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The anammox process is an economically favourable nitrogen removal process; however, low growth rates of anammox biomass block its more widespread application. As different approaches on techniques for anammox bacteria growth acceleration were tested, this study focused on long-term evaluation of hydrazine addition in the start-up phase. Effect of...
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... initial NRR during stabilization period (until day 6) was 0. 034 Fig. 1b, c). During this phase, in both reactors, average dissolved oxygen concentration was kept Fig. 1 a NH 4 -N, NO 2 -N, and NO 3 -N concentration in the influent medium. b NH 4 -N, NO 2 -N, and NO 3 -N concentration in the R1 effluent and c NH 4 -N, NO 2 -N, and NO 3 -N concentration in the R2 effluent at very low level to prevent potential inhibition: 0.03 ± 0.02 (max. 0.12) gO 2 m −3 and 0.03 ± 0.02 (max. 0.11) gO 2 m −3 for R1 and R2, respectively. ...
Context 2
... 1:523 | https://doi.org/10.1007/s42452-019-0514-4 Research Article potential estimation of share of anammox biomass in the VSS fraction is impossible due to scale of the experimental reactor where biofilm removal from reactor and used equipment was not possible. That situation explained why NLR and NRR was growing with no change of TSS of biomass (Fig. 4). Participation Anammox biomass in sludge was small and growth of that organism was impossible to measured by regular TSS measurement method. For more accurate evaluation of hydrazine addition effect in a long-term experiment, an alternative method for anammox growth rate estimation must be used, similar to activated sludge procedure ...
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Citations
... Introducing pyrrhotite (FeS) accelerated AnAOB growth in 18 days, surpassing 96 % TNRE in a lab UASB system [115]. Conversely, Miodoński et al. [116] used 3.7 mg/L of N 2 H 4 for rapid anammox initiation in a pilot SBR for sidestream wastewater treatment. This dosage was maintained over 36 days, resulting in an NRR of 0.519 g/L/d of N. ...
Nitrate (NO 3 −) is more stable than ammonia (NH 4 +) and nitrite (NO 2 −) among the majority of emerging pollutants in wastewater that can harm the ecosystem by depleting oxygen and water quality, thereby posing environmental and human health risks. Despite anaerobic ammonium oxidation (anammox) being a common method for nitrogen (N) removal from wastewater, it leaves behind residual NO 3 − of around 11 %. Maintaining the stability of N removal in the mainstream of wastewater (50-60 mg/L) is challenging due to the lack of intrinsic factors that suppress nitrite-oxidizing bacteria (NOB) and the accumulation of NO 3 −. Recently, partial denitrification/ anammox (PD/A) has been recognized as a useful approach to eliminate NO 3 − and NH 4 + from the sidestream (≥500 mg/L of N) and mainstream wastewater simultaneously. This review explores the complexities of sustaining stability in PD/A systems, including managing fluctuating NH 4 + and NO 3-levels while keeping a COD/N ratio of ≤ 3 to facilitate optimal NO 2 − production for the anammox. This review discusses the significance of temperature, pH, free ammonia, and free nitrous acid levels for optimal total N removal efficiency and PD/A stability in the long term. Strategies used for initiating and restoring the PD/A systems include optimized inoculum selection, granular sludge seeding, stepwise acclimation, bioaugmentation, unique substance incorporation , and innovative system design. Additionally, various strategies aim to enhance the stability by modifying the substance composition, introducing inorganic carbon and NO 3 − , incorporating heavy metals, embedding the biomass in gel carriers, adding microalgae, and adjusting hydraulic and solids retention time. These solutions aim to address the challenges to improve stability in the PD/A process. Future research roadmaps and supporting portfolios should address advancements and emerging technologies tackling the ongoing challenges in PD/A systems. These developments emphasize the significance of wastewater treatment for sustainable water availability to support the United Nations Sustainable Development Goal 6 (UN SDG 6) established in 2015.
... The addition of hydrazine (3.7 mg N 2 H 4 dm − 3 ) also showed an increased capacity of the reactor to treat higher NLR (with hydrazine:0.512 kgN (m 3 d) − 1 in comparison to without hydrazine 0.256 kgN (m 3 d) − 1 [34]. Thus, the application of different start-up strategies for anammox technology can increase its successful adaptation and make commercial applications more attractive. ...
Complete nitrogen removal depends on the requirement of oxygen as an electron acceptor and organics as electron donors. In the natural environment, these electron acceptors and donors regulate the nitrogen cycle in association with several nature-based processes, such as iron dependent (feammox), sulphur dependent (sul-fammox), and nitrite dependent (annamox). These processes represent the latest discoveries in the nitrification part of the nitrogen cycle and provide the electron acceptors for anaerobic ammonium oxidation. Research findings on these processes suggest that a previously undescribed pathway is available for anaerobic ammonium oxidation, which can regulate the nitrogen cycle in natural environments. It has been shown that some redox active materials can serve simultaneously as electron acceptors and donors in the nitrogen cycle. This review provides comprehensive information of the known oxidative processes in the nitrogen cycle and highlights the emergence of a new pathway for anaerobic NH 4 + oxidation, which is dependent on insoluble redox active materials as electron donors and acceptors. This new pathway is not limited to anaerobic NH 4 + oxidation, but it also includes reductive pathways to nitrogen gas, and thus can lead to complete nitrogen removal from nitrogen environments. Recent developments and knowledge advancement in the nitrogen cycle open a new path for nature-based sustainable solutions for nitrogen management. This new knowledge can provide innovative and novel approaches for conventional NH 4 + removal processes.
... Particularly, the slow growth rate of anammox bacteria, with a doubling time of approximately 7-20 days, makes biomass concentration a critical factor for successful start-up and stable operation of the anammox process [5]. While various approaches, including the use of carriers for anammox bacteria growth [6] and the addition of specific elements to enhance their growth [7], have been explored to maintain biomass concentrations, an efficient operational strategy is still needed to achieve rapid start-up, reduce biomass washout, and obtain high biomass yield [8]. ...
Two CSTRs using granules dominated by Ca. Jetteni asiatica (R1) and Ca. Brocadia sinica (R2) were operated depending on influent T-N concentrations and HRT. R1 achieved the highest NRR of 1.64 kgN/m 3 /day at HRT 8 h and T-N 600 mg/L, while R2 obtained the highest NRR of 2.05 kgN/m 3 /day at HRT 4 h and T-N 400 mg/L. The both reactors achieved high performance in high T-N concentration with the increasing of HRT in relatively short time. The sufficient T-N concentration and favorable short HRT were giving significant effects in promoting biomass increment and maintaining high removal in R1 and R2. In R1, granules larger than 2 mm accounted for over 60 %, while in R2 granules in the range of 1-2 mm comprised approximately 60 %. Granules in R1 were relatively harder and denser, and the surface of granules in R1 appeared rough, whereas the surface of granules in R2 seemed smoother. The abundance of anammox bacteria were much improved in both R1 and R2, operating under optimal operational conditions, showed significant improvement. The distribution of Ca. Brocadia sinica increased from 2.6 % to 42.0 % for R1 and from 9.1 %, to 90.5 % for R2, while there was little change in Ca. Jettenia asiatica. In this study, while the optimal HRT and nitrogen concentration as influent varied depending on the dominant anammox bacteria and granule characteristics in the inoculum, Ca. Brocadia sinica appears to play a significant role in nitrogen removal.
... However, the growth of anammox bacteria with pyrrhotite (FeS) addition was promoted within only 18 days, and the TNRE increased to > 96% in a lab-scale UASB for mainstream wastewater treatment (Zou et al., 2020). On the other hand, a hydrazine dose (3.7 mg N 2 H 4 /L) was selected for the rapid start-up of anammox over 36 days, and the NRR was 519 mg N/L⋅d in a pilot-scale SBR for side-stream wastewater treatment (Miodoński et al., 2019). ...
Anammox is a widely adopted process for energy-efficient removal of nitrogen from wastewater, but challenges with NOB suppression and NO3− accumulation have led to a deeper investigation of this process. To address these issues, the synergy of partial denitrification and anammox (PD-anammox) has emerged as a promising solution for sustainable nitrogen removal in wastewater. This paper presents a comprehensive review of recent developments in the PD-anammox system, including stable performance outcomes, operational parameters, and mathematical models. The review categorizes start-up and recovery strategies for PD-anammox and examines its contributions to sustainable development goals, such as reducing N2O emissions and saving energy. Furthermore, it suggests future trends and perspectives for improving the efficiency and integration of PD-anammox into full-scale wastewater treatment system. Overall, this review provides valuable insights into optimizing PD-anammox in wastewater treatment, highlighting the potential of simultaneous processes and the importance of improving efficiency and integration into full-scale systems.
... It is very interesting to compare the N removal rates per gram of volatile suspended solids (VSS) of anammox biomass reported in the literature and estimated in this work. The N removal rate can range from 0.0024 to 0.638 g N/g VSS/day, depending on the origin of the wastewater, temperature, N loading rate, etc. [94][95][96][97][98][99]. Considering an average removal of 55 mg N/L/day in late phase 4 and an estimate of 0.1-0.3 ...
Simple Summary
Heavy nitrogen pollution is a major ecological problem for cold aquifers near the zone of a radioactive waste surface repository. Unique microbial communities are formed in these groundwater ecosystems that could be used for sustainable bioremediation in situ. Prior to field experiments, in this work we obtained and analyzed enrichment cultures of N cycle bacteria to shed light on their metabolic capabilities. Despite high N conversion activity, surprisingly, no “conventional” nitrifying bacteria were found in enrichment cultures. Moreover, stable nitrite production could be achieved through heterotrophic denitrification, which implies great potential to produce nitrite for sustainable anammox-based bioremediation. Anammox bacteria were difficult to enrich in fed-batch culture. However, stable removal of ammonium and nitrite under anaerobic conditions could be achieved in a continuous flow reactor packed with nonwoven fabric. Intriguing was the high nonstoichiometric buildup of nitrate, which could be an adaptive mechanism of anammox bacteria to low temperature. Xanthomonadaceae was a common taxon for all enrichment cultures, indicating its exclusive role in this ecosystem. Moreover, its representatives, genera Thermomonas and Stenotrophomonas, have nitrite oxidoreductases (nxr), which may explain the observed high accumulation of nitrates. These findings may be important in anammox-based low-temperature wastewater treatment.
Abstract
Anammox bacteria related to Candidatus Scalindua were recently discovered in a cold (7.5 °C) aquifer near sludge repositories containing solid wastes of uranium and processed polymetallic concentrate. Groundwater has a very high level of nitrate and ammonia pollution (up to 10 and 0.5 g/L, respectively) and a very low content of organic carbon (2.5 mg/L). To assess the potential for bioremediation of polluted groundwater in situ, enrichment cultures of anammox, nitrifying, and denitrifying bacteria were obtained and analyzed. Fed-batch enrichment of anammox bacteria was not successful. Stable removal of ammonium and nitrite (up to 100%) was achieved in a continuous-flow reactor packed with a nonwoven fabric at 15 °C, and enrichment in anammox bacteria was confirmed by FISH and qPCR assays. The relatively low total N removal efficiency (up to 55%) was due to nonstoichiometric nitrate buildup. This phenomenon can be explained by a shift in the metabolism of anammox bacteria towards the production of more nitrates and less N2 at low temperatures compared to the canonical stoichiometry. In addition, the too high an estimate of specific anammox activity suggests that N cycle microbial groups other than anammox bacteria may have contributed significantly to N removal. Stable nitrite production was observed in the denitrifying enrichment culture, while no “conventional” nitrifiers were found in the corresponding enrichment cultures. Xanthomonadaceae was a common taxon for all microbial communities, indicating its exclusive role in this ecosystem. This study opens up new knowledge about the metabolic capabilities of N cycle bacteria and potential approaches for sustainable bioremediation of heavily N-polluted cold ecosystems.
... Hydrazine, an additional exogenous substance, helps enrich anammox bacteria in the anammox process by having a role in bacterial growth. The hydrazine addition facilitates an anammox bacterial enrichments along with enhanced nitrogen removal efficiency (0.512 kg N (m 3 d -1 ) Vs 0.256 kg N (m 3 d -1 ), control [56]. The presence of hydrazine in anammox systems facilitates the increased NH 4 + -N oxidation rates and decreased NO 2 --N reduction rate by affecting the nitrite-oxidizing bacteria activity with the simultaneous enhancement of anammox bacterial growth.The positive results with the exogenous hydrazine addition on the anammox process led to testing the other substances, such as acyl homoserine-lactones(AHLs). AHLs are mediator molecules in quorum sensing, a bacterial cell-to-cell interaction process.The enhanced anammox results with the addition of AHLs were reported in several instances where the concentration above the threshold value of AHLs triggers the respective genes with their specific phenotypes such as anchorage, activity, granulation of the anammox biomass.The addition of AHL in a CSTR-driven anammox process facilitates a 17.5% lesser startup time compared with a reference process [57]. ...
Anammox has been globally accepted as the most promising sewage treatment process. However, the full-scale application of theanammox process islimited because anammox bacteria are easily susceptible to environmental conditions and deficient in nitrite supply. Presently, nitritation and denitratation are generally considered the two-ideal nitrite-generating pathways for anammox, while operating stability and optimizing regulation have been outstanding issues. Therefore, a comprehensive summary of the potential ventures and control procedures to overcome these challenges was needed. To this end, this study firstly reviews the valuable new outcomes of the pure anammox process, including the implemented sludge morphology, various wastewater characteristics, and metabolic regulation measures to improve anammox activity. Then, the key advances in nitritation and denitratation processes which can take a couple with anammox for the advanced nitrogen removal, are well presented.Finally, a novel proposed process that develops one-step simultaneous partial nitration, denitratation, and anammox (SPNDA) for the ammonium and nitrate wastewater treatment and its feasibility into energy-efficient nitrogen removal was analyzed. This review offers a more cost-effective and environment-sustainable perspective for future engineering applications of anammox.
... Due to the extremely long doubling time of anammox bacteria (7-20 days) (Kartal et al. 2012), challenging start-up period of the process is one of the main obstacles. Therefore, in order to shorten the start-up time of the Anammox process, many researchers have focused on optimizing key parameters such as seeding sludge, operational strategy, biomass immobilization, etc. (Verma et al. 2021), and the addition of chemical reagents into the system for stimulating the bacteria (Ganesan & Vadivelu 2019;Miodonśki et al. 2019). Therefore, in full-scale applications of Anammox process, in case of a sudden toxicity, recovery would be a better way than restarting it. ...
The potential effects of nanoparticles (NPs) on biological treatment processes have become significant due to their increasing industrial applications. The purpose of this research was to investigate the self-recovery ability of anammox bacteria following acute ZnO NPs toxicity. In this context, a 2-liter lab-scale anammox reactor was operated for 550 days to enrich the biomass required to the batch exposure tests. Anammox culture was firstly exposed to four different doses of ZnO NPs (50, 75, 100 and 200 mg/L) for 24 h. Then, the ZnO NPs were removed and self-recovery performance of the anammox bacteria was assessed by evaluating the nitrogen removal capacities for 72 h. Besides the nitrogen removal performance, extracellular polymeric substances (EPS) production was also detected to deeply understand the response of the enriched anammox culture against ZnO NPs exposure. The results revealed that sudden and high load of ZnO NPs (100 and 200 mg/L) resulted in persistent impairment to the nitrogen removal performance of the enriched anammox culture. However, relatively lower doses (50 and 75 mg/L) caused deceleration of the nitrogen removal performance during the recovery period. In addition, EPS content in the reactor decreased along with escalating load of ZnO NPs. HIGHLIGHTS
Enriched anammox cultures were exposed to different ZnO NPs doses.;
Total nitrogen consumption per VSS decreased by the escalating burden of ZnO NPs.;
This study takes attention to the self-recovery ability of anammox bacteria against shock ZnO NPs loads.;
Anammox bacteria could not recover their activity following the acute inhibition of high ZnO NPs load.;
... However, most of the above-mentioned studies were based on the results of small-scale tests obtained from sequential batch experiments, and pilot tests or engineering application data for continuous water inflow have rarely been reported. Anammox bacteria are extremely sensitive to their living environment (Khramenkov et al., 2013;Miodoński et al., 2019;Strous et al., 1998). In pilot-scale and engineering applications, due to changes in the reactor and its operating conditions, relevant research results would likely differ somewhat, or even significantly, from those of small-scale tests. ...
p>A pilot-scale sequencing batch reactor (SBR) for anaerobic ammonium oxidation (anammox) of bacteria culture was used along with a batch experimental reaction device to study the effect of NO2--N concentration on the activity of anammox bacteria and the recovery of N2H4 on anammox bacteria after inhibition by high concentrations of NO2--N. The optimal influent NO2--N concentration in the pilot-scale reactor was 72.0 mg/L, with its total nitrogen consumption being approximately 40.0 g/d. Influent water NO2--N concentrations greater than 100 mg/L had a serious inhibitory effect on the anammox bacteria. At an influent NO2--N concentration of 120.35 mg/L, the addition of 10.0-15.0 mg/L of N2H4, restored the activity of granular anammox bacteria; the total nitrogen consumption was increased by 69.96%. Microbiological analysis showed that a change in NO2--N concentration within the range of 18.87-115.39 mg/L did not affect the microbial population structure of the pilot-scale reactor, wherein Candidatus Kuenenia was the dominant bacterial species. In samples collected at stages A0 (sludge inoculation), A20 (the number indicates the NO2--N concentration, which, in this stage, was 20 mg/L), A40, A60, A80, and A100, the proportion of Candidatus Kuenenia was 27%, 23%, 36%, 26%, 34%, and 33%, respectively.</p
... Effective handling of ammonium in their reject wastewater streams, inter alia, is the new goal of the wastewater treatment plants (WWTPs) (Miodoński et al., 2019). Over the years, anaerobic ammonium oxidation (anammox) has emerged as a new, energy autarchic process with lesser footprints to replace the conventional biological nitrogen removal (BNR) process (Zhang et al., 2019) and has been widely applied by the WWTPs for handling their ammonium-rich wastewater (Chen et al., 2017). ...
In this study, the start-up of anammox in a sequencing batch reactor (SBR) using conventional activated and anaerobic sludge in 1:1 ratio (v/v) as inoculum was achieved using an unconventional strategy. The ratio of NH4+-N to NO2−–N in the influent was not maintained as per the stoichiometry (1:1.32) of anammox and rather varied depending on the effluent characteristics. Nitrite was omitted during its accumulation period to avoid its toxicity during the start-up phase. The SBR having polyurethane foam impregnated with activated carbon (Levapor® carriers) was operated for 212 d (temperature, 37 °C; influent pH, 8). Anammox process was started up in ~95 d with 85% average total nitrogen (TN) removal. Thereafter, the reactor showed average TN removal efficiency of 85% and exhibited an average NH4+-N and NO2−–N removals of 99.9% each at maximum influent NH4+-N and NO2−–N concentrations of 200 mg L−1 and 264 mg L−1, respectively. The 16S rRNA gene amplicon sequencing analysis of suspended sludge samples (100 d, 150 d, and 186 d) from the reactor revealed the dominance of infrequently occurring anammox bacterial genus Candidatus Jettenia in the reactor. The phyla Chloroflexi, Proteobacteria, and Bacteriodetes were also detected in the reactor.
... The startup of Anammox process in reactors with different biomass carriers (sponge, volcanic rock and charcoal) showed no difference in the final nitrogen removal rate (NRR), however they were observed to have impacted the time needed to obtain certain NRR. Thus, its proper selection can influence the start-up time (Miodoński et al. 2019). Discussed below are some biomass carriers and their respective effects on the Anammox start-up and/or performance. ...
The Anaerobic Ammonia Oxidation (Anammox) wastewater treatment process has attracted significant attention ever since its discovery in the Netherlands in the 1990′s. This has mostly been due to the potential cost-effectiveness associated with the process in large scale application. However, the application of the Anammox process on an industrial-scale has been curtailed mainly due to the long start-up time of the Anammox bacteria. In order to ensure the feasibility of industrial-scale Anammox application, researchers have employed various means; experimenting with different reactor types, membrane types, as well as the usage of chemicals such as hydrazine, acyl-homoserinelactones (AHL), etc. Most recently however, more attention has been directed towards the addition of biomass carriers such as biochar, zeolites, sponges, non-woven membrane etc. for the optimization of the Anammox process. This article provides an up-to-date overview of the various carriers (Non-woven fabric, Biochar, Down-flow hanging sponge, Zeolite, Zero-violent iron, Polyethylene glycol gel, Activated-carbon, Polyethylene sponge, etc.) that have so far been used to better the performance of the Anammox process. It also focuses on the effect of these biomass carrier additions on the microbial growth and community structure. Understanding the metabolomics of microorganisms in carrier-amended media promises to enhance our knowledge of carriers’ influence on the microbial community structure. Generally, the metabolic effects of carrier-amendment on microbial growth and community are largely uninvestigated. Future researches focusing on this area could tremendously improve our comprehension of the inner-workings of the carrier amended Anammox set-up.
