Simultaneous denitrification and phosphorus removal by Agrobacterium sp. LAD9 under varying oxygen concentration

Abstract

Although efficient aerobic denitrification has received increasing attention, few studies have been made on simultaneous denitrification and phosphorus removal (SDPR) under aerobic condition. In this study, SDPR by an efficient aerobic denitrifier, Agrobacterium sp. LAD9, was firstly demonstrated. High nitrate and phosphorus removal rates of 7.50 and 1.02 mg L(-1) h(-1) were achieved in wide range of O2 concentration from 5.92 to 20.02 mg L(-1). The N2O production would be inhibited as O2 concentration exceeded 11.06 mg L(-1), while the phosphorus removal efficiency would be generally improved with increasing O2 concentration. (15)N mass spectrometry revealed that nitrogen removal accorded with the typical aerobic denitrification pathway, while (31)P nuclear magnetic resonance spectroscopy ((31)P NMR) indicated the fate of phosphorus to cells, extracellular polymeric substances (EPS), and polyphosphate (poly-P) of the denitrifier. EPS acted as a reservoir of phosphorus and the transformation of poly-P was dynamic and depended on initial orthophosphate (ortho-P) content. The aerobic SDPR would greatly simplify the conventional wastewater treatment processes which required separated considerations of nitrogen and phosphorus removal.

Nonnegligible Generation of Hydroxyl Radicals from UVC Photolysis of Aqueous Nitrous Oxide

“…The concentration of dissolved N 2 O was determined using the headspace method with a gas chromatograph (GC, Thermo Scientific Fisher Trace 1310, USA). , The GC was equipped with an electron capture detector (ECD) and a 5 Å molecular sieve column (30 m × 0.32 mm × 30 μm). The carrier gas was N 2 at a flow rate of 5 mL min –1 .…”

Electrified CO2 valorization in emerging nanotechnologies: a technical analysis of gas feedstock purity and nanomaterials in electrocatalytic and bio-electrocatalytic CO2 conversion

“…NO 3 → NO 2 → NO → N 2 O → N 2 ) but this would require strict anaerobic conditions, presenting significant compatibility issues with waste gas streams that contain high levels of oxygen. 70 Nevertheless, some have reported the existence of aerobic denitrifying bacteria such as Pseudomonas aeruginosa that may be useful for NOx removal from waste gases that contain oxygen. 71 As engineering an optimal MES microbiome may be a complex task, a more elegant approach to improve MES compatibility with waste gas blends may be to develop new porous 3D electrode nanomaterials.…”

Production of extracellular polymeric substances by isolate consortia obtained from mesophilic aerobic granules from the treatment of paper mill effluent

“…In addition, the use of phosphorus in the production of EPS of Agrobacterium strains was evaluated, and it was found that phosphorus limitation increases the production of substances that help in the formation of biofilms and granules by species of this bacterial genus (Huang et al 2012). The use of phosphorus in the EPS production of Agrobacterium strains was evaluated by Ma et al (2016). The limitation of phosphorus increases the production of substances that contribute to the formation of biofilms and granules by species of this bacterial genus.…”