Over the past decade, membrane bioreactors have been increasingly implemented to purify municipal wastewater. However, even with submerged modules which offer the lowest costs, the membrane bioreactor (MBR) technology remains in most cases more expensive than conventional activated sludge processes. In addition, the European municipal MBR market is to date a duopoly of two non-European producers, despite many initiatives to develop local MBR filtration systems. In 2005, the European Commission decided to finance four projects dedicated to further technological development of MBR process: the four projects AMEDEUS, EUROMBRA, MBR-TRAIN and PURATREAT were implemented from October 2005 up to December 2009 and joined their efforts within the coalition “MBR-Network” (www.mbr-network.eu). The present report synthesises the major outcomes of the project AMEDEUS, conducted from October 2005 up to May 2009. The AMEDEUS research project aimed at tackling both issues of accelerating the development of competitive European MBR filtration technologies, as well as increasing acceptance of the MBR process through decreased capital and operation costs. The project targets the two market segments for MBR technology in Europe: the construction of small plants (semi-central, 50 to 2,000 population equivalent or p.e., standardized and autonomous), and the medium-size plants (central, up to 100.000 p.e.) for plant upgrade.

Over the past decade, membrane bioreactors have been increasingly implemented to purify municipal wastewater. However, even with submerged modules which offer the lowest costs, the membrane bioreactor (MBR) technology remains in most cases more expensive than conventional activated sludge processes. In addition, the European municipal MBR market is to date a duopoly of two non-European producers, despite many initiatives to develop local MBR filtration systems. In 2005, the European Commission decided to finance four projects dedicated to further technological development of MBR process: the four projects AMEDEUS, EUROMBRA, MBR-TRAIN and PURATREAT were implemented from October 2005 up to December 2009 and joined their efforts within the coalition “MBR-Network” (www.mbr-network.eu). The present report synthesises the major outcomes of the project AMEDEUS, conducted from October 2005 up to May 2009. The AMEDEUS research project aimed at tackling both issues of accelerating the development of competitive European MBR filtration technologies, as well as increasing acceptance of the MBR process through decreased capital and operation costs. The project targets the two market segments for MBR technology in Europe: the construction of small plants (semi-central, 50 to 2,000 population equivalent or p.e., standardized and autonomous), and the medium-size plants (central, up to 100.000 p.e.) for plant upgrade.

Twelve years after the first full scale municipal application in Europe of the membrane bioreactor (MBR) technology, the process is now accepted as a technology of choice for wastewater treatment, and the market is showing sustained growth. However early misconceptions about the technology are persistent and false statements are commonly encountered in articles and conferences, generating unnecessary research efforts or even fuelling either fascination or scepticism with regards to the technology, which is ultimately detrimental to the perception of the process by water professionals. We try to provide some factual and rational clarifications on ten issues which are often wrongly reported about MBR technology.

Membrane bioreactors (MBRs) have been increasingly employed for municipal and industrial wastewater treatment in the last decade. The efforts for modelling of such wastewater treatment systems have always targeted either the biological processes (treatment quality target) as well as the various aspects of engineering (cost effective design and operation). The development of Activated Sludge Models (ASM) was an important evolution in the modelling of Conventional Activated Sludge (CAS) processes and their use is now very well established. However, although they were initially developed to describe CAS processes, they have simply been transferred and applied to MBR processes. Recent studies on MBR biological processes have reported several crucial specificities: medium to very high sludge retention times, high mixed liquor concentration, accumulation of soluble microbial products (SMP) rejected by the membrane filtration step, and high aeration rates for scouring purposes. These aspects raise the question as to what extent the ASM framework is applicable to MBR processes. Several studies highlighting some of the aforementioned issues are scattered through the literature. Hence, through a concise and structured overview of the past developments and current state-of-the-art in biological modelling of MBR, this review explores ASMebased modelling applied to MBR processes. The work aims to synthesize previous studies and differentiates between unmodified and modified applications of ASM to MBR. Particular emphasis is placed on influent fractionation, biokinetics, and soluble microbial products (SMPs)/exo-polymeric substances (EPS) modelling

This paper deals with the performance and the optimisation of the hydraulic operating conditions of the A3 Water Solutions flat sheet membrane technology in a MBR pilot-plant to achieve a satisfying fouling control and also a reduction in the required aeration. Two vertically stacked modules were tested at pilot-scale at Anjou Recherche under typical biological operating conditions (mixed liquor suspended solids concentration (MLSS) = 10 g/l; sludge retention time (SRT) = 28 days; food to microorganism ratio (F/M) = 0.12 kg COD/kg MLSS/d). The use of a double-deck and of specific backwashes for this membrane technology enabled to achieve satisfying membrane performances for a net flux of 25 L h-1m-2, 20°C at a low specific aeration demand per membrane surface (SADm = 0.2Nm3 h-1m-2) which corresponds to a specific aeration demand per permeate volume unit (SADp) of 8Nm3 air/m3 permeate, which is lower than reported for many commercial membrane systems. The mixed liquor characteristics (foaming, MLSS concentration) appeared to influence the fouling behaviour of the membranes but no correlation was found with the fouling rate. However, with the new operating conditions, the system is robust and can cope with fouling resulting from biological stress and daily peak flows for MLSS concentrations in the membrane tank up to 18 g/l.

Four international projects subsidised by the European Commission should push forward the development and application of membrane bioreactor processes in the municipal wastewater sector.