (da se odstrani otopljeni vinilacetat). U literaturi je poznata obrada koja je zaštićena patentom i to jedino obrada predtretmanom (CHEMABSTRACT vol.89 no.7977j), nakon čega nije navedeno na koji se način otpadna voda dalje obrađuje premda je jasno da se otpadna voda takve pročišćene kvalitete ne smije ispuštati u efluent. Proizvođači vinilacetata (npr. HOEST) imaju na lokacijama gdje se ta kemikalija proizvodi instalirane aerobne biološke obrade otpadnih voda, ali ovdje su u pitanju veliki protoci otpadnih voda i takav oblik obrade otpadnih voda se nameće kao tehnološki logičan. Kod nižih protoka tehnološki je vrlo prikladno rješenje tipa kombinacije flokulacije i obrade sa aktivnim ugljenom, premda nije poznato da je takav tip instalacije negdje instaliran. Procedures and devices for wastewater treatment from polyvinyl acetate and vinyl acetate are described in the literature, and these procedures or devices represent the most common combinations of primary and secondary wastewater treatment (e.g. a combination of flocculation and aerobic biological treatment with activated sludge) or primary and tertiary wastewater treatment ( eg combination of flocculation and adsorption on activated carbon). Such combinations are very logical due to the fact that the washing water from vinyl acetate reactors contains, in addition to unreacted vinyl acetate (which is soluble in water) and polyvinyl acetate (which is not soluble in water but is emulsified in water). To purify such water, it must first be pre-treated (where unreacted vinyl acetate is removed), and then additionally processed either by aerobic biological treatment or by adsorption on activated carbon (to remove dissolved vinyl acetate). In the literature, there is a treatment that is protected by a patent, and that is only pretreatment treatment (CHEMABSTRACT vol.89 no.7977j), after which it is not specified how the wastewater is further processed, although it is clear that wastewater of such purified quality must not be discharged into effluent. Producers of vinyl acetate (eg HOEST) have installed aerobic biological waste water treatment at the locations where this chemical is produced, but here we are dealing with large flows of waste water and such a form of waste water treatment is imposed as technologically logical. At lower flow rates, a solution of the combination of flocculation and treatment with activated carbon is technologically very suitable, although it is not known that this type of installation has been installed anywhere.

Na Shemi 1. u prilogu je prikazana kvaliteta efluenta koja se postiže kod tretiranja otpadne vode sa sadržajem vinilacetata, ali je i prikazan kvalitet efluenta koji se postiže "Postupkom za pročišćavanje otpadnih od vinilacetata" koji se temelji na upotrebi vodikovog peroksida. Iz Sheme 1. se može vidjeti da ukoliko se takva otpadna voda pročišćava jedino mehaničkom obradom i flokulacijora dobivena kvaliteta efluenta nije takva da bi se mogla direktno ispuštati u vodotokove ( KPK = 400-600 mg/l, BPK5 = 250-350 mg/l, TOC = 100 - 250 mg/l, vinilacetat = 10-50 mg/l) po suvremenim kriterijima o kvaliteti efluenta prije ispuštanja u vodotokove. Ukoliko se proces flokulacije kombinira sa dopunskim procesom tipa adsorpcije sa aktivnim ugljenom, odnosno aerobne biološke obrade, tada se može postići kvaliteta koja se može ispuštati u vodotokove (KPK = 40-50 mg/l, BPK5= 20-40 mg/l, TOC = 10-15 mg/l, vinilacetat = 1-2 mg/l). Scheme 1 in the attachment shows the quality of the effluent that is achieved when treating wastewater with vinyl acetate content, but also shows the quality of the effluent that is achieved by the "Procedure for purification of vinyl acetate waste" based on the use of hydrogen peroxide. From Scheme 1, it can be seen that if such wastewater is purified only by mechanical treatment and flocculators, the obtained effluent quality is not such that it could be directly discharged into watercourses ( COD = 400-600 mg/l, BOD5 = 250-350 mg/l , TOC = 100 - 250 mg/l, vinyl acetate = 10-50 mg/l) according to modern effluent quality criteria before discharge into waterways. If the flocculation process is combined with a supplementary process of the adsorption type with activated carbon, i.e. aerobic biological treatment, then a quality can be achieved that can be discharged into waterways (KPK = 40-50 mg/l, BPK5= 20-40 mg/l, TOC = 10-15 mg/l, vinyl acetate = 1-2 mg/l).

Opis rješenja tehničkog problema Description of the solution to the technical problem

Osnovni problem otpadnih voda koje sadrže vinilacetat bilo slobodni bilo polimeriziran predstavlja rezidualna koncentracija neizreagiranog vinilacetata koja zaostaje nakon obrade konvencionalnim postupcima obrade otpadnih voda sa sadržajem vinilacetata, kako je to poznato iz stanja tehnike. Vinilacetat predstavlja kemikaliju koja nije u tako masovnoj upotrebi poput nekih drugih kemikalija (npr.fenola, formaldehida) pa većina zemalja, uključujući i našu nema kvalitetu efleunta definiranu specifično na taj parametar. Međutim toksičnost vinilacetata je dovela do toga da neke zemlje (npr.SAD) počinju uvoditi zakonska ograničenja ili preporuke za granične koncentracije vinilacetata u efluentima koje se kreću u rasponu 0,2-0,4 mg/l. The basic problem of wastewater containing vinyl acetate, either free or polymerized, is the residual concentration of unreacted vinyl acetate that remains after treatment with conventional procedures for the treatment of wastewater containing vinyl acetate, as is known from the state of the art. Vinylacetate is a chemical that is not as widely used as some other chemicals (e.g. phenol, formaldehyde), so most countries, including ours, do not have effluent quality defined specifically for that parameter. However, the toxicity of vinyl acetate has led to the fact that some countries (eg the USA) are starting to introduce legal restrictions or recommendations for limit concentrations of vinyl acetate in effluents that range from 0.2-0.4 mg/l.

"Postupkom za pročišćavanje otpadnih voda od vinilacetata" omogućuje se postizavanje takve kvalitete efluenta što je jedna od prednosti postupka. Strogo tehnološki gledajući, postupak se izvodi na potpuno drugačijem principu od postupaka poznatih iz stanja tehnike. Osnova postupka je oksidacija vinilacetata sa vodikovim peroksidom u uslovima niske pH vrijednosti (pH= 3-5) i u prisustvu katalizatora na bazi dvovalentnog željeza u acetat koji se prilikom povišena pH vrijednosti otpadne vode taloži kao trovalentni željezni acetat. "Vinyl acetate waste water treatment process" enables the achievement of such effluent quality, which is one of the advantages of the process. From a strictly technological point of view, the procedure is performed on a completely different principle from procedures known from the state of the art. The basis of the procedure is the oxidation of vinyl acetate with hydrogen peroxide under conditions of low pH value (pH= 3-5) and in the presence of a catalyst based on divalent iron into acetate, which is precipitated as trivalent iron acetate when the pH value of the waste water is increased.

Postupci za korištenje vodikovog peroksida kao oksidanta za otklanjan, različitih polutanata iz otpadnih voda su poznati iz patentne literature, ali se odnose na druge tipove polutanata. Tako npr. poznati su patenti kod kojih se vodikovog peroksid koristi za pročišćavanje otpadnih voda od sulfida, tiosulfata, cijanida (U.S.Pat.4.294.703., U.S.Pat.3.705.098., Eur.Pat.Pub.No.0166557), ali nije poznato iz stanja tehnike da se vodikov peroksid koristi kao sredstvo za otklanjanje vinilacetata iz otpadnih voda. "Postupak za pročišćavanje otpadnih voda od vinilacetata", kako je prikazano na Shemi 1. pokazuje bolje kvalitete efluenta od tehničkih rješenja poznatih iz stanja tehnike. Pored toga navedeni postupak ima još jednu prednost, a to je da otpadni materijal koji nastaje postupkom je kemijski gledajući srodan otpadnom materijalu koji nastaje kod predtretmana (flokulacije), što znači da se mogu obrađivati istim postupcima obrade za otpadne materijale, dok ukoliko otpadnu vodu sa sadržajem vinilacetata tretiramo biološki odnosno adsorpcijom sa aktivnim ugljenom nastaju različiti otpadni materijali (biološki mulj odnosno zasićeni granulirani aktivni ugljen) od otpadnog materijala nastalog predtretmanom. Procedures for using hydrogen peroxide as an oxidant for the removal of various pollutants from waste water are known from the patent literature, but they refer to other types of pollutants. For example, there are known patents in which hydrogen peroxide is used to purify wastewater from sulfide, thiosulfate, cyanide (U.S.Pat.4.294.703., U.S.Pat.3.705.098., Eur.Pat.Pub.No.0166557), but it is not known from the state of the art that hydrogen peroxide is used as a means of removing vinyl acetate from waste water. "Vinyl acetate wastewater treatment process", as shown in Scheme 1, shows better effluent qualities than technical solutions known from the state of the art. In addition, the mentioned procedure has another advantage, which is that the waste material produced by the process is chemically similar to the waste material produced during pretreatment (flocculation), which means that it can be treated with the same treatment procedures for waste materials, while if wastewater with we treat the vinyl acetate content biologically, that is, by adsorption with activated carbon, different waste materials are created (biological sludge, i.e. saturated granular activated carbon) from the waste material created by pretreatment.

Primjer 1. Example 1.

U proizvodnom pogonu za proizvodnju ljepila za namještaj, reaktor za sintezu takvog ljepila koje je na bazi vinilacetata i njegovih polimera, se nakon svakog završenog ciklusa ispire vodom. Pritom nastaje 10-25 m3 otpadne vode koja sadrži vinilacetat i sve uz njega vezane parametre (Tabela 1.). Takva otpadna voda se uvodi u posudu za dekantaciju, nakon toga joj se pH vrijednost korigira na pH=8,5 i doda polielektrolit i dvovalentni željezni sulfat. Miješanje se izvrši u sljedećoj posudi. Miješanje se izvodi upuhivanjem zraka čime se pored miješanja postiže i oksigenacija iona željeza. Nakon odstajavanja u posudi, nastali mulj se istaloži, a u vodi ostane otopljeni vinilacetat.Sadržaj dekantirane otpadne vode se prebaci u sljedeću posudu, pH otpadne vode se spusti na pH=3-5 uz dodatak sumporne kiseline. Nakon toga se u posudu počinje dozirati vodikov peroksid (35 %) i dvovalentni željezni ioni. Dvovalentni željezni ioni služe kao katalizator radikalnog raspada vodikovog peroksida čiji perokso radikali oksidiraju molekulu vinilacetata i acetate, a pritom se dvovalentni željezni ioni oksdiraju u trovalentne. Kada je oksidacija vinilacetata završena, podignemo pH vrijednost otpadne vode na pH = 8,5 dodatkom natrijevog hidroksida. Pritom se iz vode kao mulj počinje izlučivati i taložiti željezni acetat. Mulj se odvodi iz sistema i zajednički obraduje sa flokulacijskim muljem, a pročišćena otpadna voda se ili ispušta u recipient ili vraća u proces. Ta činjenica ukazuje da"Postupak za pročišćavanje otpadnih voda od vinilacetata" u sebi ujedinjuje elemente primarne, sekundarne i tercijarne obrade otpadnih voda In the production plant for the production of furniture glue, the reactor for the synthesis of such glue, which is based on vinyl acetate and its polymers, is washed with water after each completed cycle. At the same time, 10-25 m3 of waste water is produced, which contains vinyl acetate and all parameters related to it (Table 1). Such waste water is introduced into the decantation vessel, after which its pH value is corrected to pH=8.5 and polyelectrolyte and divalent iron sulfate are added. Mixing is done in the next container. Mixing is performed by blowing air, which, in addition to mixing, also achieves oxygenation of iron ions. After settling in the vessel, the resulting sludge settles, and dissolved vinyl acetate remains in the water. The content of the decanted wastewater is transferred to the next vessel, the pH of the wastewater is lowered to pH=3-5 with the addition of sulfuric acid. After that, hydrogen peroxide (35%) and divalent iron ions are dosed into the container. Divalent iron ions serve as a catalyst for the radical decomposition of hydrogen peroxide, whose peroxo radicals oxidize the vinylacetate and acetate molecules, while divalent iron ions are oxidized into trivalent ones. When the oxidation of vinyl acetate is finished, we raise the pH value of the waste water to pH = 8.5 by adding sodium hydroxide. At the same time, ferric acetate begins to be excreted and precipitated from the water as sludge. The sludge is drained from the system and treated together with the flocculation sludge, and the purified wastewater is either discharged into the receiver or returned to the process. This fact indicates that the "Procedure for purification of waste water from vinyl acetate" combines elements of primary, secondary and tertiary treatment of waste water.

Tabela 1. Sustav influenta (otpadne vode) iz primjera 1. Table 1. Influent system (waste water) from example 1.

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Navod o najboljem za privrednu upotrebu prijavljenog pronalska Citation on the best commercial use of the reported find

Pronalazak pod nazivom "Postupak za pročišćavanje otpadnih voda od vinilacetata" može se koristiti za pročišćavanje otpadnih voda u kemijskoj industriji koja kao sirovinu koristi vinilacetat. Takav tip kemijske industrije u otpadnim vodama sadrži polimerizirani i nepolimerizirani vinilacetat. Redoslijed kojim se rješava tehnički problem pronalaskom je sljedeći : The invention entitled "Procedure for the treatment of waste water from vinyl acetate" can be used for the treatment of waste water in the chemical industry that uses vinyl acetate as a raw material. Such type of chemical industry in wastewater contains polymerized and non-polymerized vinyl acetate. The order in which the technical problem is solved by invention is as follows:

- otpadna voda se akumulira u egalizaciju koja služi i kao mehanička obrada otpadnih voda - waste water is accumulated in equalization, which also serves as mechanical treatment of waste water

- otpadna voda se flokulira dodatkom željeznog sulfata i polielektrolita a nastali mulj odstrani iz sistema - wastewater is flocculated with the addition of iron sulfate and polyelectrolyte, and the resulting sludge is removed from the system

- otpadna voda je u niskom pH području oksidira doziranjem vodikovog peroksida pri čemu se vinilacetat oksidira do acetata . Povišenjem pH vrijednosti u obliku taloga se izlučuje željezni acetat. - waste water in the low pH area is oxidized by dosing hydrogen peroxide, whereby vinyl acetate is oxidized to acetate. By raising the pH value, ferric acetate is excreted in the form of a precipitate.

- pročišćena otpadna voda se može ispuštati u recipient ili reciklirati nazad u proces. - the purified wastewater can be discharged into the receiver or recycled back into the process.

Postupkom nije predviđeno ništa tako što bi prevazilazilo rutinsko znanje prosječnog stručnjaka specijaliziranog za problematiku zaštite okoline. The procedure does not envisage anything that would go beyond the routine knowledge of an average expert specializing in environmental protection issues.

Claims (9)

1. "Postupak za obradu otpadnih voda sa sadržajem vinilacetata", naznačen time, da se otpadnoj vodi nakon predtretmana tipa flokulacije snizi pH vrijednost u kiselo područje uz paralelno doziranje dvovalenih željeznih iona i vodikovog peroksida pri čemu se vinil acetat sadržan u otpadnoj vodi oksidira u acetate koji se istalože povišenjem pH vrijednosti otpadne vode u obliku acetanih soli trovalentnog željeza.1. "Procedure for the treatment of waste water containing vinyl acetate", indicated by the fact that the pH value of the waste water after pre-treatment of the flocculation type is lowered into the acidic range with the parallel dosing of divalent iron ions and hydrogen peroxide, whereby the vinyl acetate contained in the waste water is oxidized in acetates that are precipitated by increasing the pH value of waste water in the form of acetate salts of trivalent iron. 2. Postupak po zahtjevu 1., naznačen time, da je Ph otpadne vode prilikom oksidacije od 3 do 5.2. The process according to claim 1, characterized by the fact that the Ph of the waste water during oxidation is from 3 to 5. 3. Postupak po zahtjevima 1. i 2., naznačen time, da je odnos doziranog vodikovog peroksida prema acetatu nastalom kao posljedica oksdiacije vinilacetata minimalno 10 % veći od stehiometrijskog odnosa.3. The method according to claims 1 and 2, characterized in that the ratio of the dosed hydrogen peroxide to the acetate formed as a result of the oxidation of vinyl acetate is at least 10% higher than the stoichiometric ratio. 4. Postupak po zahtjevima 1. i 3., naznačen time, da je koncentracija dvovalentnih željeznih iona stehiometrijska prema koncentraciji vodikovog peroksida.4. The method according to claims 1 and 3, characterized in that the concentration of divalent iron ions is stoichiometric to the concentration of hydrogen peroxide. 5. Postupak po zahtjevima 1., 2., 3. i 4. naznačen time, da željezni ioni potiču od topivih anorganskih soli dvovalentnog željeza.5. The method according to claims 1, 2, 3 and 4, characterized in that the iron ions originate from soluble inorganic salts of divalent iron. 6. Postupak po zahtjevima 1., 2., 3., 4., i 5., naznačen time, da se kod oksidacije pH vrijednost otpadne vode korigira doziranjem sumporne ili solne kiseline.6. Process according to claims 1, 2, 3, 4, and 5, characterized in that during oxidation the pH value of the waste water is corrected by dosing sulfuric or hydrochloric acid. 7. Postupak po zahtjevima 1., 2., 3., 4., i 5., naznačen time, da se pH vrijednost nakon oksidacije korigira doziranjem natrijevog hidroksida do pH vrijednosti od 8,5 pri čemu se počinje izlučivati talog trovalentnog željeznog acetata.7. The method according to claims 1, 2, 3, 4, and 5, characterized in that the pH value after oxidation is corrected by dosing sodium hydroxide to a pH value of 8.5, during which a precipitate of trivalent ferric acetate begins to be excreted . 8. Postupak po zahtjevu 1., naznačen time, da se postupak izvodi u šaržnom odnosno kontinuiranom procesu.8. The procedure according to claim 1, characterized by the fact that the procedure is performed in a batch or continuous process. 9. Postupak po zahtjevu 1., naznačen time, da je koncentracija vinilacetata u konačnom efluentu od 0,0 5 do 1 mg/l.9. The method according to claim 1, characterized in that the concentration of vinyl acetate in the final effluent is from 0.05 to 1 mg/l.