On the shrinking and hardening of EPDM rubber membranes in water sanitation filtration tanks

Hansen, Ernst Jan de Place; Estevez, Manuel Antonio Perez; Es‐Said, O.S.

doi:10.1016/j.engfailanal.2003.06.003

Cited by 10 publications

(3 citation statements)

References 1 publication

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“…Biological fouling may cause irreversible changes in the material structure of a diffuser, e.g., as a result of the biofilm bacteria penetrating the membrane (type II fouling), caused by the application of additives (e.g., softening or elasticity increasing agents) in the manufacturing process of diffusers, which then serve as a source of nutrients. As a consequence, membrane cracking and elasticity reduction occur, eventually leading to the need to replace the damaged diffuser and incurring the related costs [43][44][45][46]. However, sometimes a situation where degradation improves the oxygen transfer efficiency may occur.…”

Section: Effects Of Diffuser Foulingmentioning

confidence: 99%

Aeration Process in Bioreactors as the Main Energy Consumer in a Wastewater Treatment Plant. Review of Solutions and Methods of Process Optimization

et al. 2019

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Due to the key role of the biological decomposition process of organic compounds in wastewater treatment, a very important thing is appropriate aeration of activated sludge, because microorganisms have to be supplied with an appropriate amount of oxygen. Aeration is one of the most energy-consuming processes in the conventional activated sludge systems of wastewater treatment technology (may consume from 50% to 90% of electricity used by a plant), which makes it the most cost-generating process incurred by treatment plants. The paper presents the construction of aeration systems, their classification as well as parameters and factors that significantly affect the aeration process e.g., oxygen transfer efficiency, diffuser fouling, methods of dealing with diffuser fouling, diffuser selection. Additionally, there are briefly presented “smart control” systems in wastewater treatment and effect of application control strategy based on Supervisory Control and Data Acquisition system connected with the decrease in the energy consumption for aeration of bioreactors with activated sludge. It is noted that before the process is optimized, the system should be equipped with suitable metering devices. Only when relevant data is available, the improvements can be carried out. However, it’s important, that the operator should regularly maintain good condition and high efficiency of diffusers.

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Section: Effects Of Diffuser Foulingmentioning

confidence: 99%

Aeration Process in Bioreactors as the Main Energy Consumer in a Wastewater Treatment Plant. Review of Solutions and Methods of Process Optimization

et al. 2019

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“…The suitability of a particular polymer as a barrier material under specified application conditions is determined by its sorption/desorption characteristics as well as by the related diffusion anomalies [1][2][3][4]. Excellent works on the molecular transport of liquids through solid polymeric materials has been reported by several researchers [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…M OLECULAR TRANSPORT OF organic liquids through polymer membranes under the influence of a chemical potential occurs primarily by the process of diffusion of permeating liquid molecules. The suitability of a particular polymer as a barrier material under specified application conditions is determined by its sorption/desorption characteristics as well as by the related diffusion anomalies [1][2][3][4]. Excellent works on the molecular transport of liquids through solid polymeric materials has been reported by several researchers [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Aliphatic Liquid Transport through Heterogeneous Ethylene—Propylene— Diene Monomer Rubber/Poly (ethylene-co-vinyl acetate) Blends

George

Kumari

Unnikrishnan

2009

Journal of Elastomers & Plastics

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The sorption and diffusion of n-alkanes, namely, hexane, heptane, and octane through crosslinked Ethylene-Propylene-Diene Monomer/ Poly(ethylene-co-vinyl acetate) (EPDM/EVA) blends has been examined in the temperature interval of 28-588C. Special reference has been given to the effects of blend composition, crosslinking systems, penetrant nature, and temperature on the liquid transport. The solvent uptake was found to decrease with increase in EVA content in the blends. The blends were crosslinked by three crosslinking systems namely, sulfur, dicumyl peroxide (DCP), and a mixture consisting of sulfur and peroxide. The DCP crosslinked system exhibited the lowest solvent uptake. These observations have been correlated with the phase morphology of the blends using scanning electron micrographs. The values of the kinetic parameters of permeability and molar mass between crosslinks have been found to be complementary to the observations. The experimental diffusivity values have been compared with different theoretical models.

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A survey of biofilms on wastewater aeration diffusers suggests bacterial community composition and function vary by substrate type and time

Noble

Park

Olson

et al. 2016

Appl Microbiol Biotechnol

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Aeration diffusers in wastewater treatment plants generate air bubbles that promote mixing, distribution of dissolved oxygen, and microbial processing of dissolved and suspended matter in bulk solution. Biofouling of diffusers represents a significant problem to wastewater treatment plants because biofilms decrease oxygen transfer efficiency and increase backpressure on the blower. To better understand biofouling, we conducted a pilot study to survey the bacterial community composition and function of biofilms on different diffuser substrates and compare them to those in the bulk solution. DNA was extracted from the surface of ethylene-propylene-diene monomer (EPDM), polyurethane, and silicone diffusers operated for 15 months in a municipal treatment plant and sampled at 3 and 9 months. The bacterial community composition and function of the biofilms and bulk solution were determined by amplifying the 16S rRNA genes and pyrosequencing the amplicons and raw metagenomic DNA. The ordination plots and dendrograms of the 16S rRNA and functional genes showed that while the bacterial community composition and function of the bulk solution was independent of sampling time, the composition and function of the biofilms differed by diffuser type and testing time. For the EPDM and silicone diffusers, the biofilm communities were more similar in composition to the bulk solution at 3 months than 9 months. In contrast, the bacteria on the polyurethane diffusers were more dissimilar to the bulk solution at 3 months than 9 months. Taken together, the survey showed that the community composition and function of bacterial biofilms depend on the diffuser substrate and testing time, which warrants further elucidation.

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On the shrinking and hardening of EPDM rubber membranes in water sanitation filtration tanks

Cited by 10 publications

References 1 publication

Aeration Process in Bioreactors as the Main Energy Consumer in a Wastewater Treatment Plant. Review of Solutions and Methods of Process Optimization

Aeration Process in Bioreactors as the Main Energy Consumer in a Wastewater Treatment Plant. Review of Solutions and Methods of Process Optimization

Aliphatic Liquid Transport through Heterogeneous Ethylene—Propylene— Diene Monomer Rubber/Poly (ethylene-co-vinyl acetate) Blends

A survey of biofilms on wastewater aeration diffusers suggests bacterial community composition and function vary by substrate type and time

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