Abstract
A one-stage partial nitritation/anammox (PN/A) process with intermittent aeration is possible under sidestream conditions, but implementation in a mainstream is a challenge due to increased Carbon/Nitrogen (C/N) ratios in domestic wastewater. This study investigated the effect of C/N ratios on process efficiency and the effect of narrowing non-aeration time on process improvement at high chemical oxygen demand (COD) load. An increase in TN removal efficiency was achieved in both series with gradual change of C/N ratio from 1 to 3, from 65.1% to 83.4% and 63.5% to 78% in 1st and 2nd series, respectively. However, at the same time, the ammonium utilization rate (AUR) value decreased with the increase in C/N ratio. At a high COD (C/N = 3) concentration, the process broke down and regained productivity after narrowing the non-aeration time in both series. Shifts in the system performance were also connected to adaptive changes in microbial community revealed by data obtained from 16S rRNA NGS (next-generation sequencing), which showed intensive growth of the bacteria with dominant heterotrophic metabolism and the decreasing ratio of autotrophic bacteria. The study shows that deammonification is applicable to the mainstream provided that the C/N ratio and the aeration/non-aeration time are optimized.
Highlights
IntroductionThe most commonly applied method of biological ammonia treatment to date is a conventional method involving the combination of nitrification and denitrification processes
Ammonium is the main form of nitrogen (N) presented in the municipal wastewater
The single-stage partial nitrification/anammox/denitritation process was developed to investigate the effect of the C/N ratio on process efficiency
Summary
The most commonly applied method of biological ammonia treatment to date is a conventional method involving the combination of nitrification and denitrification processes. The conventional process is considered to be effective, it has high operational costs due to high oxygen demand and commonly requires the addition of an external carbon source to support the denitrification step [1,2]. One of the most perspective technologies seems to be partial nitritation combined with the anammox process (PN/A), mainly due to theoretically about 60% lower oxygen requirement compared to the conventional process [3]. Demand for carbon sources could be reduced up to 100%, excessive sludge production by about 90% and greenhouse gas emissions limitation is possible to gain [4]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
