Performance and inhibition recovery of anammox reactors seeded with different types of sludge

摘要

In order to study the performance, inhibition and recovery processes of different types ofnanammox sludge, three up-flow anaerobic sludge blanket reactors were inoculated with flocculentnsludge, granular sludge, and cultured inactive methanogenic granules. During stable period, withnnitrogen loading rates of 0.9–1.1 kg/m3/d, the total nitrogen removal efficiencies of these reactorsnaveraged at 86.5%, 90.8% and 93.5%, respectively. The kinetics study indicated that the reactornseeded with cultured inactive methanogenic granules possessed the highest nitrogen removalnpotential, followed by the granular anammox reactor and the flocculent anammox reactor.nThe study suggested that a concentration as high as 988.3 mg NH4nþ-N/L and 484.4 mg NO2nu0002-N/Lncould totally inhibit granular anammox bacteria and result in a inhibition of 50% flocculentnanammox activity. In addition, reactors seeded with flocculent sludge and anammox granulesncould be fully recovered by decreasing their influent substrate concentrations.nHowever, the decrease of influent substrate concentration for the reactor with cultured inactivenmethanogenic granules could only restore about 75% of its bacterial activity. In this study,nanammox bacteria purity was the major factor to evaluate the recovery ability in comparisonnwith sludge type. Free ammonia was a more appropriate indicator for the anammox recoverynprocess compared to free nitric acid.