Biodegradation of a high-strength wastewater containing a mixture of ammonium, aromatic compounds and salts with simultaneous nitritation in an aerobic granular reactor

Abstract

Long-term operation (390 days) of a continuous airlift reactor with aerobic granular biomass was successfully applied to treat a highly complex wastewater composed of: ammonium (1000 mg N L-1), o-cresol (100 mg L-1), phenol (100 mg L-1), quinoline (50 mg L-1) and salts (16 g salts L-1). High nitrogen loading rate (1.1 g N L-1 d-1) and organic loading rate of 0.7 (g COD L-1 d-1) were achieved for the simultaneous nitritation and complete biodegradation of the aromatic compounds. The successful operation of the granular airlift reactor can be related to (i) the growth of specialized microorganisms in the aerobic granules and (ii) the continuous feeding regime. Aerobic granules were maintained stable in spite of the high salinity conditions. Dissolved oxygen (DO) concentration and DO/ammonium concentrations ratio were the key parameters to select a suitable effluent for anammox or heterotrophic denitrification via nitrite. Besides, nitrous oxide emissions were related to the DO concentration in the reactor.

Simultaneous partial nitrification and 2-fluorophenol biodegradation with aerobic granular biomass: Reactor performance and microbial communities

“…1B). The presence of aromatic compounds (phenol, o-cresol and quinoline) affects ammonium oxidation, as have been previously reported in bioreactors with nitritation not starting until the aromatic compounds were completely consumed (Jemaat et al, 2013;Liu et al, 2005;Morita et al, 2007;Ramos et al, 2016a). Thus, the feeding was stopped for a period of 2 days (from day-63 to day-65) to allow the consumption of all the accumulated 2-FP and thereafter of ammonium.…”

“…Aerobic granular biomass (5 g VSS, volatile suspended solids) from a continuous airlift reactor treating an industrial wastewater containing ammonium and aromatic compounds was used as inoculum (Ramos et al, 2016a). That aerobic granular reactor performed simultaneous partial nitrification and organic matter removal, achieving complete biodegradation of the organic matter (96%) and an effluent with 95% of nitrite and 5% of nitrate.…”

“…Bacterial 16S rRNA variable regions V2-V4 were targeted using the primer pair 341F-907R. Biodiversity analysis and phylogenetic classification were performed with the methodology explained in Ramos et al (2016a). Relative abundances of the reads were determined by taxonomic level.…”

“…However, the efficiency of biological processes can be negatively affected by the presence of aromatic compounds. A promising technology to overcome related problems is the use of aerobic granular biomass reactors (Adav et al, 2008;Duque et al, 2011;Ramos et al, 2016a). Aerobic granules are dense spherical structures, formed by a microbial self-immobilization process, which have excellent settling ability.…”

“…The achievement of partial nitrification instead of full nitrification allows reduce aeration and, consequently, reducing running costs. This aerobic granular reactor was previously used to treat wastewater streams with phenol and phenol substituted with methyl-and nitro-groups (pnitrophenol and o-cresol) (Jemaat et al, 2014(Jemaat et al, , 2013Ramos et al, 2016a). However, its performance has not been studied with aromatic compounds with halogen substituents, such as chloride-or fluoride-.…”