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Research activities carried out at ENEA during the last few years allowed the development of a Sequencing Batch Reactor (SBR) that is able to remove biologically organic waste, nitrogen and phosphorus and that was shown to be particularly suited to obtaining low effluent nutrient concentrations even starting from concentrated wastes. Research on optimisation of time cycles and on process modelling, allowed an advanced comprehension of reactor behaviour and the development of a process able to obtain more than 98% removal of nitrogen, phosphorus and COD, and therefore almost capable of matching effluent standards with a sole biological process. On the basis of laboratory results and process modelling, a full scale SBR plant has been designed and realised. This plant, in ten months of operation, is achieving even better results compared to the laboratory ones.

Research activities carried out at ENEA during the last few years allowed development of a Sequencing Batch Reactor (SBR) that is able to remove biologically organic waste, nitrogen and phosphorus and that showed to be particularly suited to obtain low effluent nutrient concentrations even starting from concentrated wastes. This plant, in more than one year of operation, is quite steadily obtaining more than 98% removal of nitrogen, phosphorus and COD. On the basis of the experimental results, a simulation model has been built and calibrated. The model showed the potential to be used for forecasting the behaviour of the process, being able to reproduce a process imbalance that followed the tentative reduction of aeration time.

An Anaerobic/Anoxic Sequencing Batch Reactor (A/A SBR) with separated batch biofilm nitrification was tested for nutrient removal against a five step Anaerobic-anoxic/Oxic SBR (A/O SBR). Piggery wastewater, particularly challenging for its low COD/N ratio, was used as feed. After feeding, the A/A SBR ran under anaerobic conditions for organic carbon sequestering and phosphorus removal. A settling phase was allowed to separate an ammonia-rich supernatant to be nitrified in a external biofilm reactor. The nitrified effluent returned to the A/A SBR where nitrates were removed, being used as final electron acceptors for luxury P-uptake and organic carbon oxidation. A/A SBR showed very good N and P removal capacities with excellent sludge settling properties. On the other hand, organic carbon removal efficiency with nitrate was lower than with oxygen. Batch biofilm nitrification was very effective, with very high nitrification rates. Presence of poly-P bacteria in the A/A SBR sludge was assessed through microscopic observation and from the high cellular poly-phosphate content.