Membrane filtration techniques are distinguished among methods for wastewater treatment and fully correspond to the requirements of the green concept of chemistry and production. The limiting factor for greater application of these methods is the phenomenon of fouling and the decline of the permeate flux. In this study, polynomial neural network based on group method data handling (GMDH) algorithm was applied to predict the performance of the complexation-microfiltration process for the removal of Pb(II), Zn(II), and Cd(II) from synthetic wastewater. The influence of working parameters such as pH, initial concentration of metal ions, type of complexing agent, and pressure on flux was experimentally determined. The data obtained were used as input parameters for the GMDH model as well as for the multiple linear regression (MLR) model. Root mean square error (RMSE), mean absolute error (MAE), and mean absolute percent error (MAPE) were used for evaluation purposes. Results showed that the developed model has excellent performance in flux prediction with R² of 0.9648.

Etoposide is an antineoplastic agent used for treating lung cancer, testicular cancer, breast cancer, pediatric cancers, and lymphomas. It is a pollutant due to its mutagenic and carcinogenic potential. Disposal of waste from this drug is still insufficiently safe, and there is no appropriate waste treatment. Therefore, it is important to use advanced oxidative processes (AOPs) for the treatment and disposal of medicines like this. The use of strontium stannate (SrSnO₃) as a catalyst in heterogeneous photocatalysis reactions has emerged as an alternative for the removal of organic pollutants. In our study, SrSnO₃ was synthesized by the combustion method and characterized by X-ray diffraction (XRD), Raman, UV-Vis, and scanning electron microscopy (SEM) techniques, obtaining a surface area of 3.28 m² g⁻¹ with cubic and well-organized crystallinity and a band gap of 4.06 eV. The experimental conditions optimized for degradation of an etoposide solution (0.4 mg L⁻¹) were pH 5 and catalyst concentration of 1 g L⁻¹. The results showed that the degradation processes using SrSnO₃ combined with H₂O₂ (0.338 mol L⁻¹) obtained total organic carbon removal from the etoposide solution, 97.98% (± 4.03 × 10⁻³), compared with TiO₂, which obtained a mineralization rate of 72.41% (± 6.95 × 10–3). After photodegradation, the degraded solution showed no toxicity to zebrafish embryos through embryotoxicity test (OECD, 236), and no genotoxicity using comet assay and micronucleus test.

Wastewater from a limestone-gypsum wet desulfurization system cannot be directly reused or discharged due to its high suspended matter content and complex water composition. Desulfurization wastewater evaporation in flue gas is an effective way to dispose wastewater. Multicomponent soluble chlorine salts exist in the desulfurization wastewater. During the evaporation, chlorine enters into the flue gas due to volatilization, which accelerates the enrichment rate of the Cl⁻ concentration in the desulfurization slurry and leads to an increase in wastewater production. This study explored the chlorine migration of various chlorine salt solutions and typical desulfurization wastewater at high temperature during the evaporation process of concentrated wastewater by a laboratory-scale tube furnace and a pilot-scale system. Results showed that when NaCl-evaporated substance was heated, the chlorine ion hardly volatilized. For the evaporated substances of CaCl₂ and MgCl₂ solutions, some of the crystal water was lost, and hydrolysis occurred to generate gaseous HCl. NH₄Cl was easily sublimed, and the decomposition temperature was lowest. A pilot study on spray evaporation of desulfurization wastewater in flue gas showed that the particle size of the evaporated product increased and the main particle size was within 2.5–10 μm with increasing flue gas temperature. Increasing the mass ratio of gas to liquid significantly reduced the particle size of the atomized particles, thereby reducing the average particle size of the evaporated particles. The HCl concentration increased with increasing flue gas temperature. When the flue gas temperature was 350 °C, the concentration of HCl was 40 ppm, and the escape rate of chlorine in the desulfurization wastewater was approximately 30% using typical wastewater from a limestone-gypsum wet desulfurization system.

In this study, the removal of diclofenac (DCF) from aqueous phase by birnessite, a layered manganese oxide, was investigated by batch experiments. The results indicated that 90% of DCF was removed by birnessite within 4 h in different initial concentrations of DCF, and the kinetic experiment data were well fitted with pseudo-first-order kinetic model (R² > 0.98). The removal of DCF by birnessite was pH-dependent, and low pH was beneficial to the reaction. The presence of Fe²⁺ and Mn²⁺ strongly inhibited the removal of DCF. However, Ca²⁺, Mg²⁺, Zn²⁺, Cu²⁺, and humic acid (HA) promoted the reaction and following the order: Cu²⁺ > Zn²⁺ > HA > Mg²⁺ ≈ Ca²⁺. In addition, some typical anions, such as NO₃⁻, PO₄³⁻, and SO₄²⁻, had slight effects on the reaction. Electrochemical results demonstrated that the adsorption of DCF on birnessite was reaction rate-limiting step. Graphical Abstract ᅟ

Bacteria belonging to the Order Bacteroidales predominate the intestines of warm-blooded animals, and monitoring of these bacteria can indicate fecal pollution impacts to a waterbody. Differences in seasonal concentrations and loadings for Bacteroidales and their relationship with physicochemical water parameters were investigated in temperate, inland streams. Seasonal samples (n = 321) were collected during baseflow in three central Tennessee, USA, watersheds. To estimate total fecal bacteria in receiving streams, general Bacteroidales 16S rRNA gene targets were analyzed by quantitative PCR and reported as concentration and loadings for individual and combined watersheds. In most cases, Bacteroidales marker concentrations were highest during spring/summer and loading values were highest in the spring. Bacteroidales concentrations were positively correlated with temperature and total suspended solids and negatively with dissolved oxygen, while no consistent correlations were found between loadings and abiotic factors. Temperature, total suspended solids, and dissolved oxygen are likely drivers influencing seasonal patterns for Bacteroidales concentrations. Researchers and water quality stakeholders should carefully consider measurement type (concentration versus loading), season, and water quality parameters as elements that could impact results when developing fecal monitoring projects.

As potassium ferrate(VI) is an important kind of water treatment agent which has a high efficiency in algal removal, its effects on the cell substance are rarely discussed. The changing of the protein and enzyme was analyzed here to deeply understand the oxidation of Fe on the protein in the algae. The result of the research showed the inactivation on growth and the biochemical process of the algal cell were all inhibited by Fe, including the function of the photosynthesis system. During the process, SOD (superoxide dismutase), CAT (catalase), POD (peroxidase), and GST (glutathione S-transferase) played cooperative roles to prevent the injury on the cells from destructive oxidation stress. The lipid peroxidation strengthened the defense system. The damage was intensified with the increase of ferrate concentration.

Mine waste contaminated soils are classified as degraded soils with poor conditions such as low soil pH, low organic matter and high metal concentrations. This study evaluated the potential of fly ash enriched vermicompost in improving poor soil conditions in mine waste affected soils. The soils were amended with the vermicompost to supply 0, 10, 20, 40 and 80 mg of phosphorus per kg and incubated for 8 weeks. The soil pH increased from the original acidic range of 3.7–5.3 to 6.8–7.6. Available P significantly improved (P < 0.001) to yield the target P levels; however, at the end of incubation period, 80 mg-P/kg treatment had lower Olsen P relative to the 40 mg-P/kg treatment. Nitrogen mineralisation was enhanced with addition of the vermicompost as reflected by an average increase of 51% in NO₂/NO₃⁻-N while NH₄⁺-N decreased over time. The Mn, Zn and Pb solubility was reduced with addition of the vermicompost, with 20 mg-P/kg resulting in the most reduced solubility. However, concentrations at 20 mg-P/kg treatment were generally not different to 40 mg-P/kg. Solubility of Cu significantly increased in proportion to increase in amendment rate but did not exceed maximum permissible limits. Solubility of Cd and Cr also increased during the incubation study; however, this could not be attributed to the different vermicompost treatments but the soil properties. Therefore, in conclusion, application of fly ash enriched vermicompost at 40 mg-P/kg was found to be optimum for a balanced supply of essential nutrients and reduced metal solubility.

The brewing industry is an important sector in the world economy, and its production process generates a large amount of wastewater. It is essential the proper treatment of this wastewater and a significant amount of biomass may be recovered by coagulation/flocculation process. When using vegetable tannin as an organic flocculant, biomass can be used in the preparation of organic fertilizer, unlike what would occur if a metal base flocculant was used, some of which are considered to be toxic. This work presents a study on the use of vegetable tannin as flocculant agent (Tanfloc SL) for the treatment of brewery wastewater, which also contains microalgae originated from an aerated pond of a local brewery industry. Experiments of coagulation/flocculation and sedimentation were carried out using jar test equipment. A sequential 2² factorial design and two-factor Doehlert design were used to determine the optimum levels of pH and tannin concentration for turbidity and apparent color removals from the wastewater. The higher efficiency results in the biomass separation were obtained by employing 0.23 mL L⁻¹ of vegetable tannin at pH = 4.9, resulting in the substantial removal of approximately 99% of turbidity and apparent color. The removals of biomass and nutrient components were also evaluated: N-NH⁴⁺ (80.8%), N-NO₂- (83.6%), N-NO₃ (56.9%), total phosphorus (82.3%), orthophosphate (76.2%), COD (96.5%), BOD (69.4%), and total solids (40.8%). The Tanfloc SL showed to be efficient in flocculation of the brewery effluent, allowing the reuse of water in industry and the recovered biomass material containing nutrients in agriculture.

The toxic impacts of CuO nanoparticles (NPs) on the marine phytoplankton Nannochloropsis oculata were evaluated by measuring a number of biological parameters. Exposure to different concentrations of CuO-NPs (5–200 mg/L) significantly decreased the growth and content of chlorophyll a of N. oculata. The results showed that CuO-NPs were toxic to this microalga with a half maximal effective concentration (EC50) of 116.981 mg/L. Exposure to CuO-NPs increased the hydrogen peroxide (H₂O₂) content and induced the membrane damages. Moreover, the concentration of phenolic compounds was increased, while the levels of carotenoids were markedly decreased in comparison to the control sample. The activity of catalase (CAT), ascorbate peroxidase (APX), polyphenol oxidase (PPO) and lactate dehydrogenase (LDH) enzymes significantly was increased in response to CuO-NPs treatments. These results indicated that CuO-NPs stimulated the antioxidant defense system in N. oculata to protect the cells against the oxidative damages. The Fourier-transform infrared spectroscopy (FTIR) analyses showed that the main functional groups (C=O and C–O–C) interacted with CuO-NPs. The images of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the cell membrane damage and the change of cell wall structure which may be contributed to the nanotoxicity. These findings may provide additional insights into the mechanisms of cytotoxicity induced by CuO-NPs.

A consortium of highly degrading microorganisms was used in an integrated bioaugmentation/electrocoagulation process for treating olive mill wastewater. The system was investigated for treating 1 m³ day⁻¹, at a pilot scale, for 2 years; hydraulic loading rate and organic loading rate were 2880 l m⁻² day⁻¹ and 37,930 g COD m⁻² day⁻¹, respectively. Average removal efficiency for COD, oils, and total phenols was 63.9%, 85.2%, and 43.6%, respectively. The olive mill consortium, OMC, consisted of seven actinomycete strains. The strains were confirmed, by 16S rDNA analysis, to belong to five Streptomyces, one Kitasatospora, and one Micromonospora strains, at 100–99.06% similarities. Hydrolytic enzyme activities of OMC strains were remarkably higher for degrading cellulosic and lipid constituents (enzyme-cumulative indices, 14–16.1), than the phenolic constituents (indices, 4.1–6.5). The establishment of actinomycetes in the treatment system was indicated by their increased counts in the biofilm at the end of the biofilter, reaching 13-fold higher than that in the control bed. The treated effluent was toxic to the seedlings of Jatropha curcas (Jatropha) and Simmondsia chinensis (Jojoba). Though its application in irrigation of 3-year-old Jatropha shrubs, significantly, enhanced the fruit yield up to 1.85-fold higher than the control, without affecting the seed oil content, after 3-month application, the irrigated soil showed insignificant changes in its biochemical properties. This developed bioaugmentation/electrocoagulation process can treat wastewater with extremely high organic strength, while its approximate construction and operational costs are limited to 0.03 and 0.51 US$ m⁻³, respectively. It produces a treated effluent that can be reused in irrigation of specific plants. Graphical abstract