Reduction of membrane fouling in reverse osmosis systems and elimination of scaling of heat transfer surfaces in thermal plants are a major challenge in the desalination of seawater. Precipitation softening has the potential of eliminating the major fouling and scaling species in seawater desalination plants, thus allowing thermal plants to operate at higher top brine temperatures and membrane plants to operate at a reduced risk of fouling, leading to lower desalinated water costs. This work evaluated the use of precipitation softening as a pretreatment step for seawater desalination. The effectiveness of the process in removing several scale-inducing materials such as calcium, magnesium, silica, and boron was investigated under variable conditions of temperature and pH. The treatment process was also applied to seawater spiked with other known fouling species such as iron and bacteria to determine the efficiency of removal. The results of this work show that precipitation softening at a pH of 11 leads to complete elimination of calcium, silica, and bacteria; to very high removal efficiencies of magnesium and iron (99.6 and 99.2 %, respectively); and to a reasonably good removal efficiency of boron (61 %).

Lead (Pb) and decabromodiphenyl ether (BDE209) are the main contaminants at e-waste recycling sites, and their potential toxicological effects on terrestrial organisms have received extensive attention. However, the impact on earthworms of exposure to the two chemicals remains almost unknown. Therefore, indoor incubation tests were performed on control and contaminated soil samples to determine the Pb accumulations and toxic effects by earthworms in the presence of BDE209 for the first time. The results have demonstrated that BDE209 presence can affect Pb bioaccumulation efficiency compared with exposure to Pb alone. The Pb contents in earthworms had a highly positive correlation with the Pb concentrations in soils. For different Pb doses, almost contrary response trends were found for Pb uptake examined separately on day 7 or 28, and dose–effect relationships were clearly observed in the presence of BDE209. After 7 days of exposure, the earthworm bodies receiving 1-mg kg⁻¹BDE209 dose showed significantly lower Pb contents (average = 175.85 mg kg⁻¹) and bioaccumulation factor (average = 0.574) than those receiving non-BDE209 treatments (217.39 mg kg⁻¹and 1.209, respectively). As the incubation time extended, the influence of BDE209 presence on Pb uptake gradually declined. Additionally, either single or combined exposure to both chemicals can affect the protein synthesis in earthworms (p < 0.01), while different levels of BDE209 addition barely caused visible differences. The results of these observations have provided a basic understanding on the potential toxicological effects of joint Pb and BDE209 exposure on terrestrial invertebrates.

The aim of this work is to evaluate the effect of Parthenium-mediated compost on Eudrilus eugeniae during the process of vermicomposting. Nine different concentrations of Parthenium hysterophorus and cow dung mixtures were used to assess toxicity. The earthworms’ growth, fecundity and antioxidant enzyme levels were analysed every 15 days. The antioxidant activities of enzymes [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)], considered as biomarkers, indicate the biochemical and oxidative stresses due to the toxin from Parthenium weeds. The earthworms’ growth, biomass gain, cocoon production and antioxidant enzymes were in a low level in a high concentration of P. hysterophorus (without cow dung). The results clearly indicated that appropriate mixing of P. hysterophorus quantity is an essential factor for the survival of earthworms without causing any harm.

We expose here a detailed spatially explicit model of aphid population dynamics at the scale of a whole country (Metropolitan France). It is based on convection–diffusion-reaction equations, driven by abiotic and biotic factors. The target species is the grain aphid, Sitobion avenae F., considering both its winged and apterous morphs. In this preliminary work, simulations for year 2004 (an outbreak case) produced realistic aphid densities, and showed that both spatial and temporal S. avenae population dynamics can be represented as an irregular wave of population peak densities from southwest to northeast of the country, driven by gradients or differences in temperature, wheat phenology, and wheat surfaces. This wave pattern fits well to our knowledge of S. avenae phenology. The effects of three insecticide spray regimes were simulated in five different sites and showed that insecticide sprays were ineffective in terms of yield increase after wheat flowering. After suitable validation, which will require some further years of observations, the model will be used to forecast aphid densities in real time at any date or growth stage of the crop anywhere in the country. It will be the backbone of a decision support system, forecasting yield losses at the level of a field. The model intends then to complete the punctual forecasting provided by older models by a comprehensive spatial view on a large area and leads to the diminution of insecticide sprayings in wheat crops.

Monitored natural attenuation is widely accepted as a sustainable remediation method. However, methods providing proof of proceeding natural attenuation within the water-unsaturated (vadose) zone are still relying on proxies such as measurements of reactive and non-reactive gases, or sediment sampling and subsequent mineralisation assays, under artificial conditions in the laboratory. In particular, at field sites contaminated with hydrophobic compounds, e.g. crude oil spills, an in situ evaluation of natural attenuation is needed, because in situ methods are assumed to provide less bias than investigations applying either proxies for biodegradation or off-site microcosm experiments. In order to compare the current toolbox of methods with the recently developed in situ microcosms, incubations with direct push-sampled sediments from the vadose and the aquifer zones of a site contaminated with crude oil were carried out in conventional microcosms and in situ microcosms. The results demonstrate the applicability of the in situ microcosm approach also outside water-saturated aquifer conditions in the vadose zone. The sediment incubation experiments demonstrated turnover rates in a similar range (vadose, 4.7 mg/kg*day; aquifer, 6.4 mgₕₑₓₐdₑcₐₙₑ/kgₛₒᵢₗ/day) of hexadecane degradation in the vadose zone and the aquifer, although mediated by slightly different microbial communities according to the analysis of fatty acid patterns and amounts. Additional experiments had the task of evaluating the degradation potential for the branched-chain alkane pristane (2,6,10,14-tetramethylpentadecane). Although this compound is regarded to be hardly degradable in comparison to n-alkanes and is thus frequently used as a reference parameter for indexing the extent of biodegradation of crude oils, it could be shown to be degraded by means of the incubation experiments. Thus, the site had a high inherent potential for natural attenuation of crude oils both in the vadose zone and the aquifer.

Over the past decades, significant efforts have been invested in the development of push-in technology for site characterization and monitoring for geotechnical and environmental purposes and have especially been undertaken in the Netherlands and Germany. These technologies provide the opportunity for faster, cheaper, and collection of more reliable subsurface data. However, to maximize the technology both from a development and implementation point of view, it is necessary to have an overview of the areas suitable for the application of this type of technology. Such an overview is missing and cannot simply be read from existing maps and material. This paper describes the development of a map showing the feasibility or applicability of Direct Push/Cone Penetrometer Technology (DPT/CPT) in Europe which depends on the subsurface and its extremely varying properties throughout Europe. Subsurface penetrability is dependent on a range of factors that have not been mapped directly or can easily be inferred from existing databases, especially the maximum depth reachable would be of interest. Among others, it mainly depends on the geology, the soil mechanical properties, the type of equipment used as well as soil-forming processes. This study starts by looking at different geological databases available at the European scale. Next, a scheme has been developed linking geological properties mapped to geotechnical properties to determine basic penetrability categories. From this, a map of soil penetrability is developed and presented. Validating the output by performing field tests was beyond the scope of this study, but for the country of the Netherlands, this map has been compared against a database containing actual cone penetrometer depth data to look for possible contradictory results that would negate the approach. The map for the largest part of Europe clearly shows that there is a much wider potential for the application of Direct Push Technology than is currently seen. The study also shows that there is a lack of large-scale databases that contain depth-resolved data as well as soil mechanical and physical properties that can be used for engineering purposes in relation to the subsurface.

In this work, the removal of the worldwide non-steroidal anti-inflammatory drugs ibuprofen (IBP) and ketoprofen (KTP) by emulsion liquid membrane (ELM) was carried out. An ELM system is made up of hexane as diluent, Span 80 as the surfactant and sodium carbonate as the inner aqueous solution. Effect of experimental conditions that affect the extraction of IBP such as surfactant concentration, emulsification time, sulfuric acid concentration in external phase, acid type in external phase, internal phase concentration, type of internal phase, stirring speed, volume ratio of internal phase to membrane phase, treatment ratio, IBP initial concentration, diluent type and salt was investigated. The obtained results showed that by appropriate selection of the operational parameters, it was possible to extract nearly all of IBP molecules from the feed solution even in the presence of high concentration of salt. Under optimum operating conditions, the efficiencies of IBP removal from distilled water (99.3 %), natural mineral water (97.3 %) and sea water (94.0 %) were comparable, which shows that the ELM treatment process represents a very interesting advanced separation process for the removal of IBP from complex matrices such as natural and sea waters. Under the optimized experimental conditions, approximately 97.4 % KTP was removed in less than 20 min of contact time.

To explain the detailed process involved in phosphorus removal by periphyton, the periphyton dominated by photoautotrophic microorganisms was employed in this study to remove inorganic phosphorus (P ᵢ ) from wastewater, and the removal kinetics and isotherms were then evaluated for the P ᵢ removal process. Results showed that the periphyton was capable of effectively removing P ᵢ that could completely remove the P ᵢ in 24 h at an initial P ᵢ concentration of 13 mg P L⁻¹. Furthermore, the P ᵢ removal process by the periphyton was dominated by adsorption at initial stage (~24 h), which involved physical mechanistic process. However, this P ᵢ adsorption process was significantly influenced by environmental conditions. This work provides an insight into the understanding of phosphorus adsorption by periphyton or similar microbial aggregates.

The vertical concentration profiles and source contributions of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in respirable particle samples (PM₄) collected at 10, 100, 200 and 300-m altitude from the Milad Tower of Tehran, Iran during fall and winter were investigated. The average concentrations of total PAHs and total n-alkanes were 16.7 and 591 ng/m³, respectively. The positive matrix factorization (PMF) model was applied to the chemical composition and wind data to apportion the contributing sources. The five PAH source factors identified were: ‘diesel’ (56.3 % of total PAHs on average), ‘gasoline’ (15.5 %), ‘wood combustion, and incineration’ (13 %), ‘industry’ (9.2 %), and ‘road soil particle’ (6.0 %). The four n-alkane source factors identified were: ‘petrogenic’ (65 % of total n-alkanes on average), ‘mixture of petrogenic and biomass burning’ (15 %), ‘mixture of biogenic and fossil fuel’ (11.5 %), and ‘biogenic’ (8.5 %). Source contributions by wind sector were also estimated based on the wind sector factor loadings from PMF analysis. Directional dependence of sources was investigated using the conditional probability function (CPF) and directional relative strength (DRS) methods. The calm wind period was found to contribute to 4.4 % of total PAHs and 5.0 % of total n-alkanes on average. Highest average concentrations of PAHs and n-alkanes were found in the 10 and 100 m samples, reflecting the importance of contributions from local sources. Higher average concentrations in the 300 m samples compared to those in the 200 m samples may indicate contributions from long-range transport. The vertical profiles of source factors indicate the gasoline and road soil particle-associated PAHs, and the mixture from biogenic and fossil fuel source-associated n-alkanes were mostly from local emissions. The smaller average contribution of diesel-associated PAHs in the lower altitude samples also indicates that the restriction of diesel-fueled vehicle use in the central area of Tehran has been effective in reducing the PAHs concentration.

This study examines gaseous chlorinated species generated from the reaction of sulfur dioxide (SO₂) with sodium chlorite powder (NaClO₂₍ₛ₎) to obtain insight into the propensity of this process to enhance NO and Hg⁰oxidation. A packed bed reactor containing NaClO₂₍ₛ₎was used and the reaction temperature was set to 130 °C. Initially, we determined that the presence of SO₂enhances the oxidation of NO and Hg⁰by reaction with NaClO₂₍ₛ₎. We then introduced NO₂into the gas mixture as a radical scavenger and determined that the chlorinated species generated by the reaction of SO₂with NaClO₂₍ₛ₎are OClO, Cl, ClO, and Cl₂. Based on these results, we suggest that such gaseous chlorinated ones are responsible for the enhancement of NO and Hg⁰oxidation.