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Ihos M.,National Research and Development Institute for Industrial Ecology ECOIND | Lazau C.,Romanian National Institute for Research and Development in Electrochemistry and Condensed Matter | Manea F.,Polytechnic University of Timisoara
Environmental Engineering and Management Journal | Year: 2013

In the last years many papers have reported about the occurrence of the pharmaceuticals in the surface waters and their undesirable effects upon the aquatic life. Most of pharmaceuticals pass through the wastewater treatment plants unchanged because they are biorefractory compounds and as a result they enter the water bodies. Therefore, it is necessary to improve the biodegradability of pharmaceuticals effluents (PhEs) before their discharge in the sewerage systems. The aim of this paper was the use of Dimensionally Stable Anodes (DSA) to improve the biodegradability of PhE containing diclofenac (DCF) as pharmaceutically active compound. The refractory character of PhE was found based on biochemical oxygen demand (BOD5)/chemical oxygen demand (COD) ratio (R) value of 0.05. The DSA electrodes were prepared by thermal decomposition of the appropriate precursors and had the composition Ti/RuO2-TiO2. Besides electrochemical experiments, photoassisted electrochemical, and combined photocatalytic and electrochemical experiments were carried out. The three DSA-based methods were effective for the biodegradability improvement of the PhE. The best result for R was 0.62, which was obtained for the combined photocatalytic and electrochemical method. These promising results regarding the biodegradability improvement of PhE should constitute the base for future detailed researches involving the DSA use for the wastewater treatment.

Nitoi I.,National Research and Development Institute for Industrial Ecology ECOIND | Oncescu T.,University of Bucharest | Oancea P.,University of Bucharest
Journal of Industrial and Engineering Chemistry | Year: 2013

Because application of classical treatment methods cannot allow an easily Lindane (gamma 1α,2α,3β,4α,5α,6β-hexachlorocyclohexane) degradation, development of more powerful water treatment techniques, like advanced oxidation processes (AOPs), was necessary. The degradation of lindane (γ-HCH) has been studied using the photo-Fenton reaction. The degradation kinetics under irradiation was optimized in respect to H2O2 concentration and Fe2+ concentration at a constant lindane concentration. The degradation rate follows pseudo-first order kinetics with respect to lindane and organic clorine mineralization. Application of photo-Fenton system also assures total organic carbon removal with 95% efficiency at 2h irradiation. The possible pathways of lindane photodegradation is also proposed. © 2012 The Korean Society of Industrial and Engineering Chemistry.

Vasile G.,National Research and Development Institute for Industrial Ecology ECOIND | Tanase I.Gh.,University of Bucharest
Journal of Environmental Protection and Ecology | Year: 2010

The aim of the study was to estimate the mobile forms of Cd, Ni and Pb from a certified reference material BCR-483, which is a sewage sludge amended soil. In the study were tested 4 extraction procedures, 2 of them were used by the BCR European Commission. The BCR certificate of analysis contains certified value for mobile fraction of Cd, Ni and Pb extracted with 2 different solutions: 0.05 M EDTA and 0.43 M CH3COOH. The mobility tests include not only the values obtained with these 2 methods, but also the values obtained with another 2 single chemical extraction procedures, which used the following extractants: a buffer solution at pH = 7.3 of 0.005 M DTPA, 0.1 M TEA and 0.01 M CaCl 2, a mixture of 0.01 M EDTA and 1 M NH4OAc at pH = 7. The contents of Cd, Ni and Pb were analysed with flame atomic absorption spectrometry (FAAS). The experimental tests applied to BCR-483 with BCR methods proved that both extraction and determination procedures can provide valuable data, comparable with the certified values for exchangeable fraction of Cd, Ni and Pb. The data obtained with the other 2 methods confirm the fact that the extractant type is very important in evaluating the mobility fraction of the metals (different concentrations of metallic elements obtained with different extraction procedures).

Bumbac C.,National Research and Development Institute for Industrial Ecology ECOIND | Bumbac C.,Polytechnic University of Bucharest | Diacu E.,Polytechnic University of Bucharest
Revista de Chimie | Year: 2012

The aim of this study was to assess the feasibility of coupling chemical oxidation (active phase) with natural attenuation (passive phase) for diesel contaminated soils remediation and also, to evaluate the impact of natural organic matter in the soil matrix on the remediation efficiency. For that, two soil types with different organic matter content (TOC) were used - one sandy soil (18g/kg d.w.) and one clayey soil (39 g/kg d.w.) spiked with 6g/kg d. w. diesel fuel. As oxidants, sodium persulfate and sodium percarbonate were evaluated as active treatment step in soil remediation. Thus, four experimental and two control variants were conducted in batch tests - laboratory conditions, and monitored regularly for 11 months. The results indicated that using sodium persulfate as oxidant, for both sandy and clayey soil, lead to C8-C40 removal efficiencies of up to 53% and respectively 68% during active treatment and global removal efficiencies of 95 and 93% respectively. It must be noted that sodium persulfate affected (reversibly) the soil microbial populations; a lag period of approximately two months characterized by small removal efficiencies (1-3%) was observed. Using percarbonate as an active treatment phase lead to C8-C40 removal efficiencies of 62% for sandy soil and 34% for clayey soil and global removal efficiencies of 85 and 96% respectively. However, in case of percarbonate, no clear boundary can be set between chemical and biological treatment as it can act both as oxidant and as an oxygen source for aerobic biological processes. In case of control samples, representing natural attenuation, slow removal rates were observed during the first 4 months, removal efficiencies of only 7 and 23% being recorded. To conclude, combining chemical oxidation and bioremediation is a viable option for dealing with diesel contaminated soils, where bioremediation alone would not be time-effective and chemical oxidation alone would not be cost-efficient.

Tricolici O.,National Research and Development Institute for Industrial Ecology ECOIND | Bumbac C.,National Research and Development Institute for Industrial Ecology ECOIND | Patroescu V.,National Research and Development Institute for Industrial Ecology ECOIND | Postolache C.,University of Bucharest
Water Science and Technology | Year: 2014

A microalgae-bacteria system was used for dairy industry wastewater treatment in sequenced batch mode in a photobioreactor. The research investigated the influence of two light intensities: 360 and 820 μmol m -2 s-1 on treatment performances, microalgal cell recovery and dynamics of the protozoan community. Results showed that the light intensity of 360 μmol m-2 s-1 was found to be insufficient to support photosynthetic activity after the increase of bacterial biomass leading to the decrease of organic matter and ammonium removal efficiencies from 95 to 78% and 95 to 41%, respectively. Maximum microalgal cells recovery was about 63%. Continuous modification in the protozoan community was also noticed during this test. Increasing the light intensity to 820 μmol m-2 s-1 led to better microalgal cells recovery (up to 88%) and improved treatment performances. However, the decrease of protozoan richness to small flagellates and free-swimming ciliates was noticed. Moreover, the developed protozoan trophic network was found to be different from that identified in the conventional activated sludge system. The study emphasized that high increase of bacterial biomass promoted in nutrient- and organic matter-rich wastewater can strongly affect the treatment performances as a result of the shadow effect produced on the photoautotrophic microalgae aggregates. © IWA Publishing 2014.

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