peer reviewed | This study analyzed the potential use of Payment for Ecosystem Services (PES) as a strategy for improving water supply management. This study focused on the Siminehroud Sub-basin due to its high importance to the Basin of Urmia Lake (UL). Siminehroud is the second provider of water (by volume) to Urmia Lake. To evaluate the technical and economic feasibility of a PES scheme, the current land use map was extracted using satellite imagery. In addition, the two algorithms of Support Vector Machines (SVMs) and Maximum Likelihood (ML) are used for Landsat images classification, rather than analyzing the relationship between land use and ecosystem services. Then, the most relevant ecosystem services provided in the region were evaluated using the Benefit Transfer Method. In the last step, by designing and implementing a survey, on the one hand, the local farmers' Willingness to Accept (WTA) cash payments for reducing the area they cultivate, and on the other hand, the farmers' Willingness to Pay (WTP) for managing the water consumption were determined. The results illustrated that the WTA program is more acceptable among the beneficiaries. It is also notable that this program needs very high governmental funding. Furthermore, the results of the program indicate that the land area out of the cultivation cycle will gradually increase while the price of agricultural water will also increase.

The intensification of the human activity in urban areas as a result of the increasing population has contributed to the air pollution worsening in cities. To reverse this trend, the European Commission established a legal framework to improve the air quality. Thereby the Member States need to develop air quality plans (AQP) for zones and agglomerations where air quality limit values are exceeded, in order to implement pollution control strategies and meet the legal requirements. Understanding the reasons for the levels of air quality non–compliance as well as evaluating available and commonly used tools to predict the air quality and their effects, is crucial for the decision–making process on air quality management policies. Based on a compilation of regional and local AQP, a review of assessment capabilities and used modeling tools to evaluate the effects of emission abatement measures on the air quality and health was performed. In most cases, models are applied to estimate emissions and to assess the resulting air quality from both reference and emission abatement scenarios. Air quality’s impacts on the health and environment are rarely quantified. Regarding the air quality assessment, beyond the modeling, monitored data for validation of simulations are also used. Some studies, however, do not include the use of air quality models, considering the monitoring network as spatially representative of the study domain (e.g. Lisbon Region, Riga, Malta). In order to overcome methodological limitations for quantifying the impacts of emission abatement measures, economic evaluation techniques or even Integrated Assessment Methodologies (IAM) have been developed. IAM, already applied in some AQP or case studies, namely for Antwerp and London, are used for assessing how reductions in emissions contribute to improve air quality, reduce exposure and protect human health.

In recent years, Electric Vehicles (EVs) are contributing a major share in Thailand and benefit the environment. Most of the EV charging stations are sourced from solar energy as it becomes a carbon-free source of energy production. Secondly, Thailand is rich in solar irradiance, and higher irradiance leads to higher power production. On the other hand, in tropical conditions, solar Photovoltaic (PV) module temperature increases following the solar irradiance due to high ambient temperature, resulting negative impact on the efficiency and lifespan of photovoltaic (PV) modules. Further, to increase PV power production, in this study, different rates of cooling strategies are proposed. The study found that reducing the temperature by 5% to 25% resulted in increased average power outputs of 5947.94W, 6021.43W, 6094.92W, 6168.41W, and 6241W, respectively. Notably, 25% of the cooling rate achieved higher production. However, it is lower than the nominal power production. Following that, economic analysis and environmental impacts are analyzed for Thailand’s EV charging station using a different cooling rate of PV module. Overall, it is concluded that, depending on the economic viability of the EV charging station, cooling technology can be applied, and it will benefit the EV charging station both economically and environmentally. To further enhance the solar PV power production approach for EV charging stations in Thailand, it is imperative to prioritize future endeavors towards optimizing cooling technology, integrating energy storage, and implementing supportive policies.

In this research, the thermodynamic (energy and exergy) and economic assessments of heat pump-assisted solar still with paraffin wax was investigated under the climatic conditions of Coimbatore city in India during the year 2020. The observed experimental results in heat pump solar still (HPSS) was compared with conventional solar still (CSS) in the same climatic conditions. This model works on the principle of latent heat observed during condensation which was regenerated by heat pump to preheat the inlet basin saline water of solar still. The observed maximum productivity of HPSS was about 14.5 kg/m², which was 83.7% higher than CSS. The energy and exergy efficiency improvement in HPSS were about 65% and 82.3%, respectively, higher than CSS. The observed maximum coefficient of performance (COP) of heat pump was about 2.61. The payback period (PBP) of CSS and HPSS was estimated to be about 4.1 months and 3.2 months, respectively. The results observed in HPSS have significantly improved the daily productivity than CSS.

The proposed research work presents the performance analysis of the vertically mounted bifacial module (VBFM) with and without tracking during the summer and winter seasons. Also, various parameters like energy efficiency, electrical efficiency, electrical exergy, thermal exergy, exergy efficiency, environmental analysis, economic analysis, exergoeconomic analysis, enviroeconomic analysis, and exergoenviroeconomic analysis of the VBFM were studied and presented. The comparative analysis was carried out between two bifacial solar modules installed in two different orientations (east–west and south-north). The experiments were conducted in the real climatic condition of Minjur, Tamil Nadu, India. Under the summer and winter climatic conditions, when the lifetime period of 10, 15, and 20 years are considered higher energy production factor and higher life cycle conversion efficiency was obtained from the vertically mounted bifacial module—east–west (VBFM-EW) with tracking during summer and vertically mounted bifacial module—north–south (VBFM-SN) module without tracking during the winter season. Exergetic cost was calculated by considering 15, 20, 25, and 30 years of the system with 2%, 5%, and 10% interest rates. The maximum exergetic cost was obtained from 30 years of the system under a 2% interest rate. The enviroeconomic and exergoenviroeconomic analysis provides the carbon credits earned from the E-W module was a maximum of Rs 11,036.18 during the summer season and Rs 12,413.48 from the VBFM-SN module during the winter season, considering the life of the system as 15 years.

Freeze–thaw (F/T) and electrochemistry both are environment-friendly and efficient sludge treatment technologies. In this study, the sludge samples were frozen at − 15 °C, and 20% g/gTss activated carbon (AC) was added to the dissolved sludge. Finally, the uniformly mixed sludge was treated at a voltage of 15 V for 25 min. During the experiment, the effect of F/T on the floc structure was analyzed by a laser particle analyzer and scanning electron microscope. F/T treatment improved the dewatering performance of the sludge and promoted the aggregation of sludge flocs into larger particles either. At the same time, the median diameter (D50) increased from 45.27 to 128.94 μm. AC was added to the thawed sludge solution before electrochemical treatment (EP). The conductivity of AC enhanced the effect of EP, thereby cracking the sludge flocs. Therefore, the three-dimensional excitation–emission matrix (3D-EEM) intensity of tightly bound extracellular polymeric substances (TB-EPS) decreased significantly. The protein in TB-EPS decreased from 54 to 33%, and the D50 was also reduced to 105.3 μm. The final specific resistance of filtration and water content were reduced by 96.39% and 32.17%, respectively. The dehydrated cake elemental analysis showed that increased AC improved the sludge cake’s combustion efficiency significantly. Moreover, the preliminary economic analysis indicated that the cost of this research was low, which implied the potential application value of combined treatment.

This study aims to augment the performance of a solar desalination unit. To experimental examine this idea, a modified solar still with three different microparticles doped in black paint-coated absorber were designed, fabricated, and tested in Jaipur, India. Three different microparticles such as copper, aluminum, and tin with particle size of 50–80 μm with weight concentration of 10% were doped in black paint and then coated on the absorber of solar still. The coated absorber of solar still were compared with the conventional solar still without any microparticle coating to obtain the effect of different coating materials on the water productivity, thermal performance, economic, and environment-economics analysis of solar still. The result showed that under the water depth of 1 cm, coating of copper, aluminum, and tin on absorber augmented the full-day water yield by 33.13, 22.18, and 11.53%, compared to conventional solar still without any coating. In addition, full-day energy and exergy efficiency of solar still with copper-coated absorber exhibited maximum values compared to all other solar stills, owing to the higher thermal conductivity and excellent solar-thermal conversion behaviors of copper. The cost of water per liter estimated through economic analysis was found to be US $ 0.0074 for conventional solar still, which was significantly reduced to US $ 0.0066 in the case of solar still with copper-coated absorber along with the payback time of 2.7 months. The environment-economic assessment estimated that solar still with copper-coated absorber plate has reduced the 13.19 tons of CO₂ emission. It is concluded that augmented heat transfer rate from water basin to inner glass surface through utilization of microparticle coating would pave a pathway to develop energy-efficient low-cost solar-based desalination system.

The single-basin solar still is one of the effective ways of desalinating the seawater at an affordable price. But, the productivity of solar still is low and many kinds of research are under progress to enhance the yield. In this regard, a single-basin solar still with a solid staggered pin finned absorber inserted into a paraffin wax bed is developed to investigate the yield enhancement. This investigation is carried out by varying the seawater depths of the absorber basin from 2 to 4 cm in the developed solar still. The obtained results are compared with conventional solar still without fins and PCM bed. It is observed that the yield obtained in the developed solar still with 2-cm depth is having greater productivity when compared to other cases of seawater depths (3 cm and 4 cm). The yield of modified solar still and conventional solar still at 2-cm water depth is 3750 mL/m² and 3017 mL/m² respectively. It is also observed that thermal efficiency of the developed single-basin solar still is increased by 12.23%, 22.66% and 24.26% respectively compared to the conventional solar still for the seawater depths of 4 cm, 3 cm and 2 cm. In addition to that, it is observed from the economic analysis, the cost per litre potable water produced from modified solar still and conventional solar still is ₹ 2.1 and ₹ 2.25 respectively. Also, the environmental analysis is carried out to analyse the carbon credit from the developed single-basin solar still and found that the carbon credit gained from modified still and conventional solar still is $ 172.8 and $ 137.9 respectively. Based on this investigation, it is observed that the developed single-basin solar still with solid staggered pin finned absorber inserted into paraffin wax bed can be effectively used for the drinking water production to overcome the water scarcity.

Solar still is one of the economic and eminent ways of desalinating the available sea/brackish water into potable water. However, the distillate output from the solar still is moderate and various researches are being conducted to improve the productivity of solar still. In this research, a novel bottom finned (solid and hollow) absorber basin is designed and developed to enhance the heat transfer between absorber and phase change material (PCM) which further improves the freshwater productivity from the solar still. The results of the investigation are compared with the conventional solar still. The three single-slope solar stills considered developed for evaluating the effect of modification on the freshwater productivity are (i) conventional solar still (CSS), (ii) solar still with hollow finned absorber inserted in energy storage (SSHFES), and (c) solar still with solid finned absorber inserted in energy storage (SSSFES). The investigation results reported that the SSHFES has greater productivity when compared with the SSSFES and CSS. The freshwater productivity from the SSHFES is 4085 mL/m² day, whereas the freshwater productivity from SSSFES and CSS is 3485 mL/m² day and 2885 mL/m² day, respectively. The efficiency of SSHFES and SSSFES is increased by 41.67% and 20.81% relative to the CSS. It is observed from economic analysis that the cost per liter (CPL) freshwater produced by SSHFES, SSSFES and CSS is about ₹ 2.3 ($ 0.032), ₹ 2.5 ($ 0.034), and ₹2.6 ($ 0.036), respectively. The payback periods of SSHFES, SSSFES, and CSS is 6.3 months, 6.8 months, and 7.1 months, respectively. Also, the enviroeconomic analysis conferred that the carbon credit gained from the SSHFES is $189.28 whereas SSSFES and CSS gained only $158.2 and $132.02. Based on the current study, it is observed that the solar still with hollow finned absorber inserted in energy storage (SSHFES) is effective when compared to others and it is viable for potable water production at cheaper costs.

In this research work, the productivity, energy, exergy, and economic and enviro-economic performance in crushed gravel sand heat storage and biomass evaporator-assisted solar still (CGS-BSS) have been investigated and compared the results with conventional solar still (CSS) under the similar climatic conditions of Coimbatore City during the year 2019. The heat accumulated in crushed gravel sand and biomass evaporator have been used to preheat the inlet saline water and air vapor before entering into the solar still. This results in enhanced air vapor mixture temperature and evaporative heat transfer rate of CGS-BSS significantly. The productivity, energy, and exergy efficiencies in CGS-BSS were improved by 34.6%, 34.4%, and 35%, respectively when compared to CSS. In economic analysis, the payback period (PBP) in both CGS-BSS and CSS was estimated to be about 4.7 months and 3.9 months, respectively. Furthermore, in enviro-economic analysis, the CO₂ emission estimated in CGS-BSS and CSS was about 16.63 tons and 8.18 tons, respectively during its lifetime of 10 years.