Abatement Method Research Articles

Synergistic degradation of refractory organic pollutant by underwater bubbling plasma combined with heterogeneous Fenton process

Excessive discharge of the refractory organic pollutants endangers the development of the society and economy, thus seeking an efficient wastewater abatement method is an urgent need. Herein, Iron (Ⅱ) sulfide (FeS) was employed as the heterogeneous catalyst and coupled with underwater bubbling plasma (UBP) for the elimination of the refractory organic pollutant, malachite green (MG). FeS catalyst was synthesized using the solvothermal method and subsequently characterized comprehensively, focusing on its microstructure, specific surface area, chemical bonds and elements valence states. The UBP system combined with FeS (UBP/FeS) exhibited the robust synergism with a maximum synergistic factor of 1.89. The MG degradation percentage and rate constant were up to 94.7% and 0.237 min−1 within 12 min. The parameter experiments revealed that FeS dosage, pulse frequency, initial MG concentration and solution conductivity of 150 mg/L, 56 Hz, 5 mg/L and 21.8 μS/cm, respective, were more conducive for MG elimination. The MG removal efficiency reached 86.2% after five consecutive applications of FeS. Reactive substances including ·OH, ·O2−, eaq, O3 and H2O2 were confirmed to contribute to MG elimination. Additionally, the conversion circle between ≡ Fe(Ⅱ) and ≡ Fe(Ⅲ) promoted the catalytic conversion of H2O2 and O3 into ∙OH. The comparison of UV–vis spectra and total organic carbon of MG solution before and after reaction revealed the superior degradation of MG in the UBP/FeS system. Hypotheses regarding to the decomposition pathways of MG were formulated based on the identified intermediates. The toxicity level of MG solution was lightened after reaction. The above results indicate that UBP/FeS has the advantages of quick degradation and high efficiency, representing a promising approach for refractory pollutants treatment.

Flow fluctuation abatement method and flow characteristics of lobe pump by external noncircular gear drive

Flow fluctuation abatement method and flow characteristics of lobe pump by external noncircular gear drive

Surface functionalization of magnetite nanoparticles for remediation enhancement of phenol from aqueous solutions

Phenol is a toxic pollutant generated by industries. It can diminish the supply of clean water and is hazardous to human health. Hence, an effective abatement method is important to remove phenol from water sources. The following amine-functionalized magnetite nanoparticles, ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and polyethylenehexamine (PEHA), were used to study the adsorption performances of phenol from the prepared samples. The morphological study revealed long rod shapes with rough and sharp edges, while the elemental analysis presented the addition of two elements, C and N atoms. In addition, the TETA@MNP possessed weaker magnetism compared to MNPs, showing that the surface functionalization of MNPs was successful. TETA@MNP showed the highest percentage for phenol removal compared to others. The TETA@MNP achieved a removal efficiency of 99.2% at optimum conditions of 60 mg dosage, contact time of 25 min, and pH of 7. TETA@MNP obeyed the pseudo-second-order kinetic model and the Freundlich isotherm model, with coefficients of determination (R2) of 0.9765 and 0.9682, respectively. The reusability study has demonstrated that TETA@MNP can be reused approximately 6 times with extremely minor loss. Therefore, TETA@MNP is a good adsorbent for the adsorption of phenol from prepared sample solutions.

Actively ventilating calf hutches using solar-powered fans: Effects on hutch microclimate and calf thermoregulation

Although active ventilation via fans is an effective and widely adopted heat abatement method for use with adult dairy cattle, it has yet to be investigated in outdoor hutch-housed dairy calves despite most US calves being raised in such systems. We investigated a solar-powered fan system for outdoor calf hutches and its effect on hutch microclimate and calf thermoregulation. During summer, a 3 × 3 Latin square was replicated 4 times (n = 12 preweaning heifers) with 4-d exposure periods to minimally (CON; rear windows closed), passively (PASS; rear windows opened), or actively (ACT; solar-powered fan, activated at dry bulb temperature [Tdb] > 21°C) ventilated hutch systems. Hutch microclimate and calf thermoregulation were evaluated either continuously (Tdb, humidity, rectum surface temperature, and behavior) or after a daily 30-min inside restriction (air speed, air particle number, noise level, respiration, and sweating rate, and skin and rectal temperature). Active ventilation substantially increased hutch air speed relative to PASS and CON (1.76 vs. 0.19 vs. 0.05 m/s). However, PASS hutches had the lowest INT Tdb (27.2 vs. 26.4 vs. 27.8°C), whereas ACT INT Tdb was reduced at 0900 and 1000 h relative to CON but not PASS. Similarly, ACT reduced calf respiration rates and lowered rectum surface temperature at 0800 and 0900 h when compared with CON but not PASS. The lack of strong ACT influence on calf outcomes over PASS could partially be explained by the decreased proportion of time ACT calves spent inside their hutch (48.7 vs. 67.3 vs. 64.1% of each hour). Overall, ACT improved hutch microclimate and calf responses relative to CON but not PASS. Either ACT or PASS ventilation may be sufficient to provide heat abatement to continental hutch-housed calves.

On-Farm Water Use Efficiency: Impact of Sprinkler Cycle and Flow Rate to Cool Holstein Cows during Semi-Arid Summer

Sprinkler cooling is a common heat abatement method in dairy cows and uses huge quantities of groundwater. Sprinkler flow rate and timing affect cow cooling and water use efficiency, but little is known about how these strategies may influence dairy cow performance under heat stress conditions in Pakistan. The objective of this study was to evaluate the cooling efficiency of different sprinkler cycles and flow rates in Holstein Friesian cows under semi-arid summer conditions in Pakistan. Thirty (30) lactating cows were subjected to 2 sprinkler flow rates and 3 sprinkler cycle strategies in a crossover design. Flow rates were 1.25 and 2 L/min, and the sprinkler cycles (water on|off) were: 3 min on|3 min off, 3 on|6 off, and 3 on|9 off. Results showed that the 1.25 L/min flow rate had a similar performance to the 2.0 L/min group in terms of milk yield and behavior, despite using 37.2% less water. The respiration rate was lowest in the 3|3 sprinkler cycle (SC) group, followed by the 3|6 and the 3|9 SC groups, respectively. Milk yield in the 3|3 group was 2 kg/d higher than the 3|9 group. In conclusion, these findings suggest that the 3|3 sprinkler cycle and 1.25 L/min flow rate may be a more efficient option in terms of water use while maintaining cow performance in semi-arid heat stress conditions.

Airborne Asbestos Fiber Concentration in Buildings: Surveys Carried Out in Latium (Central Italy)

In Italy, use and production of asbestos and asbestos-containing materials (ACMs) were banned in 1992, however, the risk of exposure to asbestos still exists, because most ACMs are located in industrial and public buildings. A total of 111 Italian buildings with friable and non-friable ACMs were surveyed; 500 air samples were collected in the areas where contamination might have occurred. Airborne asbestos fiber concentration calculated from air samples was averaged for each building. Statistical analysis of the data showed no significant differences between the mean concentration measured in buildings with friable and non-friable ACMs (p = 0.258). The concentration values were below 2 f/L, the value stated by Italian regulation to ensure that the area is safe to reoccupy after asbestos removal. Samples of settled dust were also collected. The presence of asbestos fibers in the dust showed the occurrence of a release of asbestos from the material. Although the airborne asbestos fiber concentrations measured were low, current Italian regulation requires an asbestos management program. The Public Institution to which the authors of this work belong encourages asbestos removal as the preferred abatement method, in line with the asbestos-free future approach proposed by the European Commission.

Justice or Just Us? Social Death, Gang Injunctions, and the Creation of a Modern American Apartheid State

This article will discuss the practice of civil gang injunctions in Southern California, its history, and civil court procedures. It explores the gang abatement method's unconstitutionality through the lens of the First and Fourteenth Amendments of the United States Constitution, critiquing the unequal treatment of people of color in the justice system. Through philosophical theories of language and authoritarian control, the article will go on to discuss how a supposedly egalitarian nation like the United States could support and continue the utilization of such a harmful tactic. Finally, the article will contextualize gang injunctions with the South African practice of apartheid and argue that it fits the classification of an apartheid policy under the definitions of the international court and other international treaties.

A new order abatement method based on Atom search optimization

A new order abatement method based on Atom search optimization

Optimization of Circular Silencers Internally Hybridized with Multiple Reverse Chambers Using the GA Method

A noise abatement method using an eigen function in conjunction with an optimizer (Genetic Algorithm) under a space-constrain situation is proposed in this study concerning a high order wave propagation effect. An eigen function is used to describe an acoustical field and shorten the acoustical model in a four-pole transfer matrix form. The system’s four-pole matrix estimates the Transmission Loss (TL) for the silencers by multiplying individual four-pole matrices. Additionally, a case study of an air compressor’s broadband noise elimination is introduced. Three types of circular reverse silencers (silencers A-C) internally hybridized with multiple straight chambers are adopted to efficiently suppress the noise wave. Considering broadband characteristics and space-constrained situations, an average-deviation-integrating form used as an objective function is presented and linked to an optimizer-GA (Genetic Algorithm). Acoustical models for silencers A to C are checked before the numerical optimization is performed. A pure tone optimization is executed to assure the consistency of the GA scheme. The result shows that the overall noise drop is enhanced and the number of straight expansion chambers installed at the inlet/outlet of the circular reverse silencer increases. Consequently, concerning a space-constrained situation in the real world and the characteristics of the broadband noise spectrum, an efficient method is proposed in this paper for designing an optimally shaped hybrid muffler using the objective function in conjunction with an optimization scheme.

Reduction of linear dynamic systems using generalized approach of pole clustering method

A new model order abatement method based on the clustering of poles and zeros of a large-scale continuous time system is proposed. The clustering of poles and zeros are used for finding the cluster centres. The abated model is identified from the cluster centres, which reflect the effectiveness of the dominant poles of the clusters. The cluster centre is determined by taking [Formula: see text] root of the sum of the inverse of [Formula: see text] power of poles (zeros) in a particular cluster. It is famous that the magnitude of the pole cluster centre plays an important role in the clustering technique for the simplification of large-scale systems. The magnitude of the cluster centres computed by the modified pole clustering method or some other methods based on the pole clustering techniques is large as compared to the proposed technique. The less magnitude of pole cluster centre reflects the better approximations and proper matching of the abated model with the original system. Therefore, the proposed method offers better approximations matching between actual and abated systems during the transient period compared to some other clustering methods, which supports the replacement of large-scale systems by proposed abated systems. The proposed technique is a generalized version of the standard pole clustering technique. The proposed method guarantees the retention of dominant poles, stability and other fundamental control properties of the actual plant in the abated model. The proposed algorithm is illustrated by the five standard systems taken from the literature. The accuracy and effectiveness of the proposed method are verified by comparing the time responses and various performance error indices.

The perverse effect of environmental regulation on emissions: The role of product‐mix changes

AbstractWe study the effect of environmental regulation (taxation) on emissions when the only available abatement method consists of product‐mix changes. Firms choose to produce one or both varieties of a product—a pollution‐intensive (dirty) and a non‐pollution‐intensive (green)—and compete in a differentiated Cournot duopoly. We characterize the equilibrium market structure as a function of the tax rate and show that increases in the tax can promote product‐mix changes that lead to a jump in emissions for some tax range, an effect we call the perverse effect of taxation. Our work emphasizes the key role horizontal product differentiation in this process and shows that the perverse effect does not require the presence of vertical product differentiation. Further, the perverse effect of taxation is especially strong in the presence of incomplete regulation, that is, when only one of the markets is subject to taxation.

Opportunities and challenges for savanna burning emissions abatement in southern Africa

Savanna fires occurring in sub-Saharan Africa account for over 60% of global fire extent, of which more than half occurs in the Southern Hemisphere contributing ~29% of global fire emissions. Building on experience in reducing savanna fire emissions in fire-prone north Australian savannas through implementation of an internationally accredited ‘savanna burning’ emissions abatement methodology, we explore opportunities and challenges associated with the application of a similar approach to incentivise emissions reduction in fire-prone southern African savannas. We first show that for a focal region covering seven contiguous countries, at least 80% of annual savanna large fire (>250 ha) extent and emissions occur under relatively severe late dry season (LDS) fire-weather conditions, predominantly in sparsely inhabited areas. We then assess the feasibility of adapting the Australian emissions abatement methodology through exploratory field studies at the Tsodilo Hills World Heritage site in north-west Botswana, and the Niassa Special Reserve in northern Mozambique. Our assessment demonstrates that application of a savanna burning emissions abatement method focused on the undertaking of strategically located early dry season (EDS) burning to reduce LDS wildfire extent and resultant emissions meets key technical criteria, including: LDS fine fuels tend to be markedly greater than EDS fuels given seasonal leaf litter inputs; LDS fires tend to be significantly more severe and combust more fuels; methane and nitrous oxide emission factors are essentially equivalent in EDS and LDS periods under cured fuel conditions. In discussion we consider associated key implementation challenges and caveats that need to be addressed for progressing development of savanna burning methods that incentivise sustainable fire management, reduce emissions, and support community livelihoods in wildfire-dominated southern African savannas.

New Holistic Conceptual Framework for the Assessment of the Performance of Photocatalytic Pavement.

Despite serious health and environmental burdens associated with air pollution by NOx, the emission ceilings have been systematically exceeded in big European cities for several years. Photocatalytic technology can be an efficient solution for the removal of chemical air pollutants. Because diesel engine exhaust is the main source of NOx emissions, the application of a photocatalyst onto road pavement appears to be an effective NOx abatement method due to the large surface area, proximity to the emission source, and relatively good solar irradiance. Several laboratory-scale studies provided evidence demonstrating that most harmful contaminants can be readily mineralized. Furthermore, several projects were aiming to scale up this technology to pilot and real scales. Although the photocatalytic performances of selected materials in real urban environments were determined in some of these studies, the data are not conclusive for evaluating the overall performance because other material characteristics relevant to their functionality were not assessed. The lack of conformity criteria suitable for the evaluation of the overall performance of photocatalytic pavement under real operational conditions has generated skepticism and mistrust among public authorities and relevant stakeholders, which constrains the widespread implementation of this promising technology. In this context, the project LIFE–Photoscaling was focused on developing a new holistic conceptual framework to assess the photocatalytic pavement performance using the decision tool “Photoscaling Decision Maker” based on a set of quantitative indicators. For this purpose, a large volume of data obtained for 10 types of photocatalytic pavement materials was systemized on both the laboratory and pilot plant scales and three main indicators were defined: (1) photocatalytic performance effectiveness, (2) intrinsic performance, and (3) undesired secondary effects. Each top-level indicator includes several low-level subindicators associated with specific material characteristics. Finally, the ranges of the main indicators and subindicators and methods for their assessment were determined. These methods include standard, adopted, and original characterization techniques, which were selected based on the criteria such as simplicity, cost- and time-effectiveness, and relevance regarding the operational conditions.

CoMnMgAl mixed oxides prepared by a microwave assisted self-combustion synthesis for toluene total oxidation

Volatile organic compounds (VOCs) are one of the most relevant air pollutants as they act as precursor agents for photochemical smog, acid rain and other noxious compounds. Catalytic oxidation stands out as an abatement method of VOCs thanks to its high efficiency and low energy requirements. Within this approach, catalysts based on cobalt and manganese are remarkable systems due to their excellent redox properties and the oxygen mobility within the mixed oxides structures.In this work, CoMnMgAl-Ox type catalysts were prepared by a microwave (MW) assisted self-combustion synthesis method varying the Co/Mn molar ratio between 0 and 1, the MW irradiation power between 80 and 500 W and the impregnation or non-impregnation with platinum at 1.0 %. The catalysts were characterized by XRD, N2 adsorption-desorption isotherms, HR-TEM and XPS techniques and evaluated in the catalytic oxidation of toluene in diluted gas phase at atmospheric pressure. All solids prepared by MW showed higher catalytic activities than their equivalents prepared by traditional self-combustion, demonstrating that the use of microwaves in the synthesis enhances the catalytic activity of materials in the oxidation due to the prevalence of Co (III) species and a smaller particle size. Additionally, it was found that the Co/Mn = 0.6 M ratio in the oxide, gives rise to the most active catalyst, presenting conversions comparable to those of the catalysts impregnated with platinum.

How shipowners have adapted to sulphur regulations – Evidence from Finnish seaborne trade

From the beginning of 2020, the IMO regulation limiting ships’ fuel sulphur content to 0.5% will become effective. This limit has been preceded by the Sulphur Emission Control Areas (SECA) already since 2015. In practice, there are multiple abatement methods for the industry to comply with the regulation. Subject to corporate strategy, technical development and operating areas, none of them has gained dominancy. Through the case of vessels calling port in Finland, this research provides empirical evidence on how the industry has reacted on the implementation of the SECA. This paper uses descriptive analysis and logistic regression to form a profile of vessels for which the instalment of scrubbers has been considered, and for which the other abatement methods are found superior. The results indicate that younger vessels in regular traffic on the SECA areas, especially the Roll on - Roll off vessels are most likely to be equipped with scrubbers, whereas majority of ships calling at Finnish ports have switched to cleaner fuel grade. For the year 2020, this would indicate scrubbers to be the dominating abatement method for the global fleet.

Geothermal power plant layouts with water absorption and reinjection of H2S and CO2 in fields with a high content of non-condensable gases

The reinjection of non-condensable gases (NCG) back to the geothermal reservoir has recently proved to be an effective emission abatement method in Iceland, yet it would raise new challenges when applied to geothermal fields with a much higher NCG content and different reservoir’s rock composition like the Italian fields. The features of the surface equipment to implement gas reinjection are rarely reported in the literature, being the attention mostly focused on the subsurface reservoir. To fill this gap, this study examines the integration of the water absorption and reinjection equipment in dry steam and flash steam geothermal power plants fed by steam with a high NCG content (8%). Three novel plant layouts are proposed, modelled and analysed which include a packed absorption column where H2S and CO2 are absorbed in water at high pressure. The study searches for those conditions ensuring an overall H2S abatement similar to that achieved by state-of-the-art emission abatement methods (e.g., AMIS) and, at the same time, enabling a significant capture of the CO2 contained in the geothermal steam, which is currently unabated. The results show that, with minimum modifications to the original plant layout, an overall H2S abatement of 86.5% and CO2 abatement of 47% are attainable. This is obtained using a column pressure of 36 bar, a water supply of 100 ton/hr, and coping with a net power output reduction of 6% and a moderate cost of the added equipment estimated equal to 1.0–2.2 M€.

Algae-based sorbents for removal of gallium from semiconductor manufacturing wastewater

Removal of various soluble metallic impurities from wastewater in semiconductor fabrication plants is a critical issue facing the microelectronics industry. Considering the large volume of wastewater and a highly variable concentration of these contaminants, finding a robust adsorption process using a low-cost sorbent is of great value and interest to this industry. Of particular interest is the development of a flow-through abatement method for treating the process-tool effluent before it is mixed with other wastewaters. In this work, a strain of freshwater green algae (Chlorella sorokiniana), representing an algae-based sorbent, and a simulated wastewater, containing soluble gallium as the metallic impurity, are used as model compounds. The choice of gallium is based on its increased use, and the lack of related adsorption data compared to the information available for other metals such as copper and arsenic. Both batch and continuous-flow operations were used in this study. Comprehensive process models were developed and validated for both batch and flow systems. These models were found to be valuable for understanding the process steps as well as for obtaining the fundamental parameters that are needed for process design and scale-up. The sorbent was found to have high adsorption capacity even at low pH values (14.1 mg/g at pH of 2.3, and 38.5 mg/g at pH of 2.8). Based on the comparison of adsorption rate and capacity with data on previously studied and conventional sorbents, such as activated carbon and ion-exchange resins, the use of this algae-based sorbent is potentially an attractive option for the removal of gallium from the process-tool wastewater.

Partial discharge signal self-adaptive sparse decomposition noise abatement based on spectral kurtosis and S-transform

PurposeNoise abatement is one of the key techniques for Partial Discharge (PD) on-line measurement and monitoring. However, how to enhance the efficiency of PD signal noise suppression is a challenging work. Hence, this study aims to improve the efficiency of PD signal noise abatement.Design/methodology/approachIn this approach, the time–frequency characteristics of PD signal had been obtained based on fast kurtogram and S-transform time–frequency spectrum, and these characteristics were used to optimize the parameters for the signal matching over-complete dictionary. Subsequently, a self-adaptive selection of matching atoms was realized when using Matching Pursuit (MP) to analyze PD signals, which leading to seldom noise signal element was represented in sparse decomposition.FindingsThe de-noising of PD signals was achieved efficiently. Simulation and experimental results show that the proposed method has good adaptability and significant noise abatement effect compared with Empirical Mode Decomposition, Wavelet Threshold and global signal sparse decomposition of MP.Originality/valueA self-adaptive noise abatement method was proposed to improve the efficiency of PD signal noise suppression based on the signal sparse representation and its MP algorithm, which is significant to on-line PD measurement.

A full-scale study on thermal degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash and its secondary air pollution control in China.

Degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash is beneficial to its risk control. Fly ash was treated in a full-scale thermal degradation system (capacity 1 t d-1) to remove polychlorinated dibenzo- p-dioxins and dibenzofurans. Apart from the confirmation of the polychlorinated dibenzo- p-dioxin and dibenzofuran decomposition efficiency, we focused on two major issues that are the major obstacles for commercialising this decomposition technology in China, desorption and regeneration of dioxins and control of secondary air pollution. The toxic equivalent quantity values of polychlorinated dibenzo- p-dioxins and dibenzofurans decreased to <6 ng kg-1 and the detoxification rate was ⩾97% after treatment for 1 h at 400 °C under oxygen-deficient conditions. About 8.49% of the polychlorinated dibenzo- p-dioxins and dibenzofurans in toxic equivalent quantity (TEQ) of the original fly ash were desorbed or regenerated. The extreme high polychlorinated dibenzo- p-dioxin and dibenzofuran levels and dibenzo- p-dioxin and dibenzofuran congener profiles in the dust of the flue gas showed that desorption was the main reason, rather than de novo synthesis of polychlorinated dibenzo- p-dioxins and dibenzofurans in the exhaust pipe. Degradation furnace flue gas was introduced to the municipal solid waste incinerator economiser, and then co-processed in the air pollution control system. The degradation furnace released relatively large amounts of cadmium, lead and polychlorinated dibenzo- p-dioxins and dibenzofurans compared with the municipal solid waste incinerator, but the amounts emitted to the atmosphere did not exceed the Chinese national emission limits. Thermal degradation can therefore be used as a polychlorinated dibenzo- p-dioxin and dibenzofuran abatement method for municipal solid waste incinerator source in China.

Is forest carbon sequestration at the expense of bioenergy and forest products cost-efficient in EU climate policy to 2050?

Forest management affects the quantity of CO2 emissions in the atmosphere through carbon sequestration in standing biomass, carbon storage in forest products and production of bioenergy. The main question studied in this paper is whether forest carbon sequestration is worth increasing at the expense of bioenergy and forest products to achieve the EU emissions reduction target for 2050 in a cost-efficient manner. A dynamic cost minimisation model is used to find the optimal combination of carbon abatement strategies to meet annual emissions targets between 2010 and 2050. The results indicate that forest carbon sequestration is a low-cost abatement method. With sequestration, the net present costs of meeting EU carbon targets can be reduced by 23%.