Environmental Technology

Li, Yanmei; Yu, Hang; Xiong, Lingling; Zeng, Kun; Wei, Yunlin; Li, Haiyan; Ji, Xiuling

doi: 10.1080/09593330.2023.2296531pmid: 38126212

Viruses play an important role in microbial community structure and biodiversity by lysing host cells, and can also affect host metabolic pathways by expressing auxiliary metabolic genes (AMGs). As a unique low-latitude, high-altitude seasonal plateau wetland in China, Napahai has high research value. However, studies on the genetic diversity of AMGs and viruses associated with DNA biosynthesis have not been reported. Based on metagenomics, with the phylogenetic tree, PCoA, and α diversity analysis, we found that three DNA biosynthesis-related viral AMGs (cobS, mazG, and purM) in the Napahai plateau wetland were rich in genetic diversity, uniqueness, and differences compared with other habitats and host sources. Through the KEGG metabolic pathway and metabolic flow analysis of Pseudomonas mandelii (SW-3) and phage (VSW-3), the AMGs (cobS, mazG, and purM) genes of the three related viruses involved in DNA biosynthesis were upregulated and their expression increased significantly. In general, we systematically described the genetic diversity of AMGs associated with DNA biosynthesis in plateau wetland ecosystems and clarified the contribution of viral AMGs in the Napahai plateau wetland to DNA biosynthesis, as well as the changes of metabolites and genes. It further expands the understanding of phage-host interactions, which is of great significance for further revealing the role of viral AMGs in the biological evolution and biogeochemical cycle of wetland ecosystems.

Ajit, Karnapa; Anil, Ardra; Krishnan, Haribabu; Asok, Aswathy

doi: 10.1080/09593330.2023.2296532pmid: 38118134

Microbial fuel cells (MFC) have emerged as a sustainable wastewater treatment technique that offers simultaneous energy generation; however, the high cost of electrodes and their reduced catalytic activity have hindered their widespread adoption. To overcome this, an activated carbon synthesised from Areca nut husk was coated on different anodes viz. Carbon cloth and Stainless Steel (SS) mesh. Activated carbon was found to be highly porous with a carbon content of 85.39%, and a surface area of 767.98 m2/g, and was found to be amorphous with a high degree of graphitic structure. The electrical conductivities of the catalyst-coated SS mesh and carbon cloth were comparable, and the performance of the MFC was studied using both electrodes as anodes. A batch MFC with modified SS mesh as anode exhibited the highest power density of 155.35 mW/m3 in synthetic wastewater and 101.68 mW/m3 in kitchen wastewater, with COD removal efficiencies of 95.32% and 95.24%, respectively. In a continuous mode, the MFC delivered a maximum current density and power of 52.38 mA/m2 and 21.60 mW, respectively, with a maximum COD removal efficiency of 80.70% for an HRT of 20 hrs. These findings underscore the viability of using biomass-derived activated carbon as an anode catalyst in both batch and continuous modes of MFC.

Liu, Yanchao; Zhang, Zhaohui; Liu, Jiaxiang

doi: 10.1080/09593330.2023.2297750pmid: 38158752

In the present work, two common nano-alumina (NA) with different crystal forms (α-NA and γ-NA) are used to research the effects of steel slag−cement composite cementitious materials, which include the hydration properties and mechanical properties. The results show that the NA can enhance the strength of steel slag−cement composite cementitious materials, especially the early strength. Meanwhile, when the addition amount of γ-NA was 1%, the maximum compressive strength and flexural strength at 28 d were 35.43 and 5.21 MPa, respectively; when the addition amount of α-NA was 3%, the maximum compressive strength and flexural strength at 28 d were 36.27 and 4.89 MPa, respectively. In addition, according to the analysis of X-ray diffractometer and differential thermal analysis, it was concluded that the effects of the two types of alumina on the strength were mainly pozzolanic effect and filling effect. The pozzolanic effect of γ-NA was significantly stronger than that of α-NA. However, the large surface area of γ-NA affected the dispersion of the particles and the filling effect. According to scanning electron microscope analysis, compared with α-NA, γ-NA had significantly more hydration products and tighter adhesion. In conclusion, the addition of NA not only improved the properties but further realized the value-added utilization of steel slag.

Lima, Edson Thiago Gomes; Sales, Érica Danúbia Souza; Saraiva, Rogério de Aquino; Rachide Nunes, Ramom

doi: 10.1080/09593330.2023.2298663pmid: 38190259

This work studied the auxin-like activity of liquid and solid hydrochar from aboveground corn biomass prepared using hydrothermal carbonization (HTC). Understanding the action of organic compounds in regulating plant metabolism is important to develop strategies to improve plant growth and production. Bioassays were performed by testing liquid hydrochar concentrations in the range of 0.0557-5570.0 mg carbon L−1; and solid hydrochar (via extracted dissolved organic matter, DOM) in the range of 0.026-2600.0 mg carbon L−1, using seeds of Lactuca sativa. SEM, ATR-FTIR, and Py-GC/MS were applied to assess the effect of HTC on hydrochar production/composition. Liquid hydrochar presented an intense bioactivity, completely inhibiting the germination of testing seeds at higher concentrations. Liquid hydrochar also was considerably more bioactive. Py-GC/MS allowed the identification of the molecules involved in IAA-like effects: carboxylic acids (linear and aromatic) and amino acids. The concentration of more bioactive molecules, rather than their simple presence in the hydrochar fraction, determined the bio-stimulating effect, besides an excellent linear regression between the auxin-like effect and the concentration of active molecules.

Oliveira, E. M.; Rodrigues, A.; Santos, J. S.; Trivinho-Strixino, F.; Dalla Costa da Rocha, R.; Sikora, M. S.

doi: 10.1080/09593330.2023.2298664pmid: 38158753

Ciprofloxacin hydrochloride (CIP) is a broad-spectrum synthetic antibiotic often found in domestic sewage and industrial waste due to the inefficiency of conventional treatments. Given the potential risk of drug accumulation, this study presents coatings of titanium dioxide nanotubes (TiO2) doped with different bismuth (Bi) concentrations to degrade CIP through photocatalytic and photoelectrochemical processes. Characterization studies revealed that bismuth (Bi) doping affected the morphology of the materials, with concentrations of 0.01 and 0.05 mol L−1, resulting in collapsed materials with a smaller active surface area. Photocatalysis tests for all the materials exhibited a similar degree of efficiency to photolysis, approximately 33%. Ecotoxicity tests using the biomarkers Lactuca sativa L., Lemna minor, and Artemia salina indicated that, although they were similar to photolysis in terms of efficiency, the effluents generated when employing the doped catalysts showed lower levels of toxicity, with the best results achieved for the material doped with 0.005 mol L−1 of Bi, with a toxicity level approximately 40% lower. Photoelectrocatalysis proved to be the most efficient CIP degradation technique. The highest degradation rate was observed for materials doped with 0.005 mol L−1 of Bi, with an efficiency of 46%, which is 1.4 times more efficient than photolysis. These results demonstrate that materials doped with low amounts of Bi can be effectively used as photoanodes for drug degradation, as their performance is superior, and the final product generated exhibits low toxicity to living organisms.

Tong, Peipei; Hang, Zhenyu; Zhu, Weihuang; Li, Zhihua

doi: 10.1080/09593330.2023.2298665pmid: 38158763

To effectively solve the problem of tetracycline (TC) and Cu2+ contamination in wastewater, this study innovatively proposed a low-energy flow-electrode capacitive deionization (FCDI) technology to simultaneously remove TC and Cu2+ from wastewater. The removal efficiencies of TC and Cu2+ using FCDI was investigated under various voltages, electrode flow rates, influent flow rates, and electrode liquid concentrations. The results showed that the removal efficiency of TC and Cu2+ was 60.78% and 84.43%, respectively. The energy consumption for TC and Cu2+ removal was only 1.76 and 1.10 kWh kg−1, which was lower than other electrochemical systems. The ion removal performance of the FCDI system remained stable after six cycles of continuous operation. These findings demonstrated the promising potential of FCDI as an innovative technology for the simultaneous removal of TC and Cu2+, presenting a significant prospects for application in the water treatment field.

Gonçalves Piteira Carvalho, Brenda; Abreu Henriques, Daniel; Fernandes, Luyara Almeida; Leal, Cintia Dutra; Calábria de Araújo, Juliana

doi: 10.1080/09593330.2023.2298666pmid: 38286140

The combination of sewage anaerobic treatment and partial nitritation/anammox process (PN/A) can make wastewater treatment plants energetically self-sufficient. However, PN/A application has been a challenge in low-nitrogen wastewaters and it is little explored in anaerobically pretreated domestic sewage, as well as aeration strategies and the PN/A feasibility at ambient temperature. This study investigated PN/A in a sequential batch reactor (SBR) treating real anaerobically pretreated domestic sewage. After the startup, SBR was fed with real wastewater and operated at 35°C and at ambient temperature (20–31°C) without total nitrogen (TN) removal decrease (71 ± 8 and 75 ± 6%, respectively). The median ammonium and TN removals were 68 ± 21 and 59 ± 9%, respectively with 7 min on/14 min off strategy, which represents 12.3 ± 4.2 mg L−1 N-NH4 + effluent, which is lower than Brazilian discharge limits. The qPCR results showed anammox abundance in the range of 108–109 n° copies gVSS−1. Thus, results were very promising and showed the feasibility of the PN/A process for treating real anaerobically pretreated domestic sewage at ambient temperature.

Islam, Md. Shoffikul; Kashem, Md. Abul; Moniruzzaman, Mohammad; Parvin, Afsana; Das, Suman; Hu, Hongqing

doi: 10.1080/09593330.2023.2298668pmid: 38158754

Low molecular weight organic acids (LMWOAs) are common in rhizospheric soil and may impede the interaction between phosphate and metals. Thus, studying how phosphate compounds impact metal immobilization in rhizospheric soil using LMWOAs is crucial. An incubation experiment examined the effects of NaH2PO4 (a P compound) (3%), various concentrations of citric acid (CA), and combinations of P and CA, on soil cadmium (Cd), lead (Pb), and zinc (Zn) immobilization using the European Community Bureau of Reference (BCR) sequential extraction method, CaCl2 extraction method, zeta potential, fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The P, low CA (2 mmol kg–1 soil) (CA2), and P-CA2 treatments reduced acid-soluble and CaCl2-extractable Cd, Pb, and Zn, indicating metal immobilization, with the P-CA2 treatment being the most effective. High CA (>5–20 mmol kg–1 soil) or a P with high CA reversed prior patterns, suggesting metal mobilization. The zeta potential study indicated that when pH increased, treatments became more negative, notably P-CA2 followed by P, suggesting that electrostatic adsorption was the predominant metal immobilization mechanism, especially in P-CA2. XRD tests, however, showed that the P treatment alone produced Cd phosphate, pyromorphite, and hopeite, indicating that sorption and precipitation were the main metal immobilization processes in the P treatment alone. In conclusion, P-CA2 was found to be the most efficient metal immobilization and redistribution treatment for contaminated soils. Rhizospheric CA may alter Cd, Pb, and Zn mineral stability. Therefore, when treating Cd, Pb, and Zn-contaminated soils with a P compound, CA should be addressed.

Hu, Chen-Yan; Xiong, Cun; Lin, Yi-Li; Zhang, Tian-Yang

doi: 10.1080/09593330.2023.2298669pmid: 38164528

The degradation kinetics, reaction pathways, and disinfection by-products formation of an organic UV filter, benzophenone-4 (BP4) during UV/persulfate oxidation were investigated. BP4 can hardly be degraded by UV alone, but can be effectively decomposed by UV/persulfate following pseudo-first order kinetics. BP4 degradation rate was enhanced with increasing persulfate dosage and decreasing pH from 8 to 5. However, the degradation rate of BP4 at pH 9 was higher than that at pH 8 because of the presence of phenolic group in BP4 structure. and ${\rm SO}_ 4^- \cdot$ SO 4 − ⋅ were confirmed as the major contributors to BP4 decomposition in radical scavenging experiments, and the second-order rate constants between ${\rm HO}\cdot$ HO ⋅ and BP4 as well as those between ${\rm SO}_ 4^- \cdot$ SO 4 − ⋅ and BP4 were estimated by establishing and solving a kinetic model. The presence of ${\rm B}{\rm r}^-$ B r − and humic acid inhibited the decomposition of BP4, while ${\rm N}{\rm O}_ 3^-$ N O 3 − promoted it. The mineralisation of BP4 was only 9.1% at the persulfate concentration of 50 μM. Six degradation intermediates were identified for the promulgation of the reaction pathways of BP4 during UV/persulfate oxidation were proposed as a result. In addition, the formation of DBP in the sequential chlorination was evaluated at different persulfate dosages, pH values, and water matrix. The results of this study can provide essential knowledge for the effective control of DBP formation with reducing potential hazard to provide safe drinking water to the public.

Murillo, Ana M.; Kotamraju, Amulya; Mulkeen, Collette J.; Healy, Mark G.; Sulpice, Ronan; Lens, Piet N.L.

doi: 10.1080/09593330.2023.2298670pmid: 38190254

The uptake of sodium selenite (Se(IV)) and sodium selenate (Se(VI)) from aqueous medium by Lemna minor L. and the influence of different Se concentrations on its growth, morphological and ultrastructural characteristics were studied. L. minor was grown at different concentrations (1, 3, 5 and 10 mg L−1) of Se(IV) and Se(IV). The Se(IV) concentration in the plant tissue ranged between 77.7 (± 4.3) to 453 (± 0) mg kg−1 DW. The Se(VI) concentration in plant tissues ranged between 117 (± 11) to 417 (± 2) mg kg−1 DW. The highest bioconcentration factor for Se(VI) was 127 (± 7) at 3 mg/L, with a Se removal efficiency of 44%. For Se(IV), the highest bioconcentration factor was 77.7 (± 4.3) at 1 mg L−1, which had a Se removal efficiency of 23%. Growth of L. minor was suppressed at 10 mg L−1 Se in both forms. The addition of Se promoted the formation of starch granules in L. minor which occupied a chloroplast area of 74% for Se(IV) and 77% for Se(VI). The efficient uptake of both Se forms by L. minor indicates the potential application of this species for phytoremediation of Se laden wastewaters and its use as an alternative feedstock in biofuel production.