In MBBR systems (moving bed biofilm reactors), small and lightweight plastic carriers
are used to support the attachment and growth of active biomass during the treatment of
municipal wastewater. In this thesis, 3D-printed biomass carriers made from Fun To Do
Nano Clear resin were used. The aim was to evaluate the stability of 3D-printed plastic
biomass carriers in municipal wastewater. In the first part, two experiments were
conducted, differing in the duration of exposure of the 3D-printed carriers to municipal
wastewater and in the ratio between the volume of biomass carriers and the reactor
volume. In the second part, samples obtained during the leaching experiment were used
to perform a toxicity test with the aquatic plant Lemna minor (duckweed), in which we
determined the toxic effects of the carrier leachates on growth and the production of
photosynthetic pigments in the fronds of duckweed. The results showed that at higher
reactor filling ratios, organic compounds were leached from the carriers into the
wastewater. No phosphorus leaching was observed. The leachates exhibited a strong toxic
effect on growth rate, root development, and the inhibition of photosynthetic pigment
(chlorophyll) synthesis in the fronds of duckweed.
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