Nitrogen removal in MBBRs The effect of low temperatures
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Infrastructure and environmental engineering (MPIEE), MSc
Publicerad
2023
Författare
GÓMEZ MONSALVE, MANUELA
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Nitrogen removal from wastewater in regions with low temperatures and long snow-melting
periods represents a challenge for the performance of biological treatment processes and
information on the efficiency of nitrification and denitrification processes under these conditions is
lacking. This study evaluated the implementation of the MBBR treatment process in a pilot plant
for wastewater treatment at Fillan WWTP in Sundsvall, Sweden, between January and May 2023.
Each line had 6 different reactors, referred to as zones, including nitrification and denitrification
(pre- and post-). They were used to evaluate the nitrogen removal efficiency during continuous
plant operation. Furthermore, batch activity tests were performed to follow up the biomass activities
depending on temperature changes, and laboratory scale activity tests were used to analyze the
influence of DO on the denitrification process. From the results, it was concluded that high nitrogen
removal efficiencies can be achieved at low temperatures. Nevertheless, the denitrification process
was highly affected during the snowmelt period, especially in April, when the nitrogen removal
efficiency dropped below 50% in both lines. From the batch activity tests, the Arrhenius
temperature dependence coefficient was calculated for the denitrification and nitrification
processes. Although θ values were close to the values reported in the literature, no clear difference
was observed between them. From the laboratory-scale activity test, the negative effect of high DO
concentrations was evidenced not only in the denitrification process but also in NO2-N production,
which is also related to the excess available carbon source.
Beskrivning
Ämne/nyckelord
wastewater, low temperature, nitrogen removal, MBBR.