Nitrate Adsorption by Activated Carbon

Activated carbon is a type of carbon that is a known catalyst for a variety of chemical reactions. Uses of activated carbon include purifying liquids and gases, food and beverage processing, odor removal, industrial pollution control, and numerous other applications. There are a variety of different activated carbons, with most being derived from coal, peat, and wood. Activated carbon is a catalyst because the small pores of the carbon increase the surface area available for adsorption or chemical reactions. One primary use of activated carbon is how it adsorbs nitrates onto its surface. This paper delves into different adsorption rates of an activated carbon (Filtrasorb 600) that is treated with different chemicals and then subjected to a chemical activation at a constant pressure under different gaseous conditions. Data collected during experiments indicate there are significant interactions between surface functional groups and nitrate. Keywords: activated carbon, adsorption, nitrates

Pilot-Scale H2S and Swine Odor Removal System Using Commercially Available Biochar

Although biochars made in laboratory seem to remove H2S and odorous compounds effectively, very few studies are available for commercial biochars. This study evaluated the efficacy of a commercial biochar (CBC) for removing H2S and odorous volatile organic compounds (VOCs). We found that the well-known Ergun equation may not be adequate in predicting pressure drop for properly sizing a ventilation system. The H2S breakthrough adsorption capacity of the CBC was 2.51 mg/g under humid conditions, which was much higher than that for dry conditions. The breakthrough capacity increased with the influent concentration of H2S. The efficacy of a pilot-scale biochar odor removal system (PSBORS) for removing 15 odorous VOCs was evaluated by placing it in a swine gestation stall continually treating the inside air for 21 days. All VOCs in the PSBORS effluent were below detection limit except for acetic acid. However, due to the very high odor threshold of acetic acid, its contribution to the odor would be minimal. It appeared that the CBC could be used to reduce both H2S and odorous VOCs with the potential of recycling the spent CBC for soil health improvement after using it for H2S and odor removal.

Comparison Access to Odor Problems in Selected European Countries

The effects of odor are not only annoying but can also cause serious health problems, resulting in an impact on the overall qualityof the environment.Most European jurisdictions classify odor as an atmospheric pollutant and regulate it at various levels of government. This papersummarizes the approach of selected European countries to this issue, comparison in terms of acceptable concentrations, comparisonof instruments used in individual countries, requirements for the application of BAT technologies that ultimately lead to thereduction of odor emissions. Further are described, the basic features of odors, units, methods of analysis and dispersion´s modeling,application of odor removal technologies, with emphasis in relation to the Czech Republic.

Evaluation of a Wet Acid Scrubber and Dry Filter Abatement Technologies in Pig Barns by Dynamic Olfactometry

Livestock activities, in particular swine farms, are sources of odorant compounds that cause conflicts with the neighboring population. Beside the effects on the neighborhood, excessive odor emission can cause discomfort to farm workers. In this context the APPROAch project, aims to test the application of two different air cleaning technologies (a wet acid scrubber and a dry filter) to reduce dust, ammonia and odors, in naturally ventilated pig facilities. The aim of the present study is to evaluate, in a pig farm, the odor removal efficiency of the two tested abatement technologies, based on air samples analyzed by dynamic olfactometry. Odor sampling was carried out at a pig facility involved in the project and brought to the lab within 30 h from sampling, as established by the European Standard EN 13725:2004. Odor concentration was evaluated by dynamic olfactometry using an Olfaktomat-n 6 (PRA-Odournet B.V.—Amsterdam, The Netherlands). The results show that the wet acid scrubber prototype presents an average odor removal efficiency of 16%, whereas dry filter has from limited to no effect. This efficiency could be considered as a good result for a prototype even if further analysis, with longer sampling periods are needed.

Removal of Odors (Mainly H2S and NH3) Using Biological Treatment Methods

This study reviews the available and most commonly used methods of gas deodorization. Comparing various methods of odor removal, undoubtedly biological methods of pollution degradation have an advantage over others—chemical and physical. This advantage is manifestedmainly in ecological and economic terms. The possibility of using biological methods to remove H2S and NH3, as the most common emitted by the municipal sector companies, was analyzed in terms of their removal efficiency. The method of bio-purification of air in biotrickling filters is more advantageous than the others, due to the high effectiveness of VOCs and odors degradation, lack of secondary pollutants, and economic aspects—it is a method competitive to the commonly used air purification method in biofilters.

Exploring Odor Minimization in Post-Consumer Plastic Packaging Waste through the Use of Probiotic Bacteria

Plastic packaging represents a large proportion of the plastic consumption throughout the world. The negative environmental impact associated with plastic packaging waste can be in part abated by recycling plastics, and increasing numbers of regulatory frameworks are being adopted towards this goal. Despite recent advances in modern recycling technologies, the production of high-quality polyolefin recyclates remains a challenge. Among other functional requirements, odor plays a crucial role in the acceptance of recycled packaging. This presents a challenge, as odor contamination in plastic packaging waste can stem from diverse sources, such as spoilage processes, and strongly depends on the quality of the post-consumer input material. The present study addressed this issue by exploring potential odor abatement of malodors in packaging waste through the use of probiotic bacteria. Specifically, probiotics were added to a mixed post-consumer plastic packaging waste fraction, which was subsequently evaluated using human sensory and gas chromatography–olfactometric analyses. A comparison of treated with untreated plastic waste fractions revealed significant sensory differences. Further structural elucidation of the causative odorants confirmed a reduction in malodorous microbial metabolites, although complete odor removal was not achieved. However, this environmentally friendly approach may represent an essential step towards overcoming the odor burden in post-consumer plastic packaging recyclates.

The investigation of combined ventilation-biofilter systems using recycled treated wastewater on odor reduction efficiency

Objective: The present study aimed to evaluate the performance of odor abatement by using two different ventilation-biofilter systems with recycled stablized swine wastewater.Methods: The performance of odor removal efficiency was evaluated using two different ventilation-biofilter-recycled wastewater arrangements. A recirculating air-flow ventilation system connected to a vertical biofilter (M1) and a plug-flow ventilation system connected to a horizontal biofilter (M2) were installed. Water dripping over the surface of the biofilter was recycled at a flow rate of 0.83 L/h in summer and 0.58 L/h in winter to reduce odorous compounds and particulate matter (PM). The experiments were performed for 64 days with M1 and M2 to investigate how these two ventilation-biofilter systems influenced the reduction of odor compounds in the model houses. Odorous compounds, NH3 and volatile organic compounds (VOCs) were analyzed, and microclimatic variables such as temperature, humidity, and PM were monitored.Results: Ammonia concentration inside M1 was about 41% higher on average than that in M2. PM and total suspended particles (TSPs) inside M1 were about 62.2% and 69.9%, respectively, higher than those in M2. TSPs in the model house were positively correlated with the concentration of NH3 and VOCs.Conclusion: M2 emitted lower concentration of odorous compounds than M1. Moreover, M2 could maintain the optimum temperature condition for a swine house during the cooler season. The plug-flow ventilation–horizontal biofilter system could be used for pig houses to minimize air pollution produced by swine farming activities and maintain optimum microclimate conditions for pigs.