Search results for "membrane fouling"

Position paper - progress towards standards in integrated (aerobic) MBR modelling.

2020

Membrane bioreactor (MBR) models are useful tools for both design and management. The system complexity is high due to the involved number of processes which can be clustered in biological and physical ones. Literature studies are present and need to be harmonized in order to gain insights from the different studies and allow system optimization by applying a control. This position paper aims at defining the current state of the art of the main integrated MBR models reported in the literature. On the basis of a modelling review, a standardized terminology is proposed to facilitate the further development and comparison of integrated membrane fouling models for aerobic MBRs. ispartof: WATER …

The role of fouling mechanisms in a submerged membrane bioreactor during the start-up

2006

Modelling biological nitrogen and phosphorus removal with soluble microbial products (SMP) production-degradation processes

2011

Over the last two decades, Membrane Bioreactors (MBR) are increasingly used for wastewater treatment. Mathematical modelling of MBR systems has played a key role in order to better explain the effect of their peculiarities. Indeed, several MBR models have been presented in literature in order to improve the knowledge on MBR systems: biological models, hybrid models which include soluble microbial product (SMP) modelling, physical models able to describe the membrane fouling and integrated models which couple the hybrid models with the physical ones. However, among the existing MBR models only few integrated models have been developed which take into account the existing relationship between…

Optimising an outdoor membrane photobioreactor for tertiary sewage treatment

2019

[EN] The operation of an outdoor membrane photobioreactor plant which treated the effluent of an anaerobic membrane bioreactor was optimised. Biomass retention times of 4.5, 6, and 9 days were tested. At a biomass retention time of 4.5 days, maximum nitrogen recovery rate:light irradiance ratios, photosynthetic efficiencies and carbon biofixations of 51.7¿±¿14.3¿mg¿N·mol¿1, 4.4¿±¿1.6% and 0.50¿±¿0.05¿kg CO2·m3influent, respectively, were attained. Minimum membrane fouling rates were achieved when operating at the shortest biomass retention time because of the lower solid concentration and the negligible amount of cyanobacteria and protozoa. Hydraulic retention times of 3.5, 2, and 1.5 days …

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).

Production of microalgal external organic matter in a Chlorella-dominated culture: influence of temperature and stress factors

2020

[EN] Although microalgae are recognised to release external organic matter (EOM), little is known about this phenomenon in microalgae cultivation systems, especially on a large scale. A study on the effect of microalgae-stressing factors such as temperature, nutrient limitation and ammonium oxidising bacteria (AOB) competition in EOM production by microalgae was carried out. The results showed non-statistically significant differences in EOM production at constant temperatures of 25, 30 and 35 degrees C. However, when the temperature was raised from 25 to 35 degrees C for 4 h a day, polysaccharide production increased significantly, indicating microalgae stress. Nutrient limitation also see…

Minimizing membrane bioreactor environmental footprint by multiple objective optimization.

2020

This paper presents a modelling study aimed at minimizing the environmental foot print of a membrane bioreactor (MBR) for wastewater treatment. Specifically, an integrated model for MBR was employed in view of the management optimization of an MBR biological nutrient removal (BNR) pilot plant in terms of operational costs and direct greenhouse gases emissions. The influence of the operational parameters (OPs) on performance indicators (PIs) was investigated by adopting the Extended-FAST sensitivity analysis method. Further, a multi-objective analysis was performed by applying the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The results show-up that the sludge …

New applications in integrated fixed film activated sludge-membrane bioreactor (IFAS-MBR) systems

2020

Abstract This chapter provides an overview on the development and application of integrated fixed film activated sludge-membrane bioreactor (IFAS-MBR) systems. IFAS-MBRs represent a novel configuration for advanced wastewater treatment, and only a few studies are available in literature. With this aim, the results of some studies on IFAS-MBR systems already published are discussed and compared in this chapter. Literature shows that the influent carbon to nitrogen ratio (C/N) strongly affects the biological process in IFAS-MBR. The organic matter removal efficiency (removed biologically) decreases from 60% to 23.5% with the decrease of influent C/N from 10 to 2 mgCOD mgTN− 1. Nitrogen remova…

The effect of the solids and hydraulic retention time on moving bed membrane bioreactor performance

2018

Abstract The aim of the present paper was to investigate the effect of solids (SRT) and hydraulic (HRT) retention time on Integrated Fixed Film Activated Sludge (IFAS) University of Cape Town (UCT) membrane Bioreactor (MBR). In particular, three different pairs of SRT and HRT values were analysed, namely, Phase I 56 d/30 h, Phase II 31 d/15 h and Phase III 7 d/13 h. The short-term effect of these three SRT/HRT conditions was assessed by analysing several system performance indicators: organic carbon and biological nutrient (nitrogen and phosphorus) removal, biomass respiratory activity, activated sludge filtration properties and membrane fouling. The results showed that the decrease of SRT/…

The role of fouling mechanisms in a membrane bioreactor.

2007

The present study has aimed to quantify the role of pore blocking and cake layer in a laboratory scale hollow fibre membrane module in submerged configuration. The membrane reactor (MBR) was fed with raw wastewater, only screened with a 2-mm sieve, collected from the Palermo WWTP. The MBR was characterised by an operating volume of 190 L and equipped with an aeration system located on the bottom of the reactor. The MBR operated for 65 days. The permeate was extracted by imposing a constant flux through the membrane (21 Lh−1m−2). The results confirm the importance of pore blocking control during start-up. In particular, it provides a rapid irreversible fouling that takes place at the beginni…