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Sequential batch reactor (SBR) layout. (1) reaction zoom, (2) blow system, (3) water jacket, (4) threephase separator, (5) vent-pipe, (6) flow controller, (7) water tank, (8) peristaltic pump of the feeding media
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The granulation of simultaneous partial nitrification and anaerobic ammonium oxidation (Anammox) was investigated in a single, oxygen-limited, sequencing batch reactor. In this research, the reactor was started anaerobically and fed using the synthetic medium described by Van de Graaf et al. to cultivate Anammox biomass after inoculation with metha...
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... lab-scale SBR with a working volume of 7.0 L and a height-to-diameter ratio of 7 was used (Fig. 1). The plexiglass cylindrical reactor was operated at a fixed temperature of (35± 1)°C by means of an external water jacket, which was referred to be the optimum temperature for aerobic ammonia-oxidizing bacteria and Anammox bacteria [27]. A black vinyl sheet enclosure was used to keep the bacteria away from the light. The synthetic ...
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Sequencing batch reactors were used to study anaerobic ammonium oxidation (anammox) process under temperature shock. Both long-term (15–35 °C) and short-term (10–50 °C) temperature effects on nitrogen removal performance were performed. In reactor operation test, the results indicated that ammonium removal rate decreased from 0.35 kg/(m³ day) gradu...
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Citations
... The synthetic medium was supplied to the ABR reactor using a peristaltic pump (once per hour in equal portions of the medium) according to Table 3. The synthetic medium was modified from previous works [46,47] (mg/L): NH4Cl and NaNO2 according to Table 3, NaHCO3-1000, MgSO4 ⋅ 7H2O-120, CaCl2 ⋅ 7H2O-180, KH2PO4-27, trace elements solution-0.5 mL/L (EDTA-5, [48], formic acid-0.025 [48]. ...
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.
... LabVIEW was used to achieve automatic control of these devices. The temperature of the SBR was controlled at 10 ± 1 • C through an external water jacket (Li et al., 2011), and aerobic phase DO was controlled at 0.3 ± 0.1 mg/L. The volume exchange ratio was 50 %. ...
A lab-scale sequencing batch reactor was employed to study simultaneous nitrification, denitrification, and phosphorus removal (SNDPR) when treating municipal wastewater at 10℃ for 158 days. An anaerobic/aerobic configuration that had previously been effective when treating synthetic wastewater was explored, however, these conditions were relatively ineffective for real municipal wastewater. Incorporation of a post-anoxic phase (i.e., anaerobic/aerobic/anoxic) improved nitrogen and phosphorus removals to 91.1% and 92.4%, respectively while achieving a simultaneous nitrification and denitrification efficiency of 28.5%. Activity tests indicated that 15.8% and 56.0% of nitrogen were removed by denitrifying phosphorus accumulating organisms in the aerobic phase and heterotrophs using hydrolyzed carbon in the post-anoxic phase, respectively. 16S rRNA gene analysis and stoichiometric ratios indicated the system was rich in phosphorus accumulating organisms (Dechloromonas and Ca. Accumulibacter). Overall, implementation of the post-anoxic phase eliminated carbon uptake for denitrification in the anaerobic phase and was essential to maintaining SNDPR at low temperatures.
... Many agri-food industries produce a very high pollution load (Wu et al. 2011). This high pollution often leads to the death of marine organisms and the depletion of dissolved oxygen (Li et al. 2011). ...
The study is carried out at the wastewater treatment plant (WWTP) of an agricultural cooperative that operates according to the activated sludge process. Dairy industry is enlisted as one of the topmost industries in the food industry. Dairy wastewater treatment is a big issue as dairy wastewater releases a high amount of chemical oxygen demand, inorganic and organic particles, biological oxygen demand, and nutrients. But, these processes partly degrade wastewater containing fats and nutrients as dairy wastewater. The aim of this study was to evaluate the purification performance of this treatment process. The qualitative analysis of decanted raw wastewater (DRWW) and purified wastewater (PWW) shows that the concentration of orthophosphate, nitrate and sulfate ions is slightly higher. Such contaminated water if not handled appropriately, it pollutes water bodies and largely affects our ecosystem and biodiversity. Hence, our proposal is to improve the WWTP performances by using the adsorption process onto dried Carpobrotus edulis as an inert biomaterial. This adsorption process is recognized as one of the best water treatment techniques, more and more works are oriented towards the search for new materials, cheaper and having a good adsorbent potential. This study opens the path for the use of natural and abundant local material to remove orthophosphate, nitrate and sulfate ions using the C. edulis plant particles shred. The surface micromor-phology of the biomaterial was investigated using a scanning electron microscope; while the qualitative element composition was analyzed using energy dispersive X-ray and infrared spectroscopies. The found results of DRWW was about 57% for orthophosphates, 67% for sulfates and 73% for nitrates ions. For PWW, the percentage removal was found to be 62%, 73% and 84% for orthophosphates, sulfates and nitrates respectively. These results indicate that dried C. edulis plant, as an environmentally friendly adsorbent could be recommended for the removal of mineral pollutants. In conclusion, the C. edulis adsorbent can be integrated into the activated sludge process for wastewater treatment after identifying the optimal hydraulic loads, associated sizes, and shapes in continuous operations.
... when the phenol concentration was about 300 mg L −1 (Pereira et al. 2014). Therefore, the anammox technology was a promising strategy for efficiently removing nitrogen from phenolcontaining wastewater, but a stable partial nitritation stage prior to the anammox reaction was essential to treat highstrength phenol-containing wastewater (Li et al. 2011b). ...
Anammox process is considered as a promising technology for removing total nitrogen from low-strength ammonium and phenol-containing wastewater. However, it is still a challenge for the anammox process to treat high-strength ammonium and phenol-containing wastewater. A completely separated partial nitritation and anammox (CSPN/A) process was developed to remove total nitrogen from high-strength phenol-containing wastewater. About 92% of COD, 100% of phenol, and 82.4% of total nitrogen were successfully removed at a NH4+-N concentration of 200 mg L-1 with a phenol/NH4+-N mass ratio of 0.5 in the CSPN/A process. Furthermore, a shock loading of 300 mg phenol L-1 with a phenol/NH4+-N mass ratio of 1.5 led to a complete failure of partial nitritation, but the performance was rapidly recovered by the increase of NH4+-N concentration. Although the activities of ammonium-oxidizing bacteria and anammox bacteria were severely inhibited at a phenol/NH4+-N mass ratio of 1.5, the enrichment of efficient phenol degraders in the CSPN stage could strengthen the performance robustness of partial nitritation and anammox process. Therefore, this study presented a new insight on the feasibility of the anammox process for treating high-strength ammonium and phenol-containing wastewater.
... In fact, the RSM technique has been rarely used in the single-stage system with deammonification, but is well applied in this study. As a result, the nitrogen removal performance better than the reported values can be achieved (Gong et al., 2007;Lackner et al., 2014;Li et al., 2011;Zhou et al., 2018). This finding was verified through both statistical technique and experimental data. ...
A partial nitritation (PN)/anaerobic ammonium oxidation (ANAMMOX) process in sequencing batch reactor (SBR) was successfully developed to treat high-strength ammonium wastewater. The feed distribution in the SBR cycle and sub-cycles was considered as the main operating strategy, and was optimized using a response surface methodology (RSM)-based optimization technique. In the SBR cycle, the maximum nitrogen removal rate (NRR) of 0.79 ± 0.01 kg m-3 d-1 was achieved by applying a feed distribution strategy that considered the kinetic characteristics of ANAMMOX and ammonia oxidizing bacteria (AOB). However, this strategy negatively affected the nitrogen removal efficiency (NRE) due to alkalinity loss. Therefore, the feed distribution in the SBR sub-cycles with respect to the NRE and the NRR was further studied. The nitrogen removal performance was optimized in the optimum region and an NRE of 88% and an NRR of 0.84 kg m-3 d-1 were achieved. The optimized model was verified in confirmation test. The RSM-based optimization results provide insights into the feed distribution strategy for achieving single-stage PN/ANAMMOX SBR operation.
... For example, in anammox (Johansson et al., 2017) and aerobic systems (Lin et al., 2012), phosphorus precipitates have been encountered (Huang et al., 2015). This can both contribute to phosphorus removal and open up possibilities for recovery of this nutrient, but it is also associated with reduced reactor performance (Li et al., 2011). Phosphorus precipitation can also be actively induced by addition of metal salts inside aerobic granular sludge reactors to supplement biological phosphorus removal (Pronk et al., 2015). ...
Wastewater treatment processes with granular sludge are compact and are becoming increasingly popular. Interest has been accompanied by the development of mathematical models. This contribution simultaneously reviews available models in the scientific literature for anaerobic, aerobic and partial nitritation-anammox granular sludge reactors because they comprise common phenomena (e.g. liquid, gas and granule transport) and thus pose similar challenges. Many of the publications were found to have no clearly defined goal. The importance of a goal is stressed because it determines the appropriate model complexity and helps other potential users to find a suitable model in the vast amount of literature. Secondly, a wide variety was found in the model features. This review explains the chosen modelling assumptions based on the different reactor types and goals wherever possible, but some assumptions appeared to be habitual within fields of research, without clear reason. We therefore suggest further research to more clearly define the range of operational conditions and goals for which certain simplifying assumptions can be made, e.g. when intragranule solute transport can be lumped in apparent kinetics and when biofilm models are needed, which explicitly calculate substrate concentration gradients inside granules. Furthermore, research is needed to better mechanistically understand detachment, removal of influent particulate matter and changes in the mixing behaviour inside anaerobic systems, before these phenomena can be adequately incorporated in models. Finally, it is suggested to perform full-scale model validation studies for aerobic and anammox reactors. A spreadsheet in the supplementary information provides an overview of the features in the 167 reviewed models.
... It was reported that Ca 2+ had a positive effect on the aggregation of anaerobic bacteria (de Graaff et al., 2011;Tiwari et al., 2006), since Ca 2+ and other polyvalent cations could form bridges between negatively charged groups on cell surfaces and the support material (Pol et al., 2004;Schmidt and Ahring, 1994). However, Ca 2+ concentration as low as 41 mg/L was reported to have no significant effects on the aggregation of anammox bacteria (van der Star et al., 2008) (Li et al., 2011;Trigo et al., 2006). ...
Rapidly growing discharge of nitrogen-rich saline wastewater has significantly affect environment. However, due to the inhibition resulting from high salinity on microbes, it is still a challenge to treat nitrogen-rich saline wastewater efficiently. Anammox process, as a cost-effective and environment-friendly nitrogen removal approach, has shown a potential in treating nitrogen-rich saline wastewater. This review is conducted from a critical perspective and provides a comprehensive overview on the performance of anammox process treating nitrogen-rich saline wastewater. Two strategies including freshwater-derived anammox bacteria acclimatization and marine anammox bacteria enrichment are evaluated. Second, effects resulting from salinity on the performance of anammox reactor, the microbial communities and sludge characteristics are discussed. Third, salinity-tolerant mechanism of anammox bacteria is analyzed. This review also reveals some critical knowledge gaps and future research needs, which benefits application of anammox process to treat nitrogen-rich saline wastewater.
... The strategy of mechanical mixing together with aeration would improve the nitrogen removal rate of CANON granular sludge. Furthermore, most studies about CANON granular sludge have been focused on wastewater with low C/N ratio and high ammonia [11,13,14]. The application of CANON granular sludge to treat low-ammonia sewage with organic matter in a mainstream could save more energy [15][16][17]. ...
The completely autotrophic nitrogen removal over nitrite (CANON) process is an important component of energy self-sufficient sewage treatment plants, and the use of aerobic granular sludge is a profitable choice for the CANON process. In this study, the performance and microbial characteristics of CANON granular sludge were investigated for treating synthetic and mainstream domestic sewage. The average nitrogen removal rate (NRR) was 3.22 kg N m⁻³ d⁻¹ during the high-rate operating period with high MLSS (4.09 g L⁻¹) and DO (∼1.0 mg L⁻¹) for treating synthetic sewage. When the influent was mainstream sewage, the average NRR was 1.11 kg N m⁻³ d⁻¹. The effluent nitrate concentration was very low, and nitrate build-up was not found. High-throughput pyrosequencing results indicated that, Nitrosomonas and Candidatus Brocadia were the dominant genus in ammonia oxidizing bacteria (AOB) and anaerobic AOB (AAOB), respectively. The proportions of AOB and AAOB decreased during mainstream sewage treatment, but the reactor maintained good performance. The results confirmed the feasibility of using CANON granular sludge for treating mainstream sewage.
... After the physical trapping effect, the anammox biofilm would eventually grow on the surface of the biocarriers. Compared with one-stage processes, two-stage partial nitritation/anammox processes segregated the anammox process and the partial nitritation process, which firstly could avoid the inhibition on anammox bacteria due to oxygen exposure (Li et al., 2011), and achieve higher AOB activity in partial nitritation reactor because higher DO concentration could be applied (Regmi et al., 2014(Regmi et al., , 2015. In order to provide equimolar ratio of NH 4 þ -N and NO 2 À -N for subsequent anammox process, the normal strategy was to biologically oxidize about half of the ammonium to nitrite (Ma et al., 2011;Wyffels et al., 2004), which often rely on NO 3 À , NO 2 À , and NH 4 þ sensors for aeration control (Regmi et al., 2014). ...
The conventional biological processes for municipal wastewater are facing the challenges of high energy consumption and production of excessive sludge. To address these two emerging issues, this study demonstrated the feasibility to integrate mainstream anammox into an A-2B process for municipal wastewater treatment towards energy-efficient operation with reduced sludge production. In the proposed A-2B process, an anaerobic fixed bed reactor (AFBR) served as A-stage for COD capture, an anammox moving bed biofilm reactor (MBBR) was employed as B2-stage, which received effluent containing nitrite from a sequencing batch reactor (SBR) at B1-stage. The results showed that under the operation conditions studied, 58% of influent COD was converted methane gas at A-stage, and 87% total inorganic nitrogen (TIN) removal was achieved with the effluent TIN concentration of 6.5 mg /L. Moreover, it was shown that at least 75% of sludge reduction was obtained due to the COD capture at A-stage. The high-throughput sequencing analysis further revealed that Candidatus Kuenenia was the dominant genus responsible for the observed anammox at B2-stage MBBR. This study clearly demonstrated a novel process configuration for sustaining mainstream anammox for municipal wastewater reclamation towards energy-efficient operation with minimized sludge production.
... kg N/(m 3 Ád) in a one-stage reactor (Van Hulle et al., 2010). The anammox reactor was separated from the nitritation reactor, so that the activity of anammox could be enhanced as no inhibition from dissolved oxygen existed in the nitrification reactor (Li et al., 2011). ...
