Fast start-up and controlled operation during a long-term period of a high-rate partial nitrification activated sludge system

Abstract

Partial nitrification of a high-strength ammonium wastewater (1150 +/- 150 mg N-NH4(+) L(-1)), mimicking reject water, was achieved in an activated sludge pilot plant with a configuration of three continuous reactors in series plus a settler. Stable and robust partial nitrification was maintained during 800 days of operation at 30 degrees C with a sludge retention time (SRT) of 8 +/- 3 days. A high volumetric ammonium oxidation rate (2.0 g N L(-1) d(-1)) was obtained with a [N-NO2-]/[N-NO(x)-] ratio of 1, i.e. full nitritation. The start-up of the partial nitrification system was quickly and successfully performed with an on-line control system using municipal wastewater treatment plant (WWTP) sludge as inoculum. An ammonia-oxidizing bacteria (AOB) fraction of 72 +/- 10% was obtained after only 30 days of start-up. The applied SRT of 7-10 days with the combination of free ammonia inhibition and dissolved oxygen limitation provided the selective washout of nitrite-oxidizing bacteria (NOB) and an active nitrifying population with high ammonium oxidizing rates.

High-throughput nitritation of reject water with a novel ammonium control loop: Stable effluent generation for anammox or heterotrophic denitritation

“…This system was controlled to maintain complete nitritation using the original OUR control loop detailed in section 2.2. Detailed information about this system can be found in Torà et al [16]. carried out using at the same time a Cy3-labeled specific probe and Cy5-labeled EUBmix probe (general probe).…”

“…This control loop is an evolvement of a previously designed control loop based on oxygen uptake rate (OUR) measurements [15][16][17]. …”

Biological treatment of nitrogen-rich refinery wastewater by partial nitritation (SHARON) process

“…Anaerobic digester effluents, landfill leachate, effluents from livestock farming and many industrial wastewaters are characterized by high ammonium concentrations [3][4][5][6][7][8]; conventional biological nitrogen removal processes based on nitrification-denitrification are not suitable for the treatment of such ammonium-rich streams, due to the toxic effects even on those microorganisms able to degrade it [6]. Moreover, the heterotrophic denitrification process would require the addition of an external carbon source, thus leading to an increase of operating costs.…”

Start-up analysis of partial nitrification process in SBR reactors for different initial conditions

“…Such actions have been obtained for the inhibition of NOB bacteria. In the articles [15,16,17,18,19,20,8,21,22] which were focused only on the conditions, which allow to run the process, but composition of effluent was not controlled, which could be used in the two-stage deamonification. Ratio N-NO 2 /N-NH 4 was significantly superior to the values of the optimum deamonification process.…”