Microalgae have been intensively studied for CO2 capture, nutrient removal from wastewater, and biofuel production applications [...]

Low-temperature solar thermal energy is a viable and mature alternative to reduce the use of fossil fuels for domestic hot water heating. The impact of the inclusion of this technology in the energy matrix in the Andean city of Cuenca, Ecuador, is analyzed. In Ecuador, liquefied petroleum gas (LPG) is currently used to heat water due to the high state subsidy, with a cost of 0, 11 USD for an LPG kg compared to the international price of 1.18 USD a Kg of LPG in 2021. Sustainability indicators show that the urban energy matrix would be minimally affected by a high penetration of solar thermal systems. The indicators that are positively affected are related to energy self-sufficiency, emissions, and employment at the expense of an increase in the cost of energy. Moreover, the analysis of the impact on consumption exclusively in the residential sector shows that liquefied petroleum gas consumption would drop from 73 to 64%, mainly because the liquefied gas is used in cooking. However, the... [more]

Miscible viscous fingering occurs when a less viscous fluid displaces a more viscous one in porous media or a Hele−Shaw cell. Such flow instabilities are of particular interest in a variety of applications in flows and displacements in subsurface energy and environment systems. In this study, we investigate the miscible viscous fingering dynamics experimentally using water to displace glycerol in a sealed Hele−Shaw cell with two wells located in it instead of at the boundary or corners. We comprehensively examine the spatial and temporal variations of fingering dynamics, different flow regimes, and how they are affected by the water injection rate and control of pressure or rate at the outlet. Alongside the widely recognized diffusion-dominated and convection-dominated flow regimes, we identify three new regimes: a slow expansion regime prior to breakthrough, a rapid shrinkage regime immediately after breakthrough, and a uniform, slow expansion regime without fingering instability. Eac... [more]

The study addressed broad aspects related to digital technology platforms and renewable energy sources, including the integration of these systems and concepts. The main objective was to identify the implementation environment for a digital technology platform of renewable energy sources (RES) based on business and consumer feedback. This gives an insight into whether there is a favourable environment for implementing a RES digital technology platform. The study was based on research carried out using computer-assisted telephone interview (CATI) and computer-assisted web interview (CAWI) methods. Additionally, an alternative model of attitudes towards digital technology platforms (DTPs) built using CATREG (categorical regression) analysis was also referred to. The study found that currently, there is a positive attitude among companies, including those which install RES systems, as well as among consumers towards the implementation of DTP-based RES projects. This attitude is driven by... [more]

This study examined the literature on life cycle assessment on the ferromanganese alloy production route. The environmental impacts of raw material acquisition through the production of carbon reductants to the production of ferromanganese alloys were examined and compared. The transition from the current fossil fuel-based production to a more sustainable production route was reviewed. Besides the environmental impact, policy and socioeconomic impacts were considered due to evaluation course of differences in the production routes. Charcoal has the potential to substantially replace fossil fuel reductants in the upcoming decades. The environmental impact from current ferromanganese alloy production can be reduced by ≥20% by the charcoal produced in slow pyrolysis kilns, which can be further reduced by ≥50% for a sustainable production in high-efficient retorts. Certificated biomass can ensure a sustainable growth to avoid deforestation and acidification of the environment. Although gre... [more]

Batch electrocoagulation (BEC), continuous electrocoagulation (CEC), and chemical precipitation (CP) were compared in struvite (MgNH4PO4·6H2O) precipitation from synthetic and authentic water. In synthetic water treatment (SWT), struvite yield was in BEC 1.72, CEC 0.61, and CP 1.54 kg/m3. Corresponding values in authentic water treatment (AWT) were 2.55, 3.04, and 2.47 kg/m3. In SWT, 1 kg struvite costs in BEC, CEC, and CP were 0.55, 0.55, and 0.11 €, respectively, for AWT 0.35, 0.22 and 0.07 €. Phosphate removal in SWT was 93.6, 74.5, and 71.6% in BEC, CEC, and CP, respectively, the corresponding rates in AWT were 89.7, 77.8, and 74.4%. Ammonium removal for SWT in BEC, CEC, and CP were 79.4, 51.5, and 62.5%, respectively, rates in AWT 56.1, 64.1, and 60.9%. Efficiency in CEC and BEC are equal in nutrient recovery in SWT, although energy efficiency was better in CEC. CP is cheaper than BEC and CEC.

The use of biochar as an adsorbent for wastewater treatment purposes has been hindered due to its lower surface area compared to activated carbon. Current research on increasing surface functional groups on biochar surfaces to improve its adsorption performance suggests using high chemical concentration and long period of modification. This study solves these problems by focusing on improving surface functionalities of biochar via the hydrothermal functionalization process. Oil palm empty fruit bunch biochar was functionalized using autoclave with nitric acid as the functionalization agent. Functionalized biochar properties such as Brunauer−Emmett−Teller (BET) surface area and surface functional groups were analyzed and compared with untreated biochar. Fourier Transform Infrared (FTIR) spectroscopic analysis shows a significant increase in absorption by oxygen functional groups and is corroborated with energy dispersive X-ray (EDX) analysis. The process does not result in any major cha... [more]

Drying is one of the oldest methods for food preservation that removes the water from fruit and makes it available for consumption throughout the year. Dried fruits can be produced by small- and large-scale processors, which makes them a very popular food among consumers and food manufacturers. The most frequent uses of drying technology include osmotic dehydration, vacuum drying, freeze-drying and different combinations of other drying technologies. However, drying may provoke undesirable changes with respect to physiochemical, sensory, nutritional and microbiological quality. Drying process energy efficiency and the quality of dried fruits are crucial factors in fruit drying. Recently, innovative technologies such as ultrasound, pulsed electric field and high pressure may be used as a pretreatment or in combination with traditional drying technologies for process intensification. This could result in quality improvements of dried fruits and enhanced efficiency and capacity of the pro... [more]

A novel procedure to determine the environmental quality of boilers based on the combustion entropy degradation, the pollutants emission and the device efficiency is proposed. The entropy generation due to the chemical reaction was determined and then the irreversibilities on the external environment were first quantified. Successively, the entropy generation numbers of the combustion reactions were combined with the heat transfer process entropy generation of the boilers to consider the actual functioning conditions, in order to quantify the environmental damages by introducing an Environment Quality Index (EQI). A parametric study varying the heat exchanger efficiency, fluid flow rates and temperatures, for different fuel typologies, was performed to assess the environmental impact. Solar hydrogen was considered for its importance as future renewable energy carrier. The results showed that the highest EQI was produced by the natural gas, but if heat exchanger parameters are defined o... [more]

The agriculture and livestock industry generate waste used in anaerobic digestion to produce biogas containing methane (CH4), useful in the generation of electricity and heat. However, although biogas is mainly composed of CH4 (~65%) and CO2 (~34%), among the 1% of other compounds present is hydrogen sulphide (H2S) which deteriorates engines and power generation fuel cells that use biogas, generating a foul smell and contaminating the environment. As a solution to this, anoxic biofiltration, specifically with biotrickling filters (BTFs), stands out in terms of the elimination of H2S as it is cost-effective, efficient, and more environmentally friendly than chemical solutions. Research on the topic is uneven in terms of presenting performance markers, underestimating many microbiological indicators. Research from the last decade was analyzed (2010−2020), demonstrating that only 56% of the reviewed publications did not report microbiological analysis related to sulphur oxidising bacteria... [more]

The issue of sustainability is a growing concern and has led to many environmentally friendly chemical productions through a great intensification of the use of biomass conversion processes. Thermal conversion of biomass is one of the most attractive tools currently used, and pyrolytic treatments represent the most flexible approach to biomass conversion. In this scenario, microwave-assisted pyrolysis could be a solid choice for the production of multi-chemical mixtures known as bio-oils. Bio-oils could represent a promising new source of high-value species ranging from bioactive chemicals to green solvents. In this review, we have summarized the most recent developments regarding bio-oil production through microwave-induced pyrolytic degradation of biomasses.

Recent national government policy in Ireland proposes a radical transformation of the energy sector and a large reduction in CO2 emissions by 2050. Water and energy form the water−energy nexus, with water being an essential component in energy production. However, the connection between the production of energy and water is rarely made. In particular, the end-user processes are generally excluded because they occur outside the water industry. The present study includes two simple approaches for industrial sites to calculate their carbon footprint in the water sector. The assessment of the milk powder manufacturing using both approaches indicates that the combined emission factor of the water supply and treatment is approximately 1.28 kg CO2 m−3 of water. The dairy production among steel, textile, and paper industries appears to be the most carbon-emitting industry. However, the results show that the carbon intensity of the water supply and treatment can be minimized by the integration... [more]

The current research investigated the potential environmental risk of the polycyclic musk compounds, Galaxolide® (HHCB) and Tonalide® (AHTN), in the marine environments. These substances are lipophilic, bioaccumulated, and potentially biomagnified in aquatic organisms. To understand the toxicity of HHCB and AHTN, acute toxicity tests were performed by exposing marine microalgae (Phaeodactylum tricornutum, Tretraselmis chuii, and Isochrysis galbana), crustaceans (Artemia franciscana), echinoderms (Paracentrotus lividus), bivalves (Mytilus galloprovincialis), fish (Sparus aurata), and a candidate freshwater microalga (Raphidocelis subcapitata) to environmentally relevant concentrations (0.005−5 µg/L) following standardized protocols (US EPA, Environment Canada and OECD). P. tricornutum and I. galbana were sensitive to both substances and for P. tricornutum exposed to HHCB and AHTN, the IC10 values (the inhibition concentration at which 10% microalgae growth inhibition was observed) were... [more]

Conventional biological nutrient removal processes in municipal wastewater treatment plants are energy-consuming, with oxygen supply accounting for 45−75% of the energy expenditure. Many recent studies examined the implications of the anammox process in sidestream wastewater treatment to reduce energy consumption, however, the process did not successfully remove nitrogen in mainstream wastewater treatment with relatively low ammonia concentrations. In this study, blue light was applied as an inhibitor of nitrite-oxidizing bacteria (NOB) in a photo sequencing batch reactor (PSBR) containing raw wastewater. This simulated a biological nitrogen removal system for the investigation of its application potential in nitrite accumulation and nitrogen removal. It was found that blue light illumination effectively inhibited NOB rather than ammonia-oxidizing bacteria due to their different sensitivity to light, resulting in partial nitrification. It was also observed that the NOB inhibition rates... [more]

Modern and innovative dairy cattle breeding technologies are highly dependent on the level of mechanization. This article presents modern solutions for dairy cattle breeding, in particular, for livestock buildings, in which longitudinal development is possible in accordance with the farm’s needs as well as with obtaining additional energy from biogas and post-ferment for granulated organic fertilizer. In the analysed technology for milk production, methane fermentation, biogas yield, and the possibility of fertilizer production in the form of granules are considered. The presented modular cattle breeding technology includes sustainable production, which is economic; environmentally friendly, with preconditions in the facility including animal welfare; and socially acceptable, resulting from a high level of mechanization, which ensures both comfortable working conditions and high milk quality. The presented production line is an integral part of the milk production process with the poss... [more]

SO2 which is usually emitted at high temperature is one of the most important air pollutants. It is of great significance to develop high temperature SO2 adsorbent with high efficiency and low cost. In this work, a series of hydrotalcite-like compound-derived CaAlO and CaXAlO(X = Ce, Co) were prepared by coprecipitation and calcination method, and were employed as adsorbents for SO2 adsorption at high temperature (700 °C). The structure and surface properties of these adsorbents were characterized by XRD, Brunauer−Emmett−Teller (BET), Derivative thermogravimetric analysis (DTG) and CO2-TPD (temperature programmed desorption) measurement. Addition of a minor amount of Ce, Co (5 wt%) could significantly increase the number of weak alkalinity sites. CaO in CaCeAlO showed the best SO2 adsorption capacity of 1.34 g/g, which is two times higher than that of CaO in CaAlO (0.58 g/g).

Bioprocessing is a very important part of biotechnology that utilizes living organisms and their components to produce various types of products [...]

The considerable amount of Cr(VI) pollutants in the aqueous environment is a significant environmental concern that cannot be ignored. A series of novel Mxene−CS inorganic−organic composite nanomaterials synthesized by using the solution reaction method was applied to treat the Cr(VI) contaminated water. The Mxene−CS composites were characterized through SEM (scanning electron microscope), XRD (X−ray diffraction), XPS (X−ray photoelectron spectroscopy), and FTIR (Fourier transform infrared). The XRD patterns (observed at 2θ of 18.1°, 35.8°, 41.5°, and 60.1°) and the FT−IR spectra (-NH2 group for 1635 and 1517 cm−1, and -OH group for 3482 cm−1) illustrated that CS was successfully loaded on the Mxene. The effects of solution pH, the dosage of Mxene−CS, and duration time on the adsorption of Cr(VI) by synthesized Mxene−CS were investigated. The removal efficiency of Cr(VI) was increased from 12.9% to 40.5% with Mxene−CS dosage ranging from 0.02 to 0.12 g/L. The adsorption process could b... [more]

Hydroponic farms produce wastewater that need to be treated before being released into the environment. A three-step screening process (microplate, batch, and semi-continuous flasks experiments) initially designed to select an efficient microalgae strain allowed the isolation of a consortium that naturally developed in the hydroponic farm wastewater. During the non-optimized semi-continuous experiments, the best performing microalgae strain, Scenedesmus obliquus UTEX393 and the wastewater-born consortium cultures achieved good average linear growth rate (0.186 and 0.198/d, respectively) and high average nitrogen removal rates (23.5 mgN/L/d and 21.9 mgN/L/d, respectively). Phosphorus removal was very high probably due to precipitation. An integrated process was designed to treat the hydroponic farm wastewater using the wastewater-born consortium. Despite relatively low coagulation efficiencies in the preliminary tests, when integrated in a continuous process, chitosan was efficient to h... [more]

Sugar is the most important food supplement of our daily diet. During the production, sugar mills use a large volume of water and produce a significant amount of wastewater polluted with high organic compounds. Therefore, it is necessary to treat the wastewater before their disposal. For this reason, this article presents the results obtained from the monitoring of a coupled system of aged refuse filled bioreactors (ARFB) in full scale to treat wastewater from a sugar mill. The coupled system consists of two bioreactors (a primary one -ARFB1- and a rectification one -ARFB2-) arranged in a series with identical geometries. The ARFB1-ARFB2 system was evaluated in two stages. The first stage (maintenance period) for 28 weeks, and second stage (Zafra season) for 29 weeks. The system was fed with sugar mill wastewater (SMW) with a chemical oxygen demand (COD) of 2787 ± 1552 mg/L and 2601 ± 722 mg/L, respectively. As results, we observed a rapid stabilization of the system over 2 months. In... [more]

In this paper, an arc was drawn over ten years of research activities from three chairs of the Montanuniversitaet Leoben, as well as industrial partners. The superior objective of this research effort was to develop a wet-mechanical process for the recovery of polyolefin concentrates (90 wt% polyolefins) from mixed waste fraction for use in chemical recycling and to advance this new technology to commercial maturity. As a bridge technology, it would close the gap between state-of-the-art dry processing of mixed plastic waste materials and chemical plastic recycling via thermo-chemical conversion. The methods used were mainly tested in a lab-scale plant with a throughput capacity of 50 to 200 kg/h depending on the bulk density of the used feedstock. Further studies for the treatment and usage of the main products and by-products, as well as chemical analyses of them, were completed during the investigation. Within these series of tests, polyolefin concentrates, which satisfied the requi... [more]

Absorption air-conditioning systems have a great advantage in terms of energy conservation and environmental protection. However, the large amount of energy waste in the thermal regeneration process leads to lower efficiency and impedes its development. To reduce energy loss and improve performance, a local heating regeneration method is proposed in this paper. The main principle is reducing the volume of the liquid participating regeneration. Including the solar steam mode, two modes are introduced and configured. Theoretical and experimental research has been made on the new methods. Models have been developed for comparison analysis. Experiments have been conducted on water and absorbent solution with different modes. Performance has been evaluated based on the experimental data. The results expose the influence of different parameters, like liquid volume and solution concentration, on the regeneration process. The local heating method improved the regeneration efficiency by 40% in... [more]

The Europe 2020 Strategy was proposed with a long-term vision to ensure prosperity, development, and competitiveness for the member countries. This strategy is divided into three main areas named “growth”. One of these is sustainable growth. This is an area of sustainability, where the partial targets are referred to as the “20-20-20 approach”, and includes a reduction of greenhouse gas emissions, an increase in energy efficiency, and the sharing of renewable energy sources. However, questions arise, including: How do member states meet these targets? Which countries are leaders in this area? According to these stated questions, the aim of this article is to assess how EU countries are meeting the set targets for sustainable growth resulting from the Europe 2020 strategy and to identify the countries with the best results in this area. We looked for answers to these questions in the analysis of sustainable indicators, which were transformed into a synthetic measure for comparability of... [more]

This paper presents the computation of the cable ampacity and the temperature distribution through long duration based on the equivalent thermal circuit based on IEC 60287 standard and the Finite element method using COMSOL (Multiphysics environment, version 5.5). This study investigated the cable ampacity and the temperature rise of the cable core and sheath at steady state and emergency conditions. The cable ampacity was investigated at different conditions such as the variation of cable depth, soil properties, and soil temperature. The results confirmed the adaptation between the thermal circuit results and the COMSOL results as well as the effectiveness of using the numerical method to compute the cable ampacity. Using the COMSOL-based thermal properties evaluations, the transient performance of the cable is ascertained. The transient study is performed for different cable loading currents and dry zone sizes.

This study focuses on using a facile method for the green preparation of activated carbon (AC) from palm tree fiber (PTF) waste. The synthesized cost-effective AC was investigated for the removal of an anionic dye (Congo red, CR) and a cationic dye (Rhodamine B, RhB) from wastewater. The morphological and structural characterization of the synthesized AC were performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), surface area, Fourier transform infrared spectroscopy (FTIR), total pore volume, average pore diameter and pore size distribution, zeta potential, and zero-point charge. To investigate the adsorption efficiency, different parameters such as adsorbent dosage, solution pH, initial dye concentration, and duration were applied using the batch experiments. Various adsorption isotherm and kinetics models were applied to study the adsorption mechanism and dynamics. The results showed that chemical activation with a weak acid (H3PO4) at 400 °C for 30... [more]