LIFE-BRAINYMEM: Optimisation of membrane bioreactor technology to reduce costs and environmental impact

The LIFE-BRAINYMEM project is supported and funded by the European Commission within the framework of the LIFE programme. The objective of the project is to reduce energy consumption and minimise environmental impact at wastewater treatment plants. Acciona Agua will implement advanced control systems at WWTPs to reduce energy consumption, greenhouse gas emissions and the concentration of recalcitrant contaminants in wastewater. The project will be replicable at all wastewater treatment plants.

The membrane bioreactor is a compact water reclamation solution. It combines activated sludge technology with membrane filtration. With MBR technology, the secondary settler is replaced by a membrane, which directly filters the activated sludge. In this way, an effluent free of pathogens and suspended solids is obtained. It is, therefore, a technology of great interest in terms of water reuse, given that the quality of the water obtained is compliant with standards for most of the uses set out in the Reuse Act (RD1620/2007).

However, the energy consumption associated with this technology is higher than that of simpler water reclamation technologies (activated sludge followed by rotating discs, sand filters, etc.) and this limits its implementation. This is mainly due to the fact that in addition to the energy required for biological aeration, mixing and pumping, membrane bioreactors also require aeration of membranes to control fouling.
Energy consumption in wastewater treatment systems does not just imply higher operating costs.

It also has adverse environmental consequences associated with the use of fossil fuels needed to generate the electricity to power the plants and also with the direct emission of greenhouse gases (NOx, CO2 and CH4) during the biological processes. Apart from the environmental impact associated with energy consumption, both conventional activated sludge and MBR systems discharge a number of contaminants, known as emerging pollutants, into the natural environment. Emerging pollutants are not effectively removed by conventional water treatment systems and they can have a negative impact on aquatic fauna. These compounds vary in nature and include pharmaceuticals, personal care products and nanomaterials.

All these environmental impacts are being addressed and minimised in the LIFE-BRAINYMEM project, through the implementation of an advanced control system. The project commenced in July 2014 and is scheduled to finish in June 2017. It forms part of the 2013 call for projects of the European Commission LIFE programme, which provides funding for projects with clear environmental objectives. The general objective of this programme for the period 2004-2020 is to contribute to sustainable development and achieving the goals and targets set out in the Europe 2020 Strategy and other relevant EU strategies and plans in the area of the environment and climate.

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Teresa de la Torre, Engineer at the Department of R&D&i, ACCIONA Agua

Article published in: FuturENVIRO September 2015