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1
Content available Reuse of alum sludge for reducing flocculant addition in water treatment plants
Scalize Paulo S., Souza Leonora M. D., Albuquerque Antonio
Environment Protection Engineering
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2019
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Vol. 45, nr 1
57--70
EN
The recycling of water treatment residues (WTR) inside drinking water treatment plants (DWTP) to be a good option for reusing this type of waste, as well as for reducing the costs with its disposal off and with the acquisition of treatment chemicals. Therefore, a WTR was reused for auxiliary of the coagulation-flocculation processes for reducing the use of aluminium sulfate (coagulant) in a DWTP. Three series of experiments have been conducted involving three water samples with different turbidity and colour, different WTR samples with different total suspended solids (TSS) concentrations and different aluminium sulfate concentrations. The results showed that WTR can efficiently be used for the removal of turbidity between 21 NTU and 218 NTU and colour between 194 HU and 1509 HU for TSS concentration between 1635 mg/dm3 and 5420 mg/dm3, with better results in the range between 1635 mg/dm3 and 2678 mg/dm3. For higher TSS concentrations, the removal of both parameters decrease because there are excess of organics released to water, which demands the use of more coagulant.
2
Content available The role of compost properties in sorption of heavy metals
Martinho J., Campos B., Brás I., Silva E.
Environment Protection Engineering
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2015
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Vol. 41, nr 2
57--65
EN
The feasibility of various composts to operate as sorbents for heavy metals (Cu and Zn) removal from wastewater has been evaluated. Three commercial composts obtained from municipal solid wastes (MWS), sludge sewage (SS) and poultry manure (PM) were selected as potential sorbents. Kinetic and equilibrium tests were conducted in order to assess the equilibrium conditions to remove metals from aqueous samples. For all composts, the maximum time necessary to reach the equilibrium was 240 min. The Freundlich and Langmuir isotherm models were found to fit the sorption data. The SS compost proved to be the one with highest removal capability for both assessed metals, while MWS compost showed to be the less suitable for this purpose. These results can be explained in terms of the compost surface properties, namely, with the cation exchange capacity.
3
Content available Removal of hexavalent chromium from aqueous solution by adsorption on γ-alumina nanoparticles
Golestanifar H., Haibati B., Amini H., Dehghani M. H., Asadi A.
Environment Protection Engineering
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2015
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Vol. 41, nr 2
133--145
EN
The use of γ-alumina (γ-Al2O3) nanoparticles as adsorbent to remove Cr(VI) from aqueous solution was investigated using batch experiments. Adsorption experiments were carried out for various initial doses of Al2O3, initial concentrations of chromium(VI), contact times and pH. The structure and morphology of the sorbent was characterized by XRD, SEM, and TEM techniques. Results demonstrated that the removal efficiency of chromium(VI) was increased by increasing the contact time, initial concentration, and pH. The results of the study showed that adsorption of chromium by γ-alumina nanoparticles reached equilibrium after 60 min and after that a little change of chromium removal efficiency was observed. Furthermore, kinetics of chromium sorption was well fitted by pseudo-second order kinetic model, and well explained by the Freundlich isotherm (R2 > 0.992). Overall, alumina nanoparticles recognized as an effective sorbent to remove chromium(VI) from aqueous solutions.
4
Content available Influence of composition of raw wastewater on removal of nitrogen compounds in multistage treatment wetlands
Gajewska M.
Environment Protection Engineering
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2015
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Vol. 41, nr 3
19--30
EN
Influence of composition of raw wastewater on the efficiency of organic matter and nitrogen removal in multistage treatment wetlands has been examined. Commonly used indicators, like COD/BOD5 and BOD5/TN ratio, determining wastewater susceptibility to biodegradation in conventional treatment technologies were assessed. It was confirmed that multistage treatment wetland may be used for treatment of wastewater with high loads of organic pollutants and unfavorable composition for a biological treatment expressed by the ratio of COD/BOD5 and BOD5/TN equal to 2.7 and 0.7, respectively.
5
Content available Degradations of 2,4-dichlorophenol and polychlorinated biphenyls with zero valent iron under subcritical conditions. Importance of subcritical water oxidation
Oh S.-Y., Yoon M.-K.
Environment Protection Engineering
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2015
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Vol. 41, nr 3
73--86
EN
The abiotic transformations of 2,4-dichlorophenol (DCP) and polychlorinated biphenyls (PCBs) has been examined in the presence and of zero valent iron (Fe(0)) under subcritical conditions. It was found that the degradation of DCP was significantly enhanced, showing complete degradation of DCP in 3 h at 300 °C. Control experiments without Fe(0) indicated that the removal of DCP in the iron–water system was mostly due to subcritical water oxidation and that the enhancement of degradation in the presence of Fe(0) was less significant. Regardless of Fe(0), PCBs were rapidly decomposed, showing 93% destruction in 5 h at 300 °C. Product identification by gas chromatography-mass spectrometry (GC-MS) analysis showed that the reductive transformation of DCP and PCBs w Fe(0) existed under subcritical conditions. Our results suggest that subcritical water degradation may be a possible remediation option to treat DCP and PCBs in water and soil.
6
Content available remote Removal of iron, manganese and nitrogen compounds from underground waters with diverse physical and chemical characteristics
Kaleta J., Puszkarewicz A., Papciak D.
Environment Protection Engineering
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2007
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Vol. 33, nr 3
5-13
EN
Technological testing of underground waters collected in four localities in the Podkarpackie province and characterized by various physicochemical and chemical parameters is presented. In order to determine the optimum methods of pollutant removal, a number of unit processes were tested. In addition to traditional methods (aeration and filtration through sand bed), the catalytic masses proved to be effective for removing iron and manganese. In the case of water of low hardness, its alkalization with calcium appears to be a favourable process. The water of excessive hardness was softened by means of sodium hydroxide and in ion exchange process. The process of ion exchange on nitrate-selective anion exchanger appeared to be an effective way of removing nitrate ions.
PL
Przedstawiono badania technologiczne czterech wód wgłębnych o zróżnicowanych charakterystykach fizykochemicznych i chemicznych. Pochodziły one z różnych miejscowości województwa podkarpackiego. Aby określić optymalne metody ich oczyszczania, przetestowano różne procesy jednostkowe. Do usuwania żelaza i manganu oprócz tradycyjnego napowietrzania i filtracji przez złoże piaskowe skuteczne okazały się masy katalityczne. W przypadku wody o małej twardości korzystnym procesem była alkalizacja wapnem. Wodę z ponadnormatywną twardością zmiękczano wodorotlenkiem sodu i w procesie wymiany jonowej. W usuwaniu jonów azotanowych skuteczny okazał się proces wymiany jonowej na anionicie azotanoselektywnym.
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