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Denitrification Kinetics of High‐Strength Nitrate in Granular Sludge Reactors
Author(s) -
Krishna Mohan Tulasi V.,
Nancharaiah Yarlagadda V.,
Venugopalan Vayalam P.,
Satya Sai Pedapati M.
Publication year - 2018
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201800239
Subject(s) - denitrifying bacteria , denitrification , nitrate , nitrite , sequencing batch reactor , chemistry , batch reactor , nitrogen , environmental chemistry , nuclear chemistry , environmental engineering , sewage treatment , biochemistry , organic chemistry , environmental science , catalysis
Biological denitrification of high‐strength nitrate is challenging due to building‐up of toxic nitrite to high levels. In this study, denitrification kinetics of high‐strength nitrate is investigated in a granular sludge reactor operated in sequencing batch mode. The nitrate concentrations are increased from 677, 1355, 2032, 2710, 3387, 4065–4742 mg L −1 NO 3 N in the reactor. Carbon and an electron source (acetate) are supplied at a fixed acetate‐carbon to nitrate‐nitrogen ratio of 1.5. At steady state, complete denitrification of 4742 mg L −1 NO 3 N in the feed is observed within the first 20 h of sequencing batch reactor (SBR) cycle. High denitrification rate constants are observed for NO 3 N concentrations from 677 to 2032 mg L −1 . However, a decrease in denitrification rate constants is observed for nitrate‐N concentrations of 2710–4742 mg L −1 , due to inhibition caused by transient accumulation of high levels of nitrite. Denitrifying biomass formed in the SBR is predominantly consisted of granular sludge, containing cocci, and rod‐shaped microorganisms. Cultivation of nitrite‐tolerant, denitrifying microbial community in granular sludge will help in the development of high rate reactors needed for process application.