Distribution of ten taste and odor (T&O) compounds were investigated in 135 finished water samples from 43 drinking water treatment plants (DWTPs). 2-Methylisoborneol (MIB), geosmin, and 2,4,6-trichloroanisole (2,4,6-TCA) were detected in 53.4, 41.5, and 14.1% of the samples, respectively. The corresponding concentrations were in the range of 18.0–53.1 ng L⁻¹ for MIB, 4.2–6.4 ng L⁻¹ for geosmin, and 0.5–6.6 ng L⁻¹ for 2,4,6-TCA. The other seven T&O compounds, β-ionone, 2,3,6-trichloroanisole (2,3,6-TCA), 2,3,4-trichloroanisole (2,3,4-TCA), 2,4,6-tribromoanisole (2,4,6-TBA), 2-isobutyl-3-methoxypyrazine (IBMP), 2-isopropyl-3-methoxypyrazine (IPMP), and trans-2,cis-6-nonadienal (NDE) were never found in all samples. The results from finished water of DWTPs compared with associated reservoirs indicated that 2,4,6-TCA was formed in the water treatment processes. To determine the chemical formation of 2,4,6-TCA by chlorination, the concentrations of different chloroanisoles in anisole-containing water at pH 5.5–9.0 and 25 °C were measured. The results from chlorination showed that only 2-chloroanisole (2-CA), 4-chloroanisole (4-CA), and 2,4-dichloroanisole (2,4-DCA) could be detected. Their formation rates were all below 3.3% at each pH value, but the reaction was more active at pH 5.5 because of acid catalyzed effect. Accordingly, the chemical formation of 2,4,6-TCA by chlorination was not confirmed in this study, which suggested that the formation of 2,4,6-TCA was related to the methylation of 2,4,6-trichlorophenol with fungi. These findings increase our understanding on the formation of 2,4,6-TCA and provide insights into managing and controlling T&O problems in drinking water.

In industry areas of Poland such as Silesia or urban sites like Krakow and some other cities, the levels of pollutants frequently breach air quality standards. Particulate matter (PM) is the most important constituent of atmospheric pollution. Beginning on 1st February 2014 until 31st January 2015, the samples of fine particulate matter PM₂.₅ (aerodynamic diameter of particles less than or equal to 2.5 μm) were collected at a site in the south-eastern Krakow urban background area. During this period, 194 samples were taken. The samples showed daily variation of PM₂.₅ concentration. From these data, monthly variations were estimated and presented in this paper. Monthly integrated data are more representative for the Krakow urban background and show seasonal variation of PM₂.₅ pollution. The lowest monthly concentration value was found for August 2014—about 10 μg m⁻³, the highest for February 2014–70 μg m⁻³, whereas the average annual value was about 31 μg/m³. Utilizing X-ray fluorescence method, concentrations of 15 elements for each sample were determined and 8 inorganic ions were analyzed by ion chromatography. Additionally, the samples were analyzed for black carbon (BC). Receptor model PMF (positive matrix factorization) was used for source identification and apportionment. The modeling identified six sources and their quantitative contributions to PM₂.₅ total mass. The following sources were identified: combustion, secondary nitrate and sulfate, biomass burning, industry or/and soil and traffic. Finally, monthly variations of each source are presented.

This study aimed to investigate the potency of soil reflectance spectroscopy in the visible and near infrared (Vis-NIR) spectral regions in estimating soil heavy metal pollution in the western coastal front of Thessaloniki (N. Greece) and how the protocol used for chemical analyses can affect the models’ performance. For this purpose, 49 topsoil samples were collected and the concentrations of Cd, Cr, Cu, and Pb were determined by two different analytical methods, i.e., ISO 11466 based on the technique of atomic absorbance spectrometry (AAS) and ISO 14869-1 using the technique of inductively coupled plasma-atomic emission spectrometry (ICP-AES). The spectral signatures were applied for modeling the metal concentrations by using the partial least squares regression (PLSR) method. To eliminate the “noise” of data and enhance the models’ accuracy, four spectral pre-treatment methods were used. The overall results showed that there is heavy metal pollution in the soils of specific areas in the studied region and that the use of different chemical analytical methods can affect the performance of examined prediction models. Better prediction models were created for the cases of Pb, Cu, and Cr concentrations, which were estimated by the application of ISO 14869-1, while for the case of Cd better prediction models were obtained, by the application of ISO 11466. These results may indicate that soil reflectance spectroscopy can measure the total heavy metal content in soil samples.

The objective of the present study was to investigate the transport and removal of Escherichia coli, Bacillus subtilis, Staphylococcus aureus, bacteriophage MS2, and bacteriophage Phix174 in the soils and pyrophyllite-amended soils. Laboratory columns experiments were performed under saturated flow conditions. Our results showed that bacteriophages passed through the soils more easily than bacteria under the given experimental conditions (pulse injection = 15 min, flow rate = 0.5 mL/min, column length = 20 cm, inner diameter = 2.5 cm, pH = 7.6, electrical conductivity (EC) = 150.1 μS/cm); the log removals of bacteria were in the range of 0.44 to 1.72, whereas the log removals of bacteriophages were between 0.01 and 0.13. Our results also demonstrated that the transport of bacteria and bacteriophages in the soil columns could be reduced considerably in the presence of pyrophyllite. Under the same column experimental conditions above, the log removals for MS2 and Phix174 in 50% soil + 50% pyrophyllite were 2.64 and 3.05, respectively, whereas the log removals in 100% pyrophyllite were 5.70 for MS2 and 5.10 for Phix174; those values were far greater than the log removals in 100% soil (MS2 = 0.063, Phix174 = 0.128). Additional column experiments (step injection, flow rate = 0.3 mL/min, column length = 30 cm, inner diameter = 2.5 cm, solution pH = 8.4, EC = 39.8 mS/cm) showed that the log removals for B. subtilis (1.72) and Phix174 (1.48) in the pyrophyllite were greater than those in the soil (B. subtilis = 1.41; Phix174 = 0.39). This study demonstrated that the pyrophyllite amendment method could be used for protecting groundwater from microbial contamination by animal carcass burial soils.

A vermifilter (with earthworms, VF), with a conventional biofilter (no earthworms, BF) as a control, was established to examine the survival state and adaptability of earthworms in protein perspective. The VF behaved with a significantly higher organic matter decomposition and lower sludge yield due to the presence of earthworms. However, during the steady stage (12 months), the earthworm biomass decreased slightly from 32.0 to 24.2 g/L, while the earthworm average weight increased, indicating that the earthworm suffered some adverse effects from the VF. Notably, from the perspective of the earthworm protein, the earthworms showed a higher Shannon-Weaver index (from H = 2.76 to 3.06) than the BF and up-regulated some proteins to cope with the negative effects from the VF. These up-regulated differential proteins played a variety of crucial roles in many cellular processes. The results suggested that a more specialized and stable protein expression of earthworms was developed in the VF, reflecting the adaptabilities of the earthworms in the VF.

The efficiency of the following systems: photolysis (UV-C only), photocatalysis with titanium-dioxide (UV-C/TiO₂), photocatalysis with granular-activated carbon (UV-C/GAC), and by adsorption on GAC, was assessed under different initial contaminant concentrations, i.e., 0.1–100 mg L⁻¹. The experiments were conducted in a batch photocatalytic reactor (1.9 L and 32 W UV power). It was found that UV-C/TiO₂ and UV-C/GAC systems showed fairly equal removal efficiencies under lower MNZ concentrations (0.1–5 mg L⁻¹) compared to higher concentrations at similar catalyst loading of 2.5 g L⁻¹. A decline in removal rate (based on first-order reaction) was observed with respect to increase in initial MNZ concentration in all systems. MNZ removal by adsorption on GAC was much lesser compared to UV-C only, UV-C/TiO₂, and UV-C/GAC systems. The adsorption data well correlated with the Freundlich model indicated that the adsorption was on the heterogeneous surface of the catalyst. The effectiveness of the systems were evaluated by calculating electrical energy consumed per order (E EO). The lowest E EO value was found to be for UV-C/TiO₂ (0.03 kWh m⁻³ order⁻¹) for the degradation of 0.1 mg L⁻¹ of MNZ compared to UV-C/GAC (0.06 kWh m⁻³ order⁻¹), UV-C only (0.15 kWh m⁻³ order⁻¹), and adsorption (0.44 kWh m⁻³ order⁻¹). The total organic carbon and nitrogen ion analyses have confirmed the mineralization of MNZ via aliphatic carboxylic acid compounds in the photocatalytic system. Overall, the photocatalytic system seems to be an energy-efficient treatment option for the removal of MNZ and similar other micropollutants.

Uranium-contaminated environments pose a risk to human health by means of its transfer to the food chain. Overcoming this issue requires using effective methods to minimize the availability of uranium and other metals in soils. Jordan has a promising project for electricity generation from nuclear power. To move forward with this nuclear project, the Jordan Central Area has been mined for uranium. The expansion of the mining activities in this area led to elevated contents of heavy metal in the surface soil. Phytoremediation efficiency in reducing uranium content from uranium-rich carbonate soil was tested using sunflower plants. Forty-eight sunflower plants were planted in three soil samples containing three different uranium concentrations. The plants were harvested after different planting periods in order to investigate the phytoremediation efficiency over time. The ability of sunflowers to translocate uranium was investigated and the results showed that the translocated amount of uranium to plant increased as the initial concentration of uranium in the soil increased. However, most of the uranium taken up by the sunflower was accumulated in the roots, and only 3% of the uranium concentration in the roots passed to the harvestable shoots. Moreover, the biomass of the plants was not affected by increasing uranium concentration in the plants indicating that sunflower is resistant to radiation and toxicity of uranium at these levels found in the soil.

The electrochemical elimination of the herbicide diquat dibromide (DQ) in an undivided electrochemical cell (Condiacell®-type cell) and an H-type cell (a divided electrochemical cell) using boron-doped diamond (BDD) electrodes is reported for the first time. The degradation of essentially 100% of the DQ present was achieved in the undivided electrochemical cell and ca. 92% in the H-type cell. Nearly 80% of the total organic carbon (TOC) and of the chemical oxygen demand (COD) were removed after 5 h of treatment at different current densities (i.e., 0.5, 1.0, and 1.5 mA/cm² for the undivided cell, and 2.5, 5.0, and 7.5 mA/cm² for the H-type cell) with a maximum specific energy consumption of approximately 150 kWh kg⁻¹ of COD degraded in the undivided cell, and 300 kWh kg⁻¹ of COD in the H-type cell. Energy consumption of about 0.30 kWh g⁻¹ of TOC occurred in the undivided electrochemical cell and 2.0 in the H-type cell. In spite of obtaining similar percentages of DQ degradation and of COD and TOC removal, a smaller energy usage was required in the undivided cell since smaller current densities were employed. Best results were obtained with the undivided cell, since it required a smaller current density to obtain virtually the same percentage of DQ degradation and removal of COD and TOC. The results obtained herein show that the use of electrochemical advanced oxidation processes may be a good alternative for DQ degradation in polluted water.

Surface modification of the silica nanoparticles was performed using trithiocyanuric acid (TCA-SNPs) so as to enhance the adsorption of Ag⁺ from aqueous solutions. The surface modification to the adsorbent was characterized by Fourier transform infrared spectroscopy, transmission electron microscope, and X-ray photoelectron spectroscopy. The Ag⁺ adsorption capacity was found to increase with increase in the solution pH, with the optimal pH being 5.0. The Ag⁺ adsorption isotherm was generated at 25 °C at the optimal solution pH and the maximum adsorption capacity was found to be 80 mg/g, significantly higher than the adsorption capacity reported for other adsorbents in literature. The increase in adsorption capacity was attributed to the presence of thiol groups on the surface of the modified adsorbents. Additionally, the adsorption kinetics was estimated at 25 °C, which indicated very high rates of adsorption initially, with rapid reduction in rate of adsorption with time. Both adsorption isotherms as well as the adsorption kinetics were modeled with popular models. The adsorption isotherm was found to match with the Langmuir model while the adsorption kinetics was found to match with the pseudo-second-order kinetic model. The adsorption-desorption cycles indicate the TCA-SNPs to be stable adsorption performance and retain high adsorption efficiency ensuring commercial adoption. A relatively low adsorption of other ions such as Mn²⁺, Cu²⁺, Ni²⁺, Co³⁺ as compared to Ag⁺ was ensured.

Hydraulic retention time (HRT) influence improving sludge flocculation with adding the polyelectrolytes (non-ionic, anionic, and cationic) was studied on an activated sludge (AS) system fed with synthetic domestic wastewater (SDW), dairy industry wastewater (DIW), and caramel industry wastewater (CIW). The sludge volumetric index, food/microorganism ratio (F/M), and mixed liquor volatile suspended solids at different HRTs (6, 8 and 10 h) were monitored on an experimental model. Results showed that both SDW and IW had the best sludge flocculation conditions at 8 h and 100 mL of non-ionic polyelectrolyte (0.2 mg L⁻¹). In addition, this phenomenon reached the organic matter removal efficiencies of 95.9, 95.7, and 94.2% for SDW, DIW, and CIW, respectively. Therefore, optimum HRT increased the organic matter removal efficiencies by 10%, sludge concentration by 37% (22–55%), and F/M ratio by 70%. Moreover, the polyelectrolytes used in AS improved the sludge flocculation by 2.9 times.