Textile wastewater is widely produced and its discharge without treatment contributes to environmental pollution. The adsorption process is a suitable and eco-friendly process due to its low initial cost, no formation of degradation products, operation simplicity, insensitivity to toxic compounds, and the possibility of removal from greatly diluted solutions. Orange seed (OS) powder, from which lipids were removed by hexane extraction, was evaluated as a bio-adsorbent to remove dyes from real textile wastewater. In the screening step, pH was a more significant variable (p-value < 0.05) than bio-adsorbent dosage, temperature, stirring speed, and process time. Moreover, under optimized conditions (pH = 2.6, 0.58 g/L from OS powder and 26 °C), more than 95% of the dye was removed from real textile wastewater. Additionally, the dye removal percentage was reduced by only 4% when the volume of textile wastewater was increased from 0.05 L to 10 L. Then, 96% turbidity was removed using a 3 µm tubular ceramic membrane at a pH of 11. Furthermore, the permeate flux through the membrane was kept constant for longer than was observed at low pH (<11). Therefore, the proposed process is an interesting option, due to the fact that orange seeds are currently not valorized and, combined with the membrane process, this could prove a suitable option for the treatment of real textile wastewater.
Rubber is a natural product, the main car tire component. Due to the characteristics acquired by this material after its vulcanization process, its degradation under natural conditions requires very long times, causing several environmental problems. In the present work, the existence of a bacterial consortium isolated from a discarded tire found within the Socabaya River with the ability to degrade shredded tire rubber without any chemical pretreatment is explored. Taking into consideration the complex chemical composition of a rubber tire and the described benefits of the use of pretreatments, the study is developed as a preliminary analysis. The augmentative growth technique was used, and the level of degradation was quantified as a percentage through the analysis of microbial respiration. Schiff’s test and the use of comparative photographs of scanning electron microscopy (SEM) were also used. The consortium using next generation genetic sequencing was analyzed. A 4.94% degradation point was obtained after 20 days of experimentation, and it was found that the consortium was mostly made up with Delftia tsuruhatensis with 69.12% of the total genetic readings of the consortium and the existence of 15% of unidentified microbial strains at the genre level. The role played by the organisms in the degradation process is unknown. However, the positive results in the tests carried out show that the consortium had action on the shredded tire, showing a mineralization process.
Membrane fouling is caused by foulant deposition or adsorption through physical or chemical interactions on the membrane surface, causing the reduction of flux through the membrane. The main drawbacks of chemical agents used for cleaning are cost, damage caused on the membrane, and waste stream making the process unattractive. Alternative, methods such as ultrasound, enzymatic process, and osmotic backwashing were explored for membrane cleaning. Among all mentioned methods, micronanobubbles have been reported as a promising and emergent method for membrane surface cleaning; unfortunately, the information is limited, but preliminary studies have shown it as an efficient, cheap, and environmentally friendly technique. Other methods like electrically and vibratory‐enhanced membrane cleaning also could be interesting but currently are unexplored and information is limited. Practitioner Points Chemical cleaning is an efficient option; however, from an environmental point of view, it is not attractive, and high concentrations could cause damage to the membrane. Micronanobubbles are an emergent and suitable technology for membrane and surface cleaning. Membrane modification and functionalization avoid membrane fast fouling, and the cleaning process is easier, but the manufacture cost could be expensive.
La falta de energía en zonas rurales es un problema que afecta principalmente a los países en vías de desarrollo. Actualmente se buscan alternativas eficientes y sostenibles que solucionen este problema. La presente investigación evaluó la producción volumétrica y composición de biogás de 12 mezclas de tres tipos de sustratos (estiércol de vaca, cerdo y cuy). Los sustratos fueron caracterizados para conocer su porcentaje de humedad, cenizas, materia orgánica, nitrógeno Kjeldahl, relación C/N y metales totales. Luego se evaluó durante 23 días la producción volumétrica de biogás en cada sistema por triplicado y finalmente se analizó la composición del biogás. Los contenidos de materia orgánica, nitrógeno y relación C/N fueron muy similares a los reportados por varios autores; en los tres sustratos se observó la presencia de metales pesados como cobre y níquel. Solo en el estiércol de vaca de observó plomo. Por otro lado, se halló elementos traza que son beneficiosos para la digestión anaerobia, como el selenio en el estiércol de cuy. El sistema que generó mayor volumen de biogás fue el sistema S3, el cual contenía 25% de estiércol de vaca, 25% de estiércol de cerdo y 50 % de estiércol de cuy. Rindió 33.6 ± 0.42% de metano. La producción volumétrica y porcentaje de metano en el biogás se vio afectada directamente por la presencia de metales que inhiben o ralentizan el desarrollo de microorganismos metanogénicos.
Cattle slaughtering produce large amounts of wastewater containing high concentrations of organic matter and nutrients and requires significant treatment before disposal or reutilization. However, the nutrients contained can be valued as a medium for microalgal biomass generation. In this work, hydrodynamic cavitation (HC) followed by membrane filtration or biological (microalgae cultivation) treatment in continuous mode were performed. From cattle slaughterhouse wastewater (CSW), by the effect of HC treatment with air injection in batch mode, more than 20% of the chemical oxygen demand (COD) was removed. In a continuous HC process, the COD content in output was 324 mg O2/L, which is 68% lower than the supplied CSW. After that, 76% of residual COD was removed by filtration through a tubular alumina membrane (600 nm). Finally, 85% of residual COD after HC treatment in 24 h in a batch mode was removed by microalgae. On the other hand, the COD concentration in the output was around 59 mg O2/L in continuous mode, which represents 85–93% COD removal. The process involving HC and microalgae growing looks promising since in addition to water treatment, the microalgae produced could be valued in a biorefinery concept.
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