Search results for "fouling"
showing 10 items of 150 documents
The influence of solid retention time on IFAS-MBR systems: analysis of system behavior.
2018
A University of Cape Town Integrated Fixed-Film Activated Sludge Membrane Bioreactor (UCT-IFAS-MBR) pilot plant was operated at different values of the sludge retention time (SRT). Three SRTs were investigated at different durations: indefinitely, 30 and 15 days. The organic carbon, nitrogen and phosphorus removal, kinetic/stoichiometric parameters, membrane fouling tendency and sludge filtration properties were assessed. The findings showed that by decreasing the SRT, the pilot plant could maintain excellent carbon removal efficiencies throughout the experiments. In contrast, the biological carbon removal showed a slight nitrification and was slightly affected by the decrease of the SRT, s…
Haloperoxidase Mimicry by CeO2−xNanorods Combats Biofouling
2016
CeO2-x nanorods are functional mimics of natural haloperoxidases. They catalyze the oxidative bromination of phenol red to bromophenol blue and of natural signaling molecules involved in bacterial quorum sensing. Laboratory and field tests with paint formulations containing 2 wt% of CeO2-x nanorods show a reduction in biofouling comparable to Cu2 O, the most typical biocidal pigment.
Sedimentation and Fouling of Optical Surfaces at the ANTARES Site
2003
ANTARES is a project leading towards the construction and deployment of a neutrino telescope in the deep Mediterranean Sea. The telescope will use an array of photomultiplier tubes to detect the Cherenkov light emitted by muons resulting from the interaction with matter of high energy neutrinos. In the vicinity of the deployment site the ANTARES collaboration has performed a series of in-situ measurements to study the change in light transmission through glass surfaces during immersions of several months. The average loss of light transmission is estimated to be only ~2% at the equator of a glass sphere one year after deployment. It decreases with increasing zenith angle, and tends to satur…
Fouling mechanism elucidation in membrane bioreactors by bespoke physical cleaning
2018
Abstract Cake layer deposition on a membrane surface can determine both external and internal membrane fouling through negatively affecting the total filtration resistance while exerting a positive effect as a pre-filter. Membranes are usually subjected to a periodic cake layer removal through routine physical cleaning, specifically permeate backwashing of hollow fiber membranes, or enhanced cleaning through, for example, chemically-enhanced backwashing. Physical cake layer removal is crucial for sustaining permeability, yet the effect of different physical cleaning modes remains poorly evaluated. The present work attempts to analyze physical cake layer removal through the application of sp…
Multistage recovery process of seaweed pigments: Investigation of ultrasound assisted extraction and ultra-filtration performances
2017
International audience; The objectives of this study were first to evaluate the performance of seaweed pigments’ recovery through ultrasound assisted extraction (UAE) and ultra-filtration (UF), and second to investigate the membrane fouling mechanism and evidence the threshold flux during filtration. The pigments’ recovery from the extract was performed using 5 kDa and 10 kDa ultra-filtration membranes. Results showed that increasing the extraction temperature in the range of 40–60 °C was proportional to chlorophyll extraction efficiency, while the maximal carotenoid yield was achieved at 50 °C. Ultrasonic power (from 100 W to 300 W) facilitated the extraction of both chlorophylls and carot…
Comparison between two MBR pilot plants treating synthetic shipboard slops: effect of salinity increase on biological performance, biomass activity a…
2017
The paper reports the main results of an experimental campaign carried out on two bench scale pilot plants for the treatment of synthetic shipboard slops. In particular, two membrane bioreactors (MBRs) with submerged configuration were analyzed. One MBR pilot plant (namely, Line A) was fed with synthetic shipboard slop and was subjected to a gradual increase of salinity. Conversely, the second MBR pilot plant (namely, Line B) was fed with the same synthetic shipboard slop but without salt addition, therefore operating as a âcontrolâ unit. Organic carbon, hydrocarbons and ammonium removal, kinetic constants, extracellular polymeric substances (EPSs) production and membranes fouling rates…
Treatment of high strength industrial wastewater with membrane bioreactors for water reuse: Effect of pre-treatment with aerobic granular sludge on s…
2019
Abstract In this study, the treatment of citrus wastewater with membrane bioreactors (MBRs) under different configurations was investigated for water reuse. In particular, one MBR and one aerobic granular sludge MBR (AGS + MBR) bench scale plants were operated for 60 days. The experimental campaign was divided into two periods. In Phase I, a conventional hollow fiber MBR was employed for the treatment of the raw high strength wastewater, whereas in Phase II a combination of in-series reactors (AGS + MBR) was adopted for the treatment of the high strength citrus wastewater The results demonstrated that both plant configurations enabled very high COD removal, with average values close to 99%.…
Biological nitrogen and phosphorus removal in membrane bioreactors: model development and parameter estimation
2012
Membrane bioreactors (MBR) are being increasingly used for wastewater treatment. Mathematical modeling of MBR systems plays a key role in order to better explain their characteristics. Several MBR models have been presented in the literature focusing on different aspects: biological models, models which include soluble microbial products (SMP), physical models able to describe the membrane fouling and integrated models which couple the SMP models with the physical models. However, only a few integrated models have been developed which take into account the relationships between membrane fouling and biological processes. With respect to biological phosphorus removal in MBR systems, due to th…
High salinity wastewater treatment by membrane bioreactors
2020
Abstract This chapter reviews the state of the art regarding the use of membrane bioreactor (MBR) systems for saline wastewater treatment. In particular, a comprehensive review is presented discussing the most adopted MBR configurations for the treatment of saline wastewater. Further, the chapter discusses the main effects of salinity on the biological performance, kinetic parameters, fouling development, sludge rheological features, and greenhouse gas (GHG) production. Literature results show that there is a significant effect of the salinity (and/or salinity variations) on the biological performance and membrane filtration. Specifically, it was found that a gradual salinity increase, carr…
Long-run operation of a reverse electrodialysis system fed with wastewaters.
2018
The performance of a Reverse ElectroDialysis (RED) system fed by unconventional wastewater solutions for long operational periods is analysed for the first time. The experimental campaign was divided in a series of five independent long-runs which combined real wastewater solutions with artificial solutions for at least 10 days. The time evolution of electrical variables, gross power output and net power output, considering also pumping losses, was monitored: power density values obtained during the long-runs are comparable to those found in literature with artificial feed solutions of similar salinity. The increase in pressure drops and the development of membrane fouling were the main det…