RS104A

RS104A - PROCESS OF TREATMENT OF LAND CONTAMINATED BY ORGANIC UNITS

Info

Publication number: RS104A
Application number: YU104A
Authority: RS
Inventors: Rosario Pappa; Felicia Massetti; Edoardo D'angeli; Aldo Imerito
Original assignee: Ecotec S.R.L.; Enitecnologie S.P.A.
Priority date: 2001-07-06
Filing date: 2002-07-04
Publication date: 2006-12-15
Also published as: EP1404466A1; WO2003004184A1; SI1404466T1; DK1404466T3; RS50267B; PT1404466E; ES2322134T3; HRP20031077B1; ITMI20011439A1; EA005637B1; US7287933B2; ATE421907T1; HRP20031077A2; EP1404466B1; ITMI20011439A0; US20040204624A1; EA200301325A1; DE60231040D1

Abstract

Opisan je poboljšan proces uklanjanja organskih zagađivača iz zemlje ekstrakcijom sa lipofilnim rastvaračem, pri čemu se poboljšanje ogleda u činjenici da se prečišćena zemlja tretira vodom kako bi se uklonili zaostali rastvarač. Ovaj porces omogućava potpuno uklanjanje rezidulanog rastvarača iz prečišćene zemlje, što omogućava vraćanje zemlje okolini, uz malu potrošnju energije i veće bezbednosti procesa proizvodnje.An improved process of removing organic pollutants from the soil by extraction with lipophilic solvent is described, the improvement being reflected in the fact that the purified soil is treated with water to remove residual solvent. This process allows complete removal of residual solvent from the purified soil, which allows the soil to be returned to the environment, with low energy consumption and greater safety of the production process.

Description

Proces tretiranja zemljišta zagađenog organskim jcdinjenjima The process of treating soil contaminated with organic compounds

Ovaj pronalazak se odnosi na postupak tretiranja zemljišta zagađenog organskim jedinjenjima. This invention relates to a method of treating soil contaminated with organic compounds.

Tačenije, ovaj pronalazak se odnosi na unapređen proced uklanjanja organskih zagađivača iz zemljišta ekstrakcijom lipofilnim rastvaračima, gde se napredak ogleda u činjenici daje prečišćeno zemljište tretirano vodom radi uklanjanja rezidualnog rastvarača. More precisely, this invention relates to an improved process for removing organic pollutants from soil by extraction with lipophilic solvents, where the improvement is reflected in the fact that the purified soil is treated with water to remove residual solvent.

Problem zemljišta kontaminiranog organskim zagađivačima kao što su ugljovodonici, polinuklearni aromati, organohlorisani proizvodi postaje sve veći u industrijalizovanim zemljama, ne samo po pitanju uticaja zagađivača na zemljište i podzemne vode, već i po pitanju potrebe za regeneracijom površina za moguću industrijsku ili civilnu upotrebu. Drugi problem, koji je tupičan za uljnu industriju, je tretiranje otpada od sečenja pre nego što se bace u more. The problem of soil contaminated with organic pollutants such as hydrocarbons, polynuclear aromatics, organochlorine products is becoming more and more important in industrialized countries, not only in terms of the impact of pollutants on soil and groundwater, but also in terms of the need to regenerate surfaces for possible industrial or civil use. Another problem, which is a dead end for the oil industry, is the treatment of logging waste before it is dumped into the sea.

Postoji brojni izvori zagađivanja i različite karakteristike osnovnih predmeta zagađivanja. Ove okolnosti upućuju na poterbu za širokim spektrom mogućih rešenja. There are numerous sources of pollution and different characteristics of the basic objects of pollution. These circumstances point to the search for a wide range of possible solutions.

Tehnologije koje su generalno prihvaćene za tertiranje zemljišta su: ispiranje zemljišta, bioremedijacija i solidifikacija/stabilizacija. Technologies that are generally accepted for terting soil are: soil leaching, bioremediation and solidification/stabilization.

Izraz ispiranje zemljišta se odnosi na tehnike ispiranja pomoću vode, po potrebi sadrže površinski aktivne supstance. The term soil washing refers to washing techniques using water, if necessary containing surface-active substances.

Ispiranje zemljišta koristi tendenciju zagađivača da se vezuju, ili hemijski ili fizički, za fine čestice sedimenta. Ove čestice se mogu odvojiti od ostatka matriksa na načine koji su manje ili više složene serije procesa razdvajanja zasnovanih na razlici u dimenvijama, gustim ili površinskim osobinama. Sa ovom tehnologijom, razdvajanje je dobijeno za fino zagađenje frakcije i grubo dekontaminirane frakcije. Soil leaching takes advantage of the tendency of contaminants to bind, either chemically or physically, to fine sediment particles. These particles can be separated from the rest of the matrix by means of a more or less complex series of separation processes based on differences in dimensions, density or surface properties. With this technology, separation is obtained for the fine contaminated fraction and the coarsely decontaminated fraction.

Finije čestice ovako razdvojene predstavljaju samo malu frakciju inicijalno zagađene količine, ali sadrži najveći deo zagađivača. The finer particles separated in this way represent only a small fraction of the initially polluted amount, but contain the largest part of the pollutant.

Ispiranje zemljišta je tehnologija koja proizilazi iz borjnih situacija za redukovanje količine opasnih materijala koji se deponuju na stovarištima i regeneracijom dela troškova tretiranja prodajom grubljih frakcija dobijenih kao materijal za izgradnju. Soil leaching is a technology that arises from combat situations to reduce the amount of hazardous materials that are deposited in landfills and by regenerating part of the treatment costs by selling the coarser fractions obtained as construction material.

Ovaj postupak ima i velike nedostatke koji proizilaze iz potrebe za primenom velike količine agensa za ekstrakciju i teškoća vezanih za regeneracijom korišćenih aditiva. This procedure also has major disadvantages arising from the need to use a large amount of extraction agent and difficulties related to the regeneration of used additives.

Biološke tehnike tretiranja su ograničene biodegradabilnih jedinjenja i ne-toksičnim koncentracijama i veoma su ugrožene dužinom trajanja potebnog za kompletiranje procesa tretiranja. Biological treatment techniques are limited by biodegradable compounds and non-toxic concentrations and are greatly compromised by the length of time required to complete the treatment process.

Proces solidifikacije/stabilizacije se sastoji u dodavanju hidrauličnog liganda sedminetu, na primer Portland cement. Ovime zagađivači su fizički blokirani unutar cementnog matriksa i ne mogu više da migiriraju u okolinu. The solidification/stabilization process consists in adding a hydraulic ligand to the cement, for example Portland cement. These pollutants are physically blocked within the cement matrix and can no longer migrate into the environment.

U nekim procesima, kao dodatak cementu, dodaju se specifični aditivi, koji mogu da reaguju sa zagađivačima i transformišu u manje toksične ili manje mobilne vrste. In some processes, as an addition to cement, specific additives are added, which can react with pollutants and transform them into less toxic or less mobile species.

Ovaj tip tehnologije ima taj nedostatak što proizvodi povećanu zapreminu materijala koji se tretira (sediment + ligand) i u svakom slučaju ne garantuje dugotrajnu stabilnost krajnjeg proizvoda. This type of technology has the disadvantage that it produces an increased volume of material to be treated (sediment + ligand) and in any case does not guarantee the long-term stability of the final product.

Procesi tretiranja zasnovani na ekstrakciji rastvaračem odabranim na primer od metilen hlorida, razredenim C2-C4ugljovodonicima ili superkritičnim tečnostima, su takođe poznati u tehnici. Treatment processes based on extraction with a solvent selected for example from methylene chloride, graded C2-C4 hydrocarbons or supercritical fluids are also known in the art.

Primenljivost i efikasnost ovih procesa bez obzira što su limitirani prisustvom finih čestica u velikom procentu i velikim sadržajem vode koji su generalno karakterisitčni za neke vrste zemljišta. The applicability and efficiency of these processes, regardless of the fact that they are limited by the presence of fine particles in a large percentage and high water content, which are generally characteristic of some types of soil.

Da bi se prevazišli ove nedostatke, procesi ,koji su prdloženi u tehnici, za tertiranje zemljišta sa visokim sdržajem vode, koji su zasnovani na primeni smeše za ekstrahovanje koja se sastoji od para rastvarač/ko-rastvarač u takvim proporcijama da obrazuju jednu fazu sa vodom koja se nalazi u zemlji (U.S. 5,585,002) ili jednog rastvarača, poežljno etil acetata (IT 1298,543). In order to overcome these drawbacks, processes proposed in the art for the tertation of soils with a high water content, which are based on the application of an extraction mixture consisting of a solvent/co-solvent pair in such proportions as to form a single phase with the water present in the soil (U.S. 5,585,002) or a single solvent, preferably ethyl acetate (IT 1298,543).

Tačnije, prema ovim procesima, zemljište posle ekstrakcije sa organskim rastvaračem i dekantovanja se zatim suši kako bi se uklonio ostatak rastvarača koji je prisutan u količini koja se generalno kreće od 3 do 10%. More precisely, according to these processes, the soil after extraction with an organic solvent and decantation is then dried to remove the residual solvent which is present in an amount generally ranging from 3 to 10%.

U ovu svrhu, korišćena je oprema koja ja zbog bezbednosti vezanih za zapaljivost rastvarača i smanjenu emisiju u okolinu, mora biti inaktivirana azotom i opremljena odgovarajućim sistemom za prihvatanje praha. Dalje, zbog malog koeficijenta izmene zemlje, ova oprema zahteva zančajnu termalnu površinu za izemnu, veliki učinak i visoke temperature koje mogu da uzrokuju izmene u pedološkim karakteristikama zemlje, ugrožavajući time mogućnost vraćanja na originalno mesto. For this purpose, equipment was used which, due to safety related to the flammability of the solvent and reduced emission into the environment, must be inactivated with nitrogen and equipped with a suitable system for receiving powder. Furthermore, due to the low coefficient of soil change, this equipment requires a significant thermal surface for exceptional, high performance and high temperatures that can cause changes in the pedological characteristics of the soil, thereby jeopardizing the possibility of returning to the original place.

Nađeno je da tretiranjem zemljištaposle ekstrakcije rastvaračem i dekantovanja, sa dovoljnom količinom vode za rastvaranje rezidulanog rastvarača, moguće je razdvojiti iz ovako formirane disperzije, vodenu fazu, koja sadrži rastvarač i čvrstu fazu u kojoj je rezidulani rastvaarač sveden na minimalnu koncentraciju koje je tolika da omogućava vraćanje u okolinu. It was found that by treating the soil after extraction with a solvent and decanting, with a sufficient amount of water to dissolve the residual solvent, it is possible to separate from the dispersion thus formed, the aqueous phase, which contains the solvent, and the solid phase in which the residual solvent is reduced to a minimum concentration, which is such that it allows it to be returned to the environment.

Rastvarač koji sadrži gore navedenu vodenu fazu može se regenerisati jednostavnim uparavanjem uz smanjeno korišćenje energije, i nije više neophodno zagrevati celu masu zemljišta. The solvent containing the above-mentioned aqueous phase can be regenerated by simple evaporation with reduced energy use, and it is no longer necessary to heat the entire soil mass.

U skladu sa ovim, predmet ovog pronalaska se odnosi na uklanjanje organskih rastvarača iz zemljišta koje sdrži vodu u količinama od 10% do granice zasićenja polja , a sastoji se od sledećih faza: (a) mešanja zemljišta sa lipofilnim rastvaračem; (b) uklanjanje dekantovanjem ili rzdvajanje tečne faze, koaj sadrži zagađivače Accordingly, the subject of this invention relates to the removal of organic solvents from soil that contains water in amounts of 10% to the saturation limit of the field, and consists of the following stages: (a) mixing the soil with a lipophilic solvent; (b) removal by decantation or separation of the liquid phase containing contaminants

i rastvarač, od čvrste faze koja se sastoji od tretiranog zemljišta. and the solvent, from the solid phase consisting of the treated soil.

(c) Regeneracija rastvarača iz tečne faze dobijene u (b) fazi, destilacijom i recirkulacijom u fazi (a); (d) Klesanjem čvrste faze razdvojene u fazi (c) sa vodom u takvom odnosu da (c) Regeneration of the solvent from the liquid phase obtained in (b) stage, by distillation and recirculation in stage (a); (d) By milling the solid phase separated in phase (c) with water in such a ratio that

potpuno rastvori ostatke rastvarača; completely dissolve solvent residues;

(e) Razdvajanje čvrste faze, dekantovanjem , koje se sastoji od ispranog (e) Separation of the solid phase, by decantation, consisting of the washed

zemljišta i vodene faze zasićene rastvaračem. soil and solvent-saturated aqueous phases.

(f) Uklanjanje vode iz čvrste frakcije dobijene u fazi (e); (f) Removing water from the solid fraction obtained in step (e);

i and

(g) regeneracija rastvarača iz vodene faze uparavanjem i vraćanjem u fazu (a). (g) regeneration of the solvent from the aqueous phase by evaporation and return to phase (a).

Različite vrste zemljišta se mogu koristiti u procesu i sa različitim pedološkim karakteristikama, i sa visokim sadržajem peska i sa glinenim komponentama. Važno je kontrolisati da se sadržaj vode prisutne u zemlji regeneriše približno do kapaciteta u svog zemljištu. U sličaju zemljišta sa manjim sadržajem vlage, materijal bi tebalo prvo nakvasiti. Different types of soil can be used in the process and with different pedological characteristics, both with a high content of sand and with clay components. It is important to control that the content of water present in the soil is regenerated approximately to the capacity of its soil. In the case of soil with a lower moisture content, the material should be moistened first.

Ovim procesima su obično tretirana zemljišta sa ilovačom ili umerena mešavina zemljišta , sa sadržajem čestica od 10 do 50% (u odnosi na suvu težinu) sa veličinom čestica manjim od 63um i sadržajem vode od 10 do 60%, težinskih. Soils with loam or a moderate mixture of soils, with a particle content of 10 to 50% (in terms of dry weight) with a particle size of less than 63um and a water content of 10 to 60%, by weight, are usually treated with these processes.

U fazi (a), težinski odnos rastvarač/zemljište je u opsegu od 0.2 do 0.5, poželjno 0.5 do 1. U procesu, sa kontinualnom brzinom protoka u kontra toku odnos rastvarač/zemljište se kreće od 0.2 do 0.5. In phase (a), the solvent/soil weight ratio is in the range of 0.2 to 0.5, preferably 0.5 to 1. In the process, with a continuous flow rate in the counter flow, the solvent/soil ratio ranges from 0.2 to 0.5.

Ova faza se generalno odvijana sebnoj temperaturi u periodu od 10 do 120 minuta. This phase generally takes place at room temperature for a period of 10 to 120 minutes.

Prema ovom pronalasku, rastvarači koji su korišćeni u procesu su odabrani tako da budu ne-toksični i isparljivi, da nisu skupi i da su lako dostupni. According to the present invention, the solvents used in the process are selected to be non-toxic and volatile, inexpensive and readily available.

Primeri liofilnih rastarača koji su pogodni za primenu u ovom pronalasku su etil acetat i petol etar. Za potrebe ovog pronalaska, preferentan je etil acetat. Examples of lyophilic solvents suitable for use in the present invention are ethyl acetate and petol ether. For the purposes of this invention, ethyl acetate is preferred.

Faze (a) do (e) procesa prema ovom pronalasku, mogu se ponavljati nekoliko puta, po potrebi. Steps (a) to (e) of the process according to the present invention may be repeated several times, as needed.

Ekstrakcija sa rastvaračima prema fazi (a) se može sprovesti sa serijskim ili kontinualnim procesom. U prvom slučaju, oprema se sasstoji od industrijskog sistema za mešanje kao što je plužno mešanje, mešanje lopaticama i mešanje u rotirajućem bubnju, u koji se sipa količina zemljišta koje se tretira, zajedno sa rastvaračem, mešanjem u vremenskom periodu neophodnom za ekstrahovanje zagađivača. The solvent extraction according to step (a) can be carried out with a batch or continuous process. In the first case, the equipment consists of an industrial mixing system such as plow mixing, paddle mixing and rotating drum mixing, into which the amount of soil to be treated is poured, together with the solvent, mixing for the time period necessary to extract the pollutants.

U slučaju kontinualnog procesa, oprema za ekstrakciju se sastoji od pužastog sistema u kojem se rastvarač i zemlja transportuju u supreotnom smeru. Poslednji navoj razdvaja zemlju od rastvarača. In the case of a continuous process, the extraction equipment consists of a screw system in which the solvent and soil are transported in a counter-current direction. The last thread separates the soil from the solvent.

Razdvajanje prema fazi (b) se odvija neposredno posle zaustavljanja mešanja usled činjenice da se fine frakcije zemlje nalaze kao aglomerati i samo mali deo prolazi u rastvarač za ekstrakciju. The separation according to phase (b) takes place immediately after stopping the mixing due to the fact that the fine fractions of the soil are found as agglomerates and only a small part passes into the extraction solvent.

Na ovaj način, dobijena je zemlja , koja je prečišćena od zagađivača, sadrži i grubu frakciju i finu frakciju, sa 3-10% rezidulanog rastvarača i tečne frakcije koja sadrži zagađivače. In this way, the soil was obtained, which was purified from pollutants, contains both a coarse fraction and a fine fraction, with 3-10% residual solvent and a liquid fraction containing pollutants.

U fazi (c) procesa prema ovom pronalasku, čvrsta faza je isprana vodom kako bi se omogućila regeneracija preostalog rastvarača za ekstrakciju, a koji ima rastvorljivost u vodi od 8.7% (z/z); zatim je ovako regenerisan rastvarač ponovo korišćen u fazi (a) procesa prema ovom pronalasku. In step (c) of the process according to the present invention, the solid phase is washed with water to enable the regeneration of the remaining extraction solvent, which has a water solubility of 8.7% (w/w); then the solvent thus regenerated was reused in step (a) of the process according to the present invention.

U slučaju serijskog procesa, ispiranje sa vodom se izvodi u istoj opremi koja se koristi za ektrahovanje u fazi (a), dodavanjem vode u sistem posle odvajanja rastvarača, dekantovanjem. Kontinualnim procesom, ispiranje vodom se može postići u pogodnom mikseru ili u dodatnom navoju u koji su zemlja i voda dodavani na suprot struji. In the case of a batch process, washing with water is performed in the same equipment used for extraction in step (a), by adding water to the system after separation of the solvent, by decantation. In a continuous process, water flushing can be achieved in a suitable mixer or in an additional thread into which soil and water are added countercurrently.

U svakom slučaju, nije neophodno aparate podvrgnuti pritisku inertnog gasa i ne dolazi do formiranja praha, pošto je materijal dispergovan u vodi. In any case, it is not necessary to subject the devices to inert gas pressure and no powder is formed, since the material is dispersed in water.

U fazi (e) procesa prema ovom pronalasku, posle dekantovanja , čvrsta frakcija je odvojena koja sastoji se od isprane zemlje i vodena frakcija zasićena rastvaračem. Ovako dobijena čvrsta frakcija se zatim podvrgne uklanjanju vode, korišćenjem opreme poznate u tehnici, kao stoje trakasta presa , centrifugiranje. In step (e) of the process according to the present invention, after decantation, a solid fraction is separated consisting of washed soil and an aqueous fraction saturated with solvent. The solid fraction thus obtained is then subjected to water removal, using equipment known in the art, such as a belt press, centrifugation.

Regeneracija korišćenog rastvarača (faza d) se može izvesti u uparavanjem u Regeneration of the used solvent (step d) can be carried out by evaporating u

tankom sloju, pod normalnim pritiskom ili pod neznatno sniženim pritiskom, pri čemu se dobija ostatak koji sadrži frakciju ekstrahovanu iz zemljišta i minimalnu količinu vode i sa površinskim strujanjem koje se sastoji od ekstrakcionog rastvarača u skladu sa fazom (a). thin layer, under normal pressure or under slightly reduced pressure, obtaining a residue containing the fraction extracted from the soil and a minimum amount of water and with a surface current consisting of the extraction solvent according to step (a).

Alternativno, ova regeneracija se može izvesti destilacijom u prisustvu vode, pri čemu se dobija ostatak koji se sastoji od vode i zagađivača, koji se može odvojiti dekantovanjem i i sa površinskim tokom koji se sastoji od ekstrakiconog rastvarača iz faze (a). Alternatively, this regeneration can be carried out by distillation in the presence of water, yielding a residue consisting of water and contaminants, which can be separated by decantation and with the surface stream consisting of the extraction solvent from step (a).

Proces prema ovom pronalasku omogućava zagađivačima da budu uklonjeni iz zemljišta sa visokim sadržajem vode i finih čestica u uzorku na krajnje ekonomičan način. The process of the present invention allows contaminants to be removed from soil with a high water content and fines in the sample in an extremely economical manner.

Slika 1 poakzuje blok shemu procesa ovog pronalaska. Figure 1 shows a block diagram of the process of the present invention.

Primeri koji slede ilustruju ali ni na koji načine ne ograničavaju opseg pronalaska. The following examples illustrate but in no way limit the scope of the invention.

Primer 1 Example 1

Primer zemljišta uklonjenog sa mesta zagađenog ugljovodonicima ima sledeće karakteristike: An example of soil removed from a hydrocarbon-contaminated site has the following characteristics:

• pH u vodenom rastvoru = 7.02; u KC1 1N = 7.34 • pH in aqueous solution = 7.02; in KC1 1N = 7.34

• vlažnost: 18.3% • humidity: 18.3%

• Specifična provodljivost: 1.14mS/cm • Specific conductivity: 1.14mS/cm

• Koncentracija rastvora soli : 6.76mEq/100g • Concentration of salt solution: 6.76mEq/100g

• Ukupni ugljeni hidrati (ukupni naftni ugljovodonici -TPH) 18 000 ppm (određeno gasnom hromatografijom) • Agronnomske karatkeristike : šljunak 46.3%, pesak 41.4%, glina 11.3%. • Total carbohydrates (total petroleum hydrocarbons -TPH) 18,000 ppm (determined by gas chromatography) • Agronomic characteristics: gravel 46.3%, sand 41.4%, clay 11.3%.

Kilogram ove zemlje je stavljen u rotirajući cilindar zajedno sa lkg etil acetata i mešan 30 minuta na sobnoj temperaturi. A kilogram of this soil was placed in a rotating cylinder together with a kilogram of ethyl acetate and stirred for 30 minutes at room temperature.

Nakon stoje smeša ostavljena da stoji 5 minuta, tečna faza je profiltrirana na Teflon filteru sa porama od 0.45 mikrona, da bi se odredila, merenjem, frakcija fine zemlje sa rastvaračem, a koja iznosi 0.7 težinskih % zemlje. After the mixture was allowed to stand for 5 minutes, the liquid phase was filtered on a Teflon filter with pores of 0.45 microns, in order to determine, by measurement, the fraction of fine soil with the solvent, which is 0.7 wt% soil.

Etil acetat je regenerisan iz tečne frakcije destilacijom u rotor-upariveču na 90°C. Ethyl acetate was regenerated from the liquid fraction by distillation in a rotor-evaporator at 90°C.

940g rastvarača je regenerisano, koji je sa još dodatih 60 g svežeg etil acetata korišćen za drugi ciklus isprianja zemlje. 940g of solvent was regenerated, which was used with another 60g of fresh ethyl acetate for the second soil washing cycle.

Količina rastvarača koja je regenerisana posle ovog drugog ciklusa iznosi do lkg. The amount of solvent regenerated after this second cycle amounts to lkg.

U rotirajući bubanj sa zemljom dodata je voda (lkg), koja sadrži 60g rezidulanog etil acetata što je dovoljno za rastvaranje rezidulanog rastvarača, znajući da rastvorljivost etil acetata u vosi iznosi 8.7% (z/z). Water (lkg) containing 60g of residual ethyl acetate was added to the rotating drum with soil, which is sufficient to dissolve the residual solvent, knowing that the solubility of ethyl acetate in wax is 8.7% (w/w).

Posle mešanja od 10 minuta, smeša je ostavljena da odstoji 30 minuta. Gornji vodeni sloj je odvojen i sačuvan. Dispezija zemlje u vodi koja se nalazi na dnu je centrifugirana na 3000xG, pri čemu dolazi do regeenracije čvrste frakcije koja se sastoji od prečišćene zemlje u kojoj je koncentracija ukupnih naftnih ugljovodonika (TPH) iznosi do 180 ppm, u okviru granica ustanovljenih važećim zakonima. After stirring for 10 minutes, the mixture was allowed to stand for 30 minutes. The upper water layer is separated and saved. The dispersion of soil in the bottom water is centrifuged at 3000xG, during which the solid fraction is regenerated, consisting of purified soil in which the concentration of total petroleum hydrocarbons (TPH) is up to 180 ppm, within the limits established by the current laws.

Vodena faza dobijena u fazi centrifugiranja, je posle sedimentacije ostavljena da stoji, zagrejana na 90° u rotor uparivaču, pri čemu se regebneriše rastvoren etil acetat. The aqueous phase obtained in the centrifugation phase, after sedimentation, was left to stand, heated to 90° in the rotor evaporator, during which the dissolved ethyl acetate was regenerated.

Primer 2 ( komparativni) Example 2 (comparative)

Uzorak zemlje od lkg, koji ima karakteristike naznačene u Primeru 1, je sušen na vazduhu 48 sati da bi se smanjila vlažnost do 3.2% i zatim je tretiran kao što je opisano u Primeru 1. A 1 kg soil sample having the characteristics indicated in Example 1 was air-dried for 48 hours to reduce the moisture content to 3.2% and then treated as described in Example 1.

Primećeno je daje u rastvarač inkorporirano 65g fine frakcije uzorka. Ova disperzija otaje stabilna duže vreme, što uslovljava centrifugiranje da bi se razdvojio čvrsto ostatak od tečnosti. It was observed that 65g of the fine fraction of the sample was incorporated into the solvent. This dispersion remains stable for a long time, which requires centrifugation to separate the solid residue from the liquid.

Rastvarač regenerisan destilacijom je korišćen za drugo ispiranje zemlje. Posle druge centrifugacije, dve frakcije sa finom zemljom su kombinovane sa frakcijom sa grubom zemljo i sušene na vazduhu 24 sata. The solvent regenerated by distillation was used for the second soil wash. After a second centrifugation, the two fractions with fine soil were combined with the fraction with coarse soil and air-dried for 24 hours.

Koncentracija TPH posle drugog tretmana iznosi do 1670ppm, što je vrednost veća od maksimalno dozvoljene od 750 ppm odeđene zakonom za ponovnu upotrebu terena (Official Bulletin of the Region of Tuscanv nr. 36 of June 16, 1993). The concentration of TPH after the second treatment is up to 1670 ppm, which is a value higher than the maximum allowed of 750 ppm set by law for the reuse of the terrain (Official Bulletin of the Region of Tuscanv nr. 36 of June 16, 1993).

Primer 3 Example 3

Uzorak zemljišta je osušen kao u Primeru 2, pa je dodata voda, tako da vlažnost iznosi 18%. The soil sample was dried as in Example 2, and water was added, so that the humidity is 18%.

Posle tertmana opisanog u Primeru 1, uočeno je da rastvarač, dobijen jendostavnim dekantovanjem, sadrži manje od 0.7% fine frakcije. After the treatment described in Example 1, it was observed that the solvent, obtained by simple decantation, contained less than 0.7% of the fine fraction.

Analiza TPH pokazuje da koncentracija ostataka iznosi 183ppm, što je vrednost koja potvrđuje rezultat iz Primera 1, u oba slučaja u smislu tetiranja zemljišta i jednostavnosti operacija regeneracije rastvarača. The TPH analysis shows that the residue concentration is 183ppm, a value that confirms the result of Example 1, in both cases in terms of soil titration and simplicity of solvent regeneration operations.

Regeneracija rastvarača, sumiranjem količina dobijenih dekantovanjem posle ekstrakcije zagađivača i razdvajanja destilacijom i destilacije ostataka u vodenim fazama od ispiranja zemljišta, se pokazala da je praktično kvantitativna. Solvent regeneration, by summing the amounts obtained by decanting after contaminant extraction and separation by distillation and distillation of residues in aqueous phases from soil washing, was shown to be practically quantitative.

Claims

1. The process of removing organic pollutants from the soil, characterized by the fact that the water content ranges from 10% to the saturation limit of the field, which includes the following stages: (a) mixing the soil with a lipophilic solvent; (b) removal by decantation or separation of the liquid phase containing the contaminants and solvent from the solid phase comprising the treated soil; (c) regenerating the solvent from the liquid phase obtained in step (b) by distillation and recirculation in step (a); (d) mixing the solid phase separated in step (c) with water in such a ratio that the residual solvent is completely dissolved; (e) separation by decantation of the solid fraction, consisting of the washed soil, and the aqueous phase saturated with the solvent; (f) removing water from the solid fraction obtained in step (e); and (g) regenerating the solvent from the aqueous phase by evaporation and returning it to phase (a).

2. The process according to claim 1, characterized in that the lipophilic solvent is ethyl acetate.

3. The process according to claim 1, characterized in that the weight ratio of the lipophilic solvent and soil ranges from 0.2 to 5.0.

4. The process according to claim 3, characterized in that the weight ratio of the lipophilic solvent and soil ranges from 0.5 to 1.0.

5. The process according to claim 1, characterized in that in phase (a), the mixing of the components takes place at room temperature, for a period of 10 to 60 minutes.

6. The process according to claim 1, characterized in that in phase (b) of the separation process, it is performed by decanting or removing the liquid.

7. The process according to claim 1, indicated by the fact that the regeneration of the solvent in phase (d) is performed in a thin-layer evaporator with scraping from the walls, which takes place at atmospheric pressure or under slightly reduced pressure or distillation in the presence of water.

8. the process according to claim 1, characterized in that the solvent regenerated in phase (d) is returned to phase (a).

9. The process according to claim 1, characterized in that steps (a) to (e) can be repeated several times.

10. The process according to claim 1, indicated by the fact that they are organic pollutants, aliphatic and aromatic hydrocarbons, polynuclear aromatic hydrocarbons, aliphatic and aromatic organo-chlorinated products, pesticides, dioxins and dibenzofurans.

11. The process according to claim 1 to 9, characterized in that it takes place serially or continuously.