Advanced oxidation of bisphenol A (BPA) in aqueous system by O₃/Na₂S₂O₈ was investigated, the degradation of BPA was affected by ozone concentration, persulfate dosages, initial pH, and BPA concentration. Experimental results indicated that the degradation of BPA was proved to follow the pseudo-first order kinetics model and was enhanced with the increase of O₃ concentration and the decrease of initial BPA concentration. pH played a significant role in the BPA removal especially under the alkaline condition. Free radical species in the O₃/Na₂S₂O₈ system were identified by using tertiary butyl alcohol (TBA) and ethanol (ETOH) as two probes, the results found that the major free radical was SO₄ ⁻ · at acidic condition (pH = 3), and the concentration of ·OH increased with the pH increased. Eight products were detected during the reaction according to liquid chromatograph-mass spectrometry analysis. Most of the intermediates contained quinonoid derivatives, carboxylic acid, and the relevant mechanism for BPA degradation by O₃/Na₂S₂O₈ system were proposed.

This study assessed potential bioaccumulation of various trace elements in grasses and earthworms as a consequence of soil incorporation of organic amendments for in situ remediation of an orchard field soil contaminated with organochlorine and Pb pesticide residues. In this experiment, four organic amendments of differing total organic carbon content and quality (two types of composted manure, composted biosolids, and biochar) were added to a contaminated orchard field soil, planted with two types of grasses, and tested for their ability to reduce bioaccumulation of organochlorine pesticides and metals in earthworms. The experiment was carried out in 4-L soil microcosms in a controlled environment for 90 days. After 45 days of orchardgrass or perennial ryegrass growth, Lumbricus terrestris L. were introduced to the microcosms and exposed to the experimental soils for 45 days before the experiment was ended. Total trace element concentrations in the added organic amendments were below recommended safe levels and their phytoavailablity and earthworm availability remained low during a 90-day bioremediation study. At the end of the experiment, total tissue concentrations of Cu, Cd, Mn, Pb, and Zn in earthworms and grasses were below recommended safe levels. Total concentrations of Pb in test soil were similar to maximum background levels of Pb recorded in soils in the Eastern USA (100 mg kg⁻¹ d.w.) because of previous application of orchard pesticides. Addition of aged dairy manure compost and presence of grasses was effective in reducing the accumulation of soil-derived Pb in earthworms, thus reducing the risk of soil Pb entry into wildlife food chains.

Long-term irrigation with recycled water (RW) that contains high salt may pollute groundwater. The HYDRUS-1D model was texted against soil water content and electrical conductivity (ECe) observed in a summer maize and winter wheat rotational field irrigated with ground water (GW) and RW; then, the risk for polluting groundwater in two regions of Beijing was evaluated. The comparisons indicated that the simulated soil water content and ECe values were generally in agreement with the field observations, indicating the reliability of HYDRUS-1D in soils irrigated with GW and RW. The regional prediction results of the proposed simulation model indicated that the average soil ECe at the bottom of vadose zones ranged from 0.400 to 0.896 dS m⁻¹, and the values in the Tongzhou and Daxing Districts irrigated with RW were 1.40 and 1.09 times, respectively, higher than that irrigated with GW over the next 50 years. Five risk indicators represent salt transporting time and values were used. The results of the proposed evaluation model showed that the risk scores ranged from 3.04 to 9.32. In the Tongzhou and Daxing Districts, the risk scores of RW irrigation for polluting groundwater were 1.06 and 1.08 times, respectively, higher than that GW irrigation. The risk scores of GW or RW irrigation for polluting groundwater in the Tongzhou District were 1.75 or 1.72 times, respectively, higher than that in the Daxing District. Considering the small risk difference between GW and RW irrigations, RW can be used in both regions. Due to the different vadose zone structures, the Daxing District is more suitable for RW irrigation. The long-term use of RW for irrigation should consider the salt content of RW and vadose zone structure.

The present laboratory study was conducted in pot soil taken from forest. The leaching of calcium (Ca), magnesium (Mg), and potassium (K) (plant macronutrients) due to the application of a nitrogen phosphate-based long-term fire retardant (LTFR) (Fire Trol 931) was investigated. The concentrations of Ca²⁺, Mg²⁺, and K⁺ were measured in the resulting leachates from pots with forest soil and pine tree alone and in combination with fire. Magnesium is a minor component of Fire Trol 931. The leaching of Ca²⁺, Mg²⁺, and K⁺ from treated soils with the retardant pots was significantly greater than that from control pots. The leaching of Mg²⁺ was found to be of small percentage of the initially applied Mg quantities. Fire Trol 931 application resulted in the leaching of Ca²⁺, Mg²⁺, and K⁺ from a typical Mediterranean forest soil in pots, following the application of simulated annual precipitation probably due to ammonium (one of the major retardant components) soil deposition that mobilizes base cations from the soil. It seems that LTFR application may result in chemical leaching from the soil to the drainage water.

Selective adsorbent of benzene, toluene, ethylbenzene, and xylenes (BTEX) was developed based on mesoporous silica materials, RH-MCM-41. It was synthesized from rice husk silica and modified by silane reagents. The silane reagents used in this study were trimethylchlorosilane (TMS), triisopropylchlorosilane (TIPS), and phenyldimethylchlorosilane (PDMS). Physiochemical properties of synthesized materials were characterized by small-angle X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), and surface area analysis. Materials packed in passive air sampler were tested for BTEX uptake capacity. The tests were carried out under an influence of relative humidity (25 to 99 %). Overall, RH-MCM-41 modified by TMS outperformed compared to those modified by other silane agents. The comparative BTEX adsorption on this material and commercial graphitized carbon black was reported.

Use of heavy metal-tolerant bacteria for bioremediation is an environmentally safe and economical approach. Selected chromium-tolerant bacteria were tested in a greenhouse experiment. Different sets of pots were contaminated with three rates of Cr, i.e., 20, 30, and 40 ppm, using K₂Cr₂O₇ and incubated for 1 month. Helianthus annuus (sunflower) seeds of Hysun-33 variety were inoculated with already screened Cr-tolerant bacteria (SS1, SS3, and SS6) along with un-inoculated seeds as control. Completely randomized design was used and two plants per pot were maintained after thinning. At harvesting, fresh as well as dry shoot and root weights were measured. Shoot and root samples were analyzed for Cr contents. The maximum increase in dry shoot and root weight (58 and 63%) was obtained by SS6 followed by SS1 (48 and 42%) and SS3 (37 and 47%) over control at various Cr concentrations. Cr accumulation in shoot and root was also enhanced by all the bacteria compared to control. Regarding the extent of total Cr uptake, SS6 enhanced Cr accumulation up to 107–171%, SS1 99.3–135%, and SS3 91–138% at 20, 30, and 40 ppm Cr, respectively. It is concluded from the study that there was a decreasing trend in growth with the increase of Cr concentration. All the bacteria improved growth and Cr accumulation significantly over control; however, SS6 found best among all Cr-tolerant bacteria. These bacteria can effectively be used for crop improvement and bioremediation.

Adsorption of Reactive Orange 107 dye from aqueous solution was investigated using an activated carbon from Pinus elliottii sawdust chemically prepared with ZnCl₂. The optimum conditions for the adsorption of Reactive Orange 107 dye by the activated carbon, obtained by response surface methodology, were pH = 10, ionic strength = 0.4 mol L⁻¹, agitation rate = 200 rpm, and adsorbent dosage = 0.025 g. For the experimental data of the adsorption equilibrium, nonlinear models, i.e., the Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherms, were applied; the best correlation was found for the Langmuir model. The thermodynamic parameters were determined using the adsorption equilibrium constant of the Langmuir isotherm and the van ‘t Hoff equation. The parameters suggest an endothermic, ∆H°ₐdₛ = 16.97 kJ mol⁻¹, and spontaneous process, ∆G°ₐdₛ = −23.96, −25.23, −26.78, and −28.05 kJ mol⁻¹, at 298, 308, 318, and 328 K, respectively. The results indicate that the activated carbon was efficient for the adsorption of Reactive Orange 107 and has excellent potential for the treatment of colored effluents.

Polyether trisiloxane surfactants are widespread used as agricultural adjuvants because they increase the activity and the rainfastness of pesticides. On the contrary to pesticides, the environmental fate of agricultural adjuvants has not been much investigated, yet. Especially for trisiloxane surfactants, the knowledge on their environmental fate is scarce. To fill this gap, the mobility of a polyether trisiloxane surfactant on soil was studied. With a sorption batch equilibrium method, distribution coefficients between water and soil (K d, K ₒc, and K cₗₐy) were estimated for two standard soils (loam and sandy loam) and for every homologue of the trisiloxane surfactant. The obtained values for K d were between 15 and 135 cm³ g⁻¹, indicating that the trisiloxane surfactant is only slightly mobile in soil. The leaching in soil column was studied in a worst case scenario where the application of the trisiloxane surfactant was done on quartz sand and was immediately followed by a heavy rainfall. Less than 0.01 % of the initially applied trisiloxane surfactant had leached through 20 cm of quartz sand. Based on the K d values and the leaching in a soil column, the studied trisiloxane surfactant seems to be unlikely to leach through soil after application as agricultural adjuvant.

Deammonification process has been studied as an alternative technology for nitrogen removal. This process consists of the association between nitrifying and anammox bacteria, in which the process success is related to aeration, recirculation, and reactor configuration. Considering this, the present study aimed to evaluate the performance of an expanded granular sludge bed (EGSB) reactor on nitrogen removal by deammonification process. Established in a single reactor, it considered the effects of recirculation rate and variation of dissolved oxygen (DO) concentration in microbial community and nitrogen removal efficiency. Thus, two independent tests were conducted: (T1) high recirculation flow rate, performed at 43 L d⁻¹ (Qᵣ/Qᵢₙ = 16), aeration of 30 mLₐᵢᵣ min⁻¹ L⁻¹ ᵣₑₐcₜₒᵣ, and conducted during 16 days; (T2) low recirculation flow rate performed at 6.7 L d⁻¹ (Qᵣ/Qᵢₙ = 2.5), operated for 55 days, divided into three aeration phases: (T2a) 30 mLₐᵢᵣ min⁻¹ L⁻¹ ᵣₑₐcₜₒᵣ, (T2b) 20 mLₐᵢᵣ min⁻¹ L⁻¹ ᵣₑₐcₜₒᵣ, and (T2c) 30 mLₐᵢᵣ min⁻¹ L⁻¹ ᵣₑₐcₜₒᵣ. Results showed that in T1 the high recirculation rate favored nitrifying bacteria prevalence, intensified by reactor turbulence and anammox granules disintegration, changing activity from deammonification to a nitrification process. In addition, T1 reached up to 350 ± 100 mgN L⁻¹ d⁻¹ nitrogen removal rate (NRR). For T2, at low recirculation rate, deammonification process was successfully established with a NRR of 490 mgN L⁻¹ d⁻¹ at Qᵣ/Qᵢₙ = 2.5 and air flow rate of 20 mLₐᵢᵣ min⁻¹ L⁻¹ ᵣₑₐcₜₒᵣ.

Phosphogypsum (PG) is an industrial waste composed mainly by sulfate, turning it a suitable sulfate source for sulfate-reducing bacteria (SRB). In the present work, the capability of two SRB communities, one enriched from Portuguese PG (culture PG) and the other from sludge from a wastewater treatment plant (culture WWT-1), to use sulfate from PG was compared. In addition, the impact of this sulfate-rich waste in the microbial community was assessed. The highest efficiency in terms of sulfate reduction was observed with culture WWT-1. The bacterial composition of this culture was not significantly affected when sodium sulfate from the nutrient medium was replaced by PG as a sulfate source. Next generation sequencing (NGS) showed that this community was phylogenetically diverse, composed by bacteria affiliated to Clostridium, Arcobacter, and Sulfurospirillum genera and by SRB belonging to Desulfovibrio, Desulfomicrobium, and Desulfobulbus genera. In contrast, the bacterial structure of the community enriched from PG was modified when sodium sulfate was replaced by PG as the sulfate source. This culture, which showed the poorest performance in the use of sulfate from PG, was mainly composed by SRB related to Desulfosporosinus genus. The present work provides new information regarding the phylogenetic characterization of anaerobic bacterial communities with the ability to use PG as sulfate donor, thus, contributing to improve the knowledge of microorganisms suitable to be used in PG bioremediation. Additionally, this paper demonstrates that an alternative to lactate and low-cost carbon source (wine wastes) can be used efficiently for that purpose.