Florentina Zurita

Seeking a way to promote the use of constructed wetlands for domestic wastewater treatment in developing countries

The aim of this study was to evaluate the domestic wastewater treatment efficiency as well as the survivability of commercially valuable ornamental plants in subsurface flow wetlands (SSFW) for domestic wastewater (DWW) treatment in laboratory and pilot wetland studies. The laboratory scale study included five different species (Zantedeschia aethiopica, Strelitzia reginae, Anthurium andreanum, Canna hybrids and Hemmerocallis dumortieri) that were evaluated in horizontal flow subsurface treatment cells. All the plants survived during the 6-month experimental period demonstrating high wetland nutrient treatment efficiency. In order to validate and expand these preliminary results, a pilot-scale wetland study was carried out in SSFWs under two different flow regimes (horizontal and vertical flow). Four ornamental species were tested during a 1-year period: Zantedeschia aethiopica, Strelitzia reginae, Anthurium andreanum and Agapanthus africanus. The removal efficiencies were significantly higher in the vertical subsurface-flow constructed wetlands (VFCW) for all pollutants, except for nitrate (NO(3)-N), total nitrogen (TN) and total suspended solids (TSS). These results show that it is feasible to use select non-wetland plants with high market value in SSFWs without reducing the efficiency of the wastewater treatment system, although future work should continue in order to apply this technology in a large scale. The added value of floriculture in treatment wetlands can help to promote the use of constructed wetlands (CW) for domestic wastewater treatment in developing countries where economical resources are scarce and water pollution with DWW is common.

Municipal wastewater treatment in Mexico: current status and opportunities for employing ecological treatment systems

The aim of this paper is to evaluate the current status of municipal wastewater (MWW) treatment in Mexico, as well as to assess opportunities for using ecological treatment systems, such as constructed wetlands. In 2008, Mexico had 2101 MWW treatment plants that treated only 84 m3/s of wastewater (208 m3/s of MWW were collected in sewer systems). Unfortunately, most treatment plants operate below capacity owing to a lack of maintenance and paucity of properly trained personnel. The main types of treatment systems applied in Mexico are activated sludge and waste stabilization ponds, which treat 44.3% and 18% of the MWW collected, respectively. As in many other developing nations around the world, there is a great need in Mexico for low-cost, low-maintenance wastewater treatment systems that are both economically and environmentally sustainable. In 2005, 24.3 million Mexicans lived in villages of less than 2500 inhabitants and 14.1 million lived in towns with 2500–15,000 inhabitants. An opportunity exists to extend the use of ecological treatment systems to these low population density areas and considerably increase the percentage of MWW that is treated in Mexico. Small-scale and medium-size constructed wetlands have been built successfully in some states, primarily during the past five years. Several barriers need to be overcome to increase the adoption and utilization of ecological wastewater technology in Mexico, including: a lack of knowledge about this technology, scarce technical information in Spanish, and the governments concentration on constructing MWW treatment plants solely in urban areas.

Storage Effect on Phenols and on the Antioxidant Activity of Extracts from Anemopsis californica and Inhibition of Elastase Enzyme

The amount of total phenols and flavonoids and the antioxidant activity of leaf, stem, and rhizome methanolic extracts from a commonly consumed Anemopsis californica under different storage conditions were investigated. Storage conditions were at 50, 25, 4, and −20°C, protected or not from light, during 180 days. The inhibition of the elastase enzyme was also evaluated. The results demonstrated that leaf, stem, and rhizome methanolic extracts of Anemopsis californica maintain approximately up to 97 and 95% stability in phenolic content and antioxidant activity, respectively, when stored during 60 days at −20°C in the dark. Additionally, these extracts, principally from leaf and rhizome, showed an elastase inhibitory effect by 75 and 71.8%, respectively. Therefore, this study provides the basis for further research on the anti-inflammatory activity. On the other hand, Anemopsis californica could comprise a good alternative of use as antioxidant in foods.

Modulation of antioxidant defense system after long term arsenic exposure in Zantedeschia aethiopica and Anemopsis californica

Zantedeschia aethiopica (calla lily) and Anemopsis californica (yerba mansa) are plant species capable of accumulating arsenic (As) and therefore proposed as phytoremediation for removal of As from drinking water. The effects of a continuous 6 month As exposure (34±11 μg/L) from local contaminated groundwater on the antioxidant response of Z. aethiopica and A. californica were evaluated in leaves and stems of the plants bimonthly in a subsurface flow constructed wetland. As increased the activities of the antioxidant enzymes ascorbate peroxidase, glutathione reductase and catalase where higher levels were observed in Z. aethiopica than A. californica. No significant differences were detected on lipid peroxidation levels or antioxidant capacity evaluated by ORAC and DPPH assays or total phenol contents in any part of the plant, although in general the leaves of both plants showed the best antioxidant defense against the metal. In conclusion, Z. aethiopica and A. californica were able to cope to As through induction of a more sensitive enzymatic antioxidant response mechanism.

Performance of three pilot-scale hybrid constructed wetlands for total coliforms and Escherichia coli removal from primary effluent – a 2-year study in a subtropical climate

Three pilot-scale two-stage hybrid constructed wetlands were evaluated in order to compare their efficiency for total coliforms (TCol) and Escherichia coli removal and to analyze their performances in two 1-year periods of experimentation. System I consisted of a horizontal flow (HF) constructed wetland (CW) followed by a stabilization pond. System II was also configured with a HF CW as a first stage which was then followed by a vertical flow (VF) CW as a second stage. System III was configured with a VF CW followed by a HF CW. In the first year of evaluation, the HF-VF system was the most effective for TCol removal (p < 0.05) and achieved a reduction of 2.2 log units. With regard to E. coli removal, the HF-VF and VF-HF systems were the most effective (p < 0.05) with average reductions of 3.2 and 3.8 log units, respectively. In the second year, the most effective were those with a VF component for both TCol and E. coli which underwent average reductions of 2.34-2.44 and 3.44-3.74 log units, respectively. The reduction achieved in E. coli densities, in both years, satisfy the World Health Organization guidelines that require a 3-4 log unit pathogen reduction in wastewater treatment systems.

Assessment of Physicochemical Properties of Tequila Brands: Authentication and Quality

Several physicochemical properties were measured in commercial tequila brands: conductivity, density, pH, sound velocity, viscosity, and refractive index. Physicochemical data were analyzed by Principal Component Analysis (PCA), cluster analysis, and the one-way analysis of variance to identify the quality and authenticity of tequila brands. According to the Principal Component Analysis, the existence of 3 main components was identified, explaining the 87.76% of the total variability of physicochemical measurements. In general, all tequila brands appeared together in the plane of the first two principal components. In the cluster analysis, four groups showing similar characteristics were identified. In particular, one of the clusters contains some tequila brands that are not identified by the Regulatory Council of Tequila and do not meet the quality requirements established in the Mexican Official Standard 006. These tequila brands are characterized by having higher conductivity and density and lower viscosity and refractive index, determined by one-way analysis of variance. Therefore, these economical measurements, PCA, and cluster analysis can be used to determinate the authenticity of a tequila brand.

Nitrogen removal in pilot-scale partially saturated vertical wetlands with and without an internal source of carbon

The aim was to evaluate and compare total nitrogen (TN) removal in pilot-scale partially saturated vertical wetlands (PSVWs) with and without an internal solid source of organic carbon (corncob) in order to distinguish the role of nitrification-denitrification and ANAMMOX in the removal process. The height of the free-drainage zone (FDZ) was 40 cm and the saturated zone (SZ) was 30 cm in system I (SI) and system II (SII) and 40 cm in system III (SIII) and system IV (SIV). In SII and SIV, approximately 30 kg of dry, 5 cm-length corncob was added. The systems were evaluated during two periods, that is, P1 and P2. Measurements of water quality parameters including BOD5, COD, organic nitrogen (Org-N), ammonium, nitrate and nitrite were taken in the influent and effluents on a weekly basis; nitrate measurements were also taken at the interface. Measurements of pH, dissolved oxygen (DO) and oxidation-reduction potential (ORP) were taken in the SZ. The height of both SZ (40 cm vs. 30 cm in P1) and FDZ (40 vs. 25 and 30 cm in SI/SIII in P2) did not affect the efficiencies (p > 0.05) but the presence or absence of corn cob did (p < 0.05). Thus, SII and SIV were superior when compared to SI and SIII (p < 0.05) with TN average removal efficiencies of 72.9% and 73.2% in P1, and 59.8% and 64.2% in P2, respectively; showing a tendency to lower values when the biodegradable organics supplied by the corncob diminished. In SI and SIII, TN removals were 47.6% and 40.3% in P1, and 46.1% and 44.1% in P2, respectively. In SII and SIV, denitrification took place in both the lower semi-saturated part of the FDZ (probably also ANAMMOX) and SZ; whereas in SI and SIII, ANAMMOX took place in the lower semi-saturated part of the FDZ.

Treatment of tequila vinasse and elimination of phenol by coagulation–flocculation process coupled with heterogeneous photocatalysis using titanium dioxide nanoparticles

ABSTRACT In this research, we are reporting the treatment of tequila vinasse by a coagulation–flocculation process coupled with heterogeneous photocatalysis using two types of titanium dioxide nanoparticles, i.e. (1) commercial nanoparticles, and (2) nanoparticles synthesized by sol–gel. The efficiency in the elimination of phenol, which is one of the most harmful contaminants in tequila vinasse, was also included in the evaluation of the treatment process. The synthesized titanium dioxide nanoparticles were annealed in air at 400°C for 1 h and were characterized by X-ray diffraction, transmission electron microscopy, ultraviolet-visible and Raman spectroscopy. Anatase phase was observed in both samples, with a crystallite size of 22.5 and 9.8 nm for commercial and synthesized nanoparticles respectively. Tequila vinasse was characterized before and after the treatments by measuring physicochemical parameters such as pH, chemical oxygen demand (COD), colour, total suspended solids (TSS), as well as using ultraviolet-visible spectroscopy and Raman spectroscopy to identify the presence of organic compounds, and gas chromatography (GC) for phenol quantification. Raw vinasse was treated initially by coagulation–flocculation producing clarified vinasse, which in turn was treated by photocatalysis for 3 h using hydrogen peroxide as oxidizing agent. The use of synthesized titanium dioxide nanoparticles allowed the highest efficiencies, reaching reductions of 99.4%, 86.0%, and 70.0% for TSS, colour, and COD respectively. GC results showed the reduction of phenol concentrations in 89.7% with our synthesized nanoparticles in contrast to 82.7% reduction, with commercial titanium dioxide nanoparticles. GRAPHICAL ABSTRACT

In vitro clonal propagation and regeneration of the commercially important plant Mexican oregano (Lippia graveolens)

Lippia graveolens (Verbenaceae family), commonly known asMexican oregano, is an important plant widely used as both a condiment and raw material for extraction of essential oil, having multiple applications in food, pharmaceutical, and cosmetic industries (Sánchez et al. 2007; Martínez-Rocha et al. 2008). The species is an evergreen, woody shrub, native to the southern part of the USA,Mexico, and Central America (Fig. 1a). Three closely related species belonging to the genus Lippia are customarily known as Mexican oregano: L. graveolens H.B.K., Lippia berlandieri Schauer, and Lippia palmeri; though the two former species have been reported as synonyms by several authors (Avila-Sosa et al. 2010). Mexico produces about 6,500 t of dry oregano leaves annually. The industry is primarily export oriented with up to 90% of total production being traded abroad, making this country the main exporter of Mexican oregano in the world (Villavicencio-Gutiérrez et al. 2010). The average biomass yield of this crop can vary between 1 and 4 t per hectare per year, with a typical recovery of 2 kg of essential oil per metric ton, which corresponds to an average yield of 30 kg of essential oil per hectare. Since sun drying destroys the essential oil, leaves must be shade dried and the extracted oil then stored in dark flasks to protect it from light (CONAFOR 2011). Mexican oregano offers great potential for further development in terms of economic profit, since the chemical composition of the essential oil is considered superior to that obtained from Mediterranean oregano (Origanum vulgare) produced mainly in Greece and Turkey. Moreover, the proportion of essential oil contained in L. graveolens (∼2%) is higher compared to O. vulgare subsp. hirtum and O. vulgare subsp. gracite (∼1.5% in both cases; Silva-Vázquez et al. 2008). Mexican oregano is harvested mainly from natural populations and the harvest period coincides with the flowering time, which consequently alters fruit and seed development. This fact, in conjunction with deficient crop management practices, has led to critical reductions in population size and density. Additionally, it has been reported that only about 11% of flowers produce fruit, and each fruit usually contains only one seed (Ocampo-Velázquez et al. 2009). The commercial value of this nontimber forest resource increased significantly upon recognition of its medicinal properties due to the antioxidant, antimicrobial, and cytotoxic activities attributed to carvacrol, thymol, caffeic acid, flavonoids, apigenol derivatives, luteolol, kaempferol, sesquiterpenes, and p-cimene which is present in the oil (Hernández et al. 2009). Specifically, antioxidant activity has been demonstrated in leaf extracts through inhibition of linoleic acid oxidation (Avila-Sosa et al. 2010). Extracts O. A. Castellanos-Hernández (*) :G. J. Acevedo-Hernández : F. Zurita :M. Gutiérrez-Lomelí :C. L. Del Toro-Sánchez : A. Rodríguez-Sahagún Centro Universitario de la Ciénega, Universidad de Guadalajara, Av. Universidad 1115, Col. Lindavista, 47820 Ocotlán, Jalisco, Mexico e-mail: ocnoscr@gmail.com