A one-stage system with partial nitritation and Anammox processes in the moving-bed biofilm reactor

Abstract

The ability of bacterial cultures to create biofilm brings a possibility to enhance biological wastewater treatment efficiency. Moreover, the ability of Anammox and Nitrosomonas species to grow within the same biofilm layer enabled a one-stage system for nitrogen removal to be designed. Such a system, with Kaldnes rings as carriers for biofilm growth, was tested in a technical pilot plant scale (2.1 m(3)) at the Himmerfjärden Waste Water Treatment Plant (WWTP) in the Stockholm region. The system was directly supplied with supernatant originating from dewatering of digested sludge containing high ammonium concentrations. Nearly 1-year of operational data showed that during the partial nitritation/Anammox process, alkalinity was utilised parallel to ammonium removal. The process resulted in a small pH drop, and its relationship with conductivity was found. The nitrogen removal rate for the whole period oscillated around 1.5g N m(-2)d(-1) with a maximum value equal to 1.9 g N m(-2)d(-1). Parallel to the pilot plant experiment, a series of batch tests were run to investigate the influence on removal rates of different dissolved oxygen conditions and addition of nitrite. The highest nitrogen removal rate (5.2g N m(-2)2d(-1)) in batch tests was obtained when the Anammox process was stimulated by the addition of nitrite. In the simultaneous partial nitritation and Anammox process, the partial nitritation was the rate-limiting step.

Start-up and stabilization of an Anammox process from a non-acclimatized sludge in CSTR

“…Similar observations were also reported by Chamchoi and Nitisoravut [12] and Strous et al [27]. However in contrast to this, various workers have reported an increase in effluent pH during Anammox activity [19,31,32]. As per the stoichiometry in Eq.…”

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

“…The phenomenon of a significant increase in effluent pH for Anammox bioreactors was also reported by Liu et al [22]. Szatkowska et al [23] proposed that the Anammox process can increase the pH value to some extent due to cellular synthesis. However, Strous et al [6] reported that the pH variation in one cycle of a SBR was not large.…”

Reject water treatment by improvement of whole cell anammox entrapment using polyvinyl alcohol/alginate gel

“…The optimal pH range of anammox bacteria is within 7.7-8.2 (Strous et al 1997). Various researchers have reported an increase in effluent pH along with increase in anammox activity (Tang et al 2009;Liu et al 2008;Szatkowska et al 2007). On the other hand, Strous et al (1997) showed that the specific anammox activity at pH of 9 was only 1/5 of that at pH of 8.…”