Influence of dissolved oxygen concentration on deammonification process performance

• Partial nitrification together with Anammox process (deammonification) is a new method fornitrogen removal from wastewater, which nowadays is widely studied in Europe. Compared toconventional nitrification/denitrification, this method saves 100% of the required organic carbonsource and over 60% of the required oxygen. This leads to a reduction of operational costs of 90%.The deammonification process was successfully tested on a laboratory-scale pilot plant at RoyalInstitute of Technology (KTH) in Sweden for over 2 years. Two reactors of pilot plant were filledwith Kaldnes rings as a biofilm carrier and supplied with a supernatant from dewatering of thedigested sludge at the Bromma Wastewater Treatment Plant (WWTP). For the stable and efficientprocess performance a suitable values of many parameters as dissolved oxygen, pH, temperature,NO2-N and NO3-N concentration should be assured. This article presents an evaluation of theinfluence of dissolved oxygen (DO) on the deammonification process efficiency. Analysis of eightmonths operation of pilot plant proved that high N-removal efficiency of second reactor (Anammox)is assured by proper NO2-N/NH4-N ratio in the effluent from the first reactor depending on DOconcentration. To estimate influence of DO concentration on reaction rates during the Anammoxprocess several batch tests were performed. The highest ammonium and nitrite removal rates wereobtained for DO concentration amounted to 0.2÷0.4 mg O2/l. This is in agreement with theobservations from laboratory-scale pilot plant, when the best results for Anammox processefficiency took place under similar oxygen conditions. A linear correlation between inorganicnitrogen removal and conductivity in the batch tests proved that conductivity could be a suitableparameter for a nitrogen removal process control.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Samhällsbyggnadsteknik -- Vattenteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Civil Engineering -- Water Engineering (hsv//eng)

Nyckelord

ammonium removal rate

Anammox

batch test

conductivity

deammonification

dissolved oxygen

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