Search results for " membrane fouling."

The fouling phenomenon in membrane bioreactors: model description and strategies for energy saving

2015

Membrane fouling represents one of the major crucial issues for membrane bioreactor (MBR). Membrane fouling and high aeration requirements (for inducing shear stress to limit fouling) make MBR operation economically demanding due to high energy costs. Although several studies on MBR fouling have been performed, a comprehensive knowledge on how to reduce membrane fouling and consequently energy saving is still lacking. Two scenarios are analyzed and compared each implementing different operating conditions. As expected, MBR operation at low air flow rate (qa) leads to a substantial reduction of the operational costs (namely, 20% respect to the suggested manufacturers ones in terms of qa).

Sequential Batch Membrane BioReactor treating saline wastewater

2015

A sequential batch membrane bioreactor treating high strength salinity wastewater has been investigated. The salt effects on carbon and nutrient removal, fouling behaviour as well as biomass kinetics have been analysed. Salinity was increased at step of 2 g NaCl L-1 per week. The total COD removal efficiency was high (93%) along the entire experimental campaign. However, the biological contribution on the COD removal efficiency was reduced with the increase of salinity. The lowest nitrification removal efficiency (63%) was obtained at 10 g NaCl L-1 salinity due to the lower nitrifier activity. Regarding membrane fouling, the irreversible cake deposition was the predominant fouling mechanism…

Sequential batch membrane bio-reactor for wastewater treatment: The effect of increased salinity

2016

In this work, a sequential batch membrane bioreactor pilot plant is investigated to analyze the effect of a gradual increase in salinity on carbon and nutrient removal, membrane fouling and biomass kinetic parameters. The salinity was increased by 2 g NaCl L-1 per week up to 10 g NaCl L-1. The total COD removal efficiency was quite high (93%) throughout the experiment. A gradual biomass acclimation to the salinity level was observed during the experiment, highlighting the good recovery capabilities of the system. Nitrification was also influenced by the increase in salinity, with a slight decrease in nitrification efficiency (the lowest value was obtained at 10 g NaCl L-1 due to lower nitri…

Membrane bioreactors for treatment of saline wastewater contaminated by hydrocarbons (diesel fuel): An experimental pilot plant case study

2016

Abstract The paper reports the main results of an experimental campaign performed on a membrane bioreactor pilot plant designed to treat synthetic shipboard slops. The experimental campaign was divided into two phases: salinity acclimation up to 20 g NaCl L −1 (Phase I) and hydrocarbon (diesel fuel) dosing (Phase II). The observed results show that the carbon removal was not severely affected by the wastewater features. Conversely, respirometric tests showed that nitrification was strongly affected by the salinity (33% of nitrification efficiency at 20 g NaCl L −1 – Phase I) as a result of the salinity in the autotrophic biomass. Moreover, the sludge viscosity increased during Phase II due …

The fouling phenomenon in membrane bioreactors: Assessment of different strategies for energy saving

2013

Abstract Membrane fouling represents one of the major issues for a membrane bioreactor (MBR). Membrane fouling and high aeration requirements (for inducing shear stress to limit fouling) make MBR operation economically demanding due to high energy costs. Although several studies on MBR fouling have been performed, comprehensive knowledge on how to reduce membrane fouling and consequently save energy is still lacking. An integrated mathematical model for MBR is applied to a University of Cape Town membrane bioreactor with the final aim to reduce the energy costs. In particular, the influence of the aeration intensity, the duration of filtration/backwashing cycles, and the number of membrane …

Treatment of Oily Wastewater with Membrane Bioreactor Systems

2017

The aim of the present work was to investigate the behavior of a membrane bioreactor (MBR) system for the treatment of oily wastewater. A bench scale MBR was fed with synthetic wastewater containing diesel fuel. Organic carbon, hydrocarbon and ammonium removal, kinetic constants, extracellular polymeric substances production, and membrane fouling rates were monitored. The MBR plant was operated for more than 200 days, and the results highlighted good carbon removal and nitrification, suggesting a sort of biomass adaptation to hydrocarbons. Membrane fouling analysis showed an increase in total resistance, likely due to hydrocarbons, which caused an irreversible fouling (pore blocking) mainly…

Biological minimization of excess sludge in a membrane bioreactor: Effect of plant configuration on sludge production, nutrient removal efficiency an…

Power Production from Produced Waters via Reverse Electrodialysis: A Preliminary Assessment

2022

Wastewaters generated by crude oil extraction processes, called “produced waters” (PWs), are complex solutions that contain organic compounds, mainly hydrocarbons, and often exhibit high salinity. The large amounts of PWs represent a global issue because of their environmental impact. An approach widely used in the oil industry is the reinjection of this wastewater into the extraction wells after a suitable treatment. The high salt concentration of such solutions may be used in salinity gradient technologies to produce green electricity. Among these technologies, reverse electrodialysis (RED) is one of the most promising. In this work, the application of RED for energy generatio…