N2O production in a single stage nitritation/anammox MBBR process

3.2 Reactor medium
The reactor was fed with a synthetic wastewater with an inorganic nitrogen
concentration corresponding to 314 mg/l. The synthetic wastewater contained all vital
nutrients the microorganisms needed, including trace elements, see Table 4 and Table 5
for composition of reactor medium and trace element stock solution.
Table 4. Composition of synthetic medium fed to the MBBR.
Component
NaHCO3 2.6
NH4Cl 1.2
Concentration g/l
KH2PO4 5.67∙10 -3
Peptone 3.0∙10 -3
trace element solution 1 0.40 ml/l
trace element solution 2 0.40 ml/l
Table 5. Composition of trace element stock solution.
Component
Stock solution 1
MgSO4∙7H2O 4.80
MnCl2∙2H2O 1.60
CoCl2∙6H2O 0.48
NiCl2∙6H2O 0.24
ZnCl2 0.26
CuSO4∙5H2O 0.10
FeCl2∙4H2O 1.44
BH3O3 0.104
Na2MoO4∙2H2O 0.440
Na2SeO3∙5H2O 0.288
Na3WO3∙2H2O 0.280
Stock solution 2
CaCl2∙2H2O 5.80
Concentration g/l
Initially the medium was mixed in a 600 litres container situated in the workshop and
pumped to the second floor where the laboratory is situated. Microbial growth in the
tank and pump tubing were causing large differences in composition of the influent
medium to the reactor. Due to these problems the medium was mixed in a 100 litres
tank kept in the laboratory in close connection to the reactor set up.
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