The processes of pollutant sorption by soil components control their mobility, migration, and transformation in the soil-plant system and depend on numerous properties, among which the elemental composition and surface area are dominant. In a laboratory experiment, the sorption of As and Cd by Si-rich substances differing in surface area, solubility of Si, and mineralogical composition was studied. The adsorption data were fitted to the linear, logarithmic, exponential, Langmuir, and Freundlich equations. Both size of the particles and mineral solubility of Si affected the As and Cd sorption. In the systems with lower initial concentrations of As and Cd, size of the particles had more pronounced effect on the sorption capacity. In the systems with high initial concentrations of As and Cd, the concentration of monosilicic acid was more significant than the surface area.

Arsenic concentrations in a drinking water reservoir system in the Eastern Ore mountains (Osterzgebirge, Germany) were observed over a 17-year period. The region experienced an environmental change during the past 20 years with decreasing acid, sulphur and nitrogen deposition and a recovering vitality of forested catchment sites. An increase of the arsenic content in the reservoir waters during that change was observed. This was caused by a diminished nitrate supply leading to lower redox potential in the sediments favouring sediment arsenic release. The recent annual cycle in the Altenberg reservoir water arsenic concentration was found to be independent from artificial aeration of the hypoxic hypolimnion during the summer stratification. However, we found a strong seasonal dependent change in water As concentration, with a maximum in autumn and a minimum in spring. The low productive system is driven by peat derived organic matter. For the recent arsenic catchment yield coherencies to dissolved organic carbon export and runoff intensity were found, indicating rising arsenic loads due to climate-related soil organic matter destabilization. Thus, in the reservoir system, both dry and wet climate conditions can increase the water As concentrations due to an internal arsenic release and a catchment arsenic import.

A dispersive liquid–liquid microextraction (DLLME) method was optimized for the detection of chlorobenzene (CB) compounds in the drying process of municipal and dyeing sludge. Compared with traditional methods, the optimized DLLME not only has a lower limit of detection but also saves analysis time and requires less amount of organic solvent. Using this method in analyzing CB release during sludge drying, we found that drying temperature is the main factor controlling the amount of chlorobenzene release during sludge drying. In addition, we found that most CBs were released when sludge drying entered into the second falling rate stage, i.e., a period when sludge moisture content was low and temperature was high. By analyzing organic matter content in association with CB release during sludge drying, the relationship between organic matter transformation and chlorobenzene release was established. The results provide scientific basis and technical support for assessing the risks of the secondary pollution of CBs from sludge drying.

The losses of total solids, moisture, nitrogen (N), phosphorus (P), potassium (K), carbon (C), and sulfur (S) were determined in two storage events of laying-hen manure immediately removed from three different housing systems in Iowa, USA. The three laying-hen houses were conventional cage (CC), enriched colony (EC), and aviary (AV). The houses held a nominal number of 200,000, 46,700, and 50,000 Lohmann LSL lite layers, respectively. The manure collected on belts in each house was cleaned out twice a week. A fraction of the cleaned out manure was transferred to designated storage rooms wherein losses of different components were determined in two storage events. Manure was loaded into the storage rooms over 171 days during the first storage event and over 185 days during the second storage event. The total storage periods were 202 and 245 days, respectively, for the first and second storage events. Manure was weighed, sampled, and analyzed before it was loaded into the storage rooms and at the end of each storage event. Mass balance calculations were used to determine the losses of different components. Statistical analyses show that the nutrient contents, on a wet basis, of manure loaded in CC, AV, and EC storage rooms were significantly different due to the differences in manure moisture contents. However, on a dry basis, they had no significant differences. The fresh manure cleaned out from the EC layer house was drier than that from the other two houses. Loaded-in nitrogen losses in the CC, AV, and EC storage rooms were 24.6, 12.9, and 20.8%, respectively. Nitrogen losses depended on house temperature, manure moisture, and pH. The average losses of loaded-in manure mass, moisture, and total solids during the two storage events were 27.6 ± 1.9, 33.8 ± 8.3, and 20.8 ± 7.0%, respectively. The losses of N, P, K, C, and S were 19.4 ± 13.4, 11.7 ± 5.6, 10.2 ± 6.8, 27.0 ± 6.5, and 8.3 ± 8.5% of their loaded-in amounts, respectively. The total loss of N, P, K, C, and S was 56% of the total loaded-in solids loss; thereof, the loss of N, P, and K was 7%, and C loss was 48%. The laying-hen-specific losses of N, P, K, C, and S were 0.34, 0.05, 0.08, 3.2 and 0.019 g day⁻¹ hen⁻¹, respectively. The results of this research are important for assessing impacts of stored manure on environment and nutrient losses. They can also be used to develop methodologies for the mitigation of the emissions from egg production facilities.

While some countries disaggregate N₂O emission factors for urine and dung deposited onto pastures, in Canada, distinct N₂O emission factors for beef cattle urine and dung have not been defined. To help address this knowledge gap, we conducted a 1-year study to quantify N₂O fluxes from beef cattle urine and dung patches on a semiarid tame pasture in western Canada, as well as to quantify the N₂O emission factors (EF3) for urine and dung as the percentage of applied N emitted as N₂O-N. Urine and dung were deposited when soil water-filled pore space was nearly 60%, a wet soil condition for the grazing season in the semiarid study region, which led to a burst of N₂O from urine in the first 14 days of the study (42% of total N emitted). Urine emitted more cumulative N₂O (P < 0.001) and had a greater N₂O emission factor (P = 0.002) than dung. The urine patch emitted 1.30 ± 0.47 g N₂O-N m⁻² year⁻¹, while the dung patch emitted 0.083 ± 0.020 g N₂O-N m⁻² year⁻¹ (mean values ± SD). The N₂O emission factor for urine was 1.32 ± 0.49%, while for dung it was 0.03 ± 0.02%. We conclude that more study is needed to determine if distinct N₂O emission factors are required for urine and dung deposited onto pasture in western Canada to more accurately estimate national N₂O inventories.

The potential of a membrane bioreactor (MBR) system to treat Fischer-Tropsch (FT) reaction water from gas-to-liquids (GTL) industries was investigated and compared with the current treatment system: a conventional activated sludge system followed by an ultrafiltration (CAS-UF) unit. The MBR and the CAS-UF systems were inoculated with municipal activated sludge and operated in parallel for 645 days with four interruptions using synthetic FT reaction water. Both treatment systems achieved a removal efficiency of 98 ± 0.1% within 60 days after inoculation, the COD influent concentration was 1014 ± 15 mg L⁻¹. This suggests that MBRs form a suitable alternative to CAS-UF systems for the treatment of FT reaction water from the GTL industries. Moreover, the total fouling rates (F ₜ) of the membranes used from day 349 till the end were assessed. The average F ₜ was 7.3 ± 1.0 10¹⁰ m⁻¹ day⁻¹ for CAS-UF membranes and 2.8 ± 00.7 10¹⁰ m⁻¹ day⁻¹ for MBR-MT membranes. This indicates that MBR systems for the treatment of FT reaction water from the gas-to-liquids industries are less prone to fouling than CAS-UF systems.

Research was conducted on the most polluted river system in Poland, impacted by active and historical mining. Bottom sediment, suspended particulate matter and river water were collected in 2014 from Przemsza river and its tributaries. Sampling points remained the same as those chosen in a 1995 study. This allowed the comparison of heavy metal accumulation in bottom sediment over a span of almost two decades. It was concluded that Przemsza river water and its tributaries are heavily contaminated with the following (in μg/dm³): Pb (0.99–145.7), Zn (48–5020), and Cd 0.12–12.72). Concentrations of metals in bottom sediment exceeded the background values by a factor of several hundred (100 times for Zn, 150 times for Pb, and 240 times for Cd). The arithmetic mean for metal concentration in fractions <63 μm sampled in 2014 has remained comparable to the level found in 1995 (in mg/kg): Zn 16,918 and 13,505, Pb 4177 and 4758, and Cd 92 and 134. It was determined that 20–50% more metals have accumulated in suspended matter, rather than in bottom sediment (in mg/kg): 20,498 Zn, Pb 5170, and 164 Cd. This exceeds the limits of the most polluted LAWA Class IV classification. Since the concentrations of Zn, Pb, and Cd increase drastically after the outlet of the Przemsza into the Vistula, it was concluded that river Przemsza is the cause of significant degradation of Vistula’s bottom sediment and suspended matter. A two-decade legacy of extremely high contamination of the Przemsza river sediments has persisted despite decreasing mining and smelting activity in the vicinity.

Climate change affects water resources worldwide, and Southern Europe is one of the areas where water scarcity is expected to increase in the future. Different water scarcity indicators discussed in this manuscript (e.g. total annual actual renewable water resources, water exploitation index and dependency ratio) showed that some parts of this region are already facing water stress and that climate change could have a great impact on their water supply sector. As agriculture is the biggest consumer of water in the world and also in this particular region, potential water scarcity will impose the need to find new water sources. Treated wastewater reuse would decrease the pressure on the environment and is especially suitable for reuse in agriculture since it already contains some nutrients required for plant growth. However, in order to use it safely, treated wastewater must reach a certain quality that should be regulated. In the south of Europe, 4 countries out of 15 have already adopted wastewater reuse regulations (Greece, Italy, Portugal and Spain). This review compares these regulations and discusses their differences.

This study describes the effect of microwave and low-frequency ultrasonic pretreatment power intensity, time and density on thickened excess activated sludge (TEAS) characteristics and anaerobic digester performance. Key parameters affecting the efficiency of ultrasonic and microwave pretreatment were identified and optimised. The effect of change in ultrasonication and microwave pretreatment conditions on sludge degradation and other characteristics were analysed. Ultrasonication power, density and time were important factors in the sludge solubilisation process. Microwave density and pretreatment time also influenced solubilisation of TEAS, and the effects were investigated for treatment densities of 3.2, 4.6 and 6.4 W/ml and treatment duration of 1–7 min. Higher sludge degradability, higher volatile solid removal and better digester performance were achieved for anaerobic digestion with lower ultrasonication power of 80 W, ultrasonication time of 6 min, and ultrasonic density of 0.32 W/ml. The volume of biogas produced and kinetics, dewaterability of digested sludge, COD reduction and other sludge properties were optimised for the aforementioned ultrasonication and microwave pretreatment conditions for TEAS. It was observed that sludge dewaterability deteriorated with increasing sonication power density and sludge solubilisation. Hence, the balance between sludge dewaterability and solubilisation should be maintained for optimum performance. Thus, the selection of ultrasonic pretreatment time and power is a trade-off between sludge solubilisation and dewaterability.

In the present study, the performance of three selected aquatic plants [Hydrilla verticillata (H), Ceratophyllum demersum (C), and Lemna minor (L)] was evaluated for As removal from water when used in a successive application approach. The plants were subjected to 4 L of As-containing Hoagland medium (500 and 2500 μg L⁻¹ as low and high exposure, respectively) for a period of 21 days in slots of 7 days each. The results showed that total As removal in 21 days varied in different combinations. The best combination was HCL showing 27 and 18% As removal in low and high As treatments, respectively, followed by HLC (21 and 16%), and LCH (15% and 12%). The lowest As removal was achieved by LHC and CLH combination in low As treatment (11%) and by CLH in high As treatment (6%). Individual plant exhibited different removal potential from combination to combination and from application at various stages. The contribution of Hydrilla varied from 8 to 52%, Ceratophyllum from 18 to 64% and Lemna from 18 to 66%. The study advocates the combination of Hydrilla-Ceratophyllum-Lemna for achieving the maximum As removal in the same period.