An integrated financial and environmental evaluation framework to optimize residential photovoltaic solar systems in Australia from recession uncertainties.

This study assesses the financial viability and environmental evaluation of Photovoltaic (PV) panels from the perspective of the recent economic recession due to the Russia-Ukraine war. The financial viability of PV installation is calculated based on the estimated price, solar rebates, feed-in tariff, energy supply cost, and other evaluation parameters available at the assessment time. This calculation implicitly assumes variable discount rates (4%, 7%, and 12%) to show how the future will unfold and its correlations with design parameters. Details of economic appraisal integrating current inflation, rebates, and incentives of solar systems have been analyzed for the first time in this study. Financial indicators reveal the advantages of installing a grid-connected solar system (SS) over a solar battery storage system (SSWB). Compared to other installation systems, the lowest payback (PB) and highest internal rate of return (IRR) are observed for a 7 kW grid-connected solar system. Relative uncertainties of solar installation systems represent the necessity of government subsidies (r = -0.602) for solar storage batteries. LCA signifies the energy-intensive process of manufacturing metallurgical-grade (MG) silicon is the primary cause of significant greenhouse gas (GHG) emissions and cumulative energy demand (CED) for PV panels. A potential amount of metal and fossil fuels is depleted for interconnective components of solar installation systems. Amorphous solar panels exhibit lower impacts than polycrystalline, but further upgradation in service life is required to become cost-effective and cope with current inflation.

Recycling waste vehicle tyres into crumb rubber and the transition to renewable energy sources: A comprehensive life cycle assessment.

This study conducts a comprehensive life cycle assessment (LCA) on converting waste vehicle tyres into recycled crumb rubber (CR) granules as an alternative polymer for enhancing asphalt properties. The LCA study has been performed on acquired industrial primary data by incorporating CR at different proportions of binder in one ton (1-ton) of asphalt mix following the wet method. The uncertainty analysis of design variables identified a relatively strong positive relation of emissions with the equipment energy consumption (r = 0.98). Monte Carlo simulations evaluate the potential renewable sources (solar, hydro, and wind) in sequence over fossil fuels for the possible transition in the Australian grid by 2030 and 2050, as per the Paris Agreement. 71.91% reduction of CO2 emissions is achievable by recycling vehicle tyres into crumb rubber compared to landfill and incineration. Recycling by-products of CR production, such as steel and textile, significantly mitigates negative impacts. A decrease of 2.23% emissions was associated to the use of crumb rubber as a binder modifier in the asphalt mixture via the midpoint assessment. In endpoint LCA, a higher association of resource (US$) saving costs was observed than for other protective zones, i.e., human health and ecosystem damage. Recycling 466,000 tonnes of disposable waste tyres contributes to 16.1 million US$ worth of resource savings. An equitable industry-based LCA and uncertainty analysis of design parameters can assist in prioritizing suitable options to improve efficiency and future emission strategies on a global scale.

Effect of the coagulation/persulfate pre-treatment to mitigate organic fouling in the forward osmosis of municipal wastewater treatment.

The forward osmosis (FO) membrane process has recently established in many applications such as desalination, wastewater reuse, water purification, food processing, resource recovery and sustainable power generation. However, many researchers raise the demand for systematic investigation on FO membrane fouling, which leads to reduced flux yield. In this study, the effect of coagulation/persulfate as a feed pre-treatment was used to mitigate FO organic fouling during municipal wastewater treatment, and compared with a control coagulation and potassium persulfate pre-treatments. Mass balance results using size exclusion chromatography exhibited that the decrease in the flux with consecutive filtration cycles was likely due to humic-like molecules in the feedwater. Coagulation/persulfate contributed to a more significant flux improvement than stand-alone coagulation or persulfate pre-treatment, resulting in a smaller amount of organics attachment to the membrane. A better flux enhancement by coagulation/persulfate was again evidenced by a higher decrease in the attachment of reversible and irreversible organic foulants on the membrane surface. This study identified the major organic components responsible for FO fouling and established the potential of coagulation/persulfate pre-treatment for reducing organic fouling of FO membrane during municipal wastewater treatment.

Ranitidine degradation in layered double hydroxide activated peroxymonosulfate system: impact of transition metal composition and reaction mechanisms.

Ranitidine, a competitive inhibitor of histamine H2 receptors, has been identified as an emerging micropollutant in water and wastewater, raising concerns about its potential impact on the environment and human health. This study aims to address this issue by developing an effective removal strategy using two types of layered double hydroxide (LDH) catalysts (i.e., CoFeLDH and CoCuLDH). Characterization results show that CoFeLDH catalyst has superior catalytic properties due to its stronger chemical bond compared to CoCuLDH. The degradation experiment shows that 100% degradation of ranitidine could be achieved within 20 min using 25 mg/L of CoFeLDH and 20 mg/L of peroxymonosulfate (PMS). On the other hand, CoCuLDH was less effective, achieving only 70% degradation after 60 min at a similar dosage. The degradation rate constant of CoFeLDH was 10 times higher than the rate constant of CoCuLDH at different pH range. Positive zeta potential of CoFeLDH made it superior over CoCuLDH regarding catalytic oxidation of PMS. The catalytic degradation mechanism shows that sulfate radicals played a more dominant role than hydroxyl radicals in the case of LDH catalysts. Also, CoFeLDH demonstrated a stronger radical pathway than CoCuLDH. XPS analysis of CoFeLDH revealed the cation percentages at different phases and proved the claim of being reusable even after 8 cycles. Overall, the findings suggest that CoFeLDH/PMS system proves to be a suitable choice for attaining high degradation efficiency and good stability in the remediation of ranitidine in wastewater.

Reactive layered hydroxide membrane for advanced water treatment: Micropollutant degradation and antifouling potential.

The effective removal of micropollutants by water treatment technologies remains a significant challenge. Herein, we develop a CoFe layered double hydroxide (CoFeLDH) catalytic membrane for peroxymonosulfate (PMS) activation to achieve efficient micropollutant removal with improved mass transfer rate and reaction kinetics. This study found that the CoFeLDH membrane/PMS system achieved an impressive above 98% degradation of the probe chemical ranitidine at 0.1 mM of PMS including five more micropollutants (Sulfamethoxazole, Ciprofloxacin, Carbamazepine, Acetaminophen and Bisphenol A) at satisfactory level (above 80%). Moreover, significant improvements in water flux and antifouling properties were observed, marking the membrane as a specific advancement in the removal of membrane fouling in water purification technology. The membrane demonstrated consistent degradation efficiency for several micropollutants and across a range of pH (4-9) as well as different anionic environments, thereby showing it suitability for scale-up application. The key role of reactive species such as SO4•-, and O2• - radicals in the degradation process was elucidated. This is followed by the confirmation of the occurrence of redox cycling between Co and Fe, and the presence of CoOH+ that promotes PMS activation. Over the ten cycles, the membrane could be operated with a flux recovery of up to 99.8% and maintained efficient performance over 24 h continuous operation. Finally, the efficiency in degrading micropollutants, coupled with reduced metal leaching, makes the CoFeLDH membrane as a promising technology for application in water treatment.

Application of recycled crushed glass in road pavements and pipeline bedding: An integrated environmental evaluation using LCA.

The study aims to conduct a comprehensive life cycle assessment (LCA) of mixed glass waste (MGW) recycling processes to quantify the environmental impacts of crushed glass as a partial substitute for virgin aggregate. Upstream washing, crushing, and sorting conducted at material recycling facilities (MRF) are the prime activities to assess whether reprocessed MGW in pavement construction is an alternate feasible solution. None of the previous studies explicitly account for the relative uncertainties and optimization of waste glass upstream processes from an environmental perspective. The study calculates environmental impacts using the LCA tool SimaPro considering design factors attributed to transportation, electricity consumption, use of chemicals, and water for reprocessing glass waste. Relative uncertainties of design variables and the national transition policy (2021-2030) from non-renewable to renewable energy sources have been validated by performing detailed Monte Carlo simulations. The correlation coefficients (r = 0.64, 0.58, and 0.49) of successive variables explain how the higher environmental gains of the glass recycling process are outweighed by diesel, energy consumption, and transportation distances. Compared to natural quarry sand, the recycled glass aggregate produced through crushing and recycling of its by-products reduces CO2eq emissions by 16.2 % and 46.7 %, respectively. The need for a washing line at the plant, in addition to crushing, results in a higher environmental impact over natural sand by 90.1 % and emphasizes the benefits of collecting waste glass through a separate bin, hence avoiding contamination. The result indicates that the benefit of lowering emissions varies significantly when considering waste glass landfilling. Moreover, this study evaluates the potential impacts on asphalt and reinforced concrete pavements (RCP) with 5 %, 10 %, 15 %, and 20 % replacement of natural sand with recycled glass aggregate. The LCA emphasizes the limitations of energy-intensive waste glass reprocessing. The obtained results and uncertainty analysis based on primary MRF data and recycled product applications provide meaningful suggestions for a more fit-for-purpose waste management and natural resource conservation.

Identification, classification and quantification of microplastics in road dust and stormwater.

Microplastics (MP) have become a major emerging class of pollutants representing significant eco-toxicological risks for ecosystems and marine environments. The aim of this study was to identify, classify and quantify MP present in both road dust and stormwater samples. A significantly higher level of MPs within road dust samples was detected from industrial area (1130 particles/kg of dust) than from residential area (520 particles/kg of dust), while stormwater samples from industrial and residential sites yielded 26 particles/L and 17 particles/L, respectively. Fiber-like shape accounted for 53% and 74% in road dust and stormwater samples, respectively. The main polymeric materials collected for both road dust and stormwater samples were, in order of occurrence (i) low-density polyethylene, (ii) high-density polyethylene, (iii) polypropylene, (iv) polyethylene terephthalate, (v) polystyrene, (vi) polyester and (vii) poly (amide). Most of the MP had an average maximum dimension smaller than 2 mm for both road dust and stormwater samples. The results from this study demonstrates that road dust is a significant contributor to MP pollution through direct polymeric materials wear off and transfer through stormwater, which eventually will end up in open water ways and broader ecological niches.

Engineered topographies and hydrodynamics in relation to biofouling control-a review.

Biofouling, the unwanted growth of microorganisms on submerged surfaces, has appeared as a significant impediment for underwater structures, water vessels, and medical devices. For fixing the biofouling issue, modification of the submerged surface is being experimented as a non-toxic approach worldwide. This technique necessitated altering the surface topography and roughness and developing a surface with a nano- to micro-structured pattern. The main objective of this study is to review the recent advancements in surface modification and hydrodynamic analysis concerning biofouling control. This study described the occurrence of the biofouling process, techniques suitable for biofouling control, and current state of research advancements comprehensively. Different biofilms under various hydrodynamic conditions have also been outlined in this study. Scenarios of biomimetic surfaces and underwater super-hydrophobicity, locomotion of microorganisms, nano- and micro-hydrodynamics on various surfaces around microorganisms, and material stiffness were explained thoroughly. The review also documented the approaches to inhibit the initial settlement of microorganisms and prolong the subsequent biofilm formation process for patterned surfaces. Though it is well documented that biofouling can be controlled to various degrees with different nano- and micro-structured patterned surfaces, the understanding of the underlying mechanism is still imprecise. Therefore, this review strived to present the possibilities of implementing the patterned surfaces as a physical deterrent against the settlement of fouling organisms and developing an active microfluidic environment to inhibit the initial bacterial settlement process. In general, microtopography equivalent to that of bacterial cells influences attachment via hydrodynamics, topography-induced cell placement, and air-entrapment, whereas nanotopography influences physicochemical forces through macromolecular conditioning.

Spatiotemporal variations of DOM components in the Kushiro River impacted by a wetland.

Dissolved organic matter (DOM) has been recognized as a serious water quality problem in natural water bodies receiving pollution loads from point and nonpoint sources. The present study investigates the spatiotemporal variability of DOM composition in the Kushiro River and its tributaries (Eastern Hokkaido, Japan) impacted by the Kushiro wetland. Water samples were collected in the wet and dry seasons from several locations of the river and analyzed for DOM characteristics by UV-visible and excitation-emission matrix fluorescence spectroscopy techniques and by developing water quality index. Rather than the spatial effect, significant seasonal impacts on DOM pollution in the Kushiro River were observed. Overall concentrations of DOM decreased during the dry season. The increase of specific ultraviolet absorbance in the dry season indicated an increasing trend of humification, aromaticity and molecular weight of DOM. Five fluorescent peaks, including peaks A, C, M, B, and T were predicted by EEM spectra. Peaks A and C were found to be the most dominating peaks in both the seasons and indicated enrichment of humic-like matters in river water. The intensities of poly-aromatic humic substances as well as DOM components of microbial origin increase in the wet season and proteins like autochthonous DOM increase during the dry season. The study recognized the contribution of freshly produced DOM component by the decomposition of wetland plants in wet season and effect of snowfall in the dry season. Analysis of three fluorescence indices revealed that the river water primarily contains terrestrially dominated DOM. A significant impact of the adjacent WWTPs and wetland to the river water DOM were also observed. The water quality index of river water DOM showed low to medium levels of DOM pollution in the Kushiro River.

Application of Victorian brown coal for removal of ammonium and organics from wastewater.

Brown coal is a relatively abundant and low-cost material, which has been used as an effective ion-exchanger to remove ammonium from wastewater. In this study, the influences of pH, ammonium concentration and brown coal dose were investigated for removal of ammonium content from synthetic wastewater. Raw brown coal (RBC) treated with base solution has superior ammonium removal efficiency compared to RBC, which was due to chemical alterations and thus greater attachment of ammonium molecules to base-washed brown coal (BWBC), confirmed by Fourier transform infra-red spectroscopy. Scanning electron microscopy-electron diffraction scattering has identified the augmented sodium content in BWBC, which was subsequently replaced with nitrogen upon wastewater treatment. Crystallographic analysis showed a higher crystallinity formed in BWBC compared to RBC, which was likely due to formation of sodium salt crystals during NaOH treatment. Fitting batch experimental results to adsorption kinetic models suggested that the removal of ammonium was mainly governed by the reaction process rather than the physical diffusion mechanism. Both kinetic and isotherm studies confirmed higher adsorption capacity for BWBC compared to RBC. RBC in column mode was also experimented with to show organics removal from a secondary effluent. A comparatively lower removal of organics was obtained due to inability of charge neutralization as both brown coal and organics are positively charged.