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In this paper, a revised version of the Morris approach, which includes an improved sampling strategy based on trajectory design, has been adapted to the screening of the most influential parameters of a fuzzy controller applied to WWTPs. Due to the high number of parameters, a systematic approach has been proposed to apply this improved sampling strategy with low computational demand. In order to find out the proper repetition number of elementary effects of each input factor on model output (EE i) calculations, an iterative and automatic procedure has been applied. The results show that the sampling strategy has a significant effect on the parameter significance ranking and that random sampling could lead to a non-proper coverage of the parameter space.

Nutrient recovery technologies are rapidly expanding due to the need for the appropriate recycling of key elements from waste resources in order to move towards a truly sustainable modern society based on the Circular Economy.Nutrient recycling is a promising strategy for reducing the depletion of non-renewable resources and the environmental impact linked to their extraction and manufacture. However, nutrient recovery technologies are not yet fully mature, as further research is needed to optimize process efficiency and enhance their commercial applicability. This paper reviews state-of-the-art of nutrient recovery, focusing on frontier technological advances and economic and environmental innovation perspectives. The potentials and limitations of different technologies are discussed, covering systems based on membranes, photosynthesis, crystallization and other physical and biological nutrient recovery systems (e.g. incineration, composting, stripping and absorption and enhanced biological phosphorus recovery).

ElsevierRobles Martínez, Á.; Ruano García, MV.; Seco Torrecillas, A.; Ferrer, J. (2014 AbstractThe objective of this study was to evaluate the operating cost of an anaerobic membrane bioreactor (AnMBR) treating sulphate-rich urban wastewater (UWW) at ambient temperature (ranging from 17 to 33ºC). To this aim, energy consumption, methane production, and sludge handling and recycling to land were evaluated. The results revealed that optimising specific gas demand with respect to permeate volume (SGDP) and sludge retention time (for given ambient temperature conditions) is essential to maximise energy savings (minimum energy demand:0.07 kWh·m -3 ). Moreover, low/moderate sludge productions were obtained (minimum value:0.16 kg TSS·kg -1 CODREMOVED), which further enhanced the overall operating cost of the plant (minimum value: €0.011 per m 3 of treated water). The sulphate content in the influent UWW significantly affected the final production of methane and thereby the overall operating cost.Indeed, the evaluated AnMBR system presented energy surplus potential when treating lowsulphate UWW. 2 KeywordsEnergy consumption; industrial-scale hollow-fibre membranes; operating cost; anaerobic membrane bioreactor (AnMBR); sulphate-rich urban wastewater.

Elsevier Pretel, R.; Robles Martínez, Á.; Ruano García, MV.; Seco Torrecillas, A.;Ferrer, J. (2013) AbstractThe objective of this study was to assess the environmental impact of a submerged anaerobic MBR (SAnMBR) system in the treatment of urban wastewater at different temperatures: ambient temperature (20 and 33 ºC), and a controlled temperature (33 ºC). To this end, an overall energy balance (OEB) and life cycle assessment (LCA), both based on real process data, were carried out. Four factors were considered in this study: (1) energy consumption during wastewater treatment; (2) energy recovered from biogas capture; (3) potential recovery of nutrients from the final effluent; and (4) sludge disposal. The OEB and LCA showed SAnMBR to be a promising technology for treating urban wastewater at ambient temperature (OEB = 0.19 kWh·m -3 ). LCA results reinforce the importance of maximising the recovery of nutrients (environmental impact in eutrophication can be reduced up to 45%) and dissolved methane (positive environmental impact can be obtained) from SAnMBR effluent. KeywordsEnergy balance; global warming potential; life cycle assessment; submerged anaerobic MBR (SAnMBR); environmental impact. 2