Removal of antibiotics and nutrients by vetiver grass (Chrysopogon zizanioides) from a plug flow reactor based constructed wetland model

Overuse of antibiotics has resulted in widespread contamination of the environment and triggered antibiotic resistance in pathogenic bacteria. Conventional wastewater treatment plants (WWTPs) are not equipped to remove antibiotics. Effluents from WWTPs are usually the primary source of antibiotics in aquatic environments. There is an urgent need for cost-effective, environment-friendly technologies to address this issue. Along with antibiotics, nutrients (nitrogen and phosphorus) are also present in conventional WWTP effluents at high concentrations, causing environmental problems like eutrophication. In this study, we tested vetiver grass in a plug flow reactor-based constructed wetland model in a greenhouse setup for removing antibiotics ciprofloxacin (CIP) and tetracycline (TTC), and nutrients, N and P, from secondary wastewater effluent. The constructed wetland was designed based on a previous batch reaction kinetics study and reached a steady-state in 7 days. The measured concentrations of antibiotics were generally consistent with the modeling predictions using first-order reaction kinetics. Vetiver grass significantly (p \u3c 0.05) removed 93% and 97% of CIP and TTC (initial concentrations of 10 mg/L), simultaneously with 93% and 84% nitrogen and phosphorus, respectively. Results show that using vetiver grass in constructed wetlands could be a viable green technology for the removal of antibiotics and nutrients from wastewater

Evidence for Phytoremediation and Phytoexcretion of NTO from Industrial Wastewater by Vetiver Grass

The use of insensitive munitions such as 3-nitro-1,2,4-triazol-5-one (NTO) is rapidly increasing and is expected to replace conventional munitions in the near future. Various NTO treatment technologies are being developed for the treatment of wastewater from industrial munition facilities. This is the first study to explore the potential phytoremediation of industrial NTO-wastewater using vetiver grass (Chrysopogon zizanioides L.). Here, we present evidence that vetiver can effectively remove NTO from wastewater, and also translocated NTO from root to shoot. NTO was phytotoxic and resulted in a loss of plant biomass and chlorophyll. The metabolomic analysis showed significant differences between treated and control samples, with the upregulation of specific pathways such as glycerophosphate metabolism and amino acid metabolism, providing a glimpse into the stress alleviation strategy of vetiver. One of the mechanisms of NTO stress reduction was the excretion of solid crystals. Scanning electron microscopy (SEM), electrospray ionization mass spectrometry (ESI-MS), and Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the presence of NTO crystals in the plant exudates. Further characterization of the exudates is in progress to ascertain the purity of these crystals, and if vetiver could be used for phytomining NTO from industrial wastewater

Chronic Draining Ear and Cholesteatoma Recidivism: A Retrospection from Clinical, Imaging, and Surgical Perspectives

Objective:To evaluate the reasons for persistent draining ear and cholesteatoma recidivism following canal wall down (CWD) tympanomastoidectomy by studying the sensitivity of high-resolution computed tomography (HRCT) scanning in different potential etiologies, corroborating through appropriate surgical intervention, and thereby, to suggest proper preventive measures.Methods:In this observational study, 32 chronic, refractory draining ears were subjected to revision surgery following a radical or a modified radical mastoidectomy. Besides disease (cholesteatoma/granulations) eradication, pitfalls of the primary surgeries were addressed. Data were interpreted for studying the epidemiologic profile, the clinical presentation at recurrence, the type of primary surgery, the sites of recidivism, the probable causes, and the best possible management at revision.Results:Of the 32 patients/ears, 23 had residual/recurrent cholesteatoma. Major reasons were inadequate disease clearance, contracted/inadequate conchomeatoplasty, no cavity obliteration, and inappropriate bone work. HRCT predicted persistent bridge and lateral semicircular canal dehiscence with 100%, and ossicular integrity and bony overhang with >80% sensitivity. Sinus tympani and oval window niche were the commonest sites of recurrence. At revision, radical/modified radical mastoidectomies were associated with cavity obliteration and appropriate revision of conchomeatoplasty in 28 patients.Conclusion:Recurrence of cholesteatoma/granulations is an important cause for chronic drainage from post-CWD cavities. Revision surgery explores the surgical pitfalls, and ensures clearance of disease from hidden areas, adequate bone work, and optimum conchomeatoplasty following cavity obliteration to provide a safe, dry ear with hearing improvement whenever feasible

Removal of tetracycline and ciprofloxacin from wastewater by vetiver grass (Chrysopogon zizanioides (L.) Roberty) as a function of nutrient concentrations

Antibiotics have been widely used not only for the treatment and prevention of human infectious diseases but also to promote growth and prevent infections in farm animals. These antibiotics enter the environment via wastewater treatment plants, most of which cannot remove them. In addition to antibiotics, nutrients such as nitrogen (N) and phosphorus (P) also create major environmental pollution problems in surface water. Previously, we reported that vetiver grass [Chrysopogon zizanioides (L.) Roberty] successfully removed antibiotics from secondary wastewater effluent. In this study, our objective was to evaluate the potential of vetiver grass to remove two antibiotics, ciprofloxacin (CIP) and tetracycline (TTC), from wastewater in the presence of high N and P. Our results show that vetiver grass significantly (p \u3c 0.05) removed antibiotics (60–94% CIP and 89–100% TTC) and nutrients (78–89% N and 71–97% P) from the secondary wastewater effluent. The removal of antibiotics dropped with increasing nutrient concentrations. The removal efficiency was mainly affected by the presence of N rather than P in the secondary wastewater effluent. The presence of CIP induced more stress on vetiver grass compared to TTC. Vetiver also removed total organic carbon (48–73%) and chemical oxygen demand (73–82%), but their removal was also affected by the nutrient content in the secondary wastewater effluent

Removal of antibiotics and nutrients by Vetiver grass (Chrysopogon zizanioides) from secondary wastewater effluent

Persistence of antibiotics in soil and aquatic ecosystem is the primary reason for the emergence of antimicrobial resistant microorganisms. After consumption, antibiotics are poorly retained in our body, and a major fraction is excreted out. These bioactive compounds end up in wastewater. The routine treatment practiced by the conventional wastewater treatment plants does not remove the entire load of antibiotics. Cost-effective and environment-friendly treatment technologies need to be developed to address this issue. Vetiver system is being adapted throughout the world due to its removal capacity and high tolerance toward several toxic organic and inorganic pollutants. In this study, we investigated the potential of vetiver

Vetiver grass (Chrysopogon zizanioides) is capable of removing insensitive high explosives from munition industry wastewater

Synthetic organic explosive compounds in the wastewater stream of industrial munition facilities are subject to regulatory permits and require pretreatment prior to discharge. Munition industries are currently focused on developing insensitive high explosives (IHEs) such as dinitroanisole (DNAN), nitroguanidine (NQ), and 1,2,4-triazol-3-one (NTO), to replace conventional munitions such as trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). IHEs are typically more soluble than conventional explosives, and their production generates waste streams with high nitrate (N) concentrations. Several chemical remediation studies have attempted to degrade the explosive compounds within waste streams with limited success. Phytoremediation is a relatively new application for the remediation of munition industry wastewater, which is both environmentally and economically sustainable. Vetiver grass (Chrysopogon zizanioides), with its massive and dense root system and ability to grow in harsh environments, has been observed to remove many chemicals from soil and water, including nutrients and TNT. The objective of this study was to evaluate the phytoremediation potential of vetiver in removing explosive compounds and N from wastewater effluents generated in an industrial munition facility. Results show that the removal efficiency of vetiver was a factor of the initial concentration. Successive batches of vetiver removed DNAN, NQ, and RDX by 96, 79 and 100%, respectively. More than 95% of N was removed by four successive batches of vetiver grass. A major portion of NQ and RDX was translocated from root to shoot. LC-MS analysis showed the presence of transformation products of RDX, HMX (1,3,5,7-Tetranitro-1,3,5,7-tetrazocane) and DNAN in vetiver root and shoot

Uptake and transformation of ciprofloxacin by vetiver grass (Chrysopogon zizanioides)

Ciprofloxacin (CIP) is a synthetically produced and widely prescribed antibiotic. Due to incomplete metabolism and gut absorption, a significant portion of the consumed CIP is excreted and released into the environment through wastewater. Vetiver grass has been reported to tolerate many organic and inorganic pollutants. Our objectives were to evaluate the potential of vetiver grass to remove CIP from aquatic media with the ultimate goal of developing a plant-based method for wastewater treatment. We also examined the potential degradation/transformation of CIP in the plant and the metabolic pathways impacted by CIP. Results show that vetiver grass removed more than 80% CIP within 30 days. Ciprofloxacin elicited a stress response by inducing antioxidant enzymes, and metabolic profiling indicated an impact on key metabolic pathways. Transformation products of CIP in vetiver tissue indicate the potential role of root-associated microorganisms as well as plant metabolism in CIP degradation

Remediation of acid mine drainage-impacted water by vetiver grass (Chrysopogon zizanioides): A multiscale long-term study

Acid mine drainage (AMD) is an acidic discharge from mining sites that contains elevated levels of metals and sulfate (SO42−). AMD can inflict health and environmental dangers through metal toxicity and physical stress. Current methods for AMD treatment, including chemical or passive biological treatments, are often non-sustainable owing to expense, require continuous maintenance, or are unsuitable for prolonged treatment. Our ultimate goal is to develop a cost efficient and sustainable floating treatment wetland system using vetiver grass (Chrysopogon zizanioides). Year-long large- and small-scale hydroponic experiments were used to determine the effectiveness of vetiver for treating AMD-impacted waters from the Tab-Simco mine site in southern Illinois. For the large-scale mesocosmic study, vetiver rafts were suspended in 100-gallon containers. Water quality was monitored by chemical analysis of samples every 28 days and at the end of the experiment (364 days); plant health was monitored by measuring changes in biomass and recording visual changes in root and shoot coloration and morphology. There was higher net removal of Fe (81%) and Pb (81%) with lower removal of Ni (38%), Zn (35%), SO42− (28%), Mn (27%), Cr (21%), Al (11%) and Cu (8.0%). Metals were mainly localized on the root surface as Fe plaques, whereas Mn and Zn showed greater translocation from root to shoot. Furthermore, toxicity characteristic leaching procedure showed that vetiver biomass was not hazardous waste as a result of metal accumulation. From the small-scale experiment, there was near complete removal of SO42− (91%) and metals (90–100%) with the exception of Pb (15%) and Cu (0.0%). These experiments demonstrate that vetiver can effectively remediate AMD-impacted waters over an extended period of time

Tetracycline uptake and metabolism by vetiver grass (Chrysopogon zizanioides L. Nash)

Environmental contamination by antibiotics not only perturbs the ecological balance but also poses a risk to human health by promoting the development of multiantibiotic-resistant bacteria. This study focuses on identifying the biochemical pathways associated with tetracycline (TC) transformation/degradation in vetiver grass that has the potential to be used as a biological remediation system in TC-contaminated water sources. A hydroponic experimental setup was used with four initial TC concentrations (0, 5, 35, 75 ppm), and TC uptake was monitored over a 30-day period. Results show that TC transformation in the media occurred during the first 5 days, where a decrease in the parent compound and an increase in the concentration of the isomers such as epitetracycline (ETC) and anhyrotetracycline (ATC) occurred, and TC disappeared in 20 days in tanks with vetiver grass. However, the isomers ETC and ATC remained in the control tanks for the duration of the trial. Transformation products of TC in plant tissue were analyzed by using ultra HPLC high-resolution Orbitrap mass spectrometery (HRMS/MS), which indicates amide hydrolysis of TC in vetiver roots. Metabolic profiling revealed that glyoxylate metabolism, TCA cycle, biosynthesis of secondary metabolites, tryptophan metabolism, and inositol phosphate metabolism were impacted in vetiver root by TC treatment