Novel microbial-electrochemical filter with a computer-feedback pH control strategy for upgrading biogas into biomethane

The combined SHARON-Anammox process for treating wastewater streams with high ammonia concentration is discussed. Partial nitritation in the SHARON reactor should be performed to such an extent that an Anammox-optimal nitrite:ammonium ratio is generated. The SHARON process is typically applied to sludge digestion rejection water in order to relieve the ammonium load recycled to the main plant.A simulation study for realistic influent conditions on a SHARON reactor with a fixed volume and operated with constant air flow rate reveals that the actual nitrite:ammonium ratio might deviate significantly from the ideal ratio and might endanger operation of the subsequent Anammox reactor. It is further examined how the nitrite:ammonium ratio might be optimized. A cascade pH control strategy and a cascade O2 control strategy are tested. Simulation results are presented and the performance of the different strategies is assessed and quantified in an economic way by means of an operating cost index. Best results are obtained by means of cascade feedback control of the SHARON effluent nitrite:ammonium ratio through setting an O2-set-point that is tracked by adjusting the air flow rate.

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Influence of the pH control strategy and reactor volume on batch fermentative hydrogen production from the organic fraction of municipal solid waste

Waste Management & Research ◽

10.1177/0734242x19826371 ◽

2019 ◽

Vol 37 (5) ◽

pp. 478-485 ◽

Cited By ~ 7

Author(s):

Francesco Baldi ◽

Renato Iannelli ◽

Isabella Pecorini ◽

Alessandra Polettini ◽

Raffaella Pomi ◽

...

Keyword(s):

Hydrogen Production ◽

Municipal Solid Waste ◽

Solid Waste ◽

Control Strategy ◽

Ph Control ◽

Organic Fraction ◽

Experimental Conditions ◽

Reactor Volume ◽

Fermentative Hydrogen Production ◽

Fermentative Hydrogen

Three different experimental sets of runs involving batch fermentation assays were performed to evaluate the influence of the experimental conditions on biological hydrogen production from the source-separated organic fraction of municipal solid waste collected through a door-to-door system. The fermentation process was operated with and without automatic pH control, at a pH of 5.5 and 6.5, food-to-microorganism ratios of 1/3 and 1/1 (wet weight basis) and with different working volumes (0.5 and 3 L). The experimental results showed that the pH control strategy and the reactor volume did not affect the final hydrogen production yield but played an important role in determining the time evolution of the process. Indeed, although the different experimental conditions tested yielded comparable hydrogen productions (with maximum average values ranging from 68.5 to 88.5 NLH2 (kgTVSOF)−1), the automatic pH control strategy improved the process from the kinetic viewpoint resulting in a t95 reduction from an average of 34.9 h without automatic pH control to an average of 19.5 h.

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