Enhancing biological nitrogen and phosphorus removal performance in aerobic granular sludge sequencing batch reactors by activated carbon particles

In this paper, we describe the results of research aimed to evaluate the possibility of using a neural network (NN) model for predicting biological nitrogen and phosphorus removal processes in activated sludge, utilising oxidation reduction potential (ORP) and pH as NN inputs. Based on N and P concentrations predictions obtained via the NN, a strategy for controlling sequencing batch reactors (SBRs) phases duration, optimising pollutants removal and saving energy, is proposed. The NN model allowed us to reproduce the concentration trends (change in slope, or process end), with satisfactory accuracy. The NN results were generally in good agreement with the experimental data. These results demonstrated that NN models can be used as “soft on-line sensors” for controlling biological processes in SBRs. By monitoring ORP and pH, it is possible to recognise the N and P concentrations during different SBRs phases and, consequently, to identify the end of the biological nutrient removal processes. This information can then be used to design control systems.

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The Nitrogen and Phosphorus Removal and Sludge Yield Comparative Study under Anaerobic/Aerobic and Anaerobic/Anoxic Conditions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.610-613.2068 ◽

2012 ◽

Vol 610-613 ◽

pp. 2068-2073

Author(s):

Ya Jing Li ◽

Li Ping Sun ◽

Min Ji

Keyword(s):

Phosphorus Removal ◽

Aerobic Condition ◽

Anoxic Condition ◽

Batch Reactors ◽

Sequencing Batch Reactors ◽

Nitrogen And Phosphorus ◽

Nitrogen And Phosphorus Removal ◽

Anoxic Conditions ◽

Significant Difference ◽

Aerobic And Anaerobic

The nitrogen and phosphorus removal efficiency and effect of different electron acceptors (O2 and NO3-) on the sludge yield were studied through experiments in two SBRs (Sequencing Batch Reactors ) in this paper. The results showed that two systems both had good decontamination effect; the theory value of sludge yield (It was 0.435gVSS/gCOD and 0.402gVSS/gCOD for anaerobic /aerobic and anaerobic/anoxic condition, respectively) was higher than the actual value (It was 0.335gVSS/gCOD and 0.321g VSS/gCOD for anaerobic/aerobic and anaerobic/anoxic condition, respectively); There was no significant difference for the sludge yield under anaerobic/aerobic and anaerobic/anoxic conditions, because the endogenesis respiration of sludge under anaerobic/aerobic condition was stronger consequently more sludge being attenuated (Attenuation coefficient was 0.0081 and 0.0026 for anaerobic/aerobic and anaerobic/anoxic condition, respectively).

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Impacts of variable pH on stability and nutrient removal efficiency of aerobic granular sludge

Water Science & Technology ◽

10.2166/wst.2015.460 ◽

2015 ◽

Vol 73 (1) ◽

pp. 60-68 ◽

Cited By ~ 4

Author(s):

Monireh Lashkarizadeh ◽

Giulio Munz ◽

Jan A. Oleszkiewicz

Keyword(s):

Removal Efficiency ◽

Nutrient Removal ◽

Phosphorus Removal ◽

Granular Sludge ◽

Aerobic Granular Sludge ◽

Acidic Ph ◽

Alkaline Ph ◽

Nitrogen And Phosphorus ◽

Nitrogen And Phosphorus Removal ◽

Ph Shock

The impact of pH variation on aerobic granular sludge stability and performance was investigated. A 9-day alkaline (pH = 9) and acidic (pH = 6) pH shocks were imposed on mature granules with simultaneous chemical oxygen demand (COD), nitrogen and phosphorus removal. The imposed alkaline pH shock (pH 9) reduced nitrogen and phosphorus removal efficiency from 88% and 98% to 66% and 50%, respectively, with no further recovery. However, acidic pH shock (pH 6) did not have a major impact on nutrient removal and the removal efficiencies recovered to their initial values after 3 days of operation under the new pH condition. Operating the reactors under alkaline pH induced granules breakage and resulted in an increased solids concentration in the effluent and a significant decrease in the size of the bio-particles, while acidic pH did not have significant impacts on granules stability. Changes in chemical structure and composition of extracellular polymeric substances (EPS) matrix were suggested as the main factors inducing granules instability under high pH.

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