What do we know about the influence of vacuum on bacterial biocenosis used in environmental biotechnologies?

Gnida, Anna

doi:10.1007/s00253-019-10213-6

Cited by 9 publications

(4 citation statements)

References 26 publications

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“…Indeed, only a few batch studies have discussed the impact of vacuum on microbes (Gnida, 2020;Kral et al, 2011;Rajhi et al, 2016;Verseux, 2020), and thus long-term impacts are largely unexplored. Kral et al (2011) investigated the impact of vacuum on different methanogens cultivated on Mars soil simulant and reported that methanogens survived for 10 days under 400 mbar at 35 °C but displayed minimal activity when vacuum pressure reached 50 mbar, indicating that lower pressure exerted more significant stress on methanogens.…”

Section: Vacuum Evaporation and Distillation Technologiesmentioning

confidence: 99%

Anaerobic Process Intensification With Vacuum and Combined Pretreatment Technologies

Okoye

2024

Preprint

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Anaerobic digestion and fermentation are essential processes for transforming wastewater treatment plants into robust energy, nutrient, and water recovery facilities. However, these processes' slow microbial growth rate and low yields limit their application to larger facilities. To improve their efficiency, intensifying anaerobic digestion and fermentation (to a lesser extent) has been the subject of numerous research studies. This dissertation explored the principle of vacuum evaporation for combining sludge thickening, decoupling of hydraulic and retention times, and nutrient recovery into a single treatment unit. Gaps, including the efficiency of vacuum sludge thickening at different solids content, its impact on anaerobic bacteria and the overall physio and biochemical processes, were investigated. In batch fermentation, establishing 400 mbar of absolute pressure led to 49% solubilization of primary sludge in 72 hours compared to the conventional fermentation in which 11% solubilization was achieved. During fermentation of TWAS at 400 mbar, deterioration of solubilization and VFA yield was observed. The vacuum technology was used to decouple the hydraulic and solids retention time (HRT/SRT) in semi-continuous fermentation of mixed sludge. At SRT of 3 days and HRT of 1.5 days, the vacuum-assisted fermenter yielded 660 mg sCOD/g VSS compared to the conventional fermenter which achieved 513 mg sCOD/g VSS with equal HRT and SRT of 3 days. Additionally, 50% of the ammonia produced in the fermenter was extracted in the condensate with no chemical alterations. The results led to the development of IntensiCarb, a patent-pending technology that combines sludge thickening, digestion, and dewatering into a single unit. This dissertation also investigated the use of combined chemical-mechanical and chemical-chemical pretreatment technologies with free nitrous acid (FNA) to enhance the anaerobic digestion of TWAS. FNA is an environment-friendly chemical that can be produced in wastewater treatment facilities. In this study, FNA concentrations from 0.7 to 2.8 mg HNO2-N/L were combined with ultrasonication energy input from 600 to 3,000 kj/kg TS to explore the feasibility of lower energy input for effective sludge disintegration and enhanced anaerobic digestion. The energy input for ultrasonication could be halved from 3,000 kj/kg TS to 1,500 kj/kg TS by adding 2.8 mg HNO2-N /L while improving solubilization by 43% and methane yield by 18%. FNA was also combined with hydrogen peroxide, an oxidizing chemical that has shown effectiveness in improving biodegradability at low pH. The results showed that the pretreatment combination with the lowest chemical concentrations of 0.7 mg HNO2-N /L and 25 mg H2O2/g TS was the most effective for maximizing methane yield, increasing it by 50% compared to the untreated TWAS.

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Section: Vacuum Evaporation and Distillation Technologiesmentioning

confidence: 99%

Anaerobic Process Intensification With Vacuum and Combined Pretreatment Technologies

Okoye

2024

Preprint

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“…The current lowest pressure recorded for microbial growth is 0.7 kPa (7 mbar; Schuerger and Nicholson 2016 ). Nevertheless, low-pressure vacuum is used in biotechnologies, including biomining (Gnida 2020 ), and a bioreactor using low-pressure Mars-similar gas composition was successfully developed for cyanobacterial growth (Verseux et al 2021 ). This suggests that, with the appropriate adaptation and engineering, challenges posed by extraterrestrial atmospheric composition and pressure could be overcome not to limit biomining applications.…”

Section: Space Biomining Principlesmentioning

confidence: 99%

The smallest space miners: principles of space biomining

2022

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As we aim to expand human presence in space, we need to find viable approaches to achieve independence from terrestrial resources. Space biomining of the Moon, Mars and asteroids has been indicated as one of the promising approaches to achieve in-situ resource utilization by the main space agencies. Structural and expensive metals, essential mineral nutrients, water, oxygen and volatiles could be potentially extracted from extraterrestrial regolith and rocks using microbial-based biotechnologies. The use of bioleaching microorganisms could also be applied to space bioremediation, recycling of waste and to reinforce regenerative life support systems. However, the science around space biomining is still young. Relevant differences between terrestrial and extraterrestrial conditions exist, including the rock types and ores available for mining, and a direct application of established terrestrial biomining techniques may not be a possibility. It is, therefore, necessary to invest in terrestrial and space-based research of specific methods for space applications to learn the effects of space conditions on biomining and bioremediation, expand our knowledge on organotrophic and community-based bioleaching mechanisms, as well as on anaerobic biomining, and investigate the use of synthetic biology to overcome limitations posed by the space environments.

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“…While the slightly acidic pH of 5.0 -6.0 is ideal for the hydrolytic microorganisms, the neutral pH and mesophilic conditions (30 -45 °C), optimized at 37 °C, in which the methanogenic species thrive, are ideal for them [13]. Moreover, vacuum impregnation's main mechanism is to displace gas in porous material with aqueous mixture by pressure [14], and the vacuum condition, that is empty of gas (completely anaerobic), can enhance the activity of the hydrolytic microorganisms, leading to better biomass hydrolysis [15]. Therefore, improved biomass hydrolysis can be achieved through ensiling under a vacuum at an ambient temperature of 26 -30 °C.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Electromagnetic Radiation Distribution in the Human Heart Rate at Different Frequencies‏‏

Elwasife,

Yasin,

Radwan

2023

Trends Sci

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The health implications of electromagnetic radiation have been extensively debated due to the sharp increase in the usage of cell phones, Wi-Fi transmitters and other microwave equipment. Electromagnetic radiation affects the autonomic nervous system, heart rate, blood pressure and other cardiovascular functions. This study aims to present a Numerical Simulation of Electromagnetic Radiation (EMR) on the human heart tissue and to explore the effect of different frequencies in the spectral range (900, 1,800 and 2,400 MHz) on Specific Absorption Rate (SAR), power density, the Distribution of Electromagnetic Fields by Matlab program, and Finite-Difference Time-Domain (FDTD) method in One Dimension (1D). A 1-dimensional finite difference method was used to solve Maxwell’s equations in heart tissue. The heart model was subjected to electromagnetic radiation that has dielectric properties according to frequency. Frequency was chosen and the operation of the software program as Matlab and the dielectric attribute has been calculated. Concurring with the Frequency in a private program, are the conductivity, relative permittivity, wavelength and infiltration profundity. The amplitudes of the reflected and transmitted sinusoid waves, relative to the occurrence wave, were portrayed by the reflection coefficient and the transmission coefficient, which relate to the amplitudes of the electric field wave. The electric field, magnetic field and power density were simulated along the line X = Y = 0. The study showed that the impact of electromagnetic radiation depends on the frequency of the wave which hit the heart. It was found that the heart tissue reacts more at 900 MHz compared to 1,800 and 2,400 MHz, and the tissue absorption is higher at the lower frequency. There was a relation between the magnetic field in the y-dimension and the time step the in x-dimension. HIGHLIGHTS The effect of electromagnetic has been theoretically studied where the electromagnetic fields produced from electromagnetic radiation at 900 MHz,1800 MHz, and 2400 MHz on layered biological tissues (heart model) by the finite difference time domain (FDTD) method A one-dimensional finite difference method was used to solve Maxwell's equations in heart tissue The amplitudes of the reflected and transmitted sinusoid waves, relative to the occurrence wave, were portrayed by the reflection coefficient and the transmission coefficient, which relate to the amplitudes of the electric field wave The impact of electromagnetic radiation depends on the frequency of the wave which hit the heart. There was a relation between the magnetic field in the y-dimension and the time step the in x-dimension GRAPHICAL ABSTRACT

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What do we know about the influence of vacuum on bacterial biocenosis used in environmental biotechnologies?

Cited by 9 publications

References 26 publications

Anaerobic Process Intensification With Vacuum and Combined Pretreatment Technologies

Anaerobic Process Intensification With Vacuum and Combined Pretreatment Technologies

The smallest space miners: principles of space biomining

Estimation of Electromagnetic Radiation Distribution in the Human Heart Rate at Different Frequencies‏‏

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