In this study, the potential of selected psychrotolerant yeast strains for phenol biodegradation was studied. From 39 strains isolated from soil and water samples from Rucianka peat bog, three psychrotolerant yeast strains, A01₁, B02₁, and L01₂, showed the ability to degrade phenol. The result shows that all three yeast strains could degrade phenol at 500 and 750 mg l⁻¹ concentration, whereas strains A01₁ and L01₂ could degrade phenol at 1000 mg l⁻¹ concentration. The time needed for degradation of each phenol concentration was no longer than 2 days. Strains A01₁, B02₁, and L01₂ were identified based on 26S rDNA and ITS sequence analysis as belonging to species Candida subhashii, Candida oregonensis, and Schizoblastosporion starkeyi-henricii, respectively.

In this work, ciprofloxacin (CIP) degradation is investigated using different photo-chemical advanced oxidation processes (AOPs): Fe²⁺/H₂O₂/UV, TiO₂/UV, and H₂O₂/UV. At natural pH, direct oxidation at the photo-generated holes showed to be the main pathway during TiO₂/UV process, while H₂O₂/UV and Fe²⁺/H₂O₂/UV degradation mainly occurred by hydroxyl radical attack. The identification of degradation by-products confirmed the differences in the degradation pathways. Water matrix effects were also investigated by evaluating the influence of the initial pH and testing CIP degradation in mineral natural water and distilled water. Significant differences were observed associated to the pH, the H₂O₂/UV system being the less affected process. Natural water showed to be an inhibitor medium for the tested photo-chemical processes. Interestingly, H₂O₂/UV system showed again to be not considerably affected by the natural water matrix. Additionally, degradation extent of treated solutions was determined by the mineralization level (TOC removal) and the antimicrobial activity (AA) elimination using Staphylococcus aureus and Escherichia coli as probe microorganisms. Despite mineralization was no reached in any case, AA elimination was promoted by all processes suggesting the formation of by-products with non-antibiotic character. However, due to the particular degradation pathway, interesting differences were observed according to the type of bacteria when TiO₂ photo-catalysis was used.

The presence of synthetic dyes in effluents leads to an environmental imbalance characterized by a decrease in photosynthetic activity and, therefore, a reduction of available oxygen, which affects all living aquatic species. To reduce this problem, a combination adsorption and biodegradation treatment strategy is proposed. In this work, Red 40 dye was adsorbed onto a low-cost waste product, followed by degradation by Trametes versicolor under solid state fermentation conditions. The principal aim of this research was to establish the best fermentation conditions using a kinetic evaluation of both degradation and laccase enzyme activity. The process was scaled-up using a rotating drum bioreactor. The best process conditions were a carbon:nitrogen ratio of 30:1, a moisture percentage of 75%, and an inductor concentration of 0.5 mM; the maximum dye degradation was 96.04%. Under these optimized conditions, the highest enzymatic activity was 8.49 U/gdₘ after 14 days of culture at the flask scale. Using a rotating drum bioreactor, 630 mg of azo dye was degraded after 30 days of culture. Red 40 dye degradation was confirmed using infrared spectroscopy Fourier transform infrared spectrometer and HPLC-MS techniques. The results show that the degradation percentage has a direct relation with laccase activity, and the obtained efficiency in the rotating drum bioreactor confirms the potential of this methodology for implementation at the industrial level.

The purpose of this study was to determine the different kinds and concentrations of intermediates, and investigate on the effects of contact time and ozone (O₃) doses on the removal of humic acid (HA), which is served as the main disinfection by-product (DBP) precursor. Based on that, the knowledge gap of DBPs generated was made up. The results showed that HA was the major precursor material for aldehydes and carboxylic acids. The concentrations of aldehydes increased as contact time and O₃ doses, and reached up maximum at 2~10 min but approached a plateau at the higher O₃ doses. The concentrations of formic and acetic acids increased as contact time and O₃ doses. However, aromatic acids, including protocatechuic, 3-hydroxybenzoic, and benzoic acids, declined rapidly at longer reaction time and higher O₃ doses. It was worth mentioning that aromatic acids had been rarely reported. Besides, a possible formation pathway was proposed: (a) HA was degraded into fulvic acid (FA)-like compounds; (b) FA-like compounds were further converted into aromatic acids; (c) aromatic acids were transformed into low-molecular-weight organic matters; (d) chlorine reacted with aldehydes and/or carboxylic acids by addition, hydrolysis, and decarbonylation reactions, leading to DBP formation. Furthermore, not only HA were the main DBPs precursors, but also the oxidation intermediates of HA could be the DBPs precursors, and they gave a certain amount of DBPs. Consequently, aldehydes and carboxylic acids should be under control in drinking water treatment plants.

Drought is a serious concern in many parts of the world, including in California, where paucity of available irrigation water has impaired crop production and soil health through salt accumulation. With extending water and salinity crises, there is a need for advanced salt and vegetation management. To develop more efficient management solutions, Slingram electromagnetic investigations and stochastic and statistical analyses were performed for determining optimal vegetable yields in a salt-affected farmland. The Slingram results were evaluated using multi-linear regression analyses, and the yield and salinity were characterized for central tendency, variance, distributions and symmetry. The yields of two studied vegetable crops, lettuce and tomato, increased with decreasing salinity load. The average lettuce and tomato yield potentials were 55 and 75%, respectively. The minimum yield potential for tomato was 9.5 times higher than that for lettuce. The mode value for conductivity (ECₑ) was 650 mS m⁻¹, which corresponded to 50% yield loss. The yield loss was <10% in locations with ECₑ < 250 mS m⁻¹. In zones with ECₑ > 850 mS m⁻¹, the yield reductions for lettuce and tomato reached up to 96 and 60%, respectively. About 57 and 82% of the field area could be limited to 20% yield potentials for tomato and lettuce, respectively. Lettuce had a higher cost benefit than tomato albeit with a greater yield potential of the latter crop. By delineating the spatial contours of salt-induced yield variability, vegetables can be grown in segmented soil zones based on salinity levels.

This study investigates the impact of future climate change on heavy metal (i.e., Cd and Zn) transport from soils to surface waters in a contaminated lowland catchment. The WALRUS hydrological model is employed in a semi-distributed manner to simulate current and future hydrological fluxes in the Dommel catchment in the Netherlands. The model is forced with climate change projections and the simulated fluxes are used as input to a metal transport model that simulates heavy metal concentrations and loads in quickflow and baseflow pathways. Metal transport is simulated under baseline climate (“2000–2010”) and future climate (“2090–2099”) conditions including scenarios for no climate change and climate change. The outcomes show an increase in Cd and Zn loads and the mean flux-weighted Cd and Zn concentrations in the discharged runoff, which is attributed to breakthrough of heavy metals from the soil system. Due to climate change, runoff enhances and leaching is accelerated, resulting in enhanced Cd and Zn loads. Mean flux-weighted concentrations in the discharged runoff increase during early summer and decrease during late summer and early autumn under the most extreme scenario of climate change. The results of this study provide improved understanding on the processes responsible for future changes in heavy metal contamination in lowland catchments.

Ultraviolet (UV) disinfection of wastewater is adversely affected by the presence of particle-associated bacteria. Earlier studies have shown that disrupting these particles by ultrasonic cavitation can enhance the UV disinfection of wastewater. However, the use of ultrasound as a pretreatment technology for UV disinfection is hindered by its high energy demand. In this work, the addition of several organic solutes, including 1-propanol, 1-hexanol, and pentyl acetate, to promote the cavitation process and to improve the breakage of wastewater particles was examined. It was found that the enhancement in the cavitation and the breakage efficiency of particles was positively related to the hydrophobicity of surfactant. In addition, particle breakage was a function of the concentration of surfactant as well as the delivered ultrasound energy density. Sonication of wastewater samples containing small amounts of 1-hexanol (16 mM) or pentyl acetate (12 mM) increased the UV disinfection efficiency and decreased the required UV dose to achieve the disinfection target by a factor of more than 2.5.

The objective of this study was to evaluate the influence of the soil parameters (particle size, initial contamination level, etc.) on the performances of an attrition process to remove As, Cr, Cu, pentachlorophenol (PCP) and dioxins and furans (PCDD/F). Five different contaminated soils were wet-sieved to isolate five soil fractions (< 0.250, 0.250–1, 1–4, 4–12 and > 12 mm). Five attrition steps of 20 min each, carried out in the presence of a biodegradable surfactant ([BW] = 2%, w w⁻¹) at room temperature with a pulp density fixed at 40% (w w⁻¹), were applied to the coarse soil fractions (> 0.250 mm) of different soils. The results showed good performances of the attrition process to simultaneously remove PCP and PCDD/F from contaminated soil fractions initially containing between 1.1 and 13 mg of PCP kg⁻¹ (dry basis) and between 1795 and 5720 ng TEQ of PCDD/F kg⁻¹. It appeared that the amounts of contaminants removed were significantly correlated (p value < 0.05, R ² = 0.96) with the initial amounts of PCP and PCDD/F, regardless of the particle size of the soils studied. The nature of the soil (granulometric distribution, pH, total organic carbon (TOC) (organic matter) and diverse industrial origin) slightly and negatively influenced the efficiency of organic contaminants removals using attrition. However, the attrition treatment allowed an efficient removal of both PCP and PCDD/F from the coarse fraction of contaminated soil, despite the nature of the soil.

Sugarcane bagasse soot is an agro-industrial residue rich in carbon that can be transformed into value-added materials, such as activated carbons. Therefore, this work aimed at producing activated carbon from sugarcane bagasse soot, using CO₂ at 800, 850, and 900 °C, and investigating its efficiency to adsorb methylene blue as model contaminant. The results showed that the surface area and pore volume increased in the obtained carbons, with high specific areas (up to 829 m²/g), and the isotherms of the N₂ adsorption describe mesoporous materials. The morphology of the prepared activated carbons showed that sugarcane bagasse soot and the activated carbons kept the fibrous structure of sugarcane bagasse, but after activation, they have cavities that resemble a honeycomb. Adsorption studies with methylene blue dye showed that the activation process resulted in adsorption capacities up to 11 times higher than sugarcane bagasse soot, which is comparable with commercial activated carbon. Dye adsorption kinetics could be described by a pseudo-second-order dependency in the studied materials, and the adsorption isotherms were better fitted by the Langmuir model. It is emphasized that cost-effective materials that are similar to commercial activated carbon were obtained.

This paper discusses the possibility of including the culturing of microalgae within a conventional wastewater treatment sequence by growing them on the blackwater (BW) from biosolid dewatering to produce biomass to feed the anaerobic digester. Two photobioreactors were used: a 12 L plexiglas column for indoor, lab-scale tests and a 85 L plexiglas column for outdoor culturing. Microalgae (Chlorella sp. and Scenedesmus sp.) could easily grow on the tested blackwater. The average specific growth rate in indoor and outdoor batch tests was satisfactory, ranging between 0.14 and 0.16 day⁻¹. During a continuous test performed under outdoor conditions from May to November, in which the off-gas from the combined heat and power unit was used as the CO₂ source, an average biomass production of 50 mgTSS L⁻¹ day⁻¹ was obtained. However, statistical analyses confirmed that microalgal growth was affected by environmental conditions (temperature and season) and that it was negatively correlated with the occurrence of nitrification. Finally, the biochemical methane potential of the algal biomass was slightly higher than that from waste sludge (208 mLCH₄ gVS⁻¹ vs. 190 mLCH₄ gVS⁻¹).