Effect of ozone, ozone/hydrogen peroxide and hypoclorite on natural organic matter and oxidation by-products content in water after coagulation, floculation and adsorption procesess

Cilj ovog rada je bio da se ispita uticaj ozona i ozon/vodonik-peroksida na efikasnost uklanjanja POM i prekursora oksidacionih nusproizvoda, procesima koagulacije, flokulacije i adsorpcije. Posebna pažnja posvećena je ispitivanju uticaja navedenih procesa na sadržaj prekursora oksidacionih nusproizvoda hlora (trihalometana i halosirćetnih kiselina), kao i na uticaj hipohlorita na formiranje ovih jedinjenja u tretiranoj vodi. Analiza hemijskih karakteristika sirove podzemne vode korišćene u ispitivanjima pokazuje da sadrži visok nivo POM pretežno hidrofobnog karaktera (PB = 37,7±0,60 mg KMnO4/l; DOC = 9,27±0,92 mg C/l; UV254 = 0,497± 0,015 cm-1; SUVA = 5,36±0,49 1 mg-1 m-1; PFTHM = 555±128 µg/l; PFHAA = 245±54,9 µg/l), kao i visoku koncentraciju arsena (51,7±16,4 µg/l). Poređenjem uticaja dve ispitivane vrste koagulanata (FeCl3 i FeCl3/PACl) utvrđeno je da imaju različite mehanizme uklanjanja POM i prekursora oksidacionih nusproizvoda. FeCl3/PACl omogućava smanjenje sadržaja POM izraženih preko vrednosti DOC, PB, UV254 apsorbancije i SUVA za 54%, 71%, 88% i 74%, u odnosu na sirovu vodu respektivno, dok se koagulacijom sa FeCl3 postiže smanjenje DOC, PB, UV254 apsorbancije i SUVA za 51%, 48%, 61% i 21%, respektivno. U vodi nakon koagulacije sa FeCl3 zaostaju POM hidrofobnog karaktera (SUVA = 5,12 l m-1 mg-1), dok se POM u koagulisanoj vodi sa FeCl3/PACl, mogu okarakterisati kao hidrofilne (SUVA = 1,70 l m-1 mg-1). Koagulacija sa FeCl3 i FeCl3/PACl omogućila je smanjenje sadržaja arsena u vodi za preko 95%, pri čemu su koncentracije As u koagulisanoj vodi bile niže od 10 µg/l. Ozon i O3/H2O2 proces pokazuju sličnu efikasnost u smanjenju sadržaja POM i prekursora oksidacionih nusproizvoda. Poređenjem kombinovanih tretmana koji obuhvataju oksidacioni predtretman i koagulaciju, utvrđeno je da efikasnost koagulacije sa FeCl3 i FeCl3/PACl u smanjenju vrednosti DOC, PB, UV254, SUVA, PFTHM i aldehida, uglavnom zavisi od mehanizma delovanja samih koagulanata, dok ozon i O3/H2O2 proces doprinose smanjenju vrednosti ovih parametara kroz oksidaciju i izdvajanje lako isparljivih komponenti iz vode stripingom gasa. Sa aspekta promene sadržaja prekursora HAA, ozon i O3/H2O2 proces omogućavaju povećanje efikasnosti procesa koagulacije sa FeCl3 i FeCl3/PACl, u odnosu na koagulaciju bez oksidacionog predtretmana. Kada se uzmu u obzir vrednosti svih navedenih parametara, kao i primenjenje doze oksidacionih sredstava i koagulanata, najbolji rezultati u uklanjanju POM i prekursora oksidacionih nusproizvoda (smanjenje vrednosti DOC za 55%, UV254 i SUVA za više od 90%, u odnosu na sirovu vodu; PB = 7,70 mg KMnO4/l;  PFTHM =158-188 µg/l; PFHAA = 33,0-53,8 µg/l i sadržaj aldehida 16,7-17,9 µg/l) postižu se primenom tretmana koji obuhvataju oksidacioni predtretman ozonom (3,0 g O3/m3), odnosno O3/H2O2  (3,3 g O3/m3; H2O2:O3 =1:1), koagulaciju (30 g FeCl3/m3 / 30 g Al/m3) uz recirkulaciju flokulacionog mulja i adsorpciju na zeolitu, flokulaciju, sedimentaciju i filtraciju na peščano/antracitnom filtru. Za završnu obradu vode GAU filtracijom pre procesa dezinfekcije, na osnovu svih ispitivanih parametara, kao najefikasniji u uklanjanju POM i prekursora oksidacionih nusproizvoda (THM, HAA i aldehida) pokazao se GAU Norit Row 0,8 Supra. Hlorisanjem u simuliranim uslovima dezinfekcije, utvrđeno je da voda dobijena nakon GAU filtracije u ispitivanim tretmanima, ima zadovoljavajući kvalitet sa aspekta sadržaja THM i HAA (sadržaj THM je 69,7-77,4 µg/l; koncentracija DCAA je < MDL) čije su maksimalno dozvoljene koncentracije regulisane u vodi za piće (100 µg/l za THM i 50 µg/l za DCAA). Statističkom obradom podataka iz laboratorijskih i pilot ispitivanja utvrđene su empirijske zavisnosti koje se mogu primenjivati za predviđanje koncentracije THM i HAA u tretiranoj vodi nakon tretmana ispitivanih na pilot postrojenju. Da bi se mogle primeniti za druge vrste vode i drugačije dizajnirane tetmane, neophodno je izvršiti validaciju primenom nezavisnog seta podataka.         Svi rezultati dobijeni u toku istraživanja ukazuju na neophodnost primene oksidacionih sredstava u tretmanu ispitivane podzemne vode. Zbog različitog mehanizma delovanja, neophodno je izvršiti odabir odgovarajuće vrste i doze oksidacionog sredstva, kao i koagulanta u tretmanu vode za piće, uzimajući u obzir karakteristika sirove vode i efikasnost koja se želi postići. Primena optimalnih doza ozona i O3/H2O2 omogućava povećanje efikasnosti uklanjanja POM i prekursora oksidacionih nusporizvoda, procesima koagulacije, flokulacije i adsorpcije. Odabirom odgovarajućih uslova tretmana postiže se da i nakon hlorisanja u postupku dezinfekcije, voda zadovoljava kriterijume kvaliteta vode za piće, sa aspekta sadržaja trihalometana i halosirćetnih kiselina.The aim of this work was to investigate influence of ozone and ozone/hydrogen peroxide on efficiency of coagulation, flocculation and adsorption on natural organic matter and oxidation by-products removal. Special attention was dedicated to investigation of these processes on chlorine oxidation by-products (trihalomethanes and haloacetic acids) as well as on hypochlorite influence on formation of these compounds in treated water. The analysis of chemical characteristics of raw ground water used in this investigation show that it contains high amount of NOM, mainly of hydrophobic nature (PB = 37,7±0,60 mg KMnO4/l; DOC = 9,27±0,92 mg C/l; UV254 = 0,497± 0,015 cm-1; SUVA = 5,36±0,49 1 mg-1 m-1; PFTHM = 555±128 μg/l; PFHAA = 245±54,9 μg/l) as well as high arsenic concentration (51,7±16,4 μg/l). Comparing the influences of two investigated coagulants (FeCl3 and FeCl3/PACl) it was observed that they have different mechanisms of NOM and oxidation by-products precursors’ removal. FeCl3/PACl enables reduction of DOC, PB, UV254 absorbance and SUVA value for 54%, 71%, 88% i 74%, respectively, relative to raw water. Coagulation with FeCl3 provides reduction of DOC, PB, UV254 absorbance and SUVA for 51%, 48%, 61% i 21%, respectively. In water coagulated with FeCl3 remains NOM of hydrophobic nature (SUVA = 5,12 l m-1 mg-1) while NOM in coagulated water with FeCl3/PACl can be characterized as hydrophilic (SUVA = 1,70 l m-1 mg-1). Coagulation with FeCl3 and FeCl3/PACl enables arsenic content reduction for over 95% relative to raw water, with As concentrations in coagulated water below of 10 μg/l. Ozone and O3/H2O2 process demonstrates similar efficiency in NOM and oxidation by-products precursors content reduction. Comparing combined treatment which includes oxidation pretreatment and coagulation, it was observed that efficiency of coagulation in DOC, PB, UV254, SUVA, PFTHM and aldehydes reduction mainly depends on coagulants activity mechanisms, while ozone and O3/H2O2 process contributes to reduction of these parameters through oxidation and removal of volatile compounds from water by gas stripping. Ozone and O3/H2O2 process enables increase of coagulation efficiency for HAA precursor’s removal, comparing to coagulation without oxidation pretreatment. Taking into account all measured parameters as well as applied doses of oxidation reagents and coagulants, it can be concluded that the best results in NOM and oxidation by-products precursors content reduction (decrease of DOC for 55%, UV254 i SUVA for more then 90%, related to raw water; PB = 7,70 mg KMnO4/l; PFTHM =158-188 μg/l; PFHAA = 33,0-53,8 μg/l and content of aldehydes 16,7-17,9 μg/l) can be obtained by treatments which include oxidation pretreatment with ozone (3,0 g O3/m3), as well as with O3/H2O2 (3,3 g O3/m3; H2O2:O3 =1:1), coagulation (30 g FeCl3/m3 / 30 g Al/m3), with flocculation sludge recirculation and zeolit adsorption, flocculation, sedimentation and filtration on sand/anthracite filter. For the final water treatment with GAC filtration before disinfection process, based on all parameters, GAC Norit Row 0,8 Supra was the most efficient in NOM and oxidation by-products precursors reduction (THM, HAA and aldehydes). After chlorination in simulated disinfection conditions, it was determined that water after GAC filtration in investigated treatments has satisfactory quality in terms of regulated THM and HAA (content of THM is 69,7-77,4 μg/l; concentration of DCAA is < MDL) which maximal allowable level for drinking water is established (100 μg/l for THM and 50 μg/l for DCAA). By statistical analysis of data obtained in laboratory and pilot scale experiments it was determined empirical relations for THM and HAA concentration predictions in treated water. All obtained results in this research indicate that oxidation reagents need to be applied in treatment of investigated ground water. Because of different action mechanism, it is necessary to select the adequate type and dose of oxidation reagent and coagulant in water treatment, taking into account characteristics of raw water and efficiency that needs to be achieved. Application of optimal doses of ozone and O3/H2O2 enables increase of coagulation, flocculation and adsorption efficiency in NOM and oxidation by-products precursors’ removal. Selection of adequate treatment conditions provides that after chlorination in disinfection process water satisfies drinking water quality criteria, in terms of trihalomethanes and haloacetic acids

Acute abdomen in a patient with Mayer-Rokitansky-Kuster-Hauser syndrome

Background. Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome is a malformation of female genital tract (incidence 1 in 4000 female newborn children). It appears as a result of a disorder in the development of Millerian cannals. Etiology is unknown. Syndrome MRKH is the most frequent cause of primary amenorrhoea (90%). Patients with MRKH have a normal female phenotype, with normal pubic hairness and thelarche, and female karyotype (46XX) followed by primary amenorrhoea. Hormonal status corresponds to healthy women, where the appearance of ovarian tumors and tumors on rudiment parts of uterus is possible. Case report. We presented a case of acute abdomen in a patient with previously not diagnosed MRKH. The diagnosis was done during the operation. Small pelvis and an abdominal part were filled with torquated tumor lump, where ovaries, oviducts, uterus or something resembling rudiment of uterus were not recognized through careful examination. Furthemore, the patient had a short, dead-end vagina. Tumorectomy was done and hystopathological finding showed the presence of vascular leiomyoma. Conclusion. The diagnosis of complex syndromes, such as MRKH, can, despite modern diagnostics, be absent for non-medical and psycho-social reasons. We can expect ovarian and uterine pathology on hypoplastic structures in these patients, as well as in healthy women. Vascular leiomyoma in the patients with MRKH was not found in the available literature

Adsorption kinetics and mechanism analysis of cyan printing dye on polyethylene microplastics

Printing on polymer materials might result with generation of coloured wastewater, enriched with a certain amount of microplastics in a form of polyethylene or polypropylene. In that way, microplastics may acquire the function of carriers of synthetic dyes, heavy metals and other polluting substances. In this paper, kinetics and adsorption mechanism of printing Cyan dye on polyethylene (powdered and granulated), as one of the most common types of microplastics, were investigated. The experiments were performed in a batch mode, in laboratory conditions. Based on the obtained results, a similar adsorption rate degree of selected printing dye was determined on granulated (adsorbed amount was 48.04 µg/g) and powdered material (adsorbed amount was 44.32 µg/g). The adsorption data were fitted well by pseudo-second-order kinetics, while isotherm studies were evaluated using two models: Langmuir and Freundlich. Freundlich and Langmuir equations showed similar performances to fit the solid/liquid distribution of Cyan dye on powdered polyethylene (R2 = 0.987), whereas Langmuir equation showed slightly better performances for granulated polyethylene than Freundlich equation

Sorption-desorption behaviour of hydrophobic organic compounds on Danube sediment

The sorption-desorption hysteresis of naphthalene and phenanthrene onto Danube sediment was investigated. Hysteresis indices (HI) are calculated for three equilibrium concentration (Ce=1%, 5% i 50% of the solubility in water). The results of sorption-desorption hysteresis indicated that it exists for both investigated sorbates on the Danube sediment. For more hydrophobic compound, phenanthrene (logKOW< 4.55) hysteresis is less pronounced in comparison with naphthalene (logKOW< 3.36). In the case of naphthalene, the existence of hysteresis may be due to irreversible pore deformation of the sorbent which causes the formation of meta-stable states in the sorbate mesopores

Enhanced coagulation with pre-oxidation for the removal of arsenic from groundwater

One of the most wide-spread problems with current drinking water resources globally is the natural presence of arsenic in groundwaters. The aim of this work was to investigate the removal of arsenic by a variety of combined oxidation/coagulation processes, in order to identify and optimise the most critical process parameters. The most significant gains made by both preoxidation steps were observed in the techniques which combined aluminum and ferric chloride based coagulation. The most efficient coagulation treatment investigated involved application of preozonation at a dose of 7.5 mg O3/l with subsequent combined coagulation with PACl–FeCl3 (30 mg Al/l and 10 mg FeCl3/l)

New Opportunities for Endometrial Health by Modifying Uterine Microbial Composition: Present or Future?

We acknowledge the research support by Copan Italia S.p.A Inc., and Clearblue, SPD Swiss Precision Diagnostics GmbH. This study is part of a PhD Thesis conducted at the Official Doctoral Programme in Biomedicine of the University of Granada, Spain. We are grateful to Ana Yara Postigo-Fuentes for her assistance with English language.Current knowledge suggests that the uterus harbours its own microbiota, where the microbes could influence the uterine functions in health and disease; however, the core uterine microbial composition and the host-microbial relationships remain to be fully elucidated. Different studies are indicating, based on next-generation sequencing techniques, that microbial dysbiosis could be associated with several gynaecological disorders, such as endometriosis, chronic endometritis, dysfunctional menstrual bleeding, endometrial cancer, and infertility. Treatments using antibiotics and probiotics and/or prebiotics for endometrial microbial dysbiosis are being applied. Nevertheless there is no unified protocol for assessing the endometrial dysbiosis and no optimal treatment protocol for the established dysbiosis. With this review we outline the microbes (mostly bacteria) identified in the endometrial microbiome studies, the current treatments offered for bacterial dysbiosis in the clinical setting, and the future possibilities such as pro- and prebiotics and microbial transplants for modifying uterine microbial composition.This work is supported by the Spanish Ministry of Economy, Industry and Competitiveness (MINECO) and European Regional Development Fund (FEDER): grants RYC-2016-21199 and ENDORE SAF2017-87526-R; Programa Operativo FEDER Andalucía (B-CTS-500-UGR18) and by the University of Granada Plan Propio de Investigación 2016—Excellence actions: Unit of Excellence on Exercise and Health (UCEES)—and Plan Propio de Investigación 2018—Programa Contratos-Puente, and the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades, European Regional Development Funds (ref. SOMM17/6107/UGR). A.S.-L. is funded by the Spanish Ministry of Science, Innovation and Universities (PRE2018-0854409)

Photochemical degradation of alachlor in water

This study investigates the photochemical degradation of alachlor, a chloroacetanilide herbicide. All experiments were conducted in ultra-pure deionized water (ASTM Type I quality) using direct ultraviolet (UV) photolysis and the UV/H2O2 advanced oxidation process. The direct UV photolysis and UV/H2O2 experiments were conducted in a commercial photochemical reactor with a quartz reaction vessel equipped with a 253.7 nm UV low pressure mercury lamp (Philips TUV 16 W). The experimental results demonstrate that UV photolysis was very effective for alachlor degradation (up to 97% removal using a high UV fluence of 4200 mJ/cm2). The UV/H2O2 process promoted alachlor degradation compared to UV photolysis alone, with a high degree of decomposition (97%) achieved at a significantly lower UV fluence of 600 mJ/cm2 when combined with 1 mg H2O2/L. The application of UV photolysis alone with a UV fluence of 600 mJ/cm2 gave a negligible 4% alachlor degradation. The photo degradation of alachlor, in both direct UV photolysis and the UV/H2O2 process, followed pseudo first-order kinetics. The degradation rate constant was about 6 times higher for the UV/H2O2 process than for UV photolysis alone

COST Action PRIORITY: An EU Perspective on Micro- and Nanoplastics as Global Issues

Plastic fragments, weathered into or released in the form of micro- and nanoplastics, are persistent and widespread in the environment, and it is anticipated that they have negative environmental impacts. This necessitates immediate efforts for management strategies throughout the entire plastics lifecycle. This opinion paper was initiated by the EU COST Action CA20101 PRIORITY, which focuses on the need to develop an effective global networking platform dealing with research, implementation, and consolidation of ways to address the worldwide challenges associated with micro- and nanoplastics pollution in the environment

Effect of ozone, ozone/hydrogen peroxide and hypoclorite on natural organic matter and oxidation by-products content in water after coagulation, floculation and adsorption procesess

Cilj ovog rada je bio da se ispita uticaj ozona i ozon/vodonik-peroksida na efikasnost uklanjanja POM i prekursora oksidacionih nusproizvoda, procesima koagulacije, flokulacije i adsorpcije. Posebna pažnja posvećena je ispitivanju uticaja navedenih procesa na sadržaj prekursora oksidacionih nusproizvoda hlora (trihalometana i halosirćetnih kiselina), kao i na uticaj hipohlorita na formiranje ovih jedinjenja u tretiranoj vodi. Analiza hemijskih karakteristika sirove podzemne vode korišćene u ispitivanjima pokazuje da sadrži visok nivo POM pretežno hidrofobnog karaktera (PB = 37,7±0,60 mg KMnO4/l; DOC = 9,27±0,92 mg C/l; UV254 = 0,497± 0,015 cm-1; SUVA = 5,36±0,49 1 mg-1 m-1; PFTHM = 555±128 µg/l; PFHAA = 245±54,9 µg/l), kao i visoku koncentraciju arsena (51,7±16,4 µg/l). Poređenjem uticaja dve ispitivane vrste koagulanata (FeCl3 i FeCl3/PACl) utvrđeno je da imaju različite mehanizme uklanjanja POM i prekursora oksidacionih nusproizvoda. FeCl3/PACl omogućava smanjenje sadržaja POM izraženih preko vrednosti DOC, PB, UV254 apsorbancije i SUVA za 54%, 71%, 88% i 74%, u odnosu na sirovu vodu respektivno, dok se koagulacijom sa FeCl3 postiže smanjenje DOC, PB, UV254 apsorbancije i SUVA za 51%, 48%, 61% i 21%, respektivno. U vodi nakon koagulacije sa FeCl3 zaostaju POM hidrofobnog karaktera (SUVA = 5,12 l m-1 mg-1), dok se POM u koagulisanoj vodi sa FeCl3/PACl, mogu okarakterisati kao hidrofilne (SUVA = 1,70 l m-1 mg-1). Koagulacija sa FeCl3 i FeCl3/PACl omogućila je smanjenje sadržaja arsena u vodi za preko 95%, pri čemu su koncentracije As u koagulisanoj vodi bile niže od 10 µg/l. Ozon i O3/H2O2 proces pokazuju sličnu efikasnost u smanjenju sadržaja POM i prekursora oksidacionih nusproizvoda. Poređenjem kombinovanih tretmana koji obuhvataju oksidacioni predtretman i koagulaciju, utvrđeno je da efikasnost koagulacije sa FeCl3 i FeCl3/PACl u smanjenju vrednosti DOC, PB, UV254, SUVA, PFTHM i aldehida, uglavnom zavisi od mehanizma delovanja samih koagulanata, dok ozon i O3/H2O2 proces doprinose smanjenju vrednosti ovih parametara kroz oksidaciju i izdvajanje lako isparljivih komponenti iz vode stripingom gasa. Sa aspekta promene sadržaja prekursora HAA, ozon i O3/H2O2 proces omogućavaju povećanje efikasnosti procesa koagulacije sa FeCl3 i FeCl3/PACl, u odnosu na koagulaciju bez oksidacionog predtretmana. Kada se uzmu u obzir vrednosti svih navedenih parametara, kao i primenjenje doze oksidacionih sredstava i koagulanata, najbolji rezultati u uklanjanju POM i prekursora oksidacionih nusproizvoda (smanjenje vrednosti DOC za 55%, UV254 i SUVA za više od 90%, u odnosu na sirovu vodu; PB = 7,70 mg KMnO4/l;  PFTHM =158-188 µg/l; PFHAA = 33,0-53,8 µg/l i sadržaj aldehida 16,7-17,9 µg/l) postižu se primenom tretmana koji obuhvataju oksidacioni predtretman ozonom (3,0 g O3/m3), odnosno O3/H2O2  (3,3 g O3/m3; H2O2:O3 =1:1), koagulaciju (30 g FeCl3/m3 / 30 g Al/m3) uz recirkulaciju flokulacionog mulja i adsorpciju na zeolitu, flokulaciju, sedimentaciju i filtraciju na peščano/antracitnom filtru. Za završnu obradu vode GAU filtracijom pre procesa dezinfekcije, na osnovu svih ispitivanih parametara, kao najefikasniji u uklanjanju POM i prekursora oksidacionih nusproizvoda (THM, HAA i aldehida) pokazao se GAU Norit Row 0,8 Supra. Hlorisanjem u simuliranim uslovima dezinfekcije, utvrđeno je da voda dobijena nakon GAU filtracije u ispitivanim tretmanima, ima zadovoljavajući kvalitet sa aspekta sadržaja THM i HAA (sadržaj THM je 69,7-77,4 µg/l; koncentracija DCAA je < MDL) čije su maksimalno dozvoljene koncentracije regulisane u vodi za piće (100 µg/l za THM i 50 µg/l za DCAA). Statističkom obradom podataka iz laboratorijskih i pilot ispitivanja utvrđene su empirijske zavisnosti koje se mogu primenjivati za predviđanje koncentracije THM i HAA u tretiranoj vodi nakon tretmana ispitivanih na pilot postrojenju. Da bi se mogle primeniti za druge vrste vode i drugačije dizajnirane tetmane, neophodno je izvršiti validaciju primenom nezavisnog seta podataka.         Svi rezultati dobijeni u toku istraživanja ukazuju na neophodnost primene oksidacionih sredstava u tretmanu ispitivane podzemne vode. Zbog različitog mehanizma delovanja, neophodno je izvršiti odabir odgovarajuće vrste i doze oksidacionog sredstva, kao i koagulanta u tretmanu vode za piće, uzimajući u obzir karakteristika sirove vode i efikasnost koja se želi postići. Primena optimalnih doza ozona i O3/H2O2 omogućava povećanje efikasnosti uklanjanja POM i prekursora oksidacionih nusporizvoda, procesima koagulacije, flokulacije i adsorpcije. Odabirom odgovarajućih uslova tretmana postiže se da i nakon hlorisanja u postupku dezinfekcije, voda zadovoljava kriterijume kvaliteta vode za piće, sa aspekta sadržaja trihalometana i halosirćetnih kiselina.The aim of this work was to investigate influence of ozone and ozone/hydrogen peroxide on efficiency of coagulation, flocculation and adsorption on natural organic matter and oxidation by-products removal. Special attention was dedicated to investigation of these processes on chlorine oxidation by-products (trihalomethanes and haloacetic acids) as well as on hypochlorite influence on formation of these compounds in treated water. The analysis of chemical characteristics of raw ground water used in this investigation show that it contains high amount of NOM, mainly of hydrophobic nature (PB = 37,7±0,60 mg KMnO4/l; DOC = 9,27±0,92 mg C/l; UV254 = 0,497± 0,015 cm-1; SUVA = 5,36±0,49 1 mg-1 m-1; PFTHM = 555±128 μg/l; PFHAA = 245±54,9 μg/l) as well as high arsenic concentration (51,7±16,4 μg/l). Comparing the influences of two investigated coagulants (FeCl3 and FeCl3/PACl) it was observed that they have different mechanisms of NOM and oxidation by-products precursors’ removal. FeCl3/PACl enables reduction of DOC, PB, UV254 absorbance and SUVA value for 54%, 71%, 88% i 74%, respectively, relative to raw water. Coagulation with FeCl3 provides reduction of DOC, PB, UV254 absorbance and SUVA for 51%, 48%, 61% i 21%, respectively. In water coagulated with FeCl3 remains NOM of hydrophobic nature (SUVA = 5,12 l m-1 mg-1) while NOM in coagulated water with FeCl3/PACl can be characterized as hydrophilic (SUVA = 1,70 l m-1 mg-1). Coagulation with FeCl3 and FeCl3/PACl enables arsenic content reduction for over 95% relative to raw water, with As concentrations in coagulated water below of 10 μg/l. Ozone and O3/H2O2 process demonstrates similar efficiency in NOM and oxidation by-products precursors content reduction. Comparing combined treatment which includes oxidation pretreatment and coagulation, it was observed that efficiency of coagulation in DOC, PB, UV254, SUVA, PFTHM and aldehydes reduction mainly depends on coagulants activity mechanisms, while ozone and O3/H2O2 process contributes to reduction of these parameters through oxidation and removal of volatile compounds from water by gas stripping. Ozone and O3/H2O2 process enables increase of coagulation efficiency for HAA precursor’s removal, comparing to coagulation without oxidation pretreatment. Taking into account all measured parameters as well as applied doses of oxidation reagents and coagulants, it can be concluded that the best results in NOM and oxidation by-products precursors content reduction (decrease of DOC for 55%, UV254 i SUVA for more then 90%, related to raw water; PB = 7,70 mg KMnO4/l; PFTHM =158-188 μg/l; PFHAA = 33,0-53,8 μg/l and content of aldehydes 16,7-17,9 μg/l) can be obtained by treatments which include oxidation pretreatment with ozone (3,0 g O3/m3), as well as with O3/H2O2 (3,3 g O3/m3; H2O2:O3 =1:1), coagulation (30 g FeCl3/m3 / 30 g Al/m3), with flocculation sludge recirculation and zeolit adsorption, flocculation, sedimentation and filtration on sand/anthracite filter. For the final water treatment with GAC filtration before disinfection process, based on all parameters, GAC Norit Row 0,8 Supra was the most efficient in NOM and oxidation by-products precursors reduction (THM, HAA and aldehydes). After chlorination in simulated disinfection conditions, it was determined that water after GAC filtration in investigated treatments has satisfactory quality in terms of regulated THM and HAA (content of THM is 69,7-77,4 μg/l; concentration of DCAA is < MDL) which maximal allowable level for drinking water is established (100 μg/l for THM and 50 μg/l for DCAA). By statistical analysis of data obtained in laboratory and pilot scale experiments it was determined empirical relations for THM and HAA concentration predictions in treated water. All obtained results in this research indicate that oxidation reagents need to be applied in treatment of investigated ground water. Because of different action mechanism, it is necessary to select the adequate type and dose of oxidation reagent and coagulant in water treatment, taking into account characteristics of raw water and efficiency that needs to be achieved. Application of optimal doses of ozone and O3/H2O2 enables increase of coagulation, flocculation and adsorption efficiency in NOM and oxidation by-products precursors’ removal. Selection of adequate treatment conditions provides that after chlorination in disinfection process water satisfies drinking water quality criteria, in terms of trihalomethanes and haloacetic acids

Prognostic and therapeutic implication of residual timorous tissue in cervix conizate

Background/Aim. Conization is an excisive technique used for both diagnostic and therapeutic purposes. If conizate margins do not show any pathologic changes (negative findings) it is also the only therapeutic measure which should be applied. In case of conizate margins affected by the disease (positive findings), it is necessary not only to assess various parameters but also to decide on a further therapeutic approach. The aim of this study was to determine the incidence of positive findings and its impact on a further optimal therapeutic approach choice. Methods. The data for analyses were retrospectively acquired through an insight into the medical records of the female patients who had undergone conization in the Institute for Gynecology and Obstetrics, Clinical Center of Serbia, within a period from 1995 to 2000. Histopathologic analyses of the bioptic and cervical conizate and reconizate samples were performed in the same institute. The acquired data were analyzed and statistically processed. Results. Within the above mentioned period, a total of 823 conizations were done. In 76 patients, positive findings were determined. The acquired data analysis revealed positive findings decrease during this period, yet with no statistical significance. Higher statistically significant incidence of positive findings, however, was revealed in the patients over 40 years of age. Also, a statistically significantly higher incidence of positive findings was revealed in the apex as compared with other localizations. During the period observed, there was the raise of the number of patients only followed up after the conization without reconization. Also evident was decreasing in the number of histerectomies followed by increasing in the number of reconizations, as the method for reintervention. The most common cause of histerectomy was the apex positive findings with no statistical significance, while of reconization it was positive finding on lateral conizate margins with statistical significance. The association of the apical conizate positive finding with that in the curettements in all the cases was in correlation with positive findings at reintervention. Conclusion. According to the results obtained by analyzing and statistical processing of the acquired data, it could be concluded that reconization does represent a more suitable reintervention in patients with positive conizate findings as compared to histerectomy