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The deammonification process in moving bed biofilm reactors

Publicerad 2016-05-18

Dissertation

Time: Wed 2016-05-18 09.30

Location: Sal F3, Lindstedtsvägen 26, KTH

Subject area: Land and Water Resources Engineering

Doctoral student: Jingjing Yang

Opponent: Prof. Dr. Susanne Lackner. Technische Universität Darmstadt, Tyskland

Supervisor: Prof. Elzbieta Plaza

ABSTRACT

Deammonification process appears to be a good alternative to treat reject water. In this thesis, control strategies were studied at pilot scale in order to optimise the deammonification process operated in a Moving Bed Biofilm Reactor (MBBR) for reject water treatment. The processes were monitored by microbial activity tests, Specific Anammox Activity (SAA), Oxygen Uptake Rate (OUR), and Nitrate Uptake Rate (NUR) tests, in order to measure the anammox, ammonium/nitrite oxidizers and denitrifiers activity. Aeration and redox as control parameters were tested. The results showed that intermittent aeration, with 15min non-aerated period in a one hour cycle, could reduce the aeration time without loss of process efficiency. A redox value of pE=0 gave the best operational condition even if there were different nitrogen loads applied in the system. Pilot scale deammonification MBBR was tested towards to mainstream conditions. The reactor was run at different temperatures (25-19°C) to test the process stability and it was seen that the process started to become unstable when the temperature was at 19°C. Moreover, the combined treatment line, Upflow Anaerobic Sludge Blanket (UASB) reactor and MBBR with deammonification process, was established with the aim of being applied in mainstream treatment. The study results indicated that when the influent of the deammonification process shifted from reject water to UASB effluent (NH4+-N=100 mg/l), the process began to show unstable performance. N2O was measured and compared in the deammonification process treating reject water in this study. Between 0.4% and 2 % of the nitrogen load was converted to N2O in pilot and full scale studies. The results indicated that there was no significant emission difference when the process was performed with continuous or intermittent aeration; the production and consumption of N2O was dependent on the nitrogen loads and DO concentration applied in the system.

The research was conducted at the Division of Land and Water Resources, KTH . The thesis is available here .