This paper presents brief scientific information concerning the role of activated carbons (AC) in solving economic and ecological problems in our society. Data concerning synthesis and adsorption of new activated carbons, used for soil remediation and wastewater treatment are depicted. The findings of investigations aimed to compare the structure parameters and adsorption capacities of the newly obtained native activated carbons in comparison with several activated carbon marks known in the world are explained. It has been shown that currently synthesized activated carbons are competitive with foreign marks.
Disinfection by-products in drinking water distribution system of Bucharest City
Authors: IULIANA PAUN, FLORENTINA LAURA CHIRIAC, VASILE ION IANCU, FLORINELA PIRVU, MARCELA NICULESCU, NICOLETA VASILACHE
Chlorine is widely used in Romania and all over the world as a disinfectant of drinking water. During the chlorination process, the natural organic matter and inorganic ions react with chlorine forming disinfection by-products (DBPs). The predominant organic disinfection by-products are trihalomethanes (THMs) while the main inorganic disinfection by-products are chlorate and chlorite ions. THMs were detected in all investigated drinking water samples from Bucharest distribution system with values from 27.8 µg/L up to 75.1 µg/L, which are below the maximum concentration value admitted by Romanian drinking water legislation of 100 µg/L. Chloroform constitutes the major component in total THMs concentration found in all tested drinking water. Chlorate and chlorite anions were not detected in any of the investigated drinking water samples. THMs concentration was correlated with total organic carbon (TOC), residual chlorine and chloride.
Experimental method for the assessment and characterization of hazardous waste for
Long-term landfilling of hazardous waste should be a careful choice for any producer or generator of waste, as the behavior of the waste is different due to the physical-chemical conditions or following contact with other hazardous waste. In this study, the research undertaken was aimed at developing an experimental method for the assessment and characterization of hazardous waste for long-term storage. The method consists of the assessment of the behavior of heavy metals from waste, under different leaching conditions. To study various hazardous wastes, fly ash from the incineration of medical waste and slag from aluminum casting were chosen. Contact time, pH and redox potential are important parameters in the leaching process. The solubility of metals increases at pH values between 2 - 5 pH units and decreases at pH values between 6-12 pH units. The highest solubility of metals (As, Cr, Cu, Ni, Pb and Zn) in the tested waste was obtained after 48 hours at pH values between 2 - 5 pH units. Also, the values of the redox potential decrease almost linearly as the pH value increases. The developed method is a useful tool to assess the behavior of hazardous waste for long-term storage in landfills for this category of wastes.
Database with pollution sources and impact assessment in Bega and Timis rivers basins
This paper presents the ecological state of large areas of the Bega and Timis River basins, evaluated based on physical-chemical parameters of water samples in relation to the anthropogenic sources of pollution that occur along these rivers. For the monitoring program, twelve sampling points on the Bega and ten sampling points on the Timis were established in order to determine surface water quality. The potential sources of pollution were highlighted by a downstream vs. upstream analysis. Ecological conditions have been assessed taking into account the national legislation, which transposes the Water Framework Directive on promoting the sustainable use of water based on the long-term protection of water resources. The main sources of pollution were related to the discharges from localities and industry, but the current ecological status of the two water bodies analyzed is in a relatively good state.
Neonicotinoid insecticides as emerging contaminants in agricultural soil
Using an LC-MS-MS method for detection of 6 neonicotinoid insecticides (imidacloprid, dinotefuran, acetamiprid, clothianidin, thiamethoxam, nitenpyram) was developed a new performant extraction method based on sonication treatment of soil samples, which were previously dried, grounded, homogenized, sieved (2 mm) and subjected to the selective extraction process with acetonitrile. Then the obtained extracts were diluted with ultrapure water (ratio 1: 100) and subjected to purification by Strata C18 SPE extraction using cartridges loaded with 200 mg/6 mL of octa-dodecyl-silica adsorbent phase. The entire methodology allowed obtaining quantification limits at trace level that varied in the range 0.3-0.9 ng/g and recoveries between 71.4% and 109.6%. In the agricultural soil samples, taken from the lands cultivated with wheat, corn, sunflower, beans, located in Prahova and Giurgiu counties (Romania), only four neonicotinoids out of the total of six were quantified imidacloprid (0.38 ng/g-56.9 ng/g), acetamiprid (1.7-7.2 ng/g), thiamethoxam (1.05-6.7 ng/g), clothianidin (1.1-1.5 ng/g).
Environmental friendly flocculants for drinking water treatment
Authors: MIHAI STEFANESCU, LAURENTIU DINU, COSTEL BUMBAC
Coagulation-flocculation is an important step for the treatment of drinking water obtained from surface water sources. Various types of flocculants are available in the drinking water treatment market but only some of them are friendly for the environment due to their specific structure, which includes natural compounds. Starch-based flocculants are included in this category and some types of them were tested in our research work, in similar conditions with ordinary polyelectrolytes, in order to prove their efficiencies for turbidity and organic load (COD-Mn) removal. Five types of flocculants based on starch and acrylamide were tested during the classic treatment flow coagulation-flocculation-settling with aluminum sulfate as coagulant (1-10 mg Al/L) and 0.5-10 mL/L flocculant dose (0.2% active substance). Better removal efficiencies of turbidity and organic load (COD-Mn) in case of flocculants based on starch and acrylamide copolymers: over 99% for turbidity and ~90% for COD-Mn in case of 300-400 NTU initial surface water turbidity were registered.
Removal of crystal violet from aqueous solutions using an aerobic granular sludge system
Authors: COSTEL BUMBAC, ELENA ELISABETA MANEA, OLGA TIRON
The paper presents a set of comparative tests to evaluate the inhibitory effect of crystal violet on the respiration rate of microorganisms in conventional activated sludge and aerobic granular sludge. The tests were performed in similar conditions with the only variable of the type of sludge tested. The results emphasized that the aerobic granular sludge is less susceptible to the toxicity induced by crystal violet. The concentration of crystal violet that inhibits by 50% (CE50) the respiration rate of sludge microorganisms was determined to be, for the specific test conditions, 22.39 mg/L for the conventional activated sludge and 33.88 mg/L for the aerobic granular sludge. The paper also assesses the biodegradability potential of crystal violet from aqueous solution, in the presence of sodium acetate as co-substrate in a lab-scale sequential biological reactor with aerobic granular sludge. The experiments showed that most of the crystal violet is being initially absorbed in the matrix of the granules during the first minutes and subsequently is being removed with efficiencies above 95% within a treatment cycle of 8 hours.
The effects on human health of non-metallic, semimetals and heavy metals compounds generated by mining activities along the Serbian-Romanian border
This study makes an overview of the chemical pollutants, such as Be and its compounds, S and its compounds, P and its compounds, chlorine and chlorides, Na2O, K2O, Ti2O, CaO, MgO, CuO, SiO2, Al2O3, Fe2O3, Cr2O3, As2O3, that were registered in the mining operations areas in the cross-border region of Romania and Serbia. In addition, their possible effects on human health were discussed. Among the oxides, SiO2, Al2O3, Fe2O3 are the most abundant. From all these pollutants, the most health effects were registered for the compounds of P, S and Ca and the lowest number of health effects was recorded for chlorine. Among the human health effects that have been observed for these compounds, the most common are related to skin, eye and respiratory irritations in the case of acute exposure, but chronic exposure may lead to diseases affecting all the human organs. This information is important for population living in this area, due to air, water and soil pollution, but especially for professional exposure as workers in the mining operations are exposed to higher concentrations of pollutants and for long time.
Statistical evaluation of mineral water from Valcea County area through quality indices
Significant global consumption of mineral water is fueled by perceived therapeutic and medicinal qualities, cultural habits and taste. In Valcea County are several resorts with such mineral springs, which can have multiple benefits for human health. For this reason, it is important to investigate the level of their pollution with heavy metals. The aim of this study was to detect the level of heavy metals present in the studied mineral waters, to evaluate the analytical results using environmental statistical indices, and to compare the results with the legislation in force.
Thus, mineral water samples were collected from three resorts of Valcea County (Baile Olanesti, Calimanesti-Caciulata and Baile Govora). The analyzed metals (Cd, Cr, Fe, Mn, Ni, Pb and Zn) were determined with ICP-EOS technique and the obtained results were compared to enforce legislation. Statistical analyses were applied and two environmental statistical indices, namely the metal distribution coefficient (kd) and the total environmental risk index (IER) were evaluated.
The calculated values for the total environmental risk index were below 0 (IER ≤ 0), which indicates that none of the studied water samples pose a risk for the environment.
The low values of the distribution coefficient indicate a low ability to bind the metal in particles and therefore, insignificant toxicity. The distribution coefficient calculated for zinc (1.12 L/kg) and lead (0.68 L/kg) in Baile Olanesti indicates a high capacity of the metals to bind in particles, compared to other metals.
Assessment of soil quality in the area of casting parts waste storage specific to cast iron activities
Authors: BOGDAN ADRIAN STANESCU, ADRIANA CUCIUREANU
The purpose of this paper was to present an environmental assessment specific to a case study with reference to the storage of sand waste from a cast iron foundry, a factory with a long period of operation located in Transylvania, Romania. The environmental assessment started from the need to achieve compliant conditions for long-term storage of waste specific to cast iron casting parts activities. The activities performed in the project were carried out in stages and in parallel with the activities of sand waste valorification from the non-compliant deposit. The collaboration of the factory owner with the local environmental authorities was able to effectively materialize the objectives of the soil evaluation and facilitated the obtaining conditions for new compliant deposit construction. The evaluation of the soil quality was performed in areas where the deposited material, respectively the sand waste from the casting of the cast iron was already valorificated and, in that case, the access to the soil layer was facilitated. Thirty soil samples and a control sample were analyzed and interpretation of the results was performed in corelation to specific legislation. The conclusions of the study were provided to the beneficiary and, also to the environmental authorities in order to authorize future activities (capitalization of the remaining waste, arrangement of a new landfill).