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Nitrogen
Published in Robert H. Kadlec, Treatment Marshes for Runoff and Polishing, 2019
The removal of oxidized nitrogen in marshes is the result of a complex set of processes that is often termed “denitrification.” Nitrate disappearance occurs via many pathways that potentially remove nitrate (Burgin and Hamilton, 2007). The list includes: Denitrification is respiratory denitrification, in which organic matter is oxidized by nitrate in sediments and biofilms. Typically, most of the nitrate is converted to N2, but a variable fraction is converted to nitrous oxide (N2O).Dissimilatory nitrate reduction to ammonium (DNRA) is a heterotrophic process that utilizes organic matter as the energy source to reduce nitrate via fermentation.Sulfur-driven autotrophic denitrification couples the reduction of nitrate to the oxidation of reduced sulfur forms, including free sulfide (H2S and S2–) and elemental sulfur.Anammox (anaerobic ammonium oxidation) is an autotrophic process by which ammonium is combined with nitrite under anaerobic conditions, producing N2. The nitrite is derived from the reduction of nitrate.
Life Cycle Analysis of Anaerobic Digestion of Wastewater Treatment Plants
Published in Mu Naushad, Life Cycle Assessment of Wastewater Treatment, 2018
Rosalía Rodríguez, Juan José Espada, Raúl Molina, Daniel Puyol
Use of the anammox process to low-en ergy main line with complete nitrogen depletion in a single-stage process. The anammox process entails the anaerobic oxidation of ammonium to dinitrogen gas with nitrite as the electron source. In domestic wastewater applications, complete removal of C and N is feasible with partial oxidation of ammonium to nitrite (nitritation) and anammox with concomitant C removal by fermentation and microaerophilic organic oxidation in a delicate equilibrium, where the pH and the temperature play a critical role. Anammox bacteria are very sensitive to temperature changes and concentrations of unionized nitrogen forms (free nitrous acid and free ammonia), so that pH must remain in a narrow range of 7–8.5 (Cao et al., 2017).
Advanced treatment processes
Published in Rumana Riffat, Taqsim Husnain, Fundamentals of Wastewater Treatment and Engineering, 2022
The AnammoxTM process was developed in the Netherlands in the late 1990s. The term Anammox is an abbreviation for anaerobic ammonium oxidation. The Anammox process is preceded by a nitritation process that converts half of the ammonium to nitrite, without subsequent conversion of nitrite to nitrate. The oxygen uptake based on initial ammonium concentration is 1.72 g O2/g N, or 38% of the oxygen demand for oxidation of all the ammonium to nitrate (Gut, 2006). After this process, the Anammox process (Equation 13.17 and 13.18) follows without the addition of any organic material in a separate reactor (van Loosdrecht et al., 2004).
Fe(III)-mediated anaerobic ammonium oxidation: A novel microbial nitrogen cycle pathway and potential applications
Published in Critical Reviews in Environmental Science and Technology, 2022
Xin Tan, Guo-Jun Xie, Wen-Bo Nie, De-Feng Xing, Bing-Feng Liu, Jie Ding, Nan-Qi Ren
Anammox, an autotrophic nitrogen removal technology, is a promising option for energy-neutral or energy-producing wastewater treatment (Kartal et al., 2010; Khin & Annachhatre, 2004; Nie et al., 2019; Ye et al., 2020). Given the requirement for NO2- in the Anammox process, providing NO2- via the Feammox process before the Anammox reactor can be a new strategy to improve Anammox technology. Furthermore, the Feammox process may also address some of the key issues faced in wastewater treatment, e.g., 1) shortage of carbon sources in influent wastewater with low C/N ratio and 2) high NH4+-N loading of the anaerobic digestion effluent. A solution for wastewater treatment with Anammox bacteria is assumed that the Feammox process could be coupled with other available technologies, including high-rate activated sludge process, anaerobic digestion, and Anammox. The coupling strategy proposed is shown in Figure 3A.
Ex-situ manometric activity test for evaluation of mainstream anammox in Moving Bed Biofilm Reactors
Published in Environmental Technology, 2022
Dora Olsheimer, Jes la Cour Jansen, David J. I. Gustavsson
At municipal wastewater treatment plants (WWTPs), traditional nitrogen removal is accomplished by a nitrification-denitrification process that in many cases requires an addition of an external carbon source to fulfil stringent nitrogen removal standards. An interesting solution to reach an efficient nitrogen removal is a process configuration that combines nitritation and anaerobic ammonium oxidation (anammox). The anammox bacteria are autotrophs and grow anoxically on ammonium using nitrite as an electron acceptor, converting the reactants into nitrogen gas. The implementation of the anammox process has the potential to significantly decrease the energy need and increase biogas production at WWTPs [1,2]. Currently, the anammox process has been successfully implemented in WWTPs to treat ammonium-rich sludge liquor from the dewatering of anaerobically digested sludge at temperatures ranging from 25–35°C [3]. The paper also shows that installations based on suspended sludge, on granules, or on biofilm systems, all seem to have found their niche, although granular based systems seem to be dominating. Recent literature review on main stream anammox [4,5] also seem to support that processes based on suspended sludge, granules and biofilms could be part of the future development into full-scale installations although systems with stratification of biomass might be favourable for the presence of the needed large anammox population.
Research advances in anammox granular sludge: A review
Published in Critical Reviews in Environmental Science and Technology, 2022
Mabruk Adams, Junxiang Xie, Arthur wendinso Judicael Kabore, Yaofeng Chang, Jiawei Xie, Menglei Guo, Chongjun Chen
The anaerobic ammonium oxidation (anammox) process, which is a relatively novel biological nitrogen removal (BNR) process (Strous et al., 1997, 1999) has attracted a lot of attention over the years for good reason. This is largely due to its high rate cost efficiency and energy conservation (Tang et al., 2011), and its ability to treat wastewaters with low carbon to nitrogen ratio (>2.5) without any external carbon source supply (Miodoński et al., 2019). Similarly, it ensures low energy costs for aeration due to the low oxygen consumption, results in lower N-oxides production (Gutwiński et al., 2016), saves 90% of operational costs in sludge disposal (Chamchoi & Nitisoravut, 2007; Güven et al., 2004; Molinuevo et al., 2009), creates a 90% reduction in greenhouse gas emissions (Manonmani & Joseph, 2018) and has relatively small space requirement (Joss et al., 2009; van der Star et al., 2007). In addition, the anammox bacteria has the ability of reactivation after 2–5 days of being re-exposed to suitable operating conditions after it had been dormant due to adverse conditions (Isaka et al., 2006). As such, the anammox process presents a more sustainable way of treating wastewater (Guillén et al., 2016; Park et al., 2017).