Comparison between absorption and biological activity on the efficiency of the biotrickling filtration of gaseous streams containing ammonia

Polluted air streams can be purified using biological treatments such as biotrickling filtration, which is one of the most widely accepted techniques successfully tuned to treat a wide variety of exhausted gaseous streams coming from a series of industrial sectors such as food processing, flavor manufacturers, rendering, and composting. Since the degradation of a pollutant occurs at standard pressure and temperature, biotrickling filtration, whether compared with other more energy-demanding chemical-physical processes of abatement (such as scrubbing, catalytic oxidation, regenerative adsorption, incineration, advanced oxidation processes, etc.), represents a very high energy-efficient technology. Moreover, as an additional advantage, biodegradation offers the possibility of a complete mineralization of the polluting agents. In this work, biotrickling filtration has been considered in order to explore its efficiency with respect to the abatement of ammonia (which is a highly water-soluble compound). Moreover, a complete mathematical model has been developed in order to describe the dynamics of both absorption and biological activities which are the two dominant phenomena occurring into these systems. The results obtained in this work have shown that the absorption phenomenon is very important in order to define the global removal efficiency of ammonia from the gaseous stream (particularly, 44% of the ammonia is abated by water absorption). Moreover, it has been demonstrated (through the comparison between experimental results and theoretical simulations) that the action of bacteria, which enhance the rate of ammonia transfer to the liquid phase, can be modeled through a simple Michaelis-Menten relationship.

     

Atrazine,chlorpyrifos, and iprodione effect on the biodiversity of bacteria,actinomycetes, and fungi in a pilot biopurification system with a green cover

The use of biopurification systems can mitigate the effects of pesticide contamination on farms. The primary aim of this study was to evaluate the effect of pesticide dissipation on microbial communities in a pilot biopurification system. The pesticide dissipation of atrazine, chlorpyrifos and iprodione (35 mg kg^?1 active ingredient [a.i.]) and biological activity were determined for 40 days. The microbial communities (bacteria, actinomycetes and fungi) were analyzed using denaturing gradient gel electrophoresis (DGGE). In general, pesticide dissipation was the highest by day 5 and reached 95%. The pesticides did not affect biological activity during the experiment. The structure of the actinomycete and bacterial communities in the rhizosphere was more stable during the evaluation than that in the communities in the control without pesticides. The rhizosphere fungal communities, detected using DGGE, showed small and transitory shifts with time. To conclude, rhizosphere microbial communities were not affected during pesticide dissipation in a pilot biopurification system.     

Novel approach for in situ recovery of cobalt oxalate from spent lithium-ion batteries using tartaric acid and hydrogen peroxide

Journal of Material Cycles and Waste Management - Recycling Co resource from spent lithium-ion batteries (LIBs) is significant for Co deficiency and environmental protection. A novel approach for...     

Study of odor compounds in gaseous effluents generated during production of poultry feather and viscera meal using headspace solid phase microextraction

This work reports the screening and characterization of odor compounds in gaseous effluents generated during the production of poultry feather and viscera meal, the by-products of the poultry meat industry. Chemical analysis was carried out by solid phase microextraction in the headspace (HS-SPME) mode. Exhaust air of thermal processing of poultry feather and viscera were sampled online from a bench-scale digester, condensed, and collected in sampling flasks. Both volatile and semivolatile organic compounds present in the condensed gases were extracted under agitation at constant temperature. The extracts were analyzed with a gas chromatograph coupled to a mass spectrometric detector (GC/MSD). The identification of compounds was carried out by comparing the mass spectra obtained with those from the Wiley library and quantification was accomplished through authentic analytical standards. For the determination of the best extraction conditions and analysis, extraction fibers of different coatings and polarities were tested: divinylbenzene/carboxen/polydimethyilsiloxane (DVB/CAR/PDMS), carbowax/divinylbenzene (CW/DVB), and polydimethylsiloxane (PDMS) and chromatography columns of different polarities: DB-WAX (polar) and DB-5 (nonpolar). The best extraction conditions and analysis of the compounds of interest were obtained by the use of the SPME fiber with DVB/CAR/PDMS coating and analysis by GC/MSD with polar capillary column. Several carboxylic acids were identified, as well as mercaptans, amines, and aldehydes of great environmental importance.     

An air quality balance index estimating the total amount of air pollutants at ground level

A new index named Air Quality Balance Index (AQBI), which is able to characterise the amount of pollution level in a selected area, is proposed. This index is a function of the ratios between pollutant concentration values and their standards; it aims at identifying all situations in which there is a possible environmental risk even when several pollutants are below their limit values but air quality is reduced. AQBI is evaluated by using a high-resolution three-dimensional dispersion model: the air concentration for each substance is computed starting from detailed emissions sources: point, line and area emissions hourly modulated. This model is driven with accurate meteorological data from ground stations and remote sensing systems providing vertical profiles of temperature and wind; these data are integrated with wind and temperature profiles at higher altitudes obtained by a Local Area Model. The outputs of the dispersion model are compared with pollutant concentrations provided by measuring stations, in order to recalibrate emission data. A three-dimensional high resolution grid of AQBI data is evaluated for an industrial area close to Alessandria (Northern Italy), assessing air quality and environmental conditions. Performance of AQBI is compared with the Air Quality Index (AQI) developed by the U.S. Environmental Protection Agency. AQBI, computed taking into account all pollutants, is able to point out situations not evidenced by AQI, based on a preset limited number of substances; therefore, AQBI is a good tool for evaluating the air quality either in urban and in industrial areas. The AQBI values at ground level, in selected points, are in agreement with in situ observations.     

Monitoring Nitrogen Dioxide and its Effects on Asthmatic Patients: Two Different Strategies Compared

Objectives: To develop a `methodologyassessment' to evaluate the strengths and theweaknesses of two different epidemiological approachesand to identify the best suited monitoring strategy tomeasure the effects of `normal levels' of nitrogendioxide exposure on the health of an urban population.Methodology: all exposures to nitrogen dioxidewere determined with passive samplers, each samplerconsisting of 3 measuring Palmes tubes. In the firststudy the nitrogen dioxide exposure was assessed in 23school children (11 asthmatic and 12 non asthmatic).Children wore samplers for a week and parallelmeasurements were made in their kitchens, in bedroomsand outside their homes. The second study consisted ina case-control study where the relative risk ofhospital admission was calculated considering nitrogendioxide levels in a city of northern Italy. 110asthmatic patients were compared to a control group of 5322 people.Results: Personal sampler measurementshighlighted significant differences in exposure when nitrogen dioxide atmospheric levels were compared inasthmatic and healthy children (p<0.05). No otherparameters were significant in the two groups. Asignificant action of atmospheric nitrogen dioxide onhospital admission was demonstrated (p<0.01).Conclusions: Although a cause-effect relation assuch cannot be identified, the studies show a relationbetween the exposure to nitrogen dioxide and thepresence of adverse effects on people's health.However the `disadvantage' is for subjects withasthmatic pathologies, compared to the others. Tomanage this problem most effectively, a combinedapproach with the activation of specific personalmonitoring campaigns of the subjects with verifiedrisk seems necessary. This requires `reading' the dataresulting from most extensive and up to dateinformation systems, capable of a thorough controlboth of the living environment and of the clinicaloutcome of the whole population.     

Transition index maps for urban growth simulation: application of artificial neural networks,weight of evidence and fuzzy multi-criteria evaluation

Transition index maps (TIMs) are key products in urban growth simulation models. However, their operationalization is still conflicting. Our aim was to compare the prediction accuracy of three TIM-based spatially explicit land cover change (LCC) models in the mega city of Mumbai, India. These LCC models include two data-driven approaches, namely artificial neural networks (ANNs) and weight of evidence (WOE), and one knowledge-based approach which integrates an analytical hierarchical process with fuzzy membership functions (FAHP). Using the relative operating characteristics (ROC), the performance of these three LCC models were evaluated. The results showed 85%, 75%, and 73% accuracy for the ANN, FAHP, and WOE. The ANN was clearly superior compared to the other LCC models when simulating urban growth for the year 2010; hence, ANN was used to predict urban growth for 2020 and 2030. Projected urban growth maps were assessed using statistical measures, including figure of merit, average spatial distance deviation, producer accuracy, and overall accuracy. Based on our findings, we recomend ANNs as an and accurate method for simulating future patterns of urban growth.