Carmen Teodosiu

Catalytic wet peroxide oxidation of phenol over Fe-exchanged pillared beidellite

This study presents an evaluation of the catalytic performances of a Fe-exchanged Al-pillared synthetic beidellite for the wet hydrogen peroxide oxidation of phenolic aqueous wastes. The catalyst was prepared by a cation doping technique, its properties being determined by DRX, BET and chemical analysis techniques. All the tests were performed on a laboratory scale set-up. Important factors affecting catalyst activity and phenol removal efficiencies were studied, i.e. the effect of pH, temperature, catalyst concentration and the stability of the catalyst. The experimental results indicate that the use of this catalyst allows a total elimination of phenol and a significant removal of chemical oxygen demand, without significant leaching of Fe ions. Thus, considering the lowest Fe concentrations in solution after oxidation, at pH=5, 50 degrees C, and 180 min. COD removal efficiency of 87.9% was obtained. It was also observed that by using this catalyst, it is possible to extend the range of pH values for which Fenton-type oxidations can occur.

Bioaccumulation of heavy metals in marine organisms from the Romanian sector of the Black Sea

The aim of this research was to study the accumulation of heavy metals (cadmium - Cd, lead - Pb, chromium - Cr, nickel - Ni, and copper - Cu) from water and sediments into living tissues of relevant marine species from different trophic levels of a food web, representative for shallow waters of the Romanian Black Sea Coast where the main anthropogenic impacts exist. The heavy metals concentrations were analysed by using an Atomic Absorption Spectrometer with graphite furnace, the results being further used to calculate the bioconcentration factors for a few key taxa like green and red algae, molluscs and fishes. Seven sampling sites influenced by anthropogenic pollution sources (municipal wastewater treatment plants and diffuse sources) were considered and a total of 300 samples were analysed for the period 2011-2012, this being the first unitary study for the Romanian Black Sea marine ecosystem. In 2011 and 2012 there were no significant differences between the sampling areas considering the heavy metals concentrations in water. For the sediments significant differences were observed between sampling sites for some heavy metals, namely Pb in 2011 and Pb, Cu and Cd in 2012, the highest concentrations being registered in the southern sector of the Romanian Black Sea shore, where the anthropogenic pollution sources are represented by the harbour and wastewater treatment plants. The values of the bioaccumulation factors (BCFsed) shows that algae are good accumulators for Cu>Pb>Ni>Cr>Cd, in comparison with BCFwater where the order of heavy metal accumulation was different: Cr>Ni>Pb>Cd>Cu. Molluscs have higher bioconcentration factors for Cu and Cd for sediments and for Cu and Ni for water. Rapana venosa accumulated more Cd and Cu. For fishes, Pb, Cu and Ni had the highest values in the tissues of benthonic species Mullus barbatus. In bivalve molluscs and fishes, in the majority of cases, there were not recorded exceeding mean concentrations as compared to the maximum allowed concentrations for Cd and Pb.

Biosorption of lead ions from aqueous effluents by rapeseed biomass

Lead, as well as other heavy metals, is regarded as priority pollutant due to its non-biodegradability, toxicity and persistence in the environment. In this study, rapeseed biomass was used in the biosorption of Pb(II) ions in batch and dynamic conditions, as well as with tests for industrial wastewater. The influence of initial concentration (5-250mg/L), pH and contact time (0.5-6h) was investigated. The kinetic data modeling resulted in good correlations with the pseudo-second order and intraparticle diffusion models. The maximum sorption capacities of Pb(II) were 18.35, 21.29 and 22.7mg/L at 4, 20 and 50°C, respectively. Thermodynamic parameters indicated the spontaneity and endothermic nature of lead biosorption on rapeseed biomass. The biosorption mechanism involves both physical and chemical interactions. The breakthrough curves at 50 and 100mg/L were determined and evaluated under dynamic conditions. The breakthrough time lowered with increasing the influent Pb(II) concentration. The experimental data obtained from fixed-bed column tests were well fitted by Thomas and Yoon-Nelson models. The calculated sorption capacities were in good agreement with the uptake capacity of Langmuir model. The applicability of rapeseed to be used as a sorbent for Pb(II) ions from real wastewater was tested, and Pb(II) removal efficiency of 94.47% was obtained.

Environmental impact and risk quantification based on selected water quality indicators

Environmental assessments are often approached in an integrated manner, taking into consideration the decision-making processes, the stakeholders’ roles and the preservation of environmental components and human health. An environmental impact and risk assessment (EIRA) methodology could respond to the new challenges in water resources management such as those related to industrial/agricultural development and urbanization. Romania is a country that still faces problems in terms of integrated water resources management implementation, due to some industrial/agricultural activities that exceed water quality discharge limits and the influence of diffuse pollution sources over surface waters. This study presents the development and implementation of a methodology for the quantitative assessment of environmental impact and associated risk of the economic activities from four counties from the northeastern part of Romania (Botosani, Iasi, Vaslui and Galati counties) within the Prut river catchment. This methodology was developed for river basin evaluations by using representative quality indicators for the case of surface water pollution, i.e. biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), ammonia (NH4+) and detergents, with reference to the maximum concentrations allowed by the national standards. The monthly water samples from 112 wastewater discharging agents (industry, agriculture, wastewater treatment plants, and small and medium enterprises) were analyzed, and the yearly average values of these five indicators were considered in the integrated assessment procedure. The results revealed that there are consistent environmental impacts and risks within Prut river basin, these being mainly produced by industry. The integrated impact and risk assessment methodology presents the advantages of rapidity and the potential for improving the decision-making process.

Integrated Sono-Fenton ultrafiltration process for 4-chlorophenol removal from aqueous effluents: assessment of operational parameters (Part 1)

AbstractAdvanced oxidation processes (AOPs) and membrane separation processes are successfully used in the final stages of wastewater treatment for recycling and reuse purposes. This research proposes a new two stage process including in the first step a homogeneous Sono-Fenton process (as an AOP), coupled with ultrafiltration (UF), as a cleaner and safer alternative for advanced wastewater treatment, designed specially to enhance the removal of priority organic pollutants which are difficult to eliminate by means of conventional treatments. The aim of this study is to analyze experimentally the performances of an integrated ultrasonication-UF process for the removal of 4-chlorophenol (4CP) (as a model-pollutant for priority organic compounds from wastewaters), both from the removal efficiency (expressed as phenolic concentration and chemical oxygen demand reduction) and the energy consumption point of view. The most important factors with influence on both stages of the proposed process, such as acoustic amplitude, power density, and operating mode for the Sono-Fenton process and pressure, time, operating mode, and cleaning operations for the UF stage, were assessed in this paper (Part 1). The experimental results indicate that the process can be applied for such aqueous effluents, in laboratory scale equipments and represent the basis for modeling the process steps and scale-up of different process arrangements (Cailean et al. (2014): “Integrated Sono-Fenton UF Process for 4CP Removal from Aqueous Effluents: Process Modeling and Simulation (Part 2)”), with the purpose to analyze and control such a process, under various conditions and to understand better its advantages and disadvantages.

Advances in preconcentration/removal of environmentally relevant heavy metal ions from water and wastewater by sorbents based on polyurethane foam

Abstract An increased interest in the removal of heavy metal ions from aqueous media is encountered due to their toxicity and negative impacts on ecosystems, human health and economic activities. A variety of processes may be used for the removal of heavy metal ions from water and wastewater, such as chemical precipitation, ion exchange, adsorption, membrane processes, etc. However, the removal efficiencies of heavy metals by adsorption depend on several factors such as initial loads of heavy metals in the influent, purpose of treatment (drinking/industrial water production, wastewater treatment for disposal or recycling), costs of the overall process, and properties and conditions for regeneration of the sorbent materials. In this context, the use of polyurethane foams as heavy metal ion sorbents is of a special interest because they provide versatile applications in heavy metal effluent management. This study reviews relevant published researches that are concerned with new sorbents based on polyurethane foams applied in batch and dynamic systems for separation and/or preconcentration of heavy metal ions in environmental aqueous media. This review is divided into the following sections: synthesis of polyurethane foams; physical and chemical properties of polyurethane foams; preconcentration of pollutant metal ions from environmental aqueous media by different types of polyurethane foam (untreated, loaded, reacted and composite polyurethane foams); the applicability of sorbents based on polyurethane foams for water and wastewater treatment; comparison of sorbents based on polyurethane foam with other sorbents for heavy metal ion removal.

Assessment of the waste electrical and electronic equipment management systems profile and sustainability in developed and developing European Union countries

The assessment of waste management systems for electrical and electronic equipment (WEEE) from developed economies (Germany, Sweden and Italy) and developing countries (Romania and Bulgaria), is discussed covering the period 2007-2014. The WEEE management systems profiles are depicted by indicators correlated to WEEE life cycle stages: collection, transportation and treatment. The sustainability of national WEEE management systems in terms of greenhouse gas emissions is presented, together with the greenhouse gas efficiency indicator that underlines the efficiency of WEEE treatment options. In the countries comparisons, the key elements are: robust versus fragile economies, the overall waste management performance and the existence/development of suitable management practices on WEEE. Over the life cycle perspective, developed economies (Germany, Sweden and Italy) manage one order of magnitude higher quantities of WEEE compared to developing countries (Romania and Bulgaria). Although prevention and reduction measures are encouraged, all WEEE quantities were larger in 2013, than in 2007. In 2007-2014, developed economies exceed the annual European collection target of 4 kg WEEE/capita, while collection is still difficult in developing countries. If collection rates are estimated in relationship with products placed on market, than similar values are registered in Sweden and Bulgaria, followed by Germany and Italy and lastly Romania. WEEE transportation shows different patterns among countries, with Italy as the greatest exporter (in 2014), while Sweden treats the WEEE nationally. WEEE reuse is a common practice in Germany, Sweden (from 2009) and Bulgaria (from 2011). By 2014, recycling was the most preferred WEEE treatment option, with the same kind of rates performance, over 80%, irrespective of the country, with efforts in each of the countries in developing special collection points, recycling facilities and support instruments. The national total and the recycling carbon footprints of WEEE are lower in 2013 than in 2007 for each country, the order in reducing the environmental impacts being: Germany, Italy, Sweden, Bulgaria and Romania. The negative values indicate savings in greenhouse gas emissions. In 2013, the GHG efficiency shows no differences of the WEEE management in the developed and developing countries.

Toxic metals biomonitoring based on prey-predator interactions and environmental forensics techniques: A study at the Romanian-Ukraine cross border of the Black Sea

Marine cross-border areas are ideal for monitoring pollutants so as to increase ecosystems protection. This study was conducted at the Romanian-Ukraine border of the Black Sea to reveal evidence of contamination with toxic metals based on biomonitoring of: cadmium, lead, total chromium, nickel and copper at different water depths and prey-predator interactions, combined with environmental forensics techniques of biological sampling and separation in witnesses size groups. The species used were Mytilus galloprovincialis L. and Rapana venosa V. collected at 17.5m, 28m and 35m depth. An atomic absorption spectrometer with a high-resolution continuum source and graphite furnace was used for toxic metals quantification in various samples: sediments, soft tissue, stomach content, muscular leg, hepatopancreas. The best sample type, based on the pathology of metal location and bioaccumulation, is the hepatopancreas from R. venosa that proved a significant decrease of cadmium and lead at lower depths.

Occurrence and Associated Risk of Nitrates/Nitrites in the Ground Waters from the North-Eastern Part of Romania

The presence of nitrates/nitrites at high concentrations in groundwater resources represents an important issue for human health and a great environmental risk. The purpose of this study is to present an analysis of data collected by monitoring nitrates/nitrites concentrations in six counties from the NorthEastern region of Romania and to asses the risk associated with their presence. The research was conducted over 1 year (2007), taking samples from drinking water and groundwater resources (4–5 sources from every county). This study has been accomplished with the support from “Transports, Constructions and Tourism Minister” network, from the North-Eastern region of Romania. An overview of the risk zones has been made and suggestions over the necessary water treatments are presented.The secondary objective of this study was also the creation of a monitoring data base of nitrites/nitrates, which will contribute into taking the adequate integrated pollution prevention and control measures.

Sequencing batch biosorption of micropollutants from aqueous effluents by rapeseed waste: Experimental assessment and statistical modelling

Rapeseed (RS) waste was used for sequential biosorption from aqueous solutions of two target micropollutants: lead ions and Reactive blue 19 (Rb19) dye, through an integrated approach, combining experimental assessment and statistical modeling. In both cases of sequential biosorption, a pseudo-second order kinetic model fitted the biosorption data well. Intraparticle diffusion proved to be the rate-limiting step in the sequential retention of both micropollutants. A selective desorption of metal ions and anionic dye at pH 2.5 and 10.5, respectively was observed. The quadratic models generated by response surface methodology (RSM) adequately described the sequential biosorption process and the desorption process, respectively. XPS and FTIR analysis indicated the mechanisms involved in the retention of target pollutants.