Search Results (8)

This article presents the application of a novel system for the treatment of fruit and vegetable waste (FVW) using the combination of treatment by the application of the liquid fraction to an anaerobic hydrolytic bioreactor and a constructed wetland. The batch-fed anaerobic bioreactor (AB) had an average organic loading rate of 44 g COD/L-d and a hydraulic residence time (HRT) of 24 h for the degradation of the liquid fraction of the FVW with an average COD removal of 55%. Subsequently, the constructed wetlands (CWs) were fed a subsurface vertical flow of the effluent from the AB by stepwise concentration increments from 1 to 12 g COD/L and a HRT = 72 h until the limit conditions of the operation were identified. For the tropical ornamental species of the CWs in red volcanic gravel (RVG) and RVG + polyethylene (PE) supports, the monoculture of Hippeastrum rutilum and Spathiphyllum wallisii presented removals of COD, Tot-P, and TKN of 90%, 80%, and 85%, respectively. The polycultures with both species exceeded 90% effectiveness. At the end of both processes, a concentration of ~0.5 g COD/L was achieved, confirming that the use of these technologies together constitutes an efficient system for the treatment of the liquid fraction of FVW. Full article

The practice of spending time in green areas to gain the health benefits provided by trees is well known, especially in Asia, as ‘forest bathing’, and the consequent protective and experimentally detectable effects on the human body have been linked to the biogenic volatile organic compounds released by plants. Houseplants are common in houses over the globe and are particularly appreciated for aesthetic reasons as well for their ability to purify air from some environmental volatile pollutants indoors. However, to the best of our knowledge, no attempt has been made to describe the health benefits achievable from houseplants thanks to the biogenic volatile organic compounds released, especially during the day, from some of them. Therefore, we performed the present study, based on both a literature analysis and in silico studies, to investigate whether the volatile compounds and aerosol constituents emitted by some of the most common houseplants (such as peace lily plant, Spathiphyllum wallisii, and iron plant, Aspidistra eliator) could be exploited in ‘indoor forest bathing’ approaches, as proposed here for the first time not only in private houses but also public spaces, such as offices, hospitals, and schools. By using molecular docking (MD) and other in silico methodologies for estimating vapor pressures and chemico-physical/pharmacokinetic properties prediction, we found that β-costol is an organic compound, emitted in appreciable amounts by the houseplant Spathiphyllum wallisii, endowed with potential antiviral properties as emerged by our MD calculations in a SARS-CoV-2 M^pro (main protease) inhibition study, together with sesquirosefuran. Our studies suggest that the anti-COVID-19 potential of these houseplant-emitted compounds is comparable or even higher than known M^pro inhibitors, such as eugenol, and sustain the utility of houseplants as indoor biogenic volatile organic compound emitters for immunity boosting and health protection. Full article

Poor indoor quality affects people’s health and well-being. Phytoremediation is one way in which this problem can be tackled, with living walls being a viable option for places with limited space. The aim of this study was to evaluate the efficiency of five plant species in a living wall to remove Volatile Organic Compounds (VOCs) and to identify whether the type of pollutant has any influence. An enclosed chamber was used to add the contaminants n-hexane and formaldehyde independently. Total VOCs were measured for three days in two scenarios: (1) empty chamber, and (2) chamber with living wall. Five living walls were prepared, each with three plants of the same species: Spathiphyllum wallisii, Philodendron hederaceum, Ficus pumila, Tradescantia pallida, and Chlorophytum comosum. There was no correlation between leaf area/fresh weight/dry weight and the contaminant reduction. In general, all five species were more efficient in reducing TVOCs when exposed to formaldehyde than to n-hexane. Chlorophytum comosum was the most efficient species in reducing the concentration of TVOCs for both contaminants, Spathiphyllum wallisii being the least efficient by far. Full article

Nitrogen dioxide (NO₂) is a common urban air pollutant that is associated with several adverse human health effects from both short and long term exposure. Additionally, NO₂ is highly reactive and can influence the mixing ratios of nitrogen oxide (NO) and ozone (O₃). Active green walls can filter numerous air pollutants whilst using little energy, and are thus a candidate for inclusion in green buildings, however, the remediation of NO₂ by active green walls remains untested. This work assessed the capacity of replicate active green walls to filter NO₂ at both ambient and elevated concentrations within a closed-loop flow reactor, while the concentrations of NO and O₃ were simultaneously monitored. Comparisons of each pollutant’s decay rate were made for green walls containing two plant species (Spathiphyllum wallisii and Syngonium podophyllum) and two lighting conditions (indoor and ultraviolet). Biofilter treatments for both plant species exhibited exponential decay for the biofiltration of all three pollutants at ambient concentrations. Furthermore, both treatments removed elevated concentrations of NO and NO₂, (average NO₂ clean air delivery rate of 661.32 and 550.8 m³∙h⁻¹∙m⁻³ of biofilter substrate for the respective plant species), although plant species and lighting conditions influenced the degree of NO_x removal. Elevated concentrations of NO_x compromised the removal efficiency of O₃. Whilst the current work provided evidence that effective filtration of NO_x is possible with green wall technology, long-term experiments under in situ conditions are needed to establish practical removal rates and plant health effects from prolonged exposure to air pollution. Full article

Improving water quality is a relevant environmental aspect, and using constructed wetlands (CWs) is a sustainable option for this; both porous material filled cells and plants that collectively remove contaminants must be readily available and inexpensive. This study evaluated CWs and their functionality by comparing two ornamental plants (Spathiphyllum wallisii and Hedychium coronarium) planted in experimental mesocosm units filled with layers of porous river rock, tepezil, and soil, or in mesocosms with layers of porous river rock, and tepezil, without the presence of soil. The findings during the experiments (180 days), showed that the removal of pollutants (chemical oxygen demand (COD), total solids suspended (TSS), nitrogen as ammonium (N-NH₄), as nitrate (N-NO₃), and phosphate (P-PO₄) was 20–50% higher in mesocosms with vegetation that in the absence of this, and those mesocosms with the soil layer between 33–45% favored removal of P-PO₄. Differences regarding of vegetation removal were only observed for N-NH₄, being 25–45% higher in CWs with H. coronarium, compared with S. wallisii. Both species are suitable for using in CWs, for its functionality as phytoremediation, and aesthetic advantages could generate interest for wastewater treatment in rural communities, parks, schools or in domiciliary levels like floral flower boxes in the backyard. The study also revealed that a soil layer in CWs is necessary to increase the removal of P-PO₄, an ion hardly eliminated in water treatment. Full article

The effects of Canna indica (P1), Pontederia sagittata (P2), and Spathiphyllum wallisii (P3) growing in different filter media materials (12 using porous river rock and 12 using tepezyl) on the seasonal removal of pollutants of wastewater using fill-and-drain constructed wetlands (FD-CWs) were investigated during 12 months. Three units of every media were planted with one plant of P1, P2, and P3, and three were kept unplanted. C. indica was the plant with higher growth than the other species, in both filter media. The species with more flower production were: C. indica > P. sagittate > S. wallisii. Reflecting similarly in the biomass of the plants, C. indica and P. sagittata showed more quantity of aerial and below ground biomass productivity than S. wallisii. With respect to the removal efficiency, both porous media were efficient in terms of pollutant removal performance (p > 0.05). However, removal efficiency showed a dependence on ornamental plants. The higher removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), total kjeldahl nitrogen (TKN), nitrates (NO₃⁻-N), ammonium (NH₄⁺-N), and phosphates (PO₄⁻³-P) oscillated between 81% to 83%, 80% to 84%, 61% to 69%, 61% to 68%, 65% to 71%, 62% to 68%, and 66% to 69%, respectively, in P1 and P2, removals 15% to 30% higher than P3. The removal in planted microcosms was significantly higher than the unplanted control units (p = 0.023). Nitrogen and phosphorous compounds were highly removed (60%–80%) because in typical CWs, such pollutant removals are usually smaller, indicating the importance of FD-CWs on wastewater treatments using porous river rock and tepezyl as porous filter media. (BOD₅), chemical oxygen demand (COD), (NO₃⁻-N), (NH₄⁺-N), (TKN), and (PO₄⁻³-P). Full article

The current knowledge about the role terrestrial ornamental plants play in constructed wetlands (CWs) has scarcely been evaluated. Likewise, little attention has been given towards the use of new support or fill media for subsurface flow CWs, which may result in the reduction of costs when implemented on a large scale. This study evaluated, during nine months, the effect of three terrestrial ornamental plants and two substrates on the elimination of pollutants in wastewaters by using fill-and-drain vertical subsurface flow CWs (FD-CWs). Sixteen microcosms were used, nine filled with polyethylene terephthalate (PET) and nine with porous river stone (PRS). For each type of substrate, duplicates of microcosms were used, utilizing Anthurium sp., Zantedeschia aethiopica, and Spathiphyllum wallisii as vegetation and two other CWs without vegetation as controls. The environmental conditions, number of flowers, and height of the plants were registered. The results revealed that both substrates in the FD-CWs were efficient in removing pollutants. The average removal of pollutants in systems with vegetation revealed a positive effect on the reduction of the biochemical oxygen demand (55–70%), nitrates (28–44%), phosphates (25–45%), and fecal coliforms (52–65%). Meanwhile, in units without vegetation, the reduction of pollutants was nearly 40–50% less than in those with vegetation. The use of PET as a filling substrate in CWs did not affect the growth and/or the flowering of the species; therefore, its use combined with the species studied in CWs may be replicated in villages with similar wastewater problems. This may represent a reduction in implementation costs when utilizing PET recycled wastes and PRS as substrates in these systems in comparison with the typical substrates used in CWs. More studies are needed to better understand the interactions among these novel support media and the commercial terrestrial ornamental plants. Full article

The high costs involved in treating wastewater are problems that developing countries confront, mainly in rural areas. Therefore, Constructed Wetlands (CWs), which are composed of substrate, vegetation, and microorganisms, are an economically and ecologically viable option for wastewater treatment in these places. There is a wide variety of possibilities for substrates and ornamental plants that have not yet been evaluated to be implemented in future CW designs. The goal of this study was to evaluate the process of adaptation and removal of wastewater pollutants in CW microcosms using different terrestrial ornamental plants (Lavandula sp., Spathiphyllum wallisii, and Zantedeschia aethiopica). Those plants were sown in two types of substrate: red volcanic gravel (RVG) and polyethylene terephthalate (PET). CWs with vegetation reduced 5-day biochemical oxygen demand (BOD₅) by 68% with RVG substrate and 63% with PET substrate, nitrates 50% in RVG substrate and 35% in PET substrate, phosphates 38% in RVG substrate and 35% in PET substrate, and fecal coliforms 64% in RVG and 59% in PET substrate). In control microcosms without vegetation, reductions were significantly lower than those in the presence of plants, with reduction of BOD₅ by 61% in RVG substrate and 55% in PET substrate, nitrates 26% in RVG substrate and 22% in PET substrate, phosphates 27% in RVG substrate and 25% in PET substrate. Concerning fecal coliforms 62% were removed in RVG substrate and 59% in PET substrate. Regarding the production of flowers, Lavandula sp. did not manage to adapt and died 45 days after sowing and did not produce flowers. Spathiphyllum wallisii produced 12 flowers in RVG and nine flowers in PET, while Zantedeschia aethiopica produced 10 in RVG and 7 in PET. These results showed that the use of substrates made of RVG and PET is a viable alternative to be implemented in CWs. In addition, the reuse of PET is an option that decreases pollution by garbage. The plants Spathiphyllum wallisii and Zantedeschia aethiopica remarkably contribute in the removal of pollutants in wastewater. Additionally, the use of ornamental plants, with commercial interest such as those evaluated, enables an added value to the CW to be given, which can be used for flower production purposes on a larger scale and favor its acceptance within rural communities. Full article