Start-up and inhibition analysis of the Anammox process seeded with anaerobic granular sludge

Abstract

The longer start-up period of the Anammox process is due to the very low cellular yield and growth rates of Anammox bacteria. Nitrite inhibition is considered to be the key factor in the instability of the Anammox process during the operation. However, little attention was paid to the inhibitory effect of pH and free ammonia. This paper presents start-up and inhibition analysis of an Anammox biofilm reactor seeded with anaerobic granular sludge. Results showed that the start-up period could be divided into the sludge lysis phase, lag phase, propagation phase, stationary phase and inhibition phase. Optimization control could be implemented correspondingly to accelerate the start-up of Anammox bioreactors. Effluent pH increased to 8.7-9.1 when the nitrogen removal rate was higher than 1,200 mg l(-1) day(-1). The free ammonia concentration was accompanied with a higher level of 64-73 mg l(-1). Inhibitory effects of high pH and free ammonia on Anammox bacteria contributed to the destabilization of the Anammox bioreactor during the first 125 days with influent KHCO(3) of 0.5 g l(-1). Increasing the suffering capacity in the inlet by dosing 1.25 g KHCO(3) l(-1) effectively reduced the pH variation, and the nitrogen removal performance of the reactor was further developed.

Enhancing Nitrogen Removal Performance in a Bioreactor Using Immobilized Anaerobic Ammonium Oxidation Sludge by Polyvinyl Alcohol-Sodium Alginate (PVA-SA)

“…Just around 10 days were taken to start up anammox successfully in R1, indicating that the anammox bacteria entrapped in the PVA-SA gel beads could be activated rapidly and the anammox process could be triggered rapidly using whole cell entrapment of anammox biomass. In contrast, the start-up of the anammox reactor using common activated sludge as seed usually requires a much longer period of around 90-120 d due to the slow growth rate and low biomass yield as well as stringent metabolic conditions of anammox bacteria [4,17,[20][21], which is thus a large obstacle for its application. The removal efficiencies of nitrite and ammonium decreased sharply by half when the HRT was reduced from 24 h to 12 h on day 26.…”

“…3b). Acidity can be consumed in anammox reaction, with the pH level in the reactor elevated [4,21]. The effluent pH value increased gradually after the experiment began, and was clearly higher than that of the influent -especially in operational phase 2, indicating intense anammox activity in the reactor.…”

Comprehensive study for Anammox process via multistage anaerobic baffled reactors

“…This removal could be attributed to the prevalence of denitrification process. The organic released from cell lysis can be used as an electron donor by heterotrophic denitrifying bacterial communities for denitrification process [24]. The sludge lysis phase lasted for only one week.…”

“…Based on the above results, the MABR reactor exhibited excellent performance for the start-up of Anammox process within a period of 35 days using activated sludge (mixed culture bacteria, 41.6 g MLSS/L and 19.1 g MLVSS/L) as inoculum. Tang, Zheng, et al [24] demonstrated that an Anammox reactor was successfully started up on day 73. Tsushima et al observed Anammox reactions after a 55-day the start-up process [26].…”

State of The Art Strategies for Successful ANAMMOX Startup and Development: A Review

“…Application of ANAMMOX process or coupling partial nitrification with ANAMMOX seemed promising. It could result in 60% savings in O 2 generation, 100% savings of external carbon source addition, less sludge production and CO 2 emission, with a total reduction in treatment cost by 90% [14,[24][25][26].…”