This study investigated the adsorption and removal behaviour of copper (Cu) (II) and cadmium (Cd) (II) ions using rice husk and rice straw in aqueous solutions. Different parameters were used to investigate their adsorption performance in saline conditions and the optimal level of biosorption at different pH levels. The main parameters were pH (3, 6 and 9), initial concentration level of heavy metals (Cu (II) 5, 10, 20, 40 and 60 mg/L and Cd (II) 0.5, 1, 2, 4 and 8 mg/L, respectively), salinity (0, 50 and 100 mM NaCl) and contact time (ranging from 3 to 60 min). Langmuir and Freundlich isotherm models were applied to analyse the removal efficiency and sorption capacity of the pretreated rice husk and rice straw. The removal efficiency and adsorption capacity generally increased with the pH and reached a plateau in alkaline conditions. The percentage removal of Cu (II) by rice husk reached 97 % at pH 9 and 95 % by rice straw at pH 6. Biosorption performance increased in the absence of NaCl. Kinetic studies for both metals revealed that the biosorption of Cu (II) and Cd (II) onto rice straw and husk was pseudo-second order.

This study reviewed the municipal solid waste (MSW) composition, the management practices, and the use of life cycle assessment (LCA) tool for MSW management (MSWM) options in the various income group countries. LCA studies require inventory data, which is difficult to procure for any country including higher income group countries, and this issue gets compounded in low-income and lower middle-income group countries, which limits the implementation of LCA. This paper compared the use of LCA for MSWM between high-income and low-income group countries and also highlights the gap in using LCA for MSWM. A very limited number of LCA studies on MSWM were found for low-income group countries in comparison to high-income group countries. The study also provided a critical discussion on the challenges in applications of LCA in MSWM for better solid waste management in low-income and lower middle-income group countries. The study will help in taking up LCA studies in low-income countries to improve the overall MSWM efficiency.

Among the wide range of compounds reaching the soil are the veterinary antimicrobials. Since no regulations regarding acceptable levels of drug concentrations in the environment exist, monitoring tests, particularly concerning soils, are carried out very rarely. This study presents a preliminary assessment of the contamination of agricultural soils in Northern Poland with seven antimicrobial veterinary medicines which has never been carried out before. Veterinary drugs were detected in 54% of the examined soil samples; the most commonly detected drugs were sulfonamides and trimethoprim. The highest indicated concentrations refer to enrofloxacin (57.0 μg kg⁻¹) and trimethoprim (47.8 μg kg⁻¹). The presence of these target drugs in the soil environment confirms the need for further monitoring studies. The analytical methods developed in this study are an excellent tool to achieve this goal and allow an estimation of the risk connected with the presence of veterinary antimicrobials in soils.

Viscosity remedial technology, which uses a water-soluble polymer mixed with remedial fluids, has been introduced in recent years to improve the removal efficacy of perchloroethylene/tetrachloroethylene (PCE) by improving oxidant coverage (i.e. sweep efficiency). Xanthan gum and hydrolysed polyacrylamide (HPAM) are relatively stable with time and temperature and possess salt and oxidation resistance, indicating that they may be good flooding agents (the former is better than the latter in this work). In this work, we quantified the polymer directly improved oxidation of PCE during transport by using a two-dimensional flow tank. Using a low pore volume (≤3.0), the removal rate of the PCE increased with the polymer concentration before stabilizing at approximately 93.00 and 88.30% for xanthan and HPAM, respectively. In this work, over 80% of PCE was removed via less than 3.0 PV of the SDS solution, whereas complete removal (100%) was achieved with less than 3.0 PV of SDS foam. Furthermore, the new experimental discoveries demonstrate that xanthan is better than HPAM and SDS foam is a better remediation agent than the SDS solution for removing PCE. Graphical abstract (Reaction device, A - inlet device (pump 1#), B - 2D tank, C - outflow device (pump 2#), D - data recording and processing device, E - microscopic expression, E (a) - KMnO₄ flushing, E (b) - polymer solution flushing).

The treatment of mine drainage-impacted waters generates considerable amounts of sludge, which raises several concerns, such as storage and disposal, stability, and potential social and environmental impacts. To alleviate the storage and management costs, as well as to give the mine sludge a second life, recovery and reuse have recently become interesting options. In this review, different recovery and reuse options of sludge originating from active and passive treatment of mine drainage are identified and thoroughly discussed, based on available laboratory and field studies. The most valuable products presently recovered from the mine sludge are the iron oxy-hydroxides (ochre). Other by-products include metals, elemental sulfur, and calcium carbonate. Mine sludge reuse includes the removal of contaminants, such as As, P, dye, and rare earth elements. Mine sludge can also be reused as stabilizer for contaminated soil, as fertilizer in agriculture/horticulture, as substitute material in construction, as cover over tailings for acid mine drainage prevention and control, as material to sequester carbon dioxide, and in cement and pigment industries. The review also stresses out some of the current challenges and research needs. Finally, in order to move forward, studies are needed to better estimate the contribution of sludge recovery/reuse to the overall costs of mine water treatment.

High Canadian waste disposal rates necessitate landfill gas monitoring and accurate forecasting. CO₂ estimates in LandGEM version 3.02 currently rest on the assumptions that CO₂ is a function of CH₄, where the two gases make up nearly 100% of landfill gas content, leading to overestimated CO₂ collection estimates. A total of 25 cases (five formulas, five approaches) compared annual CO₂ collection at four western Canadian landfills. Despite common use in literature, the 1:1 ratio of CH₄ to CO₂ was not recommended to forecast landfill gas collection in cold climates. The existing modelling approach significantly overestimated CO₂ production in three of four sites, resulting in the highest residual sum of squares. Optimization resulted in the most accurate results for all formulas and approaches, which had the greatest reduction in residual sums of squares (RSS) over the default approach (60.1 to 97.7%). The 1.4 Ratio approach for L ₒ:L ₒ₋CO₂ yielded the second most accurate results for CO₂ flow (mean RSS reduction of 50.2% for all sites and subsection models). The annual k-modified LandGEM calculated k’s via two empirical formulas (based on precipitation) and yielded the lowest accuracy in 12 of 20 approaches. Unlike other studies, strong relationships between optimized annual k’s and precipitation were not observed.

Hydatid disease is a helminth infection with various clinical complications caused by the larval stage of the dog tapeworm Echinococcus granulosus. The scolicidal agents have been broadly applied for inactivation of the fertile cysts up to now, but these scolicidal agents have several side effects on patients. Therefore, this study aimed to explore the scolicidal activity of green synthesized gold nanoparticles (AuNPs) utilizing mycelia-free culture filtrate of Penicillium aculeatum against hydatid cyst protoscolices of E. granulosus. The size and morphology of AuNPs were affirmed by UV–visible spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) analysis. The Fourier transform infrared (FT-IR) analysis of AuNPs showed the presence of possible functional groups responsible for the bioreduction and capping. The AuNPs were formed relatively uniform with spherical shape and superior monodispersity with the average diameter of 60 nm. Consequently, various concentrations (0.05, 0.1, 0.2, and 0.3 mg/mL) of green synthesized AuNPs and different exposure times (10, 30, 60, and 120 min) were used against hydatid cyst protoscolices. Statistically, the difference between the scolicidal effects of AuNPs were seen extremely significant for all four concentrations and at various exposure times in comparison to the control group (P < 0.0001). The most mean protoscolex elimination ratio was 94% (0.3 mg/mL AuNPs and 120-min exposure time). The current investigation indicated that applying biogenic AuNPs may be considered as a potential scolicidal agent for cystic hydatid disease. However, further studies are required to evaluate the efficacy of AuNPs in vivo.

Dust pollution is a complex problem of growing interest because of its environmental, health, economic and political impact. Environmental impact assessment methods for dust pollution management are often based on the simulation of dust dispersion, which requires a precise characterization of the source term and of the source parameters. The source term model should be as simple and as accurate as possible and requires low time consumption in order to be easily connected to a more complex algorithm for the dispersion calculations. This work focuses on dust emissions from mineral storage piles, which are usually modelled as source terms by means of the algorithm proposed in the AP-42 US EPA standard. Unfortunately, this algorithm tends to overestimate emissions, and when coupled with a Gaussian dispersion model, it leads to inaccurate results in terms of estimation of both concentration and spatial distribution. This paper proposes a new methodology drawn from the original standard US EPA AP-42 https://www3.epa.gov/ttnchie1/ap42/ch13/ scheme with the purpose to account for the actual dynamics of erosion and to enhance the accuracy of the concentration and the pollutant spatial distribution assessment, thereby considering the effects of the wind interactions. The standard EPA methodology and the new one were compared by means of the AERMOD and CALPUFF dispersion models. Results are superimposable in terms of concentration values, leading to a quantification of the same order of magnitude, although with a different and more variable spatial distribution.

Exposure to fine particulate matter (PM₂.₅) has been associated with mortality, but the extent of the adverse impacts differs across various regions. A quantitative estimation of health effects attributed to PM₂.₅ in China is urgently required, particularly because it has the largest population and high air pollution levels. Based on the remote sensing-derived PM₂.₅ and grid population data, we estimated the acute health effects of PM₂.₅ in China using an exposure-response function. The results suggest the following: (1) The proportion of the population exposed to high PM₂.₅ concentrations (>35 μg/m³) increased consistently from 2000 to 2011, and the population exposed to concentrations above the threshold defined by World Health Organization (WHO) (>10 μg/m³) rose from 1,191,191,943 to 1,290,562,965. (2) The number of deaths associated with PM₂.₅ exposure increased steadily from 107,608 in 2000 to 173,560 in 2010, with larger numbers in the eastern region. (3) PM₂.₅ health effects decreased in three pollution control scenarios estimated for 2017, i.e., the Air Pollution Prevention and Control Action Plan (APPCAP) scenario, the APPCAP under WHO IT-1 scenario (35 μg/m³), and the APPCAP under WHO IT-3 scenario (15 μg/m³), which indicates that pollution control can effectively reduce PM₂.₅ effects on mortality.

To reduce fresh water consumption in a polyvinyl chloride (PVC) plant, the effluent from a biological treatment must be demineralized to be re-used in the resin polymerization process. Demineralization is a critical process, since the quality and the stability of the PVC resins are highly influenced by the water quality used in the process. The main target values for water parameters are the following: conductivity <10 μScm⁻¹, TOC < 10 mg L⁻¹, and Al < 0.1 mg L⁻¹. To achieve this quality, several reverse osmosis membranes from different materials and suppliers were tested and compared in the demineralization treatment. Polyamide membranes showed higher salt rejection compared to cellulose acetate membranes yielding both types similar flux and permeability. Two-pass reverse osmosis treatment was necessary to reach conductivities lower than 10 μS cm⁻¹. On the other hand, a good quality effluent for reuse was obtained by combining RO and ionic exchange resins. Results showed that good quality PVC resins in terms of color, granulometry, porosity, and bulk density were obtained when demineralized water from two-pass reverse osmosis was used as fresh water, proving the feasibility of the effluent reuse in the PVC industry.