Influence of temperature and pH on the kinetics of the Sharon nitritation process

Abstract

The SHARON (Single reactor High activity Ammonia Removal Over Nitrite) process is an innovative process that improves the sustainability of wastewater treatment, especially when combined with an Anammox process. It aims at ammonium oxidation to nitrite only, while preventing further nitrate formation. In order to optimize this process by means of modelling and simulation, parameters of the biological processes have to be assessed. Batch tests with SHARON sludge clearly showed that ammonia rather than ammonium is the actual substrate and nitrous acid rather than nitrite is the actual inhibitor of the ammonium oxidation in the SHARON process. From these batch tests the ammonia affinity constant, the nitrous acid inhibition constant and the oxygen affinity constant were determined to be 0.75 mgNH 3 -N L −1 , 2.04 mgHNO 2 -N L −1 and 0.94 mgO 2 L −1 . The influence of pH and temperature on the oxygen uptake rate of SHARON biomass was determined, indicating the existence of a pH interval between 6.5 and 8 and a temperature interval from 35 to 45 • C where the biomass activity is maximal. The kinetic parameters of the SHARON process were determined based on batch experiments. These parameters can now be implemented in a simulation model for further optimization of the SHARON process. LIST OF SYMBOLSb OUR (oxygen uptake rate) temperature dependency parameter c OUR temperature dependency parameter DO dissolved oxygen concentration [mgO 2 L −1 ] K e,NH 4 + acidity constant of the ammonium/ammonia equilibrium K e,HNO 2 acidity constant of the nitrite/nitrous acid equilibrium K NH I,HNO 2 inhibition constant for nitrous acid of ammonium oxidizers [mgHNO 2 -N L −1 ] K NH NH 3 max maximum growth rate of ammonium oxidizers [d −1 ] θ Arrhenius constant

Effects of cyanobacterial-driven pH increases on sediment nutrient fluxes and coupled nitrification-denitrification in a shallow fresh water estuary

“…Moreover, high pH combined with abrupt changes in NH 3 (from zero to >550 µmol l −1 ) may result in the physiological inhibition of nitrification. In laboratory observations and modeling, both high pH and NH 3 have negative effects on nitrifying bacteria, ammonium-oxidizing bacteria (AOB, Nitrosomonas) and nitrite-oxidizing bacteria (NOB, Nitrobac- ter) (Van Hulle et al, 2007). Elevation of pH above 9 could inhibit enzyme activity of AOB and NOB since the optimal pH range is 6-8.5 for AOB and 5.5-8 for NOB (Van Hulle et al, 2007;Park et al, 2010).…”

“…In laboratory observations and modeling, both high pH and NH 3 have negative effects on nitrifying bacteria, ammonium-oxidizing bacteria (AOB, Nitrosomonas) and nitrite-oxidizing bacteria (NOB, Nitrobac- ter) (Van Hulle et al, 2007). Elevation of pH above 9 could inhibit enzyme activity of AOB and NOB since the optimal pH range is 6-8.5 for AOB and 5.5-8 for NOB (Van Hulle et al, 2007;Park et al, 2010). Even though nitrifying bacteria might survive out of the optimal pH range, they would pay an energy cost to maintain their cytoplasmic pH (Wood, 1988).…”

Analysis of ammonia-oxidizing bacteria dominating in lab-scale bioreactors with high ammonium bicarbonate loading

“…Partial nitrification at high substrate loading has been the subject for many studies (Hellinga et al 1998;van Dongen et al 2001;Sinha and Annachhatre 2004;Ganigué et al 2007;van Hulle et al 2007), but so far, only a few attempted to look behind the kinetic parameters and the general characterization of the ammonium-oxidizing biomass with molecular or microbiological methods (Logemann et al 1998;Tan et al 2008). This is remarkable since the microscopic observation of the Nitrosomonas population in such systems looks clearly unusual, i.e.…”

A Model for the Simulation of the SHARON Process: pH as a Key Factor

“…Literature on activated sludge models ASMx (Henze et al, 1987;Henze et al, 1995a) and on specific models of the SHARON process such as those of Hellinga et al (1999), Volcke et al (2002) and Van Hulle et al (2004) were taken as the bases for the development of a new model for the simulation of the treatment of wastewaters with high nitrogen concentration, containing organic matter and phosphorus. Sixteen components were established (Table 1), which were involved in ten different biochemical and physical processes with the corresponding reaction rates ρ j listed in Table 2.…”