Hexavalent chromium (Cr(VI)) waste produced by chrome plating activities pollutes the surrounding environment and harms human health. However, information about the chromium (Cr) pollution characteristics of actual electroplating sites is still lacking. In this study, the concentration, leachability and speciation of Cr in soils from a typical chrome plating site were analyzed. Our results showed that this site was severely contaminated by Cr (7.2 to 7735.2 mg/kg) and Cr(VI) reached the mean concentration of 138.7 mg/kg. The spatial distribution of Cr(VI) was related to the plating processes. Chrome plating and sewage treatment areas could be considered as the hot spots of contaminated sites. The vertical distribution of Cr(VI) was mainly affected by soil properties, where the loam layer retained and reduced a large amount of Cr(VI) due to its high content of iron minerals and finer particle fractions. Additionally, the chemical extraction results showed that Cr was mainly in non-resid... [more]

Water surface plastic pollution turns out to be a global issue, having aroused rising attention worldwide. How to monitor water surface plastic waste in real time and accurately collect and analyze the relevant numerical data has become a hotspot in water environment research. (1) Background: Over the past few years, unmanned aerial vehicles (UAVs) have been progressively adopted to conduct studies on the monitoring of water surface plastic waste. On the whole, the monitored data are stored in the UAVS to be subsequently retrieved and analyzed, thereby probably causing the loss of real-time information and hindering the whole monitoring process from being fully automated. (2) Methods: An investigation was conducted on the relationship, function and relevant mechanism between various types of plastic waste in the water surface system. On that basis, this study built a deep learning-based lightweight water surface plastic waste detection model, which was capable of automatically detectin... [more]

The kinetics and performance of a biological activated carbon (BAC) reactor were evaluated to validate the proposed kinetic model. The Freundlich adsorption capacity (Ka) and adsorption intensity constants (n) obtained from the batch experiments were 1.023 ± 0.134 (mg/g) (L/mg)1/n and 2.036 ± 0.785, respectively. The effective diffusivity (Ds) of the substrate within the activated carbon was determined by comparing the adsorption model value with the experimental data to find the best fit value (4.3 × 10−4 cm2/d). The batch tests revealed that the yield coefficient (Y) was 0.18 mg VSS/mg COD. Monod and Haldane kinetics were applied to fit the experimental data and determine the biokinetic constants, such as the maximum specific utilization rate (k), half-saturation constant (K), inhibition constant (Ki), and biomass death rate coefficient (kd). The results revealed that the Haldane kinetics fit the experimental data better than the Monod kinetics. The values of k, KS, Ki, and kd were 3... [more]

A partial-denitrification coupling with anaerobic ammonium oxidation (anammox) process (PD/A) in a continuous-flow anoxic/oxic (A/O) biofilm reactor was developed to treat carbon-limited domestic wastewater (ammonia (NH4+-N) of 55 mg/L and chemical oxygen demand (COD) of 148 mg/L in average) for about 200 days operation. Satisfactory NH4+-N oxidation efficiency above 95% was achieved with rapid biofilm formation in the aerobic zone. Notably, nitrite (NO2−-N) accumulation was observed in the anoxic zone, mainly due to the insufficient electron donor for complete nitrate (NO3−-N) reduction. The nitrate-to-nitrite transformation ratio (NTR) achieved was as high as 64.4%. After the inoculation of anammox-enriched sludge to anoxic zones, total nitrogen (TN) removal was significantly improved from 37.3% to 78.0%. Anammox bacteria were effectively retained in anoxic biofilm utilizing NO2−-N produced via the PD approach and NH4+-N in domestic wastewater, with the relative abundance of 5.83% fo... [more]

An automated mechanical transmission (AMT) is proposed as a new soft starter for medium-scale belt conveyors in this paper. The AMT is used to start the belt conveyor and shift gears step by step to make the belt conveyor accelerate softly. Based on analyzing common soft-starting acceleration curves, a segmented belt acceleration curve is proposed as a new soft-starting acceleration curve. By analyzing the AMT soft-starting system, the system modeling is built and the AMT output shaft’s angular acceleration is proposed to be controlled to control the belt acceleration. The AMT soft-starting simulation model is established in the environment of AMESim, and simulation results of the soft-starting process from the first to eighth gear positions are given. The main parameter curves of the AMT soft-starting system including the belt, driving pulley, and AMT output shaft are analyzed. The simulation model can indicate the viscoelastic property of the belt. The simulation results prove that t... [more]

In Spain, most businesses are medium to small size enterprises, representing 90% of the total, but there is a lack of studies of the types of building this sector uses. The main objective of this paper is to present a method for the evaluation of small industrial construction projects to facilitate the introduction of eco-efficient solutions. For this, it is necessary to identify the most representative buildings and the aspects of these which have the most environmental impact. A methodology in place for the evaluation of dwelling construction is adapted, for the first time, to evaluate industrial buildings. The construction solutions characterized are those traditionally used in the sector, as identified through 87 surveys. A standardized classification of work units is proposed to enable the use of environmental product information, such as eco-labels and/or EPD, and LCA databases. The carbon footprint (CF) and water footprint (WF) are the indicators selected because of their straig... [more]

Gamma radiation was applied to degradation selected antidepressants in ultrapure water and surface water. Additionally, the influence of typical radical scavengers like carbonate, nitrate and humic acid was determined. The cytotoxicity towards liver cells HepG2 and colon cells Caco2 were measured during the radiation process. It was found that radiation technology, specifically ionizing radiation, can achieve satisfactory degradation efficiency with both SER and CIT. It was shown that the process of decomposition of the tested antidepressants with the highest efficiency occurs in the reaction with the hydroxyl radical.

Green human resource management (GHRM) determines the green behavior practice of employees and affects the social environment and the realization of “Beautiful China” and “Green Development”. In this study, to explore the impact mechanism of GHRM on employees’ green behavior, employees at all levels in an enterprise were selected to be research subjects and a regulated intermediary model was established, based on social exchange theory and the individual-environment matching theory. This paper investigated the enterprise’s GHRM, personal green behavior, relational psychological contract, environmental knowledge and green values. The results show that GHRM has a significant positive predictive effect on employees’ green behavior, the relational psychological contract plays an intermediary role between GHRM and employees’ green behavior and the intermediary role of the relational psychological contract is regulated by environmental knowledge and green values. These research results expla... [more]

Tomato processing leads to the production of considerable amounts of residues, mainly in the form of tomato skins, seeds and vascular tissues, which still contain bioactive molecules of interest for food, pharmaceutical and nutraceutical industries. These include carotenoids, such as lycopene and β-carotene, tocopherols and sitosterols, among others. Supercritical fluid extraction is well positioned for the valorization of tomato residues prior to disposal, because it remains an environmentally safe extraction process, especially when using carbon dioxide as the solvent. In this article, we provide an extensive literature overview of the research on the supercritical fluid extraction of tomato residues. We start by identifying the most relevant extractables present in tomatoes (e.g., lycopene) and their main bioactivities. Then, the main aspects affecting the extraction performance are covered, starting with the differences between tomato matrixes (e.g., seeds, skins and pulp) and poss... [more]

The interest in the use of biosorption for the elimination of pollutants is because this technique is an efficient and environmentally friendly process, constituting an alternative to the so-called conventional treatment processes [...]

In the present study, UV-light-driven advanced oxidation processes (AOPs) have been employed for the degradation of 4-tert-Butylphenol (4-t-BP) in water under continuous flow conditions. The effects of varying space time (10, 20, 40, 60 and 120 min) and oxidant dosage (88.3 mg/L, 176.6 mg/L and 264 mg/L) were examined. 4-t-BP degradation efficiency in the UV-induced AOPs followed the order of UV/H2O2 (264.9 mg/L) ≈ UV/Fe2+/H2O2 > UV/Fe3+/H2O2 > UV/H2O2 (176.6 mg/L) > UV/H2O2 (88.3 mg/L) > UV/Fe-TiO2 > UV/TiO2 > UV, while UV/Fe3+/H2O2 was the most efficient process in terms of Total Organic Carbon (TOC) removal (at the space time of 60 min) among those tested. The combination of UV with 88.3 mg/L H2O2 enhanced pollutant removal from 51.29% to 93.34% after 10 min of irradiation. The presence of H2O2 contributed to the highest 4-t-BP and TOC removal values. Interestingly, the increase in space time from 20 to 60 min resulted in surpassing of the activity of the Fe-TiO2 over commercial TiO... [more]

Low-altitude unmanned aerial vehicle (UAV) photogrammetry combined with structure-from-motion (SFM) algorithms is the latest technological approach to imaging 3D stereo constructions. At present, derivative products have been widely used in landslide monitoring, landscape evolution, glacier movement, volume measurement, and landscape change detection. However, there is still a lack of research into the accuracy of 3D data positioning based on the structure-from-motion of unmanned aerial vehicle (UAV-SFM) technology, itself, which can affect the measurable effectiveness of the results in further applications of this technological approach. In this paper, validation work was carried out for the DJI Phantom 4 RTK UAV, for earth observation data related to 3D positioning accuracy. First, a test plot with a relatively stable surface was selected for repeated flight imaging observations. Specifically, three repeated flights were performed on the test plot to obtain three sorties of images; t... [more]

Carbon capture, utilization, and storage (CCUS) is one of the key promising technologies that can reduce GHG emissions from those industries that generate CO2 as part of their production processes. Compared to other effective CO2 capture methods, the adsorption technique offers the possibility of reducing the costs of the process by setting solid sorbent with a high capacity of adsorption and easy regeneration and, also, controlling the performance of gas-solid contactor. In this work, an amine-functionalized mesoporous sorbent was used to capture CO2 emissions in a confined-fluidized bed. The adoption of a confined environment allows the establishment of a homogeneous expansion regime for the sorbent and allows to improve the exchange of matter and heat between gas and solid phase. The results illustrate how the different concentration of the solution adopted during the functionalization affects the adsorption capacity. That, measured as mg of CO2 per g of sorbent, was determined by b... [more]

Algae-based wastewater treatment technologies are promising green technologies with huge economical potential and environmental co-benefits. However, despite the immense research, work, and achievement, no publications were found wherein these technologies have been successfully applied in an operational environment for nitrogen and phosphorus removal of secondary treated effluent in municipal wastewater treatment plants. Based on a literature review and targeted comprehensive analysis, the paper seeks to identify the main reasons for this. The reliability (considering inlet wastewater quality variations, operating conditions and process control, algae harvesting method, and produced biomass) as well as the technology readiness level for five types of reactors are discussed. The review shows that the reactors with a higher level of control over the technological parameters are more reliable but algal post-treatment harvesting and additional costs are barriers for their deployment. The... [more]

With the development and popularization of the concept of a sustainable environment, the green energy industry represented by electric scooters has entered a vigorous development period. However, consumers are reluctant to buy electric scooters, resulting in low sales, which is limiting the development of the electric scooter industry. Therefore, from the perspective of different consumer life styles, this study explored the impact on the purchasing decisions and user demands, so as to inform design strategy for the development of a sustainable electric scooter industry. This study adopted the methods of expert interview and questionnaire survey, used the self-made consumer life style and electric scooter product attribute scale as the research tool, and carried out quantitative analysis with the help of statistical software. It showed that compared with consumers’ awareness of environmental protection, product performance is the key factor that attracts consumers to buy electric scoot... [more]

The Flight Environment Simulation System (FESS) at Altitude Ground Test Facilities (AGTF) is used to test aircraft engines. The FESS model is the basis of research and verification of advanced control algorithms. To further improve the steady and dynamic accuracy of the FESS model, a modeling method based on quasi-one-dimensional flow is proposed. Firstly, based on the unified inlet/outlet boundary specifications, the component models of test equipment, such as the quasi-one-dimensional flow model of pipe, the regulating valve model considering the heat transfer process, the multi-inlet and multi-outlet volume model reflecting the mixing characteristics of air flow, and the air source model and engine model, were established. Secondly, according to the real structure and working mechanism of the FESS, the above component models were used to build the numerical simulation model of the FESS. The simulation results showed that the relative deviation of mass flow and pressure were less tha... [more]

Oil fields in Romania were active in the period 1900−2020, some of which will close due to declining oil production and especially due to reduced processing after the application of European Community recommendations to give up fossil fuels and the use of renewable fuel. The rehabilitation of the soil affected by hydrocarbon pollution is carried out with public funds. This is why, when transferring the land to the local community, an oil pollution assessment study is carried out. If the hydrocarbon content is less than 1000 mg/kg dry matter, the soil is not depolluted. In the Moinesti oil area, Romania, against the background of the increased incidence of breast cancers in women who worked in oil facilities, a study was conducted on the natural radioactivity of abandoned oil areas. The results of this analysis are presented and discussed in this article. It is the first study of radioactivity of the oil tank farm affected by oil pollution, its purpose being to draw attention in detecti... [more]

Internet technology has provided an indescribable new way for businesses to attract new customers, track their behaviour, customise services, products, and advertising. Internet technology and the new trend of online shopping have resulted in the establishment of numerous websites to sell products on a daily basis. Products compete to be displayed on the limited pages of a website in online shopping because it has a significant impact on sales. Website designers carefully select which products to display on a page in order to influence the customers’ purchasing decisions. However, concerns regarding appropriate decision making have not been fully addressed. As a result, this study conducts a comprehensive comparative analysis of the performance of ten different metaheuristics. The ant lion optimiser (ALO), Dragonfly algorithm (DA), Grasshopper optimisation algorithm (GOA), Harris hawks optimisation (HHO), Moth-flame optimisation algorithm (MFO), Multi-verse optimiser (MVO), sine cosine... [more]

An integrated forward osmosis (FO)-membrane distillation (MD) process is promising for the treatment and resource recovery from municipal wastewater. As higher temperature is applied in MD, it could affect the performance of both FO and MD units. This study aimed to investigate the effects of the type of draw solution (DS) and feed solution (FS) such as ammonium solution or municipal wastewater containing ammonium at higher temperatures on membrane treatment performance. It is found that higher FS and DS temperatures resulted in a higher water flux and a higher RSF with either NaCl or glucose as DS due to the increased diffusivity and reduced viscosity of DS. However, the water flux increased by 23−35% at elevated temperatures with glucose as DS, higher than that with NaCl as DS (8−19%), while the reverse solute flux (RSF) increase rate with NaCl as DS was two times higher than that with glucose as DS. In addition, the use of NaCl as DS at higher temperatures such as 50 and FS at 42 °C... [more]

This study researched the effects of using various nitrogen (N) conservation measures on the residual characteristics of nitrate and ammonium N in soil and the associated N uptake by cotton plants. A field experiment with six treatments was conducted, as follows, no N application (DT1), conventional N application (DT2), 60% conventional N application combined with DCD (DT3), 60% conventional N application combined with NBPT (DT4), 60% conventional N application combined with cotton straw returning (DT5), and 60% conventional N application combined with DCD, NBPT, and cotton straw returning (DT6). The results showed that the cotton straws in the DT5 treatment were beneficial for the vegetative growth of cotton seedlings. However, it was observed that the later performance of the plants in this sample was poor in terms of height, biomass, and yield of cotton. The plant height in the DT6 sample increased by 15 cm compared with those in DT1, and the soil and plant analyzer development (SPA... [more]

Energy demand is increasingly the most relevant cost item in chemical plants. Operating expenses indeed play a main role in all plants processing large amounts of feedstock via well-established processes in the petrochemical industry. In staged operations, the optimal number of stages is usually obtained by means of an economic optimization. However, the designed equipment, external duties, and thus operating expenses may considerably vary under the effect of external disturbances. The main purpose of this paper is to outline a simple but effective procedure to account for perturbations in the assessment of the optimal number of stages. The analysis shows that appropriate investments could lead to a unit design able to mitigate the higher duty requirements when external perturbations occur. The results highlight that the optimal number of stages varies when uncertainty is considered and, with low computational effort, this can be effectively quantified by means of the applied methodolo... [more]

At the 2021 United Nations Climate Change Conference (COP26), many countries in the world agreed to reach the goal of net-zero greenhouse gas emissions by 2050. This issue constrains energy use, petrochemical use, and related manufacturing production patterns. It is undeniable that the diesel engine of large equipment is still widely used in engineering applications, and it will not disappear in a short time. Many industrial projects still have to face the use of diesel engines. This study was focused on the development of oil-producing microorganisms to generate lipids. The oleaginous yeast Rhodotorula mucilaginosa (R. mucilaginosa) was selected for liquid-state cultivation, and the conditions for growth of the yeast cells were assessed. For the liquid fermentation culture with a fixed inoculation amount of 5%, it was determined that a suitable oil-producing culture was obtained on the sixth day, and the optimum conditions involved a carbon source concentration of 60 g/L, a yeast extr... [more]

Post-consumer plastic management, otherwise termed waste plastic (WP) management, is a great challenge in today’s world, mainly because of its characteristic biodegradation properties. The quantity of waste plastics correspondingly increases with the increase in demand for plastic use. Research has shown that this demand increases yearly. Most of these waste plastics include high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyethylene terephthalate (PET) and polystyrene (PS). Potentially, these wastes are a wealth, and studies have explored that pyrolysis is a reputable mechanism to accomplish this. In this critical review, an extensive investigation on waste plastics thermal pyrolysis (WPTP) is carried out. The factors that affect the product’s yield and selectivity are discussed, and a comparative quality guarantee of WPTP is examined. This paper presents an assurance into the current findings of WPTP and reveals some common gaps and misconceptions surrounding this... [more]

Spatiotemporal variations of oxygen concentration affect the cell behaviors that are involved in physiological and pathological events. In our previous study with Dictyostelium discoideum (Dd) as a model of cell motility, aggregations of Dd cells exhibited long-lasting and highly stable migration in a self-generated hypoxic environment, forming a ring shape that spread toward the outer higher oxygen region. However, it is still unclear what kinds of changes in the migratory properties are responsible for the observed phenomena. Here, we investigated the migration of Dd to clarify the oxygen-dependent characteristics of aerokinesis and aerotaxis. Migratory behaviors of Dd cells were analyzed under various oxygen concentration gradients and uniform oxygen conditions generated in microfluidic devices. Under hypoxic conditions below 2% O2, corresponding to less than 25 µM O2 in the culture medium, the migration of Dd cells was enhanced (aerokinesis) and the oxygen gradient guided the cells... [more]

The use of geothermal energy (GE) and the green economy in the environment of Slovak municipalities and towns is significant, due to the reduction in the negative influences and impacts of human society’s constant consumer lifestyle. The authors highlight the use of modern scientific knowledge, practical experience, and ever-improving technologies in the field of renewable energy sources RES. The aim of this contribution is to draw attention to the under-utilization of GE’s potential in Slovakia. Given the country’s commitment to meeting emission limits under EU carbon neutrality agreements by 2050, the use of this resource is very pertinent. Slovakia has significant geothermal resources that are not currently sufficiently utilized. The article suggests using GE to heat housing units of the housing estate near the geothermal source. Three scenarios (60 °C (pessimistic), 65 °C (conservative), and 70 °C (optimistic)) were considered in our energy balance and economic advantage calculatio... [more]