The aim of this study was to evaluate and compare the capacities of cattail (Typha latifolia L.) and reed (Phragmites australis L.) for heavy metal storage in the phytomass. Samples were studied in the fourth of the four interconnected natural lagooning basins of a constructed treatment wetland, developed as an integrated pilot system for the treatment of leachates in a domestic landfill site at Etueffont (Territoire de Belfort, France). The efficiency of the lagooning system was evaluated through physical and chemical parameter measurements over a period of three seasons. Anion/cation and heavy metal concentrations were sampled and analyzed in water flowing into and out of the lagooning basin. Simultaneously, reed and cattail biomass samples (roots/rhizomes, shoots) were collected at both inflow and outflow, and the biomass characteristics were determined. The average above-ground biomass of T. latifolia and P. australis varied, respectively, from 0.41 to 1.81 kg DW m−2 in the fall, 0.31 to 1.34 kg DW m−2 in winter, and 0.38 to 1.68 kg DW m−2 in spring, with significant seasonal variations. The greatest mean concentrations of heavy metals were found in the below-ground plant parts of the two species during the spring season. The average standing stock of heavy metals was higher in the below-ground than in the above-ground phytomass, whatever the season. With the exception of nickel, heavy metal concentrations in the inflow were correlated to the plant content of both species.

Despite the importance of periphyton–metal interactions in bioremediation schemes and in phosphorus (P) cycling, the processes controlling metal accumulation in periphytic mats are still poorly understood. Iron (Fe) accumulation in periphytic mats was examined across a Fe settlement lagoon receiving mine drainage in Scotland, UK, between March and June 2008. Quantification and mapping of intracellular and extracellular Fe concentrations in periphyton samples using scanning electron microscopy–energy dispersive spectroscopy suggested that Fe accumulation was dominated by the association of Fe-rich precipitates with the extracellular polymeric substances matrix, rather than biotic uptake. Intracellular Fe concentrations were significantly higher in periphyton samples exposed to the highest dissolved Fe concentrations. Neither intracellular nor extracellular Fe concentrations were significantly affected by light availability or cell density. While diatoms dominated the periphyton communities there was no significant association of diatom functional groups with Fe accumulation, indicating that community composition may not affect the function of periphytic mats with respect to Fe removal. Scale-up calculations based on the mean measured Fe accumulation rate by periphyton substrates of 0.021 g m−2 day−1 showed that exposure of large surface areas of periphyton substrate in the settlement lagoon would only increase the Fe removal efficiency of the lagoon by c.1%.

An investigation was made to evaluate the capacity of a colorimetric artificial nose to detect toxic gas at low concentration. A low-cost and simple colorimetric sensor array for identification and quantification of NH3 with different concentrations (30, 90, 150, and 210 ppb) were reported. Using porphyrin, porphyrin derivatives (mainly metalloporphyrins), and chemically responsive dyes as the sensing elements, the developed sensor array of artificial nose showed a unique pattern of colorific change upon its exposure to NH3 with different concentrations. The dynamic responses of colorimetric sensor array to NH3 and colorimetric sensor array to various NH3 concentrations at the same time point showed that there was a positive relationship between the color change values of spots and contractions of NH3. NH3 with four concentrations were measured, and the response values at six different collection times were conducted by linear discrimination analysis (LDA) and artificial neural network (ANN). The four concentrations were discriminated completely by LDA. The response value of the colorimetric artificial nose at 0.4 min was optimum for discrimination. The method of ANN was performed and less than 5% of error by using T-S fuzzy neural network.

The use of azo dyes is popular in different branches of industry. Discharge of colourants to surface water cause harmful environmental effects. The aim of the present study was evaluation of effectiveness of diazo Evans blue decolourization by two Pseudomonas strains and estimation of process byproducts toxicity. In static conditions, both tested strains removed more than 85 % of dye after 48 h and completely decolorized samples after 120 h. Agitation had negative impact on Evans blue removal (less than 70 % of dye removed after 120 h). Ecotoxicological effects were different for both studied strains beside comparable decolourization effectiveness. Increase of zootoxicity was noticed for strain Sz6 and decrease from IV to III class was noticed for strain SDz3. Optimization of process conditions for the most promising strain SDz3 should be deeply examined.

In this study, we test whether the δ¹³C and δ¹⁵N in a peat profile are, respectively, linked to the recent dilution of atmospheric δ¹³CO₂ caused by increased fossil fuel combustion and changes in atmospheric δ¹⁵N deposition. We analysed bulk peat and Sphagnum fuscum branch C and N concentrations and bulk peat, S. fuscum branch and Andromeda polifolia leaf δ¹³C and δ¹⁵N from a 30-cm hummock-like peat profile from an Aapa mire in northern Finland. Statistically significant correlations were found between the dilution of atmospheric δ¹³CO₂ and bulk peat δ¹³C, as well as between historically increasing wet N deposition and bulk peat δ¹⁵N. However, these correlations may be affected by early stage kinetic fractionation during decomposition and possibly other processes. We conclude that bulk peat stable carbon and nitrogen isotope ratios may reflect the dilution of atmospheric δ¹³CO₂ and the changes in δ¹⁵N deposition, but probably also reflect the effects of early stage kinetic fractionation during diagenesis. This needs to be taken into account when interpreting palaeodata. There is a need for further studies of δ¹⁵N profiles in sufficiently old dated cores from sites with different rates of decomposition: These would facilitate more reliable separation of depositional δ¹⁵N from patterns caused by other processes.

To provide good quality of drinking water, a biological system to remove ammonium-nitrogen (NH₄-N) from groundwater was studied in this research. The NH₄-N removal system consists of two attached growth reactors: one for nitrification and the other for hydrogenotrophic denitrification (H. denitrification). The nitrification reactor, fed by the NH₄-N contained water, could remove NH₄-N without any need of aeration. The nitrification efficiency was increased by reactor length; the highest efficiency of 92 % was achieved at the longest reactor of 100 cm. A high Fe in groundwater affected the reactor performance by decreasing the efficiency, while a low inorganic carbon (IC) had no effects. Despite of good efficiency in terms of NH₄-N removal, the nitrification reactor increased the concentration of NO₃-N in its effluent. To treat the NO₃-N, a H. denitrification reactor was set up after the nitrification reactor. Efficiency of the H. denitrification reactor was enhanced by increasing H₂ flow rates. The efficiencies were 3, 27, and 90 % for 30, 50, and 70 mL/min of H₂ flow rates, respectively. It was also found that the NO₃-N contained water (water from the nitrification reactor) had to supply IC (i.e., NaHCO₃ or CO₂) for efficient H. denitrification; however, an on-site reactor showed that it can be achieved even without IC addition. The treated water contained low NH₄-N and NO₃-N of <1.5 and <11.3 mg/L, respectively, which comply with drinking water standards. The good performance of the reactors in terms of high efficiency, no aeration need, and low H₂ supply indicated appropriateness of the system for groundwater treatment.

We investigated the potential application of pyrolysis treatment to a mixture of woody biomass and a metal-contaminated soil as an alternative eco-friendly option to stabilize metals in soils. Our specific objective was to test the optimum combination of high heating temperature (HHT) and heating time to effectively encapsulate metals in a contaminated soil into a biochar. For this purpose, we used a laboratory bench batch reactor to react a mixture of multi-element metal contaminated soil with 0% (control) 5%, 10%, and 15% (w/w) sawdust. Each mixture was reacted at 200°C and 400°C HHT for 1 and 2 h heating times. Physicochemical and morphological characterization along with standard EPA Synthetic Precipitation Leaching Procedure (SPLP) test were conducted to assess the effectiveness of the heat treatment to immobilize the metals in the contaminated soil. Compared to controls, we recorded up to 93% reduction in Cd and Zn leachability after 1 h heat treatment at 400°C, with the addition of 5–10% biomass. Pb leaching was reduced by 43% by the same treatment but without the addition of biomass. At lower pyrolysis temperature (200°C), however, there was a substantial increase in both As and Zn leaching compared to the untreated controls. Our study suggests that several factors such as the type of metal, heating temperature, heating period, and the addition of biomass influence the efficiency of pyrolysis to immobilize metals in the contaminated soil.

We performed a 2-year microcosm study to assess the effectiveness of red mud, a by-product of bauxite processing, in stabilizing contaminated mine waste and agricultural soil. Our study used red mud from a long-term disposal area in Almásfüzitő, Hungary with a pH of 9.0. A 5% (by weight) red mud addition decreased the highly mobile, water-extractable amount of Cd and Zn by 57% and 87%, respectively, in the agricultural soil and by 73% and 79%, respectively, in the mine waste. In a laboratory lysimeter study, the addition of red mud reduced the concentration of Cd and Zn in the leachate by about two third of the original. The metal content of the leachate was below the Maximum Effect Based Quality Criteria for surface water as determined by a risk assessment in the metal-contaminated area of the Toka valley near Gyöngyösoroszi, Hungary. The addition of red mud did not increase the toxicity of the treated mine waste and soil and decreased the Cd and Zn uptake of Sinapis alba test plants by 18–29%. These results indicate that red mud applied to agricultural soil has no negative effects on plants and soil microbes and decreases the amounts of mobile metals, thus indicating its value for soil remediation.

The effect of different humic fractions on polychlorinated biphenyl (PCB) contamination in soils was tested in the field by means of 53 soil samples from a high-altitude grassland plateau in the Italian Alps. Three humic fractions (humin, humic acids, and fulvic acids) were characterized in parallel by quantifying 12 PCB congeners to establish a direct relationship between PCB levels and humic fraction concentrations. Humin (the most hydrophobic fraction) appears to be the most closely correlated with the amount of PCBs in soil (R ²â€‰= 0.83), while fulvic acid shows the lowest correlation (R ²â€‰= 0.49). The idea of preferential sorption of hydrophobic compounds in the humin fraction is discussed, and the humin carbon content (f ₕᵤₘᵢₙC) is proposed as an improved parameter for evaluating the potential for POP accumulation in soils, replacing total organic carbon (f ₒc). Congener studies revealed that penta- and hexa-substituted-CBs show the optimal combination of physicochemical properties for equilibrating with the humin content in soil. Moreover, f ₕᵤₘᵢₙC/f ₒc is conceptually equivalent to the empirical coefficients used in predictive K ₛₐ equations. In our samples, the f ₕᵤₘᵢₙC/f ₒc was 0.55, a value in between the empirical coefficients proposed in the literature. In predictive equations, the use of f ₕᵤₘᵢₙC instead f ₒc avoids the necessity of using an empirical parameter for a ‘generic’ condition by introducing an experimental parameter (f ₕᵤₘᵢₙC) that takes into account local conditions (organic matter composition).

This paper analyses the influence of activated sludge technologies on the Particle Size Distribution (PSD) of urban wastewater treatment plants operating under real conditions. The activated sludge treatment systems selected for the analysis are the most widely used in wastewater treatment installations: (a) double step activated sludge, (b) medium load activated sludge, (c) prolonged aeration, and (d) membrane bioreactors The main quality parameters (suspended solids, turbidity, and COD) and PSD in the influent and effluent of each different activated sludge treatment were analyzed during 1 year. The PSD was fitted using the power law ([Formula: see text]) obtaining coefficients A and b to define the particle distribution. Mathematical correlations between this coefficients and the rest of parameters studied were found [Formula: see text]. The relation with the average particle size by mass was also found, ([Formula: see text]). Moreover, a relation between PSD and the particle elimination efficiency of the secondary treatment was study, ([Formula: see text]). Finally, the particulate matter nature was assessed by SEM-EDX. It can be concluded that membrane bioreactor is the technology that produces the best water quality effluent due to physic process of particle separation by ultrafiltration membrane technology.