One of the most used ecotoxicity bioassays is based on the luminescence of Vibrio fischeri, for which commercial kits such as Microtox® and several others are available. However, this assay might not always be suitable for several reasons: Its protocol cannot be easily adapted for particular purposes, and it requires the continuous purchases of the kit and the availability of specialized equipment or at least, a luminometer. As a versatile alternative, this paper describes an optimized and kit-free protocol, referred to as “Macrotox”, which allows a wide range of treatment periods (for example, 1, 3, 7, 12, 24, 30 and 36 h) to follow the effects on the luminescence and proliferation of V. fischeri. While the optimized protocol involves 1-mL treatments, it could be easily adapted to use other volumes and times. Importantly, to evaluate the effects on luminescence, only a digital came...

In this study the degradation of polycyclic aromatic hydrocarbons (PAHs) present in waste street sweeping by aerobic treatment was assessed using four different samples of compost quality. It was possible to reduce the concentration in the samples ƩHAPs reaching removal rates of greater than 80% within 120 days of aerobic treatment, samples of compost with anaerobic pretreatment promote further degradation of PAHs reaching higher removals than 90%, this may influenced by the presence of microorganisms capable of degrading organic matter and humic substances produce. The toxic effect evaluated as BaPeq is reduced by over 66% in the first 30 days of treatment for waste shows similar percentages sweep streets can be achieved in more than 90 days of treatment. The ecotoxicological effects assessed on Daphnia magna and Lactuca sativa, indicate that PAH metabolites being produced cometaboliza...

In this work the toxic and ecotoxicological effect of black sand (ANM) from artisanal gold extraction in the department of Madre de Dios was studied. Toxicity Characteristic Leaching Procedure (TCLP) was used to evaluate the toxic effect and with the leachates,acute ecotoxicity tests were performed according to EPA protocol 600 / 3-88 / 029 using test microorganisms, Daphnia Magna neonates , with 24 hours of birth and in seeds of Lactuca Sativa. The quantification of total mercury in ANM samples and in leachates was performed by Inductively Coupled Plasma Atomic Emission Spectroscopy. The values obtained of total mercury in the ANM samples were in the range of 0.1 and> 275 mg/kg of black sand indicating that they exceed the background values by 1000 times. In the leachates the total mercury concentration was in the range of 0.001 and> 2.75 mg/L, some of these values exceed the maxi...

El presente estudio tuvo como objetivo analizar mediante el método de análisis por componentes principales (ACP), la influencia de los parámetros de diseño de la metodología de explosión de vapor sobre la remoción de lignina y variación de otras propiedades físicas en la cascarilla de arroz, residuo agrícola de amplio interés para la producción de etanol 2G. Mediante este proceso se facilita el acceso de enzimas en la hidrólisis de la celulosa. Del análisis se encontró que la presión y el factor de severidad (FS), parámetros del proceso explosión de vapor, se relacionan estrechamente con el pH del lixiviado y la cantidad remanente de lignina en la cascarilla, debido principalmente a la formación de ácidos débiles, autohidrólisis y reacciones de despolimerización - repolimerización de la lignina. Adicionalmente se encontró que otros parámetros como la humedad y l...

Traditional methods of leather production in Peru consume on average between 60 to 80% of chromium for tanning process , generating wastewater with high concentrations of total chromium that must be treated in order to meet the Maximum Allowable Values ( VMA ) established by the DS 029-2009 - Vivienda. The use of complexing agents in the chrome tanning process reduces the supply of chromium to increase skin absorption. The main objective of this study was to evaluate the treatability by chemical precipitation of wastewater from traditional and alternative tanning process. It was determined that the optimal pH for the precipitation was between 7.36 and 9.99, the doses used besides sodium hydroxide were between 0.5 and 5.5 g / L, is the traditional process that requires higher dose . It was determined that the cost of the inputs used in the production of wet blue leather is more than the c...

The present study evaluated the removal of lignin from the rice husk, by means of steam explosion at different severity conditions. The process of lignin removal was evaluated as lignin Klason was performed in samples with pretreatment at pressures of 0.4; 0.6; 0.8 and 1.0 MPa, times of 6, 8, 10 and 12 minutes with a decompression of between 5 to 7 seconds; it is a lignin removal from 18.02 % up to 12.7 % at 1.0 MPa and 12 min compression, factor of 3.3 severity. The evaluation by FTIR of the husk without pretreatment, with pretreatment at 0.4 MPa and 12 min, 1.0 MPa and 12 min, shows a reduction in the transmission generated by the peaks corresponding to the presence of lignin -OH (2920 cm-1 ), CH and CO (1320 and 1360 cm-1), COC a (1060 cm-1) among others. The promover per screening electronic microscopy (SEM) showed the degree of introducción Sud cantidades of the surface of the rice...

Arsenic is an inorganic pollutant that, depending on oxidation–reduction and pH level conditions, may be found in natural waters in two variants: As(III) and As(V). Any treatment to effectively remove arsenic from water will be conditioned by the presence of one or both variants. In this context, this study assesses using electrochemically produced Fe(VI) with Fe(III) to remove As(III), As(V), and their combinations from the Synthetic Bangladesh Groundwater (SBGW) containing anions that interfere with iron-based arsenic removal processes. The combined use of Fe(VI) and Fe(III) allowed us to remove the total arsenic below the 10 mg L-1 threshold established by the World Health Organization and Peruvian regulations for drinking water. An optimum combination of 1 mg L-1 of Fe(VI) and 30 mg L-1 of Fe(III) was identified and tested on the removal of four different proportions of As(III):As(...

The present study aims to optimize the application of a microbial fuel cell (MFC) in the treatment of slaughterhouse wastewater and the production of electricity. The methodology included the response surface analysis (RSA) to evaluate the effect of three factors: the standard reduction potential, SRP (copper, zinc, and graphite; electrode surface area (ESA), and the doses of ruminal liquor (DOSE). The power density (PD) and the removal of the chemical oxygen demand (COD) were determined as the main response variables. The results indicated that the generation of electrical energy depended significantly on the SRP applied, highlighting the copper-graphite arrangement that generated a maximum PD (0.5685 W/m3) and the graphite-graphite that produced the highest removal of COD (81.33%). Consequently, the RSA produced significant predictive models for the generation of PD (R2 = 0.9485, p = 0...

Water scarcity and the planning of socioeconomic activities are challenges in the management of water resources. Therefore, the objective of this study was to use reliability indicators (RI) to simulate management scenarios in the Lurin River Basin. First, flow rates for the period 1969–2019 were calculated using the EvalHid HBV hydrological model and SIMGES, both from the AQUATOOL decision support system, to simulate demands. The estimation of agricultural demand IRs was made under three conditions: that the deficits for one, two, and 10 years should not exceed 20–40, 40–60, and 80–100% of the annual demand. The goodness-of-fit indices obtained for flow calibration were 0.716, 0.89, and 0.901 for Nash index (NSE), Nash natural logarithm (Ln NSE), and Pearson's correlation coefficient (R), representing the values of satisfactory, very good, and good, respectively. Agricultural de...

En esta investigación se evaluó la cinética de reducción de la turbidez inicial (1455 UNT) de aguas residuales de una industria curtiembre mediante la aplicación de biofloculantes directos elaborados a partir del alga Chondracanthus chamissoi (alginato) y de las mudas del crustáceo Emerita analoga (quitosano). Se recolecto el material biológico precursor en las playas de Lima, Perú, a partir de este material; se produjo ácido algínico fibroso y posteriormente alginato de sodio. Se usaron los procesos de desmineralización, desproteinización y posterior desacetilación para obtener el quitosano a partir de las mudas del crustáceo. Se evaluó el efecto del pH, la dosis de los biofloculantes, el tiempo de equilibrio del proceso. Además, se determinó el orden cinético de la velocidad de floculación mediante la prueba de jarras. Los resultados indicaron una remoción de la tur...