INDOOR AND OUTDOOR VOLATILE ORGANIC COMPOUNDS MONITORING IN A MULTI-STOREY CAR PARK

A VOC monitoring was carried out inside and outside a multi-storey car park in order to characterize the emission profile of vehicular traffic source in an indoor environment. BTEX, and in particular toluene, were the most abundant compounds in all monitored sites, with different compositions between indoor parking areas and outdoor sites. The motor vehicle exhaust and gasoline vapor emission in these enclosed parking garages were characterized by diffusion or degradation phenomena different from those that occur in urban areas as the BTEX compositions, their ratios and their reactivity with OH and with NO3 radicals demonstrate. In detail, xylenes/BTEX and ethylbenzene/BTEX ratios in indoor environments were twice than those in outdoor ones, while toluene/BTEX ratio resulted half than that obtained in outdoor sites. In this work, BTEX concentrations depend both on number of vehicles, on vehicular characteristics (age, emission control technology, fuel quality etc.) and on factors related to the characteristics of parking facilities (volume of the monitored areas, indoor or open facilities, ventilation systems, size and maintenance). However, it was found that the external contribution (intrusion of pollutants from outdoor and from the other floors) and the influence of mixing air (removal of pollutants by ventilation and air exchange) on BTEX concentrations were not significant if inside the multi-storey car park there was a strong source (due to the number of vehicles) such happened in the first and second floors and along the ramp that connected them.

RESEARCHES ABOUT THE CHARACTERIZATION OF METALLURGICAL SLAGS FOR LANDFILLED WASTES MINIMIZATION

ENERGY CONSUMPTION IN DRYING OF FROZEN SPRUCE WOOD

Drying wood requires a significant amount of energy. This includes both thermal energy, necessary to heat-up wood, evaporate the water inside it and cover the insulation and vent losses, as well as electric energy consumed to force air circulation through the stacks. When wood is frozen, both energy consumptions increase; on one hand because frozen water requires a supplementary heat for transformation into liquid and then into gaseous state, and on the other hand, because of the low initial temperature of wood that also increases the drying time. Frozen spruce samples, as well as unfrozen control samples were kilndried in a conventional kiln within the same batch. The moisture content and temperature inside the samples was monitored throughout the process. Based on the measured drying time, the energy consumption was estimated to be up to 40% higher in the case of drying wood from frozen state. The paper concludes with some recommendations of interest for the industrial practice regarding which situation should be preferred and adopted when planning timber storage & drying in wintertime.

COMPARISON OF FAAS AND XRF PERFORMANCE FOR METAL MONITORING IN BROWNFIELDS

Flame atomic absorption spectrometry (FAAS) and X-ray fluorescence spectrometry (XRF) were used as investigation techniques in the assessment of soils contaminated with metals such as Pb, Cu and Zn. The investigation focused on the comparability of the concentrations determined by the two methods, in order to identify the most suitable approach for Pb, Cu and Zn quantification, with respect to metal monitoring in brownfields. Generally, the concentrations obtained through FAAS were comparable with those given by XRF, indicating the suitability of both techniques for contamination monitoring. FAAS proved to be a precise method for the quantification of metal concentrations in soil and had lower limit of detection (LOD) and limit of quantification (LOQ), but was more laborious and required sample processing, while XRF was a faster and practical tool for the metal monitoring in the investigated brownfield.

SUSCEPTIBILITY OF THERMOPLASTIC BASED COMPOSITES TO DEGRADATION BY MICROORGANISMS

In the present study, several selected formulations based on recycled (rPP) or virgin polyolefins (vPP) and lignocelluloses were prepared and subjected to microorganism attack. Biodegradation tests were performed with microbial strains belonging to fungal genera, like Aspergillus, Penicillium and Fusarium. The initiation of biodegradation was demonstrated by Scanning Electron Microscope (SEM) micrographs showing the colonization of surface samples by microbial strains. The crystallinity of composites calculated based on Differential Scanning Calorimetry (DSC) curves evidenced some fluctuations as effect of biodegradation process. The most significant increase of crystallinity was obtained for v(PP)-wood samples, from 35.4% (sample without microbial contact) to 58.84% (sample incubated with Fusarium), 47.97 % (sample incubated with Penicillium) and 51.37 % (incubation with Aspergillus), respectively. The microbial activity upon rPP based composites did not induce significantly changes of crystallinity. Fourier Transform Infrared Analysis (FTIR) showed the increase of the peak corresponding to the carbonyl group at 1740 cm-1 that indicated the oxidative reactions in the chain in polymer matrix. Also there were observed new bands at 1647-1651, 1547 cm-1 assigned to protein materials from microorganisms, and at 1046-1450 cm-1 assigned to polysaccharides. The results showed that the some polymeric composites suffered a slowly biodegradative process, the process depending on polymer characteristics (structure, complexity, composition) and microorganism ability. From the obtained results, it can be concluded that Aspergillus strain is active in the biodegradation of tested composites.

INFLUENCE OF FIREBALL COUPLED WITH A TOXIC PUFF RELEASE ACCIDENT CONDITION ON CONSEQUENCES AND POSSIBLE DOMINO EFFECT OCCURRENCE FOR TWO RISKY NEIGHBORING CHEMICAL PLANTS

A study of a classical BLEVE fireball model associated with a toxic Puff release one was made in order to evaluate the influence of accident conjugate conditions on its consequences in two neighbouring industrial plants. The possible occurrence of the Domino effect is also exemplified for the approached chemical complex including two sensitive neighbouring chemical plants including tubular reactors for catalytic oxidation of butane to maleic anhydride and catalytic hydrogenation of nitrobenzene to aniline. The analysis is estimating the effects of accident condition severity on accident consequences at different distances from source. Evaluation of the individual and joint probability indices of human causalities reveals the importance of parameters influencing the accident magnitude, such as plant capacity, operating conditions, plant location and stock quantities of hazardous substances in intermediate storage vessels.

INTEGRATION LEVEL OF ENVIRONMENTAL ISSUES INTO THE COMPANY STRATEGIES. CASE STUDY

As a result of the stakeholders’ growing pressure and global environmental challenges, many corporations across the world have to integrate environmental issues into their strategic decision-making system and operations function. The objective of this paper is to identify to what extent the activities regarding the environmental issues are successfully integrated into general and functional strategies of a multinational company from production field. We have analyzed these aspects using the model proposed by Paul de Baker and data were collected by applying questionnaires. The results show that the highest score was obtained in the case of production strategy, while integration of environmental issues into human resource strategy is the biggest challenge that an organization has to face. The value of global diagnosis points out an average concern for integrating the environmental aspects in the overall company strategy, fact that is also confirmed by the scores obtained for each dimension and per total.

CRITICAL VARIETY UNDER PARAMETRIC UNCERTAINTY IN AN INDUSTRIAL REACTOR FOR BENZENE CATALYTIC OXIDATION

Safe operation of highly thermally sensitive industrial reactors is still considered a major issue in chemical engineering practice. The problem becomes even more stringent when highly exothermic reactions are conducted under randomly fluctuating operating variables, and especially when the set-point is located in a close vicinity of the runaway boundaries for increasing the reactor productivity. This study is aiming to derive the runaway boundaries and their associated region of confidence in the operating variable space for such a highly risky fixed-bed catalytic reactor by applying a very effective Morbidelli and Varma generalized criterion. In a subsequent step of the risk assessment, such a critical variety is approximated by adequate simple multi-variate correlations of the control variable safety limits, usually of mixed logarithmic-polynomial form, from bringing together all critical curves separately derived in parametric planes. Such simple correlations allow quickly evaluating the associated variance of the critical limits to be further used in the reactor multi-objective robust optimization step. Exemplification is made for an industrial fixed-bed multi-tubular reactor for benzene catalytic oxidation to maleic anhydride in vapour-phase by using a more detailed kinetic model.

NOVEL BIOACTIVE AND BIODEGRADABLE MATERIALS FOR MEDICAL APPLICATIONS

Poly(vinyl chloride) (PVC) is the most widely used material for the production of medical devices such as intravenous fluid bags and tubing, enteral feeding, dialysis equipment and catheters. Despite of their numerous advantages, the plastic medical devices are non biodegradable and prone to microbial colonization causing biofilm associated infections which are difficult to treat and tend to chronicisation. A possible solution to surpass these limitations could be the fabrication of new biodegradable polymeric materials with optimized biocompatibility and antimicrobial properties. In this regard, biodegradable polymeric materials, such as poly(ε-caprolactone) (PCL), poly(DL-lactic acid) (PLA) etc. have been considered the most desirable solution from the environment management point of view. In this paper, Alg(1%)Zn, Alg(2%)Zn, Alg(3%)Zn compounds were obtained from sodium alginate (AlgNa) crosslinked with ZnCl2. Antimicrobial activity of the AlgZn compounds was assessed by the microdilutions and the diffusion methods, towards Gram-positive and Gram-negative bacterial strains (reference and clinical isolates). The Alg(3%)Zn compound was selected as antimicrobial agent to obtain the biocomposites encoded: PLA/PCL/AlgZn0.1 and PLA/PCL/AlgZn0.3. The PLA/PCL sample was used as control. Antibiofilm activity against Staphylococcus xylosus, cytotoxic effect on mammalian cells and thermal analysis by DSC were investigated for the obtained biocomposites. The obtained results show that the addition of the Alg(3%)Zn compound in the biocomposites decreased the glass transition temperature as well as the degree of crystallinity both of the PCL and PLA components in samples. Although the results suggest that the biocomposites containing Alg(3%)Zn did not inhibit the staphylococcal colonization and mature biofilm formation, the high degree of biocompatibility of blends leads to conclusion that these materials could be used for the development of novel bioactive and biodegradable polymeric materials with medical applications.

SELENIUM IN THE ENVIRONMENT: ESSENTIAL OR TOXIC TO HUMAN HEALTH?

Selenium (Se) is a mineral of fundamental importance for human health. Se status in general population is very important due to its remarkable benefits to the human body: antioxidant, hormonal regulator, anti-carcinogen. At the same time Se can be toxic leaving a narrow optimal range for optimal intake. Both excess and deficit are known to cause a wide range of clinical manifestations. Even though a large body of evidence provides vast information about Se, the exact molecular mechanisms of its effect in physiologic and pathologic conditions remain unknown. The individual Se requirements are still in debate, as there is a marked difference in the distribution of serum selenium levels of individuals in the general population. The general opinion is that in the last 20 years the requirements were higher than the international dietary reference values for selenium. There are several issues related to environmental Se and human health: the link between Se status in soil-plants-human body (plants extract Se from soil incidentally and the type of soil influences the Se content in food), necessity of Se supplementation in general population, therapeutic effects of Se in various diseases. The lack of suitable frameworks in general population represents an issue for the assessment of health/economic impact of Se deficiency. Further researches are needed in: agriculture, economics and health in order to determine the costs/benefits relationship and monitor the health outcomes of Se supplementation.