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Application of Fenton's Reagent in the Textile Wastewater Treatment Under Industrial Conditions

Application of reactive dyes is very popular in textile industry as these dyestuffs are characterized by good fastness properties. Constapel et al in 2009 estimated the production of this type of dyes for over 140,000 Mg/year. The reactive dyes are mostly (50%) employed for coloration of cellulosic fibers, however they can also be applied on wool and nylon. Unfortunately, they possess a low degree of fixation (50÷90%), since the functional groups also bond to water, creating hydrolysis and the excess of dyes applied cause a colored pollution of aqueous environment. Moreover, dyeing process requires the use of: electrolytes in the form of aqueous solutions of NaCl or Na2SO4 in the concentration up to 100 g/dm3, alkaline environment (pH > 10) and textile auxiliary agents (including detergents). Therefore, the wastewater generated during the reactive dyeing processes is characterized by high salinity, pH value and color, and due to low value of the BOD5/COD ratio are nonbiodegradable. The successful methods of textile wastewater treatment could be Advanced Oxidation Processes (AOPs), amongst which the Fenton reagent seems to be most promising as it is the cheapest and easy in use. Based on the newest literature survey it was found that many successful tests with Fenton reaction were performed mainly in decolorization. However, not enough attention was devoted to decolorization of real industrial wastewater containing dyes, detergents and salts NaCl, or Na2SO4. The experiments carried out in a laboratory scale were focused on the impact of NaCl and textile auxiliary agent (liquid dispersing and sequestering agent) on an inhibition of decolorization process by Fenton's reagent. The objects of the investigation were synthetic mixtures simulating the composition of real textile wastewater as well as the real industrial wastewater generated in the reactive dyeing. The inhibition of the Fenton decolorization in the presence of NaCl and liquid dispersing and sequestering agent was demonstrated. Additional experiments using pulse radiolysis were carried out in order to confirm the inhibition of chloride in the decolorization process.

Wet Oxidation of Dairy Sewage

Results of kinetic studies on the process of wet oxidation of dairy sewage are presented. Experiments were carried out in a stirred batch tank reactor at the oxygen partial pressure equal to 1 MPa and at temperature ranging from 473 to 523 K. Dairy sewage was subjected to oxidation at a natural pH close to 4. The efficiency of decomposition of organic compounds was estimated on the basis of TOC measurement. The highest TOC reduction rate reached 79.6%. A kinetic model of the process was proposed and its parameters were determined experimentally. Good agreement of the experimental and calculated results was obtained.

Abstract

The water quality of the open channels (Foughal, OumDhar and Tamagnounte) flowing into Beni-Mellal city were assessed in a bid to determine impacts of anthropogenic activities. Physicochemical and bacteriological parameters comprising temperature, pH, alkalinity, electrical conductivity, oxidizability, total hardness, ammonia, nitrite, nitrate, total coliforms, fecal coliforms and geochemical analyses were determined for the channels water before reaching the irrigation areas. While biological parameters demonstrated substantial variability, other parameters showed relatively little spatial variations. The spatial variations in water quality may be attributed to the effects of the urban wastewater discharge in the channels and to surface urban and agricultural runoff. Compared with drinking water quality standards of Moroccan and WHO, the results indicated that the channels water was suitable for drinking purpose with prior treatment. Various determinants such as electrical conductivity, residual sodium carbonate, total dissolved solids and hardness revealed that all water samples were suitable for irrigation.

Abstract

The article presents the results of kinetic studies of the wet oxidation process of dairy sewage. The dairy sewage, obtained straight from the production line, was subjected to oxidation at pH close to the natural value of 7. Experiments were carried out in a stirred batch tank reactor at the oxygen partial pressure equal to 1 MPa and at temperature ranging from 473 to 593 K. The effectiveness of organic compounds decomposition was estimated based on the measurement of TOC. The kinetics of decomposition of milk components, ie lactose, protein and fat, as well as the kinetics of oxidation of intermediate products was the aim of the study. Measurement of the concentration of protein, fat and lactose was done with a milk composition analyzer, calibrated in relation to the dairy sewage. The obtained results were used to develop a mathematical model of wet oxidation of dairy sewage, including the group of analyzed compounds.

Streszczenie

Badania przeprowadzono w oparciu o wyniki uzyskane z eksperymentu polowego. Celem badań było określenie wpływu oczyszczonych ścieków miejskich, zastosowanych w dawce pojedynczej, optymalnej dla danej rośliny (ustalona w oparciu o ładunek N i wody) i podwójnej dawce ścieków na zawartość i specjację Cd i Fb w glebie organicznej obojętnej. W pobranych z każdego obiektu, uśrednionych próbach glebowych, oznaczono zawartość ogółem Cd i Fb oraz specjację tych metali. Wyodrębniono 5 frakcji Cd i Pb zdefiniowanych operacyjnie: wymienną (FI), węglanową określaną jako „związaną specyficznie” (F2), związaną z tlenkami Fe-Mn (F3), organiczną(F4) i pozostałości (F5). Stwierdzono, że całkow ita zawartość ołowiu w badanej glebie odpowia- dała wartościom naturalnym, zaś ilość kadmu przekraczała dopuszczalne normy ustalone dla gleb organicznych. Wyniki chemiczne- go frakcjonow ania Cd i Fb w glebie wytworzonej z torfu niskiego, zarówno z obiektów' naw ożonych oczyszczonymi ściekami, jak i z obiektu kontrolnego przedstaw iają następujące uszeregow anie procentowy ch zawartości poszczególnych frakcji w kolejności ma- lejącej: F3>F2>F4>F1>F5 - kadm, F3>F4>F2>F5>F1 - ołów. Oczyszczone ścieki miejskie, będące źródłem łatwo rozpuszczalnych związków organicznych, mogą w'pływać nawiązanie Cd i Fb we frakcji organicznej, co potwierdza odnotowany w badaniach wzrost ilości metali w tej frakcji w glebie.

Abstract

The important factors that strongly influence the particle size distributions measured by the laser diffraction method are the optical parameters of the suspension (refractive index and absorption coefficient). Knowledge of the values of these parameters is necessary for Mie theory. Mie theory is applied for conversion of the intensity of light recorded on detectors into particle size distribution (PSD) of tested material. Both wastewater and activated sludge are mixtures of a variety of elements (mineral or organic, including living organisms). In practice, it is not possible to define clearly the values of the optical parameters, as the composition of the suspension changes over time. The aim of the study was to estimate the impact of assumed values of the optical parameters on particle size distributions obtained. The PSDs of suspensions sampled in different stages of wastewater treatment are the most reproducible when the following optical parameters are defined: absorption coefficients - 1.0 and the refractive index - 1.52.

-88. GUDELIS-MATYS K. 2004. Oczyszczanie šcieków w zakładach mięsnych. Gospodarka Mięsna 09: 50-52. KONIECZNY P. SZYMAŃSKI M. 2007. Šcieki przemysłu spożywczego-charakterystyka, zagrożenia, korzyšci, Przegląd Komunalny 02: 88-100. NARDI I.R., Del NERY V., AMORIM A.K.B., SANTOS N.G., CHIMENES F. 2011. Performances of SBR, chemical-DAF and UV disinfection for poultry slaughterhouse wastewater reclamation, Desalination 269: 184-189. NECZAJ E., KACPRZAK M., KAMIZELA T., LACH J., OKONIEWSKA E. 2008. Sequencing batch reactor system for the co-treatment of landfill leachate and

Galvanic Wastewater Treatment by Means of Anionic Polymer Enhanced Ultrafiltration

This work is focused on polyelectrolyte enhanced ultrafiltration as an effective heavy metal separation technique. Three types of effluents, containing Zn(II), Cu(II) and Ni(II) ions, were subjected to the separation process. Poly(sodium 4-styrenesulfonate) - PSSS, a water soluble anionic polyelectrolyte was used as a metal binding agent. Two Sepa® CF (Osmonics) membranes: EW, made of polysulfone and a modified polyacrylonitrile membrane MW, were used in the ultrafiltration process. The preliminary UF tests were carried out on model solutions with target metal ion concentrations of 10, 100 and 250 mg dm-3. The main parameters affecting the metal retention (the polyelectrolyte quantity and solution pH) were examined. The values of pH 6 and polymer : metal concentration ratio CPSSS : CM = 7.5 : 1 (mol of mer unit per mol of metal) were selected to perform the galvanic wastewater ultrafiltration-concentration tests. Three types of wastewater containing Zn(II), Ni(II) and Cu(II) ions within the concentration range of 30÷70 mg dm-3 were used in the investigations. Very high metal retention coefficients, up to > 99%, were achieved. The retentates obtained were subjected to the decomplexation-ultrafiltration (pH = 1) and subsequent diafiltration step, which enabled partial recovery of concentrated metal ions and the polyelectrolyte. The recovered polyelectrolyte was reused toward Ni(II) ions and the high effectiveness of metal separation has been achieved.

Abstract

Increased production and consumption of drugs influences the pollution pharmaceuticals. Recent years have seen a significant increase in the consumption of non-prescription medicines, among which, are a large group of non-steroidal anti-inflammatory drugs (NSAIDs). Research conducted in Poland and abroad showed the presence of NSAIDs, both in treated wastewater in surface waters and drinking waters. One of the most frequently detected drugs in the environment is diclofenac, belongs to NSAID. Its concentration in surface waters range from 9 to 3363 ng/L. Traditional wastewater treatment plants are not specialized enough in removing the pharmaceuticals and their metabolites, and with purified wastewater are introduced into surface waters. Diclofenac concentrations in treated wastewater range from 0.29 to 2.5 μg/L, the average removal efficiency is about 40%.

Treatment of the Processing Wastewaters Containing Heavy Metals with the Method Based on Flotation

The aim of the studies carried out at full technological scale was to indicate optimal systems of the two-stage precipitation and coagulation (PIX 113 - SAX 18, PAX XL1 - SAX 18, ALCAT 102 - lime milk and SAX 18 - PAX 16) in the process of eliminating heavy metals from wastewaters made in the processing plant producing sub-systems for domestic appliances. Precipitated pollutions were thickened by flocculation and separated by hydrogen peroxide enhanced pressure flotation. The experimental installation of maximal flow capacity: 10.0 m3/d consisted of: the storage-equalization tank, the processing pipe reactor, the pressure flotation station, and the reagent preparation and dosing station. Optimal doses of reagents and a flocculent as well as pressure and saturation time were defined for which maximal reductions in the load of heavy metals were achieved. The usefulness of hydrogen peroxide as a means of enhancing flotation was tested. The use of two-stage precipitation permitted the reduction in heavy metals (Cd, Cu, Cr, Ni, Sn, Zn), eg by applying ALCAT 102 - lime milk at the level exceeding 80%.