Journal of Hazardous, Toxic, and Radioactive Waste

Wastewater containing a high concentration of organic and emerging pollutants has been and remains a common and urgent issue, though many conventional methods are losing their effectiveness due to wastewater's chemical complexity. Electron beam (EB) is a common type of irradiation used in wastewater treatment, as it has the ability to create free radicals to break down chemical bonds, which is beneficial for treating modern wastewater complex matrix. As a result, many systems have been developed that make EB cheaper and easier to scale up. This paper reviews the application of EB in wastewater treatment along with many factors (especially scavengers) attributing to the effectiveness of this treatment. It has been proven that EB is used in a variety of ways and is ultimately effective in wastewater treatments. However, in order to achieve high efficiency, EB has been utilized in a relatively high dose, which results from the competition between scavengers and target compounds and the complex structure of many organic compounds. Also, the subordinate radical forming also plays an important role in the pollutants degradation by using EB when there is still a limitation in this field. It is important to perform more research on scavengers and secondary radicals in order to overcome the limitation of EB and make it become state-of-the-art technology.

This paper will focus on the challenges associated with algae-based wastewater treatment (ABWWT). To elucidate the issue, this review will investigate the following: (1) microalgal strain selection, (2) wastewater characteristics, and (3) the effect of various biotic and abiotic factors. Mostly, monocultures of microalgae are used in wastewater treatment (WWT), but microalgae–bacteria consortia have received significant attention recently. Their interaction mechanisms and the sheer number of possible combinations pose a significant challenge in the strain selection. Various types of wastewaters have varying nutrient loads and different types of biochemical composition, which affect the efficiency of their treatment process significantly. Because microalgae are photosynthetic organisms, environmental factors, such as light, temperature, and pH play a significant role in the phycoremediation of wastewater. Light intensity and its duration, the maintenance of optimum temperature, and pH range pose major challenges in ABWWT. In addition to abiotic factors, biotic factors, such as biopollutants that include pathogenic microorganisms greatly affect the quality of treated wastewater. Their proper detection and elimination is a significant requirement in the wastewater process. Therefore, this paper will carry out a critical review of all the previously mentioned key challenges, which act as an impediment in the large scale implementation of ABWWT.

The hybrid bioelectrochemical systems (BES), a self-sustaining novel technology, was tested for evaluating its efficiency for removal of hexavalent chromium from electroplating industry wastewater. The BES reactor was designed and optimized for different parameters, such as substrate concentration, mixed liquor volatile suspended solids (MLVSS), hydraulic retention time (HRT), and chromium concentration. The concentration of hexavalent chromium [Cr(VI)] in the electroplating industries was found in the range of 0.43–48.7 mg/L. Whereas in the experiments Cr(VI) concentration, it varied from 10 to 50 mg/L (10, 20, 30, 40, and 50 mg/L). The BES demonstrated 87.88% of Cr(VI) removal at an influent concentration of 50 mg/L and HRT of 24 h. Correlation analysis revealed that chromium removal efficiency (CRE) was directly proportional to substrate consumption, voltage generation, MLVSS, and HRT, and had an inverse relation with chromium concentration in the cathode chamber. Principal component analysis (PCA) extracted two principal components that together explained approximately 82.15% of data variability (PC1: 62.73%; PC2: 19.41%). The kinetics of substrate degradation and chromium removal was assessed, revealing that substrate degradation and chromium removal can be better described by a first-order kinetic model.

The application of native mixed algal strains for wastewater treatment will be investigated in this study. Native mixed algal strains will be collected from Khorda district, Odisha, India, and acclimatized to the secondary treated gray water in a stepwise manner. The algal species in the mixed strain were identified as Oscillatoria sp., Nannochloropsis limnetica, Dictyosphaerium ehrenbergianum, and Chlorella vulgaris. The mixed algal strains will be grown in different systems with combinations of natural light (N) or artificial light (A) and open system (O) or closed system (C). The mixed algal strains grew well in natural light compared with artificial light. The maximum algal biomass concentration of 0.99 and 0.79 g/L, respectively, were observed in the natural light open (NO) and natural light closed (NC) systems. In contrast, the algal strains grown in the closed system indicated improved gray water treatment compared with that of the open system. The organics [(measured as chemical oxygen demand (COD)], NO₃⁻, and PO₄³⁻ removal from gray water were 85.25%, 88.50%, and 73.12%, respectively, in the NC system. In addition, proximate analysis revealed that the biomass obtained from the NC system was slightly superior with the volatile matter, ash content, and fixed carbon of 28.5%, 69.9%, 29%, and 1.6%, respectively. In addition, the heating value of algal biomass obtained from the NC system (3.86 MJ/kg) was slightly higher than that of the NO system (3.52 MJ/kg).

Self-designed electrokinetic setups were constructed to examine the differences in electromigration and electroosmotic rates in both sand and clay. Two dyes were analyzed separately to measure these phenomena within these two media types. The dyes used were a red food coloring (primary compound Allura Red) and a green food coloring (referred to as a “blue dye,” as its migrating component was C-phycocyanin (C-PC) via Spirulina Blue extract). The power supply had a 30 V output with a measured 9.36 ± 0.04 mA current (0.054 mA/cm²) output. Electromigration was readily apparent for the red dye in both sand (9.12 ± 1.57 cm/d) and clay (0.93 ± 0.16) cm/d. It was also observed for the blue dye (C-PC) in sand (7.28 ± 0.57 cm/d) but not in clay. A confirmation experiment for the blue dye in sand was performed at an identical voltage but a slightly lower current output (0.040 mA/cm²), and the migration rate was found to be similar, at 6.60 ± 0.20 cm/d. For the blue dye in clay, the migration rate proceeded toward the cathode at 0.17 cm/d. Calculations indicate this phenomenon to be due to electroosmosis but may be due to a weak electromigration of the dye in protonated form.

The production and use of radioactive tracers for positron emission tomography (PET) diagnostics in Poland generates various kinds of solid radioactive waste, the disposal of which requires special procedures. This study analyzes the replaceable elements of a medical cyclotron (i.e., a Havarfilm used for ¹⁸F- and ¹¹C-label production). Nine samples were taken from the cyclotron between 2014 and 2016. In all of them, the quality and quantity of radioactive isotopes were analyzed. All samples of the Havar window were classified as high-activity radioactive waste, and after a time of cooling to reach medium level, a radioactive waste protocol was proposed. Storage of the waste materials in a selected room (e.g., in lead shields in a bunker at a medical center) enabled reduction of transportation and transfer costs to a radioactive waste disposal plant.

Vehicular pollution is one of the major sources of air pollution in urban locales that have reportedly elevated concentrations of air pollutants. This study aims to examine the performance of two air quality dispersion models, STREET and CALINE 4 to predict pollutant concentrations for an urban monitoring location that is en route to the high traffic volumes in Shimla, Himachal Pradesh, India. This study will compare the predicted and observed concentrations (for the urban monitoring location) using both quantitative and statistical methods for the 2 years of the study. The pollutant selected for the study is PM₁₀. It was observed from the modeling studies that the performance of CALINE4 was slightly better than the STREET model. The models selected to a certain extent are defined by the available parameters for successful run completions. The application of detailed modeling studies is the first of its kind for the study location, to the best of the authors’ knowledge. Hence, the application of basic and simplistic models and the examination of their performance could potentially find the best fit model to predict approximately precise concentrations. Further scope of this study should include the use of advanced air quality dispersion models for the improved prediction of concentrations.

This study will evaluate the feasibility of treating diesel contaminated soil excavated from a metro rail construction site in Chennai, Tamil Nadu, India. Total petroleum hydrocarbon (TPH) concentration present in the soil varies in the range of 12,900–13,550 mg/kg, which is higher than the permissible limits. The combined chemical oxidation and microwave (MW) heating techniques will be evaluated for the decontamination of the soil. The effects of different parameters, such as dosage of oxidizing agents, MW power, and treatment time on the removal of TPH will be optimized. Under optimized conditions of 450 W power and 60 min, a combination of MW and hydrogen peroxide [H₂O₂ (2.5 wt%)] showed an improvement in TPH degradation efficiencies by 23.82%, 17.36%, and 20.89% for three different soils compared with MW heating alone. The soil samples will be analyzed using gas chromatography-mass spectroscopy (GS-MS) for fingerprinting and to assess the reduction (%) in C₁₁ to C₂₅ hydrocarbon levels. The results from this study could be used to design and scale-up the technology for remediation of the contaminated site.

Aluminum-impregnated tea waste activated carbon (Al-TC) synthesized for adsorption of arsenate at optimum conditions. The Al-TC produced through slow pyrolysis of tea waste followed by the impregnation of anhydrous aluminum. The operating conditions (initial metal concentration, pH, contact time, and adsorbent dose) were optimized using response surface methodology–central composite design statistical technique, with percentage arsenate removal as a targeted response. The response surface analyses and analysis of variance reveals an excellent fit of experimental data into the quadratic model, and the interactive effect of pH and initial concentration was highly significant on arsenate removal capacity. The obtained optimal conditions corresponding for good percentage arsenate removal were at 100 μg/L, pH 6.0, adsorbent dose 1.0 g, and contact time 1 h. The synthesized mesoporous adsorbent possesses a high surface area of 396 m²/g and an excellent uptake capacity of 99.6 μg/g. The probable mechanism for adsorption proposes that electrostatic forces and hydrogen bonding are responsible for adsorption of arsenic species (H₂AsO₄⁻ and H₃AsO₄) at pH 2.0, the arsenic species, including HAsO₄⁻² and H₂AsO₄⁻ are removed through adsorption and ion exchange at pH 6.0, and weak adsorption of AsO₄³⁻ through ion exchange at pH 10.0. Coexisting PO₄³⁻ and SiO₃²⁻ ions negatively affect the arsenate adsorption whereas CO₃²⁻, SO₄²⁻, Ca²⁺, and Mg²⁺ ions do not have a significant impact on the adsorption process. The arsenate’s using Al-TC obeyed the Langmuir isotherm model and the kinetic data best fits into the pseudo-second order model. The adsorption process has proven to be spontaneous and endothermic. The produced Al-TC can be used very effectively for the treatment of arsenate containing aqueous media.

An environmental impact assessment (EIA) tool is used to assess any proposed development activity. It is beneficial for a detailed study of large projects, but less feasible for quick assessments of a smaller project. The rapid impact assessment matrix (RIAM) serves the purpose of quick quantitative assessments of any project. In this study, the RIAM technique used to assess waste management practices of various hospitals in the city of Prayagraj, India. Based on RIAM scores, the level and nature of the sustainability of waste management practices in hospitals are checked by the model of sustainability. In addition, the environmental performance index (EPI) is applied with RIAM scores for comparative study. Hospital “A” was ranked as the most promising sustainability option, with sustainability value (S-value) of 0.2815 and EPI of 211.921, indicating good sustainability. Strict abidance to rules and regulations and regular monitoring is needed to substantially improve waste management in hospitals.

The safety and stability of municipal solid waste (MSW) slopes are governed by unit weight (γ), cohesion (c), and friction angle (ϕ) of the MSW. Variability associated with the unit weight, cohesion, and friction angle of MSW is a major problem in the design of landfills because it negatively affects the performance of the slope. Variability associated with these properties may trigger catastrophic slope failures. The reported studies on the reliability-based design of MSW landfills adopted either Gaussian or lognormal distributions based on a reasonable approximation. The limitations are apparent when a coefficient of variation (COV) is higher. The accuracy of reliability-based designs depends on the selection of best-fit continuous and extreme value distributions (such as Gumbel and Weibull) that can model a high degree of variability precisely. The present study has undertaken to propose a suitable statistical model that gives a better representation of variability by optimizing the statistical parameters. A high degree of variability associated with the unit weight, cohesion, and friction angle of MSW is also investigated. A novel approach is proposed to determine reliable continuous probability density functions (PDFs) that can be fitted to the database consisting of 184 sample points collected from the most comprehensive experimental studies reported in the literature. The best-fit PDFs are recommended by optimizing the mean and standard deviation such that errors associated with quantiles (Q­­–Q), percentiles (P–P), and cumulative distribution functions (CDFs) are as minimum as possible. This study signifies the selection of optimized PDFs for the representation of parameter variability, and it is proved that the probability of failure is either underestimated or overestimated considerably when other conventional PDFs are chosen. The recommended mean, COV, and PDF can be useful in the reliability-based design of engineered MSW landfills and for judging the performance of existing MSW slopes.

The analytical study was conducted to evaluate the concentration of ciprofloxacin (CIP), chlortetracycline (CTC), and chosen metals in a wastewater treatment plant. The concentration of CIP was slightly higher in the effluent (0.703 ± 0.045 µg/L) than the influent (0.467 ± 0.049 µg/L) in wastewater samples. More than 70% of CTC was recovered during wastewater treatment; its concentration in wastewater effluent was at 6.13 ± 0.863 µg/L. High concentration of CIP and CTC, 3.9 and 11 mg/kg, respectively, were detected in the solid fractions of sludge. This elevated concentration might have been due to interactions with metals in sludge (i.e., 64–89 g/kg of Ca, 52–109 g/kg of Fe) as both antibiotics have the capacity to form complexes with them. The chemical speciation of all sludge types was carried out to further investigate the distribution of targeted metals and antibiotics and to establish if there is any interdependence. The positive correlation between CTC/CIP concentration and Mg, Ca, and As concentration in primary sludge was observed. This suggests that metal-antibiotic interaction may contribute to primary wastewater treatment.

Sewage sludge produced by many municipal wastewater treatment plants contains various heavy metals that limit its use on agricultural land. The existing treatment processes for removing heavy metals are not cost-effective or eco-friendly due to the requirement of aeration or the use of various harmful leaching agents. This paper explores the solubilization of heavy metals present in the sewage sludge using the acidogenesis phase of the anaerobic digestion process without using any harmful compounds. To achieve this objective, an anaerobic batch reactor was used, in which sewage sludge was added with different solid concentrations and carbon source (glucose) concentrations. During this process, volatile fatty acids were produced, which decreased the pH of the system. The maximum decrease in the pH was observed in the reactor that had the maximum glucose concentration and the minimum total solid concentration. In this reactor, the pH dropped below 4.5. The solubilization of heavy metals was observed as Zn: 41% (333 mg/kg), Ni: 31% (8.5 mg/kg), Cr: 30% (13 mg/kg), Pb: 29% (11 mg/kg), Co: 28% (1.4 mg/kg), and Cd: 27% (0.5 mg/kg).

Excess use of antibiotics has led to antibiotic pollution in the environment, and now polluted sites have become hotspots for evolution and spread of antibiotic resistance in environmental bacteria. Subinhibitory concentration of antibiotics combined with other pollutant exerts selective pressure on environmental microbes, driving evolution and spreading antibiotic resistance. A mathematical model has been developed to have a better understanding of the subject of development of antibiotic resistance and its management in the aquatic environment. The model includes state variables such as fluoroquinolone, organic matter, heavy metals, resistant bacteria, and susceptible bacteria. The model was applied to the Musi River, which is heavily polluted with antibiotics. Simulations were carried out with hydraulic conditions and initial boundary conditions for state variables using actual site-specific data. Spatial pattern predicted by simulated results of the model is able to match with the observed spatial pattern of proliferation of resistance in the river. The developed model is also simulated for different pollution loading scenarios to predict and compare the future conditions for the river management. The simulated results showed that factors such as substrate concentration, antibiotic concentration, horizontal rate of transfer of plasmid, total population density of bacteria, and rate of losing plasmid dictate the dynamics of resistance in the river.

Groundwater is an indispensable source of drinking water for the survival of mankind. The preservation of aquifers is essential in recent times due to the constant deterioration of groundwater experienced across the globe. Knowledge about regional groundwater contamination and vulnerability is essential in the effective management of groundwater. The present study aims to develop a regional model (ASSIGN) that is a modified DRASTIC model that captures the local variability using field samples to make it more feasible at a local scale. The study is performed in the holy city of Haridwar, India where millions of devotees visit every year and which has become a hub of industrial activities. Three strategies, (1) DRASTIC, (2) ASSIGN, and (3) ASSIGN optimized, were deployed to determine the groundwater vulnerability zone for the study region. The effective groundwater vulnerability model was determined based on the correlation observed with the field values of seven groundwater parameters at 16 site locations. The comparative assessment shows that the ASSIGN optimized model outperforms other models with the highest R2 values. The results obtained from this analysis envisioned that the inclusion of experimentally derived parameters can be an alternative to the classic DRASTIC model with more accurate results. The study highlights the regions and the zones that are under the influence of very high contamination. This will facilitate water planners in effective decision-making concerning the sustainable use of aquifers with minimum groundwater contamination.

Anthropogenic activities have lead to the accumulation of toxic and hazardous waste materials, such as dyes and heavy metals, into the environment. The entry of these waste materials into the food chain have emerged as a threat to food and health security. As a result, several conventional physical and chemical-based systems were developed to remove these toxic dyes and heavy metals from wastewater. However, because the conventional methods were costly, energy intensive, and ineffective, microbe-based bioremediation systems gained attention of the scientific community. Among several bioremediations approaches, the microbial electrochemical system (MES) has shown promising results in the selective removal of dyes and heavy metals from wastewater. The chemical energy of the biodegradable substrates is converted to electrical energy using the inherited electrochemical system of the electroactive microorganisms. This is collectively termed a “microbial electrochemical/bioelectrochemical system” (MES/BES). The MES in presence of electroactive microbes can remediate the toxic compounds from a wide range of wastewaters. Thus, the present review provides detailed insight into the principle, mechanisms, electrochemistry, and biochemical capabilities of electroactive microbes during bioremediation of heavy metals and dyes. In addition, the paper discusses the challenges faced in designing large-scale MES and its implementation/commercialization. The future prospect and strategies for the development of a self-sustainable multipurpose MES for bioremediation and recovery of toxic and value-added compounds, respectively, have also been elaborated.

The significant generation of fly ash from coal fired thermal power plants tends to cause air pollution and health hazards. The cenospheres that are a component of fly ash are spherical in shape, light density, and particle size ranges from 100 to 400 μm. Therefore, for the effective utilization of this solid waste, in this study, an ultralight cement slurry will be prepared for low-fracture gradient formation by the incorporation of varying doses of fly ash cenospheres (FAC). The cement sheath often shrinks, which instigates fluid migration across the isolated zones. Therefore, for additional shrinkage compensation, dead burned magnesia (DBM) combined with FAC will be added to the cement slurry. The morphology of the cenospheres in the cement sheath will be observed using a scanning electron microscope (SEM). The water contact angle of 108.3° revealed that the cement sheath is hydrophobic. Moreover, the consistency test revealed that when 30% cenosphere was incorporated into the cement slurry it exhibited a consistency of 30 Bearden units of consistency (Bc) after 2 h, which resulted in better pumpability under downhole conditions. Furthermore, expansion studies will be conducted on the prepared cement slurry under permeable and impermeable conditions. In addition, the rheological properties and compressive strength of the cement slurries will be investigated. The prepared cement slurry exhibited a specific gravity of approximately 0.9 along with a compressive strength of approximately 24 MPa, which is acceptable for its application in oil well cement. Therefore, the solid waste cenosphere and DBM could provide a sustainable solution in oil well cementing for low-fracture gradient formation with improved zonal isolation.

In developing country such as India, due to the significant boom in the infrastructure development the virgin aggregates (VAs) resources are diminishing at a high pace and thus creating an ecological imbalance. In contrast, an immense quantity of recycled aggregates (RAs) is generated from construction and demolition waste. Thus, in view of sustainability, utilization of RA can be a great source of aggregate in the development of structural concrete. This paper outlines the development of self-compacting concrete (SCC) with full replacement of coarse VAs with coarse RAs. In addition, to make the SCC more sustainable, utilization of supplementary cementing materials such as coal fly ash (CFA), ground granulated blast furnace slag (GGBS), and metakaolin (MK) were used as cement replacement materials. Finally, the mechanical and durability performance of SCCs were examined to see whether they could be adopted for structural applications with greater confidence. A total of nine SCC mixes were designed containing GGBS, CFA, and MK content as cement replacement (by weight) with full replacement of VAs with RAs. Fresh performance of SCC mixes was scrutinized by slump flow, T₅₀₀, V-funnel, and L-box test. Furthermore, compressive strength test, split tensile test, flexural test, and E-modulus test were performed to study the mechanical characteristics. Durability performance was examined by conducting water permeability, sorptivity, rapid chloride penetration test, surface resistivity, pH, and carbonation tests. The experimental results concluded that 15% replacement of cement with MK exhibited an excellent mechanical as well as durability performance of self-compacting recycled aggregate concrete with a ceiling strength of 75 MPa. The use of GGBS also yielded excellent durability performance. In contrast, the use of CFA exhibits moderate mechanical and durability performance. It can be inferred from the outcomes of this study that it is possible to develop high-performance SCC using 100% RA, by employing mineral admixtures such as CFA, GGBS, and MK.

This paper aims to study the simultaneous adsorption of multiple heavy metal ions present in municipal solid waste (MSW) leachate. Leachate samples have been found to contain the heavy metal ions copper [Cu (1.22 mg/L)], zinc [Zn (2.86 mg/L)], lead [Pb (2.62 mg/L)], chromium [Cr (1.5 mg/L)], and nickel [Ni (0.65 mg/L)]. Ground granulated blast furnace slag (GGBS) will be used in this paper as adsorbent. The adsorptive capability of GGBS will be studied using the extended Langmuir isotherm model, Langmuir–Freundlich isotherm model, and multicomponent isotherm model. The extended Langmuir adsorption isotherm model fits the experimental values better than the other two models. The synergism, antagonism, and noninteraction effects will be studied based on the equilibrium metal uptake values. For all heavy metals present in the leachate used in this paper, the values of q_mix/q_o were >0, which indicated that multimetal adsorption was feasible by GGBS. This is the indication of enormous active sites on its surface. In addition, this was confirmed by the values of q_mix/q_o, because synergism was followed by antagonism. Ni ions showed a higher synergism effect that increased with an increase in GGBS dose. The adsorption effect of Cr experienced a transition from antagonism to synergism effect above 0.4 g of GGBS dose, which indicated the competition between Ni and Cr. The interactive effect for Pb fluctuated. Cu and Zn showed a strong antagonistic effect, Pb showed a moderate synergic effect, and Cr and Ni showed a strong synergic effect. The dose of GGBS has a predominant role in the adsorption of multiple heavy metal ions.

The toxicity of pharmaceutical pollutants affects aquatic life as well as the environment on all levels of the natural hierarchy. Therefore, to maintain the natural environment it is crucial to exclude pharmaceutical compounds, such as ofloxacin (OFX), sunset yellow (SY), and tartrazine (TRT) from aqueous systems. In this study, a green nanoadsorbent (CS@GOn) will be prepared by the electrostatic interaction of chitosan (CS) and graphene oxide (GO). Characterization using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and Fourier-transform Infrared (FTIR) spectroscopy analysis of CS@GOn will be performed and the cross-linking of CS with GO will be confirmed. Further, batch electrocoagulation (EC) and ultrasonication adsorption (UA) assisted processes will be performed individually and as hybrid systems for the removal of OFX, TRT, and SY from aqueous solutions. The optimum conditions will be evaluated by considering the minimum operating cost (OC). In EC processes, based on the economic >70% removal of OFX, TRT, and SY were achieved at optimum conditions of pH 7, 10 min, and OFX 200 mg/L. However, in UA processes, >83% OFX, TRT, and SY were removed under the same conditions. In hybrid EC and UA processes, >98% OFX, TRT, and SY were removed at the optimized conditions (pH 7, 10 min, and OFX 200 mg/L, dose 0.1 g/200 mL, and 25°C). CS@GOn was reused up to five times after the regeneration. Compared with EC and UA individual processes, hybrid EC and UA processes were more effective for the removal of OFX, TRT, and SY. A feasibility study of EC + UA process will be explored for the removal of chemical oxygen demand (COD) from actual sewage effluent and 95% removal was achieved for a 10 min reaction time of EC and UA. This study provides a promising hybrid EC and UA process with CS@GOn that has excellent biocompatibility, reusability potential, and could be used in a wide range of industrial effluents.

This study will investigate the applicability of α-MnO₂ nanorods, green synthesized using sugarcane juice for the treatment of toxicants in wastewater; Bisphenol A (BPA) and methylene blue (MB). Analysis of parameters that influence adsorption, such as pH, adsorbent dose, concentration of pollutant, contact time, temperature, humic acid (HA), ionic strength, ultrasound frequency, and power will be performed. Treatment results for silent (86.1%, 97.54%) and ultrasonic assisted (36.52%, 94.98%) adsorption of BPA and MB respectively, will be obtained at optimum conditions. The impact of ultrasonication and mechanisms that control adsorption will be assessed. Improved results (BPA: 36.52% to 81.2%) under ultrasonic assisted coadsorption might be due to hydrophobic interactions. Among various isotherms and kinetic models, the Langmuir isotherm and pseudo-second-order kinetic model showed the best correlation for both water contaminants. The growth mechanism of α-MnO₂ nanorods is explained using LaMer's theory. The adsorbent characterization will be performed using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunaeur-Emmet-Teller (BET), X-ray photoelectron spectroscopy (XPS), and Fourier Transform Infrared (FTIR) spectroscopy. The results suggest α-MnO₂ nanorods are a potential nanomaterial for the adsorption of persistent micropollutants and dyes.

Indian rivers carry large sediment loads. During monsoon season when river discharge is high, rivers carry suspended particles, silt, clay, and organic substances, causing river water turbidity that is not suitable for drinking. Riverbank filtration (RBF) is a natural process in which one can abstract good quality water from a highly polluted river through abstraction wells. As RBF water is a mixture of riverbank filtered water and groundwater, assuming no turbidity was picked up by the river water as it travelled through the soil matrix to reach the pumping well. A strategy-A was developed in which flow of groundwater contribution toward pumping well was neglected, while simultaneously measuring source water and abstracted water quality; it was observed that the variation of K, the kinetic coefficient, captured the variation in ln(C₀), natural logarithm of influent quality, with R² equal to 0.974. The kinetic coefficient, K, also captured the variation with ln(C₀) of turbidity after travel times of 14 days and 21 days, having R² equal to 0.991 and 0.989, respectively. A strategy-B was developed using the mass balance relationship, wherein the flow of groundwater contribution toward pumping well was utilized in refining the abstracted water quality. It was observed that K, the kinetic coefficient, of strategy-B captured the variation with ln(C₀), the natural logarithm of the influent quality of turbidity with R² equal to 0.972. If both the strategies were to be compared, strategy-B was found to be superior to strategy-A. However, one additional data of measurement on the groundwater turbidity was required for strategy-B. Further, strategy-C was developed with the assumption that there was no turbidity in groundwater, as a low value of turbidity was observed in groundwater. The variation of K, the kinetic coefficient, with ln(C₀), the natural logarithm of influent quality of turbidity in strategy-C, showed that when the groundwater turbidity was ignored, the agreement between observed and computed turbidity was adversely affected. The average contribution of groundwater toward pumping well was observed nearly 12.43% and the average contribution of river water toward the pumping well was observed nearly 87.57%, considering the depth of river water. In strategy-C also, the agreement between simulated and observed values of turbidity was satisfactory.

The biodegradability improvement of simulated textile dyeing (reactive), printing, and overall wastewater was carried out by electron beam (e-beam) radiation for an activated sludge process. The change in values of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and ratio of BOD/COD were analyzed with respect to the applied e-beam dose. The ratio of BOD/COD for unirradiated dyeing, printing and overall textile wastewater was observed in the range of 0.05–0.3, which indicates it as nonbiodegradable wastewater. This ratio increased with the e-beam radiation in the case of reactive dye effluent, indicating transformation of nonbiodegradable contaminants to degradable ones. This ratio was found to have decreased further for the printing effluent, indicating the formation of nonbiodegradable constituents. The UV-visible absorbance and FTIR spectrum were obtained for the dyeing and printing effluent. A similar study was carried out for mixed effluent with and without presence of printing constituents. This study showed that irradiation with e-beam as a pretreatment can improve the biodegradability for dye house (reactive dye) effluent; however it is not as effective for printing effluent even at higher doses.

Groundwater is the main source of water supply to the public in the upper Kodaganar basin in the state of Tamilnadu in India. Wastewater from the tannery industries of the basin is discharged into Sengulam Lake. For this study, a model was developed to simulate the magnitude and direction of groundwater flow in the aquifer. This model was extended as a chromium-transport model that demonstrated the transport of hexavalent chromium from the lake to the aquifer. The chromium concentration in the lake was found to be 4 mg/L. The chromium concentration in the groundwater of the nearby aquifer ranged from 0 to 2 mg/L. The migration behavior of the chromium was analyzed by the developed contaminant-transport model. The spatial extent of the damage caused in the aquifer by chromium contamination was demarcated by modeling the velocity vectors. It was estimated that the groundwater in an area of about 10 km² was polluted by chromium. The average velocity of groundwater was estimated to be 1.9 m/day. The time taken for the chromium particles to reach the Kodaganar River was estimated to be 12 years.

This paper presents a case study for an approach toward the regionalization of solid waste management facilities. A shared facility of engineered landfill termed divisional landfill has been proposed for the regional level waste management of the Prayagraj division (that consists of four cities). The total quantity of waste produced by the entire division was 1,000 metric ton (MT)/day and that corresponded to an area required for the landfill facility for the entire division of 64 acres. The potential sites for the feasibility of divisional landfill in the Prayagraj division were selected using ArcGIS software. The ranking of sites to find the best site between all the potential sites was carried out by providing appropriate weighting to different attributes according to the site ranking criteria provided by the Ministry of Environment and Forests (MoEF) (MoEF 1991) and Central Pollution Control Board (CPCB), Government of India (CPCB 2003). This paper concluded that the divisional landfill might prove to be an effective and economic solution for waste management in the densely populated state of Uttar Pradesh (UP), India.

This study investigated electrokinetic removal of cadmium and copper from contaminated soil of the Koushk mine tailing dam. The effect of ethylenediaminetetraacetic acid (EDTA) 0.1 M as catholyte and NaOH 0.1 M as an anolyte was investigated. Two voltage gradients, 1 and 2 V/cm, were used in the study. Therefore, six sets of tests were conducted, five 10-day tests and one 13-day test. The study measured pH, electroosmosis flow, electric current, and the concentration of the target metals. The energy expenditure of each test was calculated based on the measured electrical current. The results indicate that usage of EDTA as the catholyte along with distilled water as anolyte did not enhance the cadmium and copper removal. This could be due to antagonistically affected results from competition between metal cations and the EDTA. Application of NaOH instead of distilled water as an anolyte incorporated with EDTA as catholyte showed better remediation results, which might be due to facilitating metal–EDTA movement and formation. A study on the voltage intensity revealed that higher voltage applications can improve metal removal. The final 13-day test showed better removal efficiency compared with similar 10-day test.

The prime purpose of this study was to determine the polycyclic aromatic hydrocarbons (PAHs) from the water zone. A total of 15 PAHs were measured in 22 surface water samples and 22 sediment samples. The samples were collected from four water bodies and five soil samples, out of which four samples were collected from near the four water bodies' bank in Jamshedpur, and one was collected from near a highway. The total concentration of PAHs in water, sediment, and soil range from 25.2 to 310.4 ng/L, from 19 to 291.7 ng/g, and from 106.8 to 240.1 ng/g dry weight, respectively. The composition pattern of PAHs in the surface water, sediment, and soil samples of four water bodies were studied and the results show that the Kharkai and Subarnarekha rivers were more contaminated with PAHs when compared with a lake. In almost all samples the low molecular weight Naphthalene and high molecular weight Pyrene were dominant in concentration. The toxic equivalent quotient and mutagenic equivalent quotient values were dominated by the carcinogenic PAH Benzo(a)Pyrene and the calculated values of the incremental lifetime cancer risk were found under the guideline values. The Diagnostic ratios and Principal Component Analysis for source analysis suggested combustion and petrogenic as the main PAHs source inside the city. Jamshedpur being a fast-growing city and its huge amount of vehicular emissions may be the main origin of PAHs sources.

Radioactive sources are used in different fields and mainly in medicine, industry, agriculture, and research. However, the use of these sources should be accompanied with adequate safety and security measures. In Lebanon, large number of radioactive sources, including Category I and Category II sources, have been used since the 1960s in different sectors. These sources require high-security levels, improved protection and control, and restricted access to authorized persons during the whole life cycle. The Lebanese government had exerted efforts to combat illicit trafficking, enhance physical protection of radiological facilities, and assure adequate management of sources of Category I and Category II, especially after the end of their life cycle. Several missions were conducted by the International Atomic Energy Agency upon request of the Lebanese government in order to enhance the national capabilities to develop physical protection measures for radiological and nuclear materials, combat illicit trafficking, and establish a comprehensive nuclear security regime. The Lebanese Integrated Nuclear Security Support prepared in 2008, and updated in 2012, 2016, and 2019 is described here. This paper describes the national context to manage disused sources of Category I and Category II and materials out of regulatory control. The temporary storage of the radioactive wastes, especially the orphan sources, is described and the facility security plan is highlighted.

The purpose of this work is the radioactive control of long-term-stored materials [historically radioactive waste, Types LLW (low-level waste) and ILW (intermediate-level waste)] in an interim storage room at a nuclear research reactor facility in Greece and their segregation into radioactive and cleared materials based on the dose rate and their surface contamination. The radioactive materials were spectroscopically evaluated to assess types of radionuclides and their activity. The results indicated that of the 122 stored items, 102 were classified as cleared materials and were removed for recycling, while 20 were spectroscopically evaluated as radioactively contaminated with ⁶⁰Co (1,332 and 1,173 keV) and ¹³⁷Cs (661 keV) and remained in storage. Exposure of the staff to radiation during the procedure was moreover assessed, and the dose was found between 0.7 and 7.5 μSv/day. These radiation exposure values were lower than the set local dose limit of 500 μSv set by the radiation protection officer for the duration of the work and significantly lower to the annual dose constraint of the facility of 6 mSv. Moreover, dose rates to nonhuman biota are, on the other hand, several orders of magnitude below the screening limit. Hence, we conclude with high confidence that by protecting humans the environment is also protected in this case. The main scientific contribution of this paper is to serve as a guide for handling stored historically radioactive materials in an interim storage room of a nuclear research reactor upon the criteria of (1) minimum radioactive exposure of staff; and (2) protecting biosystems against the potential disposal of radioactively contaminated materials therein.

The presence of toxic chemicals in landfill deteriorates the quality of liner material by affecting its adsorption capacity and hydraulic properties. In this study, the influence of various concentrations of copper will be examined on two bentonites with different mineralogical and chemical composition. A series of batch studies in the pH range of 2–8, scanning electron microscope (SEM), Fourier Transform Infrared (FTIR) analyses, isotherm study, and consolidation tests will be carried out to investigate the adsorption capacity, change in surface morphology, and hydraulic conductivity of the bentonites. It was observed that pH 5 was more effective in the removal of Cu²⁺. The test results indicated an adsorption capacity of 22.8 and 20.4 mg/g at 2,000 mg/L of Cu²⁺ solution for both bentonites. Furthermore, FTIR characterization of both bentonites in the presence and absence of Cu²⁺ confirmed the involvement of Si–O–Si stretching and water (−OH). From the SEM study, a change in surface morphology was witnessed for Cu²⁺ adsorbed bentonites. The isotherm study indicated that the Freundlich model closely fits the equilibrium data. The results revealed that hydraulic conductivity increased with the increase in copper concentration. Conclusive evidence suggested that bentonite with higher cation exchange capacity (CEC), swelling volume, and specific surface area (SSA) possessed a larger adsorption capacity and removal efficiency.

Biosolids contain high amounts of human pathogenic bacteria that are excreted in feces and urine. The enteric pathogenic bacteria Salmonella sp., Escherichia coli (enteropathogenic and enterotoxigenic variants), coliforms, Clostridium sp., Campylobacter sp., Listeria sp., and Yersinia sp., might be present in biosolids. A large proportion of these bacteria are both human pathogenic and zoonotic, which means that they can cause infections in both humans and animals. In addition, these organisms have a strong ability to persistently adapt to changes in the surrounding environment. According to the 86/278 EC Directive on the protection of the environment and of the soil when sewage sludge is used in agriculture, the minimum requirement for alternative treatments to produce sanitized sludge is defined as containing <500 colony forming units E. coli/g (cfu/g) and 0 Salmonella sp. in 50 g wet weight. This study reviews the current technologies employed for the reuse of treated biosolids in agriculture and unveils an emerging process that could lead to pathogenic microorganism reduction. The process refers to atmospheric pressure air cold plasma of electrical discharges and appears to be an effective treatment with the potential to destroy pathogenic cells of disease-causing and antibiotic-resistant bacteria, such as E. coli, coliforms, and Salmonella sp. of different serotypes.