Inactivation of pathogens present in animal manure prior to land application has justified the use of advanced technologies. However, some alternatives are expensive or not effective due to the organic material and suspended solids present in the effluent (e.g., ozone, UV light). The use of hydrated lime (calcium hydroxide, Ca(OH)₂) is an attractive wastewater treatment option due to the ability of lime to kill pathogens and to extract phosphorus from manure at an alkaline pH. The present study aimed to evaluate the soluble phosphorus removal and pathogen inactivation (Escherichia coli, Salmonella enterica serovar typhymurium and Porcine circovirus type 2), in the liquid fraction and in the solid generated after Ca(OH)₂ addition in swine wastewater, exposed for 3 and 24 h at different pH conditions: 9.0, 9.5, and 10.0. The results showed the efficiency of pH elevation with Ca(OH)₂ in the removal of soluble P at pH 9.0 and the total inactivation of E. coli, Salmonella, and P. circovirus type 2 at pH 10.0. The liquid fraction (reuse water) could be safely used for cleaning the swine production facilities, and the solid fraction (precipitated P) could be used as a secondary product and fertilizer.

The present and past mining activity left several abandoned tailings and dams in the Panasqueira tin–tungsten mining area. Seasonal water samples and stream sediments were collected during two different periods (rainy and dry seasons) and analyzed for a wide range of major and trace elements, in order to define the present hydrochemical situation. Rain waters interact with the altered sulfides stored in the tailings which generate runoff waters with high metal concentrations. The waste material derived from the exploitation enhanced acidification and metal-releasing processes, due to the increase in the specific surface, which favors the oxidation of sulfide minerals. Acid drainage and high metal(loid)s (Cd, Fe, Mn, Zn, Cu, As) concentrations in solution were observed in waters leaching the Panasqueira tailing deposits. In dry season, generally the acidic waters, enriched in metals, evaporate progressively depositing sulfate efflorescences characteristic of acidic environments. The elements distribution in precipitated minerals helps in the interpretation of aqueous geochemical data. Aqueous concentrations may be attenuated by goethite, gibbsite, and/or ferrihydrite precipitation in the oxidation zone through adsorption processes. The use of these waters for human consumption and for irrigation represents a threat to humans as they have a potential carcinogenic risk, especially due to the As concentrations. The acid water precipitation is present on the stream sediments, with concentrations exceeding the toxicity limits. Stream sediments are good receptors of metals and metalloids transported by waters. The enrichment factor values, of heavy metal(loid)s from Casinhas stream and Zêzere river sediments, are extremely high in Ag, As, Cd, and Cu revealing enrichments for these potential toxic elements. Igₑₒvalues shows that samples are strongly to very strongly polluted for Ag, As, Bi, Cd, and Cu. According to the consensus-based SQGs, 80 % of the samples were classified at the level of great concern and adverse biological effects are to be expected frequently in this area.

Uranium soil depollution is of great concern as, like any other radionuclide, it may accumulate in time and generate a negative impact on human health. There are several decontamination technologies, among these the acid washing still in use for its simplicity and low cost. Though a classical method, it still can be improved by using the best operating conditions to increase the decontamination degree. The present study aims to propose an optimization approach based on experimental design. The investigation takes into account the main operating parameters (duration, temperature, and pH) and the soil characteristics (texture and organic matter content). This work presents an “ex situ” uranium-contaminated soil treatment using a 0.1 M H₂SO₄solution with pulp density of 0.5. The experiments followed a 2³factorial design for the evaluation of factors and interaction effects. The factors’ influence differed from one type of soil to another. The 2³experiment was augmented using a non-central composite design that allowed the formulation of a second degree model for the response surface. The best values for the operating parameters were identified using optimization procedures. Statistical modelling and optimization were performed in Matlab® v7.7. The results obtained proved that the soil type is very important for selecting better operating conditions. These improvements determined an increased decontamination degree of up to 10–13 % compared with standard operating conditions that were considered as central point in the experimental plan.

For many years, atmospheric mercury has been perceived as a global pollutant. Transport of mercury compounds in the atmosphere and its deposition on the earth’s surface is an important issue that requires knowledge regarding the circulation of the various forms of this metal between environmental components. There are many numerical models that can be used to study and image this phenomenon. These models are based on data concerning mercury emission sources, concentrations of this contaminant on modelling areas and meteorological data to assess air mass inflow on a regional and global scale. A method to assess mercury deposition fluxes on a local scale based only on stream intensity analysis of mercury is proposed in this study. Mercury deposition fluxes (bulk) that were assessed by the MDC method at the Zloty Potok station (regional background station for the Silesian Agglomeration) varied from 22.8 μg · m⁻² · year⁻¹ (an 8-month period in 2013) to 54.2 μg · m⁻² · year⁻¹ in 2012. Developing procedures to estimate the mercury deposition coefficient (MDC) is useful in areas where only meteorological parameters and mercury concentrations in the atmospheric air are measured. The obtained deposition coefficient values enable quantification of a selected pollutant concentration and its potential impact resulting from deposition.

In the present work, the role of chemical compounds of one abundant vegetable waste, exhausted coffee, on Cr(VI), Cu(II), and Ni(II) sorption has been investigated. For this purpose, exhausted coffee was subjected to sequential extractions by using dichloromethane (DCM), ethanol (EtOH), water, and NaOH 1 %. The raw and treated biomass resulting from the extractions were used for metal ions sorption. Sorption results were discussed taking into consideration polarity and functional groups of raw and treated biomass. In general, the successive removal of extractives led to an insignificant increase in the studied metal ions sorption after DCM, EtOH, and water. The sorption results using free-extractive materials showed that metal sorption can be effectively achieved without this non-structural fraction of the sorbent. Alkaline hydrolysis destroyed in part the structural compounds of the sorbent resulting in an insignificant decrease of chromium removal while a significant increase of copper and nickel sorption was observed. The determination of elemental ratios of exhausted coffee and all treated biomass evidenced the involvement of oxygen functional groups in copper and nickel sorption. FTIR analysis confirmed the involvement of lignin moieties in the chromium sorption by exhausted coffee. As a final remark, this study shows that the sequential extraction opens new expectations to the total valorisation of lignocellulosic-based biomasses. The extractives can be removed and used as a biosource of valuable compounds, and the resulting waste can be used as a sorbent for metal ions keeping the same capacity for metal sorption as the non-extracted biomass.

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals are the two most important groups of pollutants associated with rail transport. Both have a serious negative impact on the natural environment, including human health and degradation of sensitive ecosystems. In our study, apart from qualitative and quantitative analysis of the main PAHs and heavy metals associated with rail, we tried to assess composition of specific compounds related to functional areas of railway infrastructure and to distinguish potential chemical markers which can be used for identification of pollution. Moreover, we evaluated the applicability of plants overgrowing railway infrastructure as bioindicators of rail-associated pollution. Though we confirmed that high amounts of PAHs and heavy metals in soil are characteristic for intensively used railway infrastructure, we found no typical pollution profiles for the differently used areas (i.e. platforms, sidings, cleaning bays). The major source of these contaminants is petroleum products used in conservation of railway infrastructure and rolling stock. As far as the use of plants overgrowing railway infrastructure as bioindicators of rail-associated pollution is concerned, it is rather limited, due to frequent application of herbicides for security and track stability reasons.

Scallop shell-Fe₃O₄ nanoparticles were synthesized by co-precipitation and hydrothermal methods. The removal efficiency of RB5 was studied as a function of pH, adsorbent dosage, initial RB5 concentration, ionic strength, and temperature. Coating of Fe₃O₄ nanoparticles onto Scallop shell was identified by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) analysis. Maximum adsorption was obtained at pH 3. The removal efficiency of RB5 was increased with increasing adsorbent dosage. However, it was decreased with increasing initial RB5 concentration, temperature and in the presence of any anions. Adsorption kinetic study revealed that the pseudo-second order model better described the removal rate than the pseudo-first order model and intra-particle diffusion model. Adsorption isotherm was analyzed by both Langmuir and Freundlich equation. Experimental result was well described by the Langmuir equation. Maximum adsorption capacity was estimated to be 1111.11 mg/g. Thermodynamic studies indicated that the adsorption of RB5 onto Scallop shell-Fe₃O₄ nanoparticles was an endothermic (∆H = 178.14 KJ mol⁻¹) process. The negative values of free energy (∆G) for the adsorption indicated that adsorption of RB5 was spontaneous reaction. Adsorption activity of RB5 by Scallop shell-Fe₃O₄ nanoparticles was maintained even after six successive cycles.

During the extraction of coal bed methane (CBM), entrapped in the deep layers of different coal beds, large amount of coal bed water (CBW) is also simultaneously released. The quality of this water is generally very poor which may often contaminate the adjoining soil environment adversely. In the present study, some major changes occurring in CBW-contaminated soils were assessed with relation to nearby non-affected soils. The CBW was found to be moderately saline and highly alkaline in nature with high sodium absorption ratio (SAR) values. Contamination with this water affected the soil environments substantially resulting in significantly increased pH and exchangeable sodium percentage (ESP) in the affected soils thus rendering the soils unsuitable for undertaking common agricultural practices. However, in spite of moderately high electrical conductivity values of this contaminating water, the resultant increments in salinity status of the soils were not observed to reach near the critical level. This behaviour was attributed to light texture of these soils which probably helped in leaching of a part of the soluble salts. Some microbial properties as well as availability of nitrogen and phosphorus were also found to decline in these CBW-affected soils. The study showed that utmost care needs to be exercised before release of CBW during extraction of CBM. In case of any contamination to nearby arable soils, suitable amendment practices for alkaline soils need to be adopted to mitigate the adverse effects of such water on soil environment.

Photocatalysis is one of environment-friendly and efficient methods for municipal wastewater disinfection. In this research, two pathogens, Staphylococcus aureus and fecal coliform, were chosen to investigate the disinfection effects of several TiO₂ photocatalysts on sewage plant secondary treatment effluent, compared with UV disinfection. The results show that TiO₂ species and concentrations, light intensity, light time, and pH all have significant influences on the pathogen deactivation. It was found that the optimum operation parameters were as follows: the P25 commercial TiO₂ powder at the concentration of 0.5 g/L, the light intensity of 40 W, and the radiation duration of 20 min. The photocatalyst performed better at either acid or alkaline condition than neutral. The TiO₂ photocatalytic deactivation to S. aureus was more effective than the UV.

A significant amount of artificial radionuclides has been introduced into the environment in the last century during atmospheric nuclear weapons tests and the Chernobyl accident. In this study, we investigated the temporal changes of concentrations and amounts of these radionuclides (⁹⁰Sr and ¹³⁷Cs) in surface water and river bed sediments. In order to evaluate the artificial radionuclide contamination diminution, we used and compared two different approaches: using a kinetic equation of the first order and, if needed, dividing the monitored period into two intervals, and in addition expressing the whole process in one equation with a series of exponential functions. Effective ecological half-lives were estimated as rates of decrease. In most cases, the ecological processes were proven to affect the radionuclide removal from the hydrosphere besides their radioactive decay. Furthermore, based on the assessment made, the ⁹⁰Sr and ¹³⁷Cs data were extrapolated and the radionuclide concentrations, which occurred in the hydrosphere after the fallout deposition in 1986, were estimated.