"El Agave lechuguilla está ampliamente distribuido en México. Comúnmente, se usa para obtener fibras de ixtle. Las fibras representan únicamente el 15% del total de la cosecha y el 85% restante llamado guishe se desecha ocasionando graves problemas ambientales. Estudios recientes, demostraron que el guishe contiene saponinas, flavonoides y azúcares. Las saponinas han sido estudiadas por su capacidad de reducir el contenido de amonio y productos nitrogenados en el agua. Por esta razón, el objetivo de este trabajo es evaluar el efecto del guishe sobre la calidad de agua en cultivos de camarón, para proponer estrategias de valorización para este desecho, que además representen una opción sustentable para la acuicultura del camarón. Durante este trabajo se realizó un análisis de expresión diferencial de tres regiones productivas de A. lechuguilla para determinar la región en la que el guishe contiene la mayor concentración de saponinas. Con la región seleccionada, se obtuvieron dos extractos ricos en saponinas, uno crudo y otro hidrolizado (J y H), y se cuantificaron con cromatografía líquida. También se determinó su contenido de azúcares. Después se realizaron bioensayos con juveniles de camarón a los que se les adicionaron diferentes concentraciones de los extractos, 18 mg/L, 36 mg/L y 72 mg/L, se monitoreó la concentración de NH4+ y el comportamiento microbiológico ambiental durante 36 días. Los resultados mostraron que al añadir el tratamiento J2 (36 mg/L) los camarones tuvieron menor ganancia en peso y que al añadir el tratamiento H3 (72 mg/L) al agua del cultivo se puede mantener la calidad de agua dentro de los parámetros establecidos sin comprometer la salud y talla de los organismos. Además, se observó que la adición del extracto H3 promueve la propagación de bacterias benéficas para el cultivo de camarón. En conclusión, altas concentraciones de hidrolizado enzimático procedente del guishe tienen un efecto sobre la calidad del agua, al disminuir significativamente la concentración de NH4+ y la carga bacteriana de Vibrios totales." | "Agave lechuguilla is wide distributed in Mexico. Commonly, it is used to obtain ixtle fibers. The fibers represent only 15% of the total harvested while 85% called guishe is discarded, causing serious environmental problems. Recent studies have shown that guishe contains saponins, flavonoids and sugars. Saponins have been studied for their ability to reduce the content of ammonia and nitrogenous products in water. For this reason, the objective of this work is to evaluate the effect of guishe on water quality in shrimp farming, to propose valorization strategies for this waste, and a sustainable option for shrimp aquaculture. During this work, a differential expression analysis of three productive regions of A. lechuguilla was carried out to determine the region in which the guishe contains the highest concentration of saponins. With the selected region, two extracts rich in saponins were obtained, one raw and another hidrolizated (J and H). Both extracts were quantified with liquid chromatography. Its sugar content was also determined. Subsequently, bioassays were carried out with juvenile shrimp, different concentrations of the extracts were added, 18 mg/L, 36 mg/L and 72 mg/L, and the NH4+ concentration and environmental microbiological behavior were monitored for 36 days. The results showed that by adding J2 treatment (36 mg/L) shrimps had a lower weight gain although adding the H3 treatment (72 mg/L) to the culture water, quality can be maintained in the parameters established without compromising the health and size of the organisms. In addition, it was observed that the addition of the H3 extract promotes the propagation of beneficial bacteria in water. In conclusion, high concentrations of enzymatic hydrolysate from guishe have an effect on water quality, by significantly decreasing the concentration of NH4+ and the bacterial load of total Vibrios."

Resumen: Este estudio evaluó la eficiencia de eliminación de materia orgánica (DQO), nitrógeno (NH4+, NO3 -) ortofosfatos, y coliformes totales y fecales en cuatro humedales construidos de flujo subsuperficial horizontal a escala piloto usando dos especies de plantas locales. Dos sistemas fueron plantados con Cyperus ligularis y dos con Echinochloa colonum. El experimento constó de un tanque de almacenamiento de 760 litros (tratamiento primario), desde donde se vertió el agua residual, mediante tubería de PVC, al sistema de humedales. Cada humedal fue rellenado con grava granítica de unos 8 mm de diámetro y porosidad de 0.4. Una vez al día y durante cuatro meses, se adicionó a los humedales un caudal de 42 l.día-1, para mantener un tiempo de residencia hidráulico de tres días. Las muestras de agua residual (afluente y efluente) se recolectaron tres veces por semana para determinar la concentración de DQO y nutrientes. Una vez por semana se determinó coliformes fecales y totales. La eliminación de DQO, amonio, nitrato y ortofosfatos fue de 93, 65, 71 y 32%, respectivamente, para C. ligularis, y de 85, 54, 67 y 57%, respectivamente, para E. colonum. La eficiencia de eliminación de bacterias coliformes fue de 99.9% para ambas especies. Los resultados indicaron que hubo una diferencia significativa (P < 0.05) en la eliminación de los principales contaminantes en el humedal plantado con C. ligularis, indicando una mayor capacidad de esta especie para el tratamiento del agua residual doméstica. | Abstract: This study evaluated the removal efficiency of organic matter (COD), nitrogen (NH4 -, NO3 ~) orthophosphate and total and fecal coliforms in four horizontal subsurface flow pilot scale constructed wetlands using two species of local plants. Two systems were planted with Cyperus ligularis and two Echinochloa colonum. The experiment consisted of sedimentation tank of 760 L (primary treatment) from where water was poured, through PVC pipe to constructed wetlands system. Each wetland was filled with gravel of a diameter of 8 mm and porosity of 0.4. Once a day during four months, wetlands added a flow rate of 42 L.day-1 to maintain a hydraulic residence time of three days. Wastewater samples (influent and effluent) were collected three times by week for COD and nutrients concentrations. Once a week the fecal and total coliforms were analyzed. Removal efficiency of COD, ammonium, nitrate and orthophosphate were of 93%, 65%, 71% and 32% respectively for C. ligularis and of 85%, 54%, 67% and 57% respectively for E. colonum. Removal efficiency of total and fecal coliforms was on 99.9% for both species. The results indicated no significant difference (P < 0.05) in the removal of principals contaminants in the wetland planted C. ligularis indicating higher ability of this species for the treatment of domestic wastewater

Algal blooms and fish kills were reported on a river in coastal Georgia (USA) downstream of a poultry-processing plant, prompting officials to conclude the problems resulted from overland flow associated with over-application of wastewater at the plant’s land application system (LAS). An investigation was undertaken to test the hypothesis that contaminated groundwater was also playing a significant role. Weekly samples were collected over a 12-month period along an 18 km reach of the river and key tributaries. Results showed elevated nitrogen concentrations in tributaries draining the plant and a tenfold increase in nitrate in the river between the tributary inputs. Because ammonia concentrations were low in this reach, it was concluded that nitrate was entering via groundwater discharge. Data from detailed river sampling and direct groundwater samples from springs and boreholes were used to isolate the entry point of the contaminant plume. Analysis showed two separate plumes, one associated with the plant’s unlined wastewater lagoon and another with its LAS spray fields. The continuous discharge of contaminated groundwater during summer low-flow conditions was found to have a more profound impact on river-water quality than periodic inputs by overland flow and tributary runoff.