Respirometric evaluation of side-stream treatment of reject water as a source of nitrifying bacteria for main-stream activated sludge bioreactors

摘要

A laboratory-scale bioreactor study was conducted to characterize differences in nitrificationnfunction in main-stream reactors due to bioaugmentation from side-stream reactors treatingnreject water. The objective was to evaluate how configuration of a suspended growth side-streamnbioreactor impacts nitrification function in the main-stream bioreactor. A bioaugmentation effectnwas not observed in main-stream reactors operated at warm temperatures. Complete oxidationnof ammonia to nitrate was observed in the bioaugmented and control main-stream reactorsnalthough nitrite accumulation was observed in each case. Furthermore, respirometry did notnreveal superior kinetics in bioaugmented reactors operated at warm temperatures. At coldntemperatures bioaugmentation may have stabilized ammonia oxidation in main-stream reactornB2 bioaugmented from a PFR side-stream. Complete ammonia oxidation was observed for mostnof cold period of operation in the main-stream bioreactor B2. Furthermore, respirometry revealedna higher rate of ammonia oxidation and more stable nitrite oxidation compared with the controlnbioreactor.