Grass from municipal roadside verges is a potential yet largely unused resource for bioenergy recovery, which is mainly due to its unknown elemental composition. Therefore, we measured the concentration of 16 elements (Ca, K, Mg, N, Na, P, S, Al, Cd, Cl, Cr, Cu, Mn, Pb, Si and Zn) in a material from the city of Kassel harvested in different management intensities. The element concentrations were mainly close to reference values of agricultural or nature conservation grassland and usually within the range of literature data. Concentrations of most elements, including heavy metals, were below limiting values. Only N and Cl concentrations in the raw material exceeded the limiting values for combustion, but washing and dewatering of the biomass with the “integrated generation of solid fuel and biogas from biomass” technique resulted in concentrations in the press cake well below the limiting values. Considering the element concentrations of grass from urban roadside verges, utilisation for energy recovery may be possible, provided an appropriate technology is applied.

Leachate from unlined or leaky landfills can create groundwater contaminant plumes that last decades to centuries. Understanding the dynamics of leachate movement in space and time is essential for monitoring, planning and management, and assessment of risk to groundwater and surface-water resources. Over a 23.4-year period (1986–2010), the spatial extent of the Norman Landfill leachate plume increased at a rate of 7800 m²/year and expanded by 878 %, from an area of 20,800 m²in 1986 to 203,400 m²in 2010. A linear plume velocity of 40.2 m/year was calculated that compared favorably to a groundwater-seepage velocity of 55.2 m/year. Plume-scale hydraulic conductivity values representative of actual hydrogeological conditions in the alluvium ranged from 7.0 × 10⁻⁵to 7.5 × 10⁻⁴ m/s, with a median of 2.0 × 10⁻⁴ m/s. Analyses of field-measured and calculated plume-scale hydraulic conductivity distributions indicate that the upper percentiles of field-measured values should be considered to assess rates of plume-scale migration, spreading, and biodegradation. A pattern of increasing Cl⁻concentrations during dry periods and decreasing Cl⁻concentrations during wet periods was observed in groundwater beneath the landfill. The opposite occurred in groundwater downgradient from the landfill; that is, Cl⁻concentrations in groundwater downgradient from the landfill decreased during dry periods and increased during wet periods. This pattern of changing Cl⁻concentrations in response to wet and dry periods indicates that the landfill retains or absorbs leachate during dry periods and produces lower concentrated leachate downgradient. During wet periods, the landfill receives more recharge which dilutes leachate in the landfill but increases leachate migration from the landfill and produces a more concentrated contaminant plume. This approach of quantifying plume expansion, migration, and concentration during variable hydrologic conditions provides increased understanding of plume behavior and migration potential and may be applied at less monitored landfill sites to evaluate potential risks of contamination to downgradient receptors.

The phenolics and high organic content present in palm oil mill effluent are the major contributors to its dark brown color, toxicity, and antimicrobial properties. In this study, ten white rot fungi were screened for their potential in the dephenolization and decolorization of treated palm oil mill effluent (TPOME) in solid and liquid state cultures. Among them, Trametes hirsuta strain AK 04 was found to be more tolerant to high TPOME concentrations and showed the highest phenolics and color removal activities. This strain was immobilized onto oil palm fibers (OPFs) and appeared more resistant to inhibitory compounds such as phenolics in TPOME than the free cell culture. The OPF-immobilized fungus was able to effectively remove phenolics and color of TPOME without effluent dilution and addition of nutrients. The activities of laccase and manganese peroxidase were found during dephenolization and decolorization processes. Moreover, the degradation rate of immobilized fungus could be accelerated by pretreatment of phenolics with phenol-degrading bacteria. This method improved the fungal dephenolization and decolorization simultaneously up to 82.2 ± 3.8 % and 87.1 ± 1.1 % after 8 days of incubation. Therefore, a two-stage biological process containing phenol-degrading bacteria and OPF-immobilized fungus could be a feasible and economical method for simultaneous improvement of dephenolization and decolorization of TPOME.

Effects of pH, As species, and Fe/Mn minerals on the fractions of adsorbed As in aquifer sediments were evaluated. Kinetic data showed that As adsorption was controlled by diffusion through the external film. Isothermal data of both As(III) and As(V) fitted the Langmuir isotherm well, revealing a monolayer adsorption process. Sequential extraction demonstrated that water-soluble As and non-specifically sorbed As were the major fractions of adsorbed As. Assessing the relationship between the Freundlich K F and the increases in the amounts of As fractions showed that the pH played a key role in weakly adsorbed As, especially water-soluble As. Although inorganic As species converted each other during the adsorption processes, more non-specifically sorbed As was adsorbed in As(V)-treated sediment than in As(III)-treated sediment, showing that the electrostatic selectivity controlled the non-specific adsorption. Additionally, specifically sorbed As and As associated with the amorphous phases were predominated by Fe/Mn minerals, especially Fe(III) (hydr)oxides. These results suggested that pH, As species, and Fe/Mn minerals would regulate the As fractions in aquifer sediments, and therefore control As cycling in aquifer systems.

Biofiltration of an air stream polluted with diffuse CH₄ concentrations of 0.19 % (v v⁻¹) was carried out. These emissions can be encountered at different industrial facilities such as wastewater treatment plants and landfills. The effect of ammonium supplied in the nutrient solution was studied in a range from 0 to 1 g N-NH₄ ⁺ L⁻¹, taking account its effect on CH₄ removal efficiency (RE), CO₂ production, ammonium conversion and the occurrence of exopolymeric substances. Additional batch assays were performed in order to evaluate the most suitable pH and temperature ranges for the biomass used as inoculum. A conventional biofilter was operated along 225 days achieving maximum CH₄ elimination capacities of up to 11.2 g CH₄ m⁻³ h⁻¹, corresponding to REs of 62 %, using 0.52 g N L⁻¹ of ammonia as nitrogen source in the nutrient solution and operating at an empty bed residence time of 4.4 min. CO₂ production values confirmed that most of this elimination was biological and not absorption into the liquid phase. The occurrence of instability periods resulted in a clear increase of the soluble microbial products (SMPs) contained in the liquid phase, especially in the protein fraction, which could be used as a monitoring tool to follow the stress conditions of the biofilter. Results indicate interesting links between the performance of the biofilter and the presence of extracellular polysaccharide and protein concentration in the liquid phase, with increasing concentrations detected when the process was not stable.

Genotoxicity of 5-fluorouracil (5-FU), etoposide (ET) and cadmium chloride (CdCl₂) was evaluated in Limnodrilus udekemianus, cosmopolitan tubificid species, by alkaline single-cell gel electrophoresis (comet assay). Groups of 50 individuals were exposed in vivo in water-only short-term (96 h) tests to 5-FU (0.004, 0.04, 0.4, 4 and 40 μM), ET (0.004. 0.04, 0.4 and 4 μM) and CdCl₂ (0.004, 0.04, 0.4, 4 and 40 μM). Mortality of worms was observed only for CdCl₂ (4 and 40 μM). Cell viability lower than 70 % was detected for 5-FU (0.4, 4 and 40 μM), ET (4 μM) and CdCl₂ (0.4 and 4 μM). All tested substances induced significant increase of DNA damage except 0.004 μM of ET. L. udekemianus being sensitive to all tested substances indicates that it can be used in ecogenotoxicology studies. Concern should be raised to cytostatics, especially to 5-FU, since concentration of 0.004 μM induced DNA damage is similar to ones detected in wastewaters.

Early detection of landfill leachate plumes may minimise aquifer degradation and financial expenditure for the landfill operator. Current methods of landfill leachate monitoring typically include analysis of groundwater field parameters such as electrical conductivity (EC), coupled with laboratory analysis of a selection of major cations and anions. In many instances, background influences can mask the impact of leachate, which only becomes apparent once a significant impact has occurred. Here, we investigate the potential for changes in fluorescent dissolved organic material (FDOM) concentration to be used as an indicator of leachate impact. The research was undertaken in a fractured rock aquifer located downgradient of a local government-operated putrescible landfill in Central West NSW, Australia. Field measurement of groundwater FDOM was undertaken using an in situ fluorometer (FDOM probe) which provides a relative measurement of FDOM. To quantify the FDOM values, a bench fluorescence spectrophotometer was used to collect excitation/emission spectra. A plume of elevated FDOM and EC levels within the fractured rock system up to 600 m downgradient of the landfill was identified, whereas analysis of major cations and anions from boreholes within the plume did not detect leachate impacts above background. Excitation/emission matrices of groundwater from these locations confirmed that similar fluorescence signatures to those collected from the landfill were present. Photodegradation experiments were conducted to determine if fluorescent whitening agents (FWAs) were a component of the fluorescence signal. Observed photodegradation of 40 % compared to background (8 %) suggests that a component of the fluorescence signal can be attributed to FWAs. FDOM in groundwater therefore provides an indicator of low-level (up to 98 % dilution) leachate influence, and the identification of FWAs within groundwater can be considered confirmation of a leachate signal.

Road dust organic matter plays a vital role in mobilization of contaminants. This study investigated and characterized organic matter (OM) presents in road dust particles of various sizes. Road dust samples were collected from an industrialized city of Ulsan, Republic of Korea and fractionated into four groups: <75, 75–180, 180–850, and 850–2000 μm. OM extracted from the four fractions was characterized by excitation-emission matrix fluorescence and analyzed by parallel factor analysis (PARAFAC). The PARAFAC identified four major fluorophore components (C1–C4). These components were related to microbial humic-like, anthropogenic organic, fulvic-like, and low molecular weight OM contributed by anthropogenic activity, respectively. There were subtle changes in specific OM composition with change in particle size. The finest fraction contained more microbial humic-like substances whereas the coarse fraction was enriched with fulvic acid. The OM in two fractions (75–180 and 180–800 μm) showed dual characteristics. Our findings demonstrated that PARAFAC approach can assist to assess the accumulation of pollutants in road dust.

In this work, we developed a method based on ultrasound-assisted emulsification microextraction (USAEME) for the determination of nickel by flame atomic absorption spectrometry (FAAS). The method is based on the use of the organic solvent trichloroethylene and 2,2′-thiazolylazo-p-cresol (TAC) as a chelating reagent in a solution containing nickel ions. After ultrasonic emulsification, the mixture is centrifuged to separate the phases. Subsequently, the supernatant is discarded, and the enriched phase is diluted with nitric acid. The nickel content in this new mixture is quantified by FAAS. The following variables were optimized: type of solvent (trichloroethylene), type of chelating reagent (TAC), volume of extraction solvent (100 mL), concentration of chelating reagent (0.015 % w/v), pH (8.0), time of sonication (5.0 min), and time of centrifugation (4.0 min). The limits of detection and quantification were calculated under optimum conditions (0.23 and 0.77 μg L⁻¹, respectively). The enrichment factor obtained was 190. The relative standard deviation (RSD%) of the method (10.0 μg L⁻¹) was 2.3–4.1 %. The proposed method is simple, economical, fast, and efficient for the determination of nickel by FAAS. The procedure was applied to the determination of nickel in certified reference material (BCR-713, wastewater) and water samples.

In this work, metal sorption onto grape stalks waste structural compounds and extractives has been studied for determining their role in Cr(VI), Cu(II) and Ni(II) metal sorption. For this purpose, a sequential extraction of extractives and other compounds from the lignocellulosic material has been carried out. The resulting solid samples obtained in the different extraction processes were used as sorbents of Cr(VI), Cu(II) and Ni(II). Sorption results were discussed taking into account the elemental composition and polarity of the solid extracts. Results indicated that tannins and polyphenols are involved in chromium reduction and sorption. Lignin and celluloses are involved in chromium, Cu(II) and Ni(II) sorption. FTIR analysis confirmed the involvement of lignin moieties in the studied metal ions sorption by grape stalks waste. This study presents a new approach on metal sorption field as the knowledge of the role of the sorbent chemical compounds is essential to determine the key sorbent compounds in the sorption process.