Ozone and ozone-based advanced oxidation processes were applied for the treatment of a recalcitrant wastewater generated by wood-based industries that contains different inorganic and organic constituents and high chemical oxygen demand (COD) varying between 3,400 and 4,000 mg/L. The investigation used a tubular ozone reactor combined with an UV reactor designed for different hydraulic retention times. The dependent variables addressed to evaluate the treatment efficiency were the reduction of COD and total organic carbon (TOC) and the biodegradability of the treated effluent based on respirometric studies using activated sludge from a wastewater treatment. The results showed that even though ozonation alone at acid pH promoted COD and TOC reductions of 65 and 31 % respectively, a decrease in the biodegradability was observed. The most effective treatment (COD and TOC reductions of 93 and 43 %, respectively) was obtained when applying ozone combined with UV light at basic pH. The ozone-UV combination was capable of increasing the amount of readily available COD by 75 % with an additional reduction of TOC by 60 %. In conclusion, ozonation at low pH effectively reduces the COD content in wastewater generated by the wood-based industry; however, in order to combine advanced oxidation with biological process, ozone combined with UV is recommended.

A sensitive, high-throughput, and cost-effective method for screening bacterial pathogens in the environment was developed. A variety of environmental samples, including aerosols, soil of various types (sand, sand/clay mix, and clay), wastewater, and vegetable surface (modeled by tomato), were concomitantly spiked with Salmonella enterica and/or Pseudomonas aeruginosa to determine recovery rates and limits of detection. The various matrices were first enriched with a general pre-enrichment broth in a dilution series and then enumerated by most probable number (MPN) estimation using quantitative PCR for rapid screening of amplicon presence. Soil and aerosols were then tested in non-spiked environmental samples, as these matrices are prone to large experimental variation. Limit of detection in the various soil types was 1–3 colony-forming units (CFU) g⁻¹; on vegetable surface, 5 CFU per tomato; in treated wastewater, 5 CFU L⁻¹; and in aerosols, >300 CFU mL⁻¹. Our method accurately identified S. enterica in non-spiked environmental soil samples within a day, while traditional methods took 4 to 5 days and required sorting through biochemically and morphologically similar species. Likewise, our method successfully identified P. aeruginosa in non-spiked aerosols generated by a domestic wastewater treatment system. The obtained results suggest that the developed method presents a broad approach for the rapid, efficient, and reliable detection of relatively low densities of pathogenic organisms in challenging environmental samples.

The scarcity of clean water affecting many parts of the world encourages efforts to improve water reclamation processes, which rely on their capability to remove diverse types of water pollutants and contaminants. Thus, this study reports the application of bamboo fiber powders as potential low-cost sorbent for removal of noxious organic compounds in aqueous solution. Bisphenol A, a biorefractory endocrine disruptor compound, was chosen as model compound in order to easily follow the separation process. Principal component analysis of the FTIR spectra and BET surface area measurements were performed on treated bamboo fiber powders. Treatment of the raw powders with alkali, ionic and non-ionic surfactants appeared to improve the bisphenol A removal performance of the bamboo fiber powders with the best removal efficiency reached at 39 % for a sorbent dosage of 4 g L⁻¹ gained after a bamboo treatment using the cationic surfactant. Effects of contact time, sorbent dosage, and particle sizes (55, 300, and 1000 μm) of cationic surfactant-treated bamboo fiber powders towards removal of bisphenol A were further assessed in a batch system with an optimum removal observed for 55 μm in particle size.

Surfactant can reduce the interfacial tension in liquid–gas system and may probably improve the rate and/or extent of dissolution. This study was conducted to evaluate the effect of three different surfactants (viz., sodium dodecyl sulfate (SDS), Triton X-100, and cetyltrimethylammonium chloride (CTAC)) on CO₂biomineralization by two ureolytic microorganism—Sporosarcina pasteurii and Bacillus megaterium. In S. pasteurii-mediated biomineralization, headspace CO₂content (2.5 mM) was decreased by 40, 52, and 68 % in the presence of SDS, Triton X-100 or CTAC, respectively within the first 8 h of incubation. CO₂removal with B. megaterium in the presence of Triton X-100 (64 %) and CTAC (56 %) was better in comparison to control without surfactant (48 %). However, appreciable CO₂depletion was not observed with SDS, which was just 4 %. On other hand, headspace CO₂loss in the presence of CTAC with B. megaterium did not get biomineralized, as no calcium carbonate was detected. Crystalline phase and morphology of CaCO₃precipitate also varied between ionic and nonionic surfactants. The result suggests that the effect of surfactant on CO₂capture and biomineralization can be largely different, depending on the surfactant and concerned microbial species involved.

Aggregation of environmental monitoring data into indices is a common procedure when the objective of the assessment is the evaluation of some environmental criterion for large areas, usually with planning purposes. Two types of aggregation functions are commonly used in the construction of indices: the weighted sum and the constant elasticity of substitution. Several criteria have been proposed for the selection of aggregation functions, namely, (i) ambiguity, which happens when all indicators indicate non-contamination, but the index fails to reflect this observation; (ii) eclipsing, i.e., the index fails to reflect contamination indicated by one of the variables; (iii) rigidity occurs when the introduction of more variables result in increased failure in the classification given by the index, as indicated by a decrease of the index. The first two criteria are easily checked, but the latter is more difficult to evaluate. A method to assess rigidity is here proposed and applied. Two other criteria are also proposed: sensitivity and accuracy. The present study compares and discusses the use of pollution indices for the classification of soils as to heavy metal pollution, with both empirical and real-world data. In the end, some criteria for index selection are indicated, along with their ranking for different practical circumstances. The Nemerow pollution index and the ecological risk index complied with all the fundamental criteria making them good general-use indices.

Recently, the increased use of monocyclic non-steroidal anti-inflammatory drugs has resulted in their presence in the environment. This may have potential negative effects on living organisms. The biotransformation mechanisms of monocyclic non-steroidal anti-inflammatory drugs in the human body and in other mammals occur by hydroxylation and conjugation with glycine or glucuronic acid. Biotransformation/biodegradation of monocyclic non-steroidal anti-inflammatory drugs in the environment may be caused by fungal or bacterial microorganisms. Salicylic acid derivatives are degraded by catechol or gentisate as intermediates which are cleaved by dioxygenases. The key intermediate of the paracetamol degradation pathways is hydroquinone. Sometimes, after hydrolysis of this drug, 4-aminophenol is formed, which is a dead-end metabolite. Ibuprofen is metabolized by hydroxylation or activation with CoA, resulting in the formation of isobutylocatechol. The aim of this work is to attempt to summarize the knowledge about environmental risk connected with the presence of over-the-counter anti-inflammatory drugs, their sources and the biotransformation and/or biodegradation pathways of these drugs.

Alkyl polyglucosides, due to their low toxicity and environmental compatibility, could be used in biodegradation of hydrophobic compounds. In this study, the influence of Lutensol GD 70 on the cell hydrophobicity and zeta potential was measured. The particle size distribution and surfactant biodegradation were also investigated. Microbacterium sp. strain E19, Pseudomonas stutzeri strain 9, and the same strain cultivated in stress conditions were used in studies. Adding surfactant to the diesel oil system resulted in an increase of the cell surface hydrophobicity and the formation of cell aggregates (a high polydispersity index). The correlation between cell hydrophobicity and zeta potential in examined samples was not found. The results showed a significant influence of Lutensol GD 70 on the changes in cell surface properties. Moreover, a high biodegradation of a surfactant (over 50 %) by tested strains was observed. The biodegradation of Lutensol GD 70 depends on the length of both polar and nonpolar chains. A long-term contact with diesel oil of stressed strain modifies not only cell surface properties but also its ability to a surfactant biodegradation.

The reaction of Hg²⁺with sulfite is a major identified reduction pathway in the atmosphere. UV absorption spectroscopy was used to study the kinetics of Hg²⁺reduction by sulfite (Na₂SO₃) in the presence of fly ash. Upon the addition of Cumberland and Shawnee fly ash samples, the reduction rates were 0.0071 ± 0.0008 and 0.0009 ± 0.0006 s⁻¹, respectively. This represents c.a. 40 and 90 % decreases in the homogeneous rate, 0.013 ± 0.007 s⁻¹. The reduction reaction was also observed when Cumberland was added without Na₂SO₃. Sulfur elemental analyzer and high-resolution field emission scanning microscopy with energy dispersive X-ray spectroscopy (HR-FE-SEM-EDS) characterization confirmed that Cumberland fly ash particles were rich in sulfur. Nanoparticle Tracking Analysis (NTA) determined the mean particle size in solution to be 246 ± 25 nm for Cumberland fly ash and 198 ± 14 nm for Shawnee. To obtain further insight on observed Hg²⁺homogeneous reduction rates by sulfite, the effects of several environmental variables were investigated. Hg(NO₃)₂and HgO were used as the sources of Hg²⁺. Extended pH (1–7) and temperature (1.0–45.0 °C) ranges were studied for the first time. The enthalpies of activation for the HgO reduction were 94 ± 3 kJ mol⁻¹at pH 1 and 92 ± 4 kJ mol⁻¹at pH 3, while the entropies were 33 ± 9 J mol⁻¹ K⁻¹at pH 1 and 30 ± 10 J mol⁻¹ K⁻¹at pH 3. It was determined that increasing ionic strength, especially with nitrate species, slows down the reaction at pH = 7. Significance of the results on the variability of mercury reduction by sulfite at various environmental conditions, and its implication in modelling are discussed.

In this study, nanosized zero-valent iron-reduced graphene oxide (nZVI-rGO)-activated persulfate (PS) was used to investigate the generation of reactive oxygen species (ROS) for the degradation of trichloroethylene (TCE) in the aqueous solution. More than 98 % of TCE was degraded within 2 min under experimental conditions. The generation of ·OH increased when the pH was shifted toward the basic region while ·SO₄⁻ radicals’ intensity increased in the acidic pH. Different scenarios have been observed in ·O₂⁻ generation in the neutral and strong basic pH and decreased in acidic or slightly basic pH. In addition, the intensity of ·OH was increased with the addition of HCO₃⁻ (10 mM) and NO₃⁻ (100 mM) but decreased in the presence of Cl⁻ (10 and 100 mM), HCO₃⁻ (100 mM), and NO₃⁻ (10 mM). The degradation of anisole, probe for both ·OH and ·SO₄⁻, was slightly enhanced by 10 mM NO₃⁻ anions but decreased in 100 mM salt solution. ·O₂⁻ intensity was increased while HCO₃⁻ (10 and 100 mM) and NO₃⁻ (100 mM) anions were used. nZVI-rGO-activated PS process could remove TCE in aqueous effectively, and the ROS generation and intensity were influenced by solution pH values and anions.

Deterioration of natural water resources due to runoff from agricultural land is a major problem in the US Great Plains. Changes in earth climate can create heavy storms and alter precipitation patterns which would affect the element concentrations in runoff. A 2-year study (dry and wet years) was conducted to assess the impact of annual precipitation on element concentrations in runoff from soils and element loadings to Salt Creek in the Roca watershed, NE. Both dissolved and sediment-associated forms of five elements (Al, Fe, Mn, Cu, and Zn) were determined in runoff. The amount of dissolved element in runoff during the wet year was greater than the dry year. Except for Zn, the total amount of element associated with sediment was greater than that found in dissolved form. The Mehlich3 extraction was applied to determine the reactive fraction of element in sediment. A small fraction of element associated with sediment was in reactive form, ranging from 1 to 33 % of the total element content. The sum of both the reactive fraction of element in sediment and amount of element dissolved in water were used to calculate the total bioactive element concentration (BEC) in runoff. During the dry year, the total BEC in runoff was 424, 349, 387, 5.2, and 26.8 μg/L for Al, Fe, Mn, Cu, and Zn, respectively. The corresponding total BEC during the wet year was 622, 479, 114, 3.7, and 19.8 μg/L for Al, Fe, Mn, Cu, and Zn, respectively. Further, the bioactive element loading (BEL) into Salt Creek was greater during the wet year than the dry year. Aluminum, Fe, and Mn contributed to the greatest BEL into the surface water body while Zn and Cu had the least contribution. We concluded that greater precipitation during the wet year would increase the negative impact of runoff from soils and BEL to surface water systems in the US Great Plains.