Water hyacinth (WH) has high tolerance in extreme environmental conditions. Here, we examined the potentials of WH (Eichhornia crassipes (Mart) solms) to remove excess nutrients from sewage wastewater. We used four prototypes of water systems: prototypes A (WH + underlay water) and C (WH + sewage water), whereas prototypes B and D were experimental control for A and C, respectively. For prototype A, the percentage removal efficiencies (%Rₑ) for nitrate and phosphate achieved were 75.12 ± 4.22% and 78.90 ± 8.72%, respectively, with a pH increase from 6.29 to 7.69; whereas for prototype C, the values were 54.7 ± 8.11% and 86.10 ± 7.34%, respectively, with a pH decrease from 8.13 to 7.15. For the 3-week retention time, the biomass weight increased in both prototype A (33.26%; [Formula: see text] rate = 15.46 g/week) and prototype C (26.43%; [Formula: see text] rate = 12.54 g/week). Further, the respective mechanical strength and nutritional values of the WH’s fiber and the organic extracts were examined. The air-dried WH stem showed an average tensile stress of 0.04 MPa on a load at maximum stress of 137.1 N. By comparison, a strand of WH has a tensile strength of 14 MPa, inferior to 15, 61, and 400 MPa shown by timber, wood, and steel, respectively. However, by knitting, four strands of WH yielded a much-improved tensile strength of 315 MPa. Finally, a gas chromatography-mass spectrometer analysis of the plant’s extract showed that it contains 35.51% oleic acid, a nutritional extract of high value. Thence, we established a profound economic significance of WH, a macrophyte with latent immense benefits.

Currently, to reduce the use of nonrenewable energy sources in energy matrices, some industries have already incorporated biomass as a source of energy for their processes. Additionally, filters are used in an attempt to retain the particulate matter present in exhaust gases. In this work, the emission gases of a cashew nut shell (CNS) combustion reactor and the deleterious effects on the respiratory system of mice exposed to gaseous fraction present in CNS emissions (GF-CNS) are analyzed. The system for CNS combustion is composed of a cylindrical stainless steel burner, and exhaust gases generated by CNS combustion were directed through a chimney to a system containing two glass fiber filters to retain all the PM present in the CNS exhaust and, posteriorly, were directed to a mice exposure chamber. The results show changes in the variables of respiratory system mechanics (G, H, CST, IC, and PV loop area) in oxidative stress (SOD, CAT, and NO₂⁻), as well as in the histopathological analysis and lung morphometry (alveolar collapse, PMN cells, mean alveolar diameter, and BCI). Through our results, it has been demonstrated that even with the use of filters by industries for particulate material retention, special attention should still be given to the gaseous fraction that is released into the environment.

Bamboo forests are one of the most important forest resources in subtropical China. A pure, single-layer bamboo forest is considered an optimal habitat for intercropping medicinal herbs. Soil microorganisms have an important role in various ecological processes and respond quickly to environmental changes. However, changes in soil nutrients and microbial communities associated with agroforestry cultivation methods remain poorly documented. In the present study, a pure moso bamboo (Phyllostachys edulis) forest (Con) and three adjacent moso bamboo–based agroforestry (BAF) systems (moso bamboo–Paris polyphylla (BP), moso bamboo–Tetrastigma hemsleyanum (BT) and moso bamboo–Bletilla striata (BB)) were selected; and their soil chemical properties and bacterial communities were studied and compared to evaluate the effects of agroforestry on soil bacterial communities and the relationship between soil properties and bacterial communities in BAF systems. Results showed that compared with soils under the Con, soils under the BAF systems had more (p < 0.05) soil organic carbon (SOC) and available nitrogen (AN) but lower (p < 0.05) pH and available potassium (AK). In addition, compared with the Con system, the BB and BT systems had significantly greater (p < 0.05) available phosphorus (AP). Compared with that in the Con system, the Shannon index in the BAF systems was significantly greater (p < 0.05), but the Chao1 index not different. On the basis of relative abundance values, compared with the Con soils, the BAF soils had a significantly greater abundance of (p < 0.05) Bacteroidetes and Planctomyces but a significantly lower abundance of (p < 0.05) Verrucomicrobia, Gemmatimonadetes and Candidatus Xiphinematobacter. Moreover, compared with the Con system, the BB and BT systems had a greater (p < 0.05) abundance of Actinobacteria, Rhodoplanes, Candidatus Solibacter and Candidatus Koribacter. Redundancy analysis (RDA) revealed that soil pH, SOC and AP were significantly correlated with bacterial community composition. Results of this study suggest that intercropping medicinal herbs can result in soil acidification and potassium (K) depletion; thus, countermeasures such as applications of K fertilizer and alkaline soil amendments are necessary for BAF systems.

The modern agricultural practices have led to improve the contaminated soils with a variety of heavy metals that have become a major environmental concern. The use of arbuscular mycorrihizal fungi (AMF) is considered a potential tool for the sustainable agriculture especially in contaminated sites. Moreover, recently, the use of AMF has become a fascinating and multidisciplinary subject for the scientists dealing with plant protection. The present study was carried out to evaluate the interaction among arsenic (As) species, AMF, and two plant species: Pteris vittata and Astragalus sinicus, differing in their metal tolerance. Results about A. sinicus revealed that the biomass was affected as As (III and V) accumulated in the roots of A. sinicus, and in rachis and pinnae of P. vittata. The inoculation of AMF markedly increased the biomass yield of the both plants when exposed to As species. The exposure to the As species resulted variation and non-significant results about antioxidant enzymes and non-enzymes when grown in As stress with and without AMF. The inoculation of AMF under As species improved the organic acids concentrations in both plant species. Overall, the concentration of oxalate acid was more than formic and malic acids; however, AMF inoculation improved more organic acids in A. sinicus. P. vittata exhibited more activities of antioxidant enzymes and non-enzymes under As stress with and without AMF than A. sinicus, and hence had a more efficient defense mechanism.

Ammonia (NH₃) volatilization from paddy soils is a main source of atmospheric NH₃ and the magnitude is affected by many factors. Because of the complex field condition, it is difficult to identify the relative importance of individual factor on NH₃ volatilization process in different locations and at different times. In this study, the grey relational entropy method was used to evaluate the relative impact of four main factors (i.e., nitrogen fertilizer application rate, NH₄-N concentration, pH, and temperature of the floodwater) on NH₃ volatilization loss from three different field experiments. The results demonstrated that floodwater NH₄-N concentration was the most important factor governing NH₃ volatilization process. Floodwater pH was the second most important factor, followed by temperature of the floodwater and nitrogen fertilizer application rate. We further validated the grey relational entropy method with NH₃ volatilization loss data from other published study and confirmed the order of importance for the four factors. We hope the findings of this study will be helpful for guiding design to reduce paddy soil NH₃ emission.

Emerging contaminants present a challenge for water preservation, threatening humans’ health and all ecosystems. They consist of a variety of molecules ranging from pharmaceutical and personal care products to pesticides and endocrine disruptors detectable in wastewater, sewage effluent, surface water, drinking water, and ground waters at trace level concentrations (e.g., ng/L, μg/L). Conventional wastewater treatment plants (WWTPs) possess low efficiency to remove them. Therefore, new technologies capable of removing such residues are needed. Lignin recognized as a renewable and abundant biopolymer is transformed through electrospinning into an anionic nanofibrous nonwoven adsorbent to extract those contaminants and dispose them safely. Electrospinning allows the manufacture of fibers at the micro- or nanoscale under the influence of an electric current. In this study, nanofibers of alkali lignin and a co-polymer, poly(vinyl alcohol), were developed and tested on the adsorption of a pharmaceutical contaminant (fluoxetine) in an aqueous solution. Results showed that the lignin nanofibers, of 156 nm in diameter, adsorbed 70% of fluoxetine in solution which corresponds to 32 ppm of contaminants removed in water.

The aim of this work is to study the byproducts formed as a result of the photocatalytic process under different conditions of light wavelength and photocatalyst doping, rendering valuable information about the fate of pollutants for water treatment applications. Salicylic acid was selected as a model emerging pollutant and powders of nitrogen-doped titanium dioxide (N-TiO₂) and TiO₂ were prepared by the sol-gel process, using TiO₂ P-25 Degussa as benchmark. Two light sources, UVA fluorescent tubes (372 nm) and blue LEDs (462 nm), were employed for photolysis and photocatalysis experiments. Transformation products formed during the process were studied by high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). Major differences were found in the amount and identity of the transformation products due to the different light sources, detecting similar transformation products among the studied catalysts. Under UVA light, hydroxylated and carbonylated byproducts were the first intermediates to reach maximum abundances whereas presumed ring opening products were the last ones. On the other hand, under blue LED illumination byproducts accumulated with decreased mineralization. Photocatalytic degradation pathways were proposed based on the findings.

In this study, the magnetic fraction (MF) of a low-grade titanium ore (TO) was successfully used as an alternative Fe²⁺ source in five reuse cycles, in combination with persulfate (PS) and simulated sunlight (SSL) for the degradation of ciprofloxacin (CIP). The best response of the CIP initial concentration, irradiation time, and doses of MF and PS to degrade completely this pollutant were determined based on an experimental design. However, the individual application of MF, PS, or SSL fails to achieve this goal at the optimal experimental condition. Furthermore, the MF-PS-SSL system showed a higher production of sulfate radicals and a concentration of dissolved Fe²⁺ ions compared with data obtained for the MF-PS system. The best performance attained by the former system is due to the synergy produced between the photo-generated electrons, and the reaction of PS with the Fe²⁺ ions leached gradually from the MF, which increased sulfate radical production. After five reuse cycles of the MF, the oxidation system showed a CIP degradation of 100% in 100 min, no residual content of PS, a CIP mineralization of 6%, a marginal increase in the biodegradability (BOD₅/COD ratio), a MF loss of 7.5%, and a twofold increase in toxicity; however, this parameter was lower than the effective concentration at 50% inhibition (EC₅₀). The substitution of MF with an iron salt decreased the degradation efficiency of the antibiotic by 14%, probably owing to the immediate excess of Fe²⁺ in the solution, which can be oxidized to Fe³⁺ ions, and as a consequence of this, the production rate of the sulfate radical was also reduced.

To explore an effective approach of simultaneous nitrification and denitrification in wastewater with low C/N ratios, integrated packed bed bioreactors based on poly(3-hydroxybutyrate-hydroxyvalerate) (PHBV) with different dosing methods were designed. The removal efficiency of NH₄⁺-N in bioreactor with aeration was 88.62%, and higher NO₃⁻-N removal efficiency was observed in bioreactor filled with grainy PHBV (95.21%) than bioreactor filled with strip PHBV (93.34%). Microbial study indicated that microbes harboring amoA and nirS genes preferred to attach on the surface of ceramsite, and significant differences in microbial community compositions at phylum and genus levels were observed. To summarize, it is feasible to utilize grainy PHBV for simultaneous and efficient removal of NH₄⁺-N and NO₃⁻-N from wastewater with low C/N ratios.

Cities have turned to permeable pavements as one tool to mitigate the detrimental effects of urban runoff. Permeable pavements permit rainfall to infiltrate through a series of aggregate layers, where pollutants are filtered out before the water discharges via an underdrain or exfiltrates into native soils. This study reports on the water quality performance of a parking area retrofitted with permeable interlocking concrete pavement in Vermilion, OH, USA. The practice was constructed in 2015, received run-on from an asphalt traffic lane and was operational for 2 years before the onset of monitoring. During the 15-month monitoring period, the permeable pavement provided significant reductions of sediment and particulate nutrients, which were removed via filtration in the upper aggregate layers. Despite poorly draining underlying soils, runoff volumes were reduced by 26%, leading to significant load reductions for nearly all nutrient and heavy metals in the study. Seasonal variations in runoff and effluent composition were investigated, showing that restorative maintenance performed in spring and fall has the potential to further improve the treatment provided by the practice by removing entrained particulates from the upper aggregate layers and restoring the filtering capacity of the system. Correlation analyses revealed a first flush of particulate nitrogen species, as well as the potential occurrence of erosive flows within the aggregate subbase which resulted in elevated sediment concentrations during high intensity rain events. Results from this study demonstrate the effectiveness of permeable pavements several years after construction, even when design features to specifically improve treatment were not implemented and additional run-on is routed onto the pavement from adjacent impervious surfaces. Findings also highlight the importance of timely maintenance of these practices, which could further improve their performance by removing seasonally deposited pollutants throughout the year.