Biological nitrogen removal of ammonia-rich centrate in batch systems

Abstract

This study addressed the removal of ammonia from recycled centrate via biological nitrification and denitrification in batch reactors. Nitrification was successful at ammonia feed concentrations up to 400 mg/L and carbon-to-nitrogen (C/N) ratios greater than 1. The use of pre-exposed biomass to ammonia-rich centrate reduced considerably the overall time required for nitrification, which was also reflected on the corresponding specific rates. The denitrification of naturally-generated nitrates proceeded smoothly, with methanol modestly outperforming acetate as external carbon source. Furthermore, simultaneous nitrification and denitrification (SND) was induced in the presence of readily biodegradable organic carbon (i.e., methanol or acetate) under aerobic conditions. Overall, total nitrogen removal from ammonia-rich centrate by biological methods was viable under the conditions investigated.

Utilization of Bidirectional Cation Transport in a Thin Film Composite Membrane: Selective Removal and Reclamation of Ammonium from Synthetic Digested Sludge Centrate via an Osmosis–Distillation Hybrid Membrane Process

“…Removal of ammonium nitrogen (NH 4 + –N) from high-strength ammonium waste streams, such as digested sludge centrate, is one of the crucial challenges faced during wastewater treatment. , Ammonium-rich centrates generated in the dewatering of anaerobically digested biosolids contain NH 4 + –N with concentrations of 600–1000 mg L –1 and are generally treated by recycling to raw wastewater influent, which contributes 15–20% of the total nitrogen loading. − The unbalanced nutrients caused by the excessive NH 4 + –N input increase the costs of operation, raise the risk of poor effluent water quality, and introduce potential pollution into the aquatic environments (e.g., the eutrophication of water bodies). Nitrogen is also an essential element for organisms and plants, thereby being a valuable resource remaining in the nutrient-rich centrate. , Therefore, it is crucial to develop effective strategies for the sustainable removal and recovery of NH 4 + –N from centrate.…”

“…Previous studies on the removal of NH 4 + –N from ammonium-rich centrate mainly focused on biological treatment and chemical/physical extractions (Table S1 of the Supporting Information, SI). Classical biological treatment, i.e., combination of nitrification and denitrification (ND) processes, is widely used in practical engineering. ,, The need for external carbon sources and inhibition of nitrification caused by the existence of free ammonia with a relatively high concentration still restrict the development of ND processes . In recent years, the anaerobic ammonium oxidation (ANAMMOX) process, which utilizes nitrite as an electron acceptor to oxidize ammonium and produce gaseous nitrogen, has been widely studied owing to its improved energy efficiency in the treatment of ammonium-rich wastewater. ,,, However, the ANAMMOX process has several constraints, such as the growth of nitrite oxidation bacteria and unstable performance of nitritation .…”