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The influence of Aspidisca cicada on nitrifying bacteria and the morphology of flocs in activated sludge
Author(s) -
Sobczyk Mateusz,
PajdakStós Agnieszka,
Fiałkowska Edyta,
Fyda Janusz
Publication year - 2020
Publication title -
water and environment journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 37
eISSN - 1747-6593
pISSN - 1747-6585
DOI - 10.1111/wej.12571
Subject(s) - nitrifying bacteria , nitrification , bioreactor , effluent , bacteria , activated sludge , flocculation , biology , segmented filamentous bacteria , pulp and paper industry , microbiology and biotechnology , chemistry , environmental engineering , sewage treatment , botany , environmental science , nitrogen , genetics , organic chemistry , engineering
Crawling ciliates play important role in activated sludge as they improve flocculation and remove loosely attached bacteria from the flocs. However, there are discrepancies concerning their influence on nitrifying bacteria and nitrification efficiency. We conducted a five weeks experiment in six bioreactors simulating the Sequencing Batch Reactor (SBR) process using activated sludge from a plant in start‐up phase. Half of bioreactors were inoculated with dense Aspidisca cicada culture and the remaining bioreactors served as control. The density of protozoa was regularly evaluated. Artificially increased density of A. cicada did not impair nitrifying bacteria abundance nor flocs structure. On the contrary, when A. cicada abundance was the highest, the total nitrogen in effluent was significantly lower in treatment in comparison to control. Most probably nitrifying bacteria occurring in form of dense colonies or hidden inside the flocs were inaccessible for ciliates.