Mature Landfill Leachate Research Articles

Performance of a fuel cell coupled with Pt-Te nanowires for the removal of the organic matter in landfill leachate

Performance of a fuel cell coupled with Pt-Te nanowires for the removal of the organic matter in landfill leachate

The molecular differences of young and mature landfill leachates: Molecular composition, chemical property, and structural characteristic

Landfill leachate is a highly contaminated and complex organic wastewater. It can be categorized into young (YL) and mature leachate (ML) based on the landfill age, with significant differences in the composition of organic matter, resulting from the significant differences in humification degree. To compare the organic composition of YL and ML, ESI FT-ICR MS was applied to systematically investigate their molecular composition, chemical properties, and structural characteristics. The molecular weight of YL organics was lower than that of ML organics. In addition, O/C and H/C distributions of YL and ML organics were significantly different. YL mainly consisted of CHO compounds and aliphatic compounds. ML mainly consisted of CHON compounds and high oxygen highly unsaturated and phenolic compounds. The unsaturation degree of YL organics was expressed by carbon double bond equivalents ((DBE-C)/C = −0.0336) and was not significantly different from that of ML (−0.0241), but nominal oxidation state of carbon (NOSC = −0.8010) and aromaticity (AImod = 0.1254) of YL were significantly lower than of ML (NOSC = −0.0692; AImod = 0.2464). In addition, YL and ML organics were rich in functional groups, but the YL organics contained more straight-chain structures. The ML organics contained fewer straight-chain structures, a larger number of benzene-ring structures, and more oxygen-containing functional groups. The more complex structural properties of ML organics may be the result of the transformation of YL organics after a long series of reactions, including electrocyclization, decarboxylation, and hydrogen abstraction reactions, which eventually increased the humification degree of leachate organic matter.

Novel strategy for controlling colloidal instability during the flocculation pretreatment of landfill leachate

Flocculation is an economical and effective pretreatment technology for landfill leachate. An iron salt flocculant is often used in landfill leachate pretreatment, but the flocs that are formed are affected by the operation sequence, which subsquently influences flocculation. This study selected three representative landfill leachates (i.e., mature landfill leachate (MLL), biologically treated landfill leachate (BTL), and nanofiltration concentrate leachate (NFCL)). The effect of different operation modes on the removal of organic matter from landfill leachate by flocculation was studied, and a strategy to control colloidal instability is put forward. The results revealed that adjusting the pH value to 9 using NaOH changes the zeta potential of leachate when the leachate and sludge are not separated, which affects electric neutralization in flocculation and colloidal stability. Furthermore, a part of the collected organic matter is released to the leachate again, leading to a decrease in the flocculation pretreatment effect. In this improved flocculation process, the leachate and sludge are first separated, and the pH value of the system is then adjusted to 9. The effect of OH− on electric neutralization is avoided and the remaining Fe3+ can further remove organic matter from leachates. Finally, the UV254 removal efficiencies of MLL, BTL, and NFCL increased by 20.38%, 28.67%, and 22.67%, respectively. In a full-scale application, i.e., an NFCL treatment facility, the UV254 removal efficiency during long-term operation reached 87.50%. Therefore, the colloid instability control strategy this study proposes can provide theoretical and engineering references for the flocculation pretreatment of landfill leachate.

Anammox-Based Processes for Mature Leachate Treatment in SBR: A Modelling Study

Mature landfill leachates are characterized by high levels of ammoniacal nitrogen which must be reduced for discharge in the sewer system and further treatment in municipal wastewater treatment plants. The use of anammox-based processes can allow for an efficient treatment of ammonium-rich leachates. In this work, two real scale sequencing batch reactors (SBRs), designed to initially perform partial nitritation/anammox (PN/A) and simultaneous partial nitrification and denitrification (SPND) for the treatment of ammonium-rich urban landfill leachate, were modelled using BioWin 6.0 in order to enable plant-wide modelling and optimizing. The constructed models were calibrated and validated using data from long- and short-term (one cycle) SBR operation and fit well to the main physical-chemical parameters (i.e., ammonium, nitrite and nitrate concentrations) measured during short-term (one cycle) operations. Despite the different strategies in terms of dissolved oxygen (DO) concentrations and aeration and mixing patterns applied for SBR operation, the models allowed for understanding that in both reactors the PN/A process was shown as the main contributor to nitrogen removal when the availability of organic carbon was low. Indeed, in both SBRs, the activity of nitrite oxidizing bacteria was inhibited due to high levels of free ammonia, whereas anammox bacteria were active due to the simultaneous presence of ammonium and nitrite and their ability to recover from DO inhibition. Increasing the external carbon addition, a prompt decrease of the anammox biomass was observed, with SPND becoming the main nitrogen removal mechanism. Models were also applied to estimate the production rates of nitrous oxide by aerobic ammonia oxidizing bacteria and heterotrophic denitrifiers. The models were found to be a robust tool for understanding the effects of different operating conditions (i.e, temperature, cycle phases, DO concentration, external carbon addition) on the nitrogen removal performances of the two reactors, assessing the contribution of the different bacterial groups involved.

Development of a novel partial nitrification, fermentation-based double denitrification bioprocess (PN-F-Double/DN) to simultaneous treatment of mature landfill leachate and waste activated sludge

Introducing fermentation technology into sewage treatment is a sustainable development concept, but future application still faces many challenges. A novel partial nitrification, fermentation-based double denitrification bioprocess (PN-F-Double/DN) was achieved in three separated SBR type reactors, simultaneously treating high ammonia (1766.6 mg/L) mature landfill leachate and external waste activated sludge (WAS, MLSS = 20.6 g/L). Firstly, NH4+-N was oxidized to NO2−-N in partial nitrification reactor (PN-SBR), with nitrite accumulation ratio (NAR) of 96.5%. Next, the PN-SBR effluent (NO2−-N = 1529.8 mg/L) coupled with the WAS were introduced to an anoxic reactor for integrated fermentation-denitrification (IFD-SBR). The occurrence of fermentation was mainly attributed to free nitrous acid (FNA, nitrite protonate form) promoting the splitting decomposition of sludge spatial configuration and interfacial forces. The released volatile fatty acids (VFAs) were utilized in situ during the denitrification process (NO2−-N→N2), obtaining 0.6 kg/m3•d nitrogen removal rate and 3.3 kg/m3•d sludge reduction rate. Finally, undesirable fermentation by-products from IFD-SBR (NH4+-N = 119.2 mg/L) were further removed in the endogenous post-denitrification reactor (EPD-SBR) through operational strategy of anaerobic/aerobic/anoxic by residual VFAs as the carbon source. In the EPD-SBR, Defluviicoccus (0.9%) and Candidatus Competibacter (5.8%) dominated carbon source storage and nitrogen removal, acting as a typical denitrifying glycogen-accumulating organism (DGAO), with an intracellular carbon storage efficiency of 83.1% and nitrogen removal contribution of 93.7%. After 200 days of operation, the PN-F-Double/DN process provided effluent containing, on average, 1.86 mg/L NH4+-N and 5.5 mg/L NOx−-N, with 98.5% TN removal. Compared with traditional bioprocesses, PN-F-Double/DN allowed up to 25% saving in aeration energy consumption, 100% decrease in carbon source demand, and achieve 46.1% external WAS reduction.

Struvite precipitation as pretreatment method of mature landfill leachate

The pretreatment method of mature landfill leachate during the dry session was evaluated using struvite precipitation. Then, magnesium sulfate (MgSO4·7H2O) and phosphoric acid wastewater were used as precipitation reagents. Visual MINTEQ was used to predict the formation of struvite and compared to the laboratory experiments. Effective magnesium dosage and pH were at [Mg]:[PO4] 2:1 and pH 9 ± 0.2 under initial phosphate content of leachate with ~28% ammonium, ~64% phosphate, and ~5% COD were removed. Removal efficiency was enhanced with the addition of phosphate with an effective molar ratio at [Mg]:[NH4]:[PO4] 2:2.5:1 or equal to 81.45 mL phosphoric wastewater. Experimental results were in good agreement with visual MINTEQ prediction when humic acid and mass transfer for ammonium were included. XRD and SEM-EDX examined the struvite content and crystal characteristics. Magnesite as alternative magnesium source was considered applicable to prevent excessive anion but altered the purity of the produced struvite.

Stable nitritation of mature landfill leachate via in-situ selective inhibition by free nitrous acid

In-situ free nitrous acid (FNA) and free ammonia (FA) treatments are more feasible than side-stream methods to achieve nitritation. To assess the optimum conditions and long-term performance of in-situ inhibition by FNA, batch tests and a sequencing batch reactor (SBR) treating mature landfill leachate were conducted and established. As a result, the selective inhibition characteristic by FNA was more conspicuous than FA, and FNA (0.175 mg N/L, 6 h) treatment are more biocidal to nitrite oxidizing bacteria (NOB). Moreover, ammonia oxidizing bacteria (AOB) were more sensitive to the FA environment but its activity recovered preferentially compared to NOB. The SBR achieved a sustained nitrite accumulation rate above 90% for 200 days, with a significant decrease of NOB activity and microbial abundance according to qPCR and 16S rRNA gene sequencing results. In-situ selective inhibition by FNA (0.175 mg N/L, 6 h) has been proved to be effective to maintain stable nitritation.

Improving stability of mainstream Anammox in an innovative two-stage process for advanced nitrogen removal from mature landfill leachate

This study presents an innovative mainstream Anammox based on multiple NO2−-N supplement pathways to treat actual mature landfill leachate over 180 days. Desirable effluent quality of 11.8 mg/L total nitrogen (TN) and nitrogen removal efficiency of 98.8% were achieved despite fluctuation conditions of 1.5-fold influent substrates and 8.0-fold dissolved oxygen overload. Nitrogen mass balance confirmed Anammox was the dominant nitrogen removal pathway, contributing up to 87.9%. Functional genes of ammonia monooxygenase (amoA), hydrazine synthase (hzsB), and ratio of nitrate/nitrite reductase were highly detected. Anammox genera, Candidatus_Kuenenia (4.1%) and Candidatus_Brocadia (5.3%) were dominant in two functional systems, respectively, due to the different affinity of nitrite, oxygen, and organic carbon. As an economical and sustainable technology, the innovative process enabled a 95.1% decrease in organic carbon demand, a 61.5% reduction in aeration energy consumption, and 77.6% lower biomass production compared with traditional nitrification–denitrification process.

Recombinant Rhodococcus erythropolis expressing HAO and AMO genes promotes nitrogen and organic matter removal efficiency in the treatment of landfill leachate

AbstractThe purpose of this study was to investigate the treatment efficacy of recombinant Rhodococcus erythropolis (RH) expressing hydroxylamine oxidase (HAO) and ammonia monooxygenase (AMO) genes (rRH‐HA) in removing nitrogen and organic matter in landfill leachate. Results demonstrated that rRH‐HA efficiently expressed HAO and AMO during the treatment of landfill leachate in aerobic system. Enhanced rRH‐HA production increased pH control and the activity and stability of activated sludge (AS); decreased carbon source addition and decreased total organic carbon (TOC), chemical oxygen demand (COD), organic matter and heavy metal concentration compared with AS system. In conclusion, data indicate that enhanced rRH‐HA production promotes pollutants removal efficiency in the treatment of landfill leachate.

Treatment of young and stabilized landfill leachate by integrated sequencing batch reactor (SBR) and reverse osmosis (RO) process

In this paper, the performance and effectiveness of combined sequencing batch reactor (SBR) and reverse osmosis (RO), as well as differences in treating young and matured landfill leachate, was investigated. Samples of young and stabilized leachate were collected from a municipal landfill in north-eastern Poland. The general pollution parameters, organic and inorganic indicators were determined in raw leachate and after each step of leachate treatment. The performance characteristics of the reverse osmosis system were made based on permeate flux, electroconductivity removal rate, concentration factor and removal rate. The use of biological pre-treatment had a good efficiency (>98% for both leachate) in ammonia nitrogen removal. The SBR treatment effectiveness for BOD (64%), Fe (29%), Cl− (0.2%) and Total Organic Carbon (-5.3%) was lower for young leachate compared to a stabilized. Pretreated leachate was directed to a RO system which was characterized by better operational parameters during the filtration of stabilized leachate: the average permeate flux was higher by 3.3 L/m2⋅s⋅10−6 and the filtration time was shorter by 110 min compared to the young leachate. The main reason of membrane clogging during young leachate filtration was a higher content of organic matter and its neutralization by Ca2+ and N-NH4+ presented in leachate, causing clogging of negatively charged RO membrane. Another reason could be complex formation between iron and natural organic matter that may precipitate on the membrane surface or inside the pores. This study has shown a high removal efficiency (over 80%) of the integrated SBR-RO method for all analyzed parameters.

In-situ neutralize methane emission from landfills in loess regions using leachate

In loess regions, landfilling is the predominant solid waste disposal and loess is usually used as landfill cover soil. However, the methane (CH4) bio-oxidation activity of virgin loess is usually below 0.01 µmol/(h g-soil). In this study, we proposed a method to improve CH4 removal capacity of loess by amelioration with mature landfill leachate, which is in-situ, easily available, and appropriate. The organic matter content of the ameliorated loess increased by 180%, reaching 19.69–24.88 g/kg-soil, with more than 90% being non-leachable. The abundance of type I methane-oxidizing bacteria and methane monooxygenase gene pmoA increased by 5.0 and 79 times, respectively. Consequently, the maximum CH4 removal rate of ameliorated loess reached 0.74–1.41 µmol/(h g-soil) at 25°C, which was 4-fold higher than that of water-irrigated loess. Besides, the CH4 removal rate peaked at 10 vt% CH4 concentration and remained at around 1.4 µmol/(h g-soil) at 15°C–35°C. The column test confirmed that the highest CH4 removal efficiency was at 30–10 cm below the surface, reaching 26.1%±0.4%, and the 50-cm-thick loess layer irrigated with leachate achieved more than 85% CH4 removal efficiency. These results could help to realize carbon neutrality in landfill sites of global loess regions.

Insight into removal TOC and NH4+ from mature landfill leachate using coupled bio-coagulation from Moringa oleifera seeds and ZVI/H2O2 process

In this research, protein was extracted from Moringa oleifera (MO) seeds using protease from Bacillus licheniformis and evaluated for effectiveness as a bio-coagulant to be applied in leachate pretreatment. Leachate samples were collected from part of a closed municipal landfill with total organic carbon (TOC) of 1465 mg/L and ammonium ion (NH4+) of 1245 mg/L. A Fenton-like reaction with a mediated zero-valent iron (ZVI) system was applied to the leachate after coagulation. A response surface methodology (RSM) based on a Box-Behnken design (BBD) was adopted to optimise the Fenton-like process. A quadratic polynomial model was used on the data, with R2 of 0.996 and 0.998 for total organic carbon (TOC) and NH4+ removal, respectively. Influence of three main factors was investigated, namely pH, molar ratio of H2O2/ZVI, and concentration of H2O2 for TOC and NH4+ removal. In optimum conditions of 30 min reaction time, pH = 3, [H2O2] =43.82 mM, molar ratio H2O2/ZVI of 3.89, effectiveness of elimination of TOC and NH4+ was 59.98 % and 98.3 %, respectively. Combined technology of bio-coagulant and Fenton-like reaction was confirmed to be a competent process for treating leachate, with 72.6 % TOC and 98.98 % NH4+ removal. Supposed operation costs for the coupling of treatments can be estimated at 5.67 $/m3. Thus, reductions in NH4+ and mineralization were achieved cost-effectively by combining bio-coagulation with protein extracted from MO seeds and a Fenton-like process activated by ZVI.

A novel additional carbon source derived from rotten fruits: Application for the denitrification from mature landfill leachate and evaluation the economic benefits

Rotten fruits could be used as an available resource due to the high organic content and low pollution introduction. In this study, four kinds of rotten fruits including banana, apple, pear and grape, were utilized as additional carbon source to improve the nitrogen removal from mature landfill leachate. With the optimal condition of carbon–nitrogen ratio 6.5 and operation time 2 d, the rotten banana group had a higher denitrification rate of 11.78 mg/(gVSS·h) than that of other groups, corresponding the 99.55% of nitrate nitrogen (NO3−-N), 99.36% of total nitrogen and 94.60% of organics removal. High carbon–nitrogen ratio would contribute to more degradation of organic and humus matters, and the low cost of 0.65 €/kgNO3−-N was obtained. Biodiversity analysis indicated that denitrificans and organic-degrading bacterial were enriched after the addition of rotten banana. Overall, the novel carbon source of rotten banana was a cost-efficient choice for the denitrification.

Scaling-Up and Long-Term Operation of a Full-Scale Two-Stage Partial Nitritation-Anammox System Treating Landfill Leachate

(1) Background: Biological treatment of leachate in landfill sites using anaerobic ammonium oxidation (anammox) is challenging because of the intrinsic characteristics of this complex wastewater. In this work, the scale-up and subsequent full-scale implementation of the PANAMMOX® technology (LEQUIA Research Group, Girona, Catalonia, Spain) are presented as a case study to achieve long-term nitrogen (N) removal from mature leachate mostly through a completely autotrophic pathway. (2) Methods: The treatment system consists of two sequencing batch reactors (SBRs) running in series to individually operate partial nitritation (PN) and anammox (A). Following biological treatment, physicochemical oxidation (i.e., Fenton-based process) was used to remove the remaining non-biodegradable organic matter. A cost analysis comparative was conducted in relation to the former technology used on-site for treating the leachate. (3) Results: The scale-up of the process from pilot- to full-scale was successfully achieved, finally reaching an average removal of 7.4 kg N/d. The composition of the leachate changed over time, but especially once the landfill site stopped receiving solid waste (this fact involved a marked increase in the strength of the leachate). The adjustment of the alkalinity-to-ammonium ratio before feeding PN-SBR helped to improve the N-removal efficiency. Values of conductivity above 25 mS/cm in A-SBR could negatively affect the performance of the anammox process, making it necessary to consider a dilution strategy according to the on-line monitoring of this parameter. The analysis of the operational costs showed that by implementing the PANAMMOX® technology (LEQUIA Research Group, Girona, Catalonia, Spain) in the landfill site, savings up to 32% were achievable. (4) Conclusions: Treatment of mature landfill leachate in such a two-stage PN-A system was demonstrated as feasible and economically appealing despite the complexity of this industrial wastewater. Accurate expert supervision of the process was a key factor to reaching good performances.

Optimization of the humic acid separation and coagulation with natural starch by RSM for the removal of COD and colour from stabilized leachate.

The removal of concentrated colour (around 5039 Pt-Co) and chemical oxygen demand (COD; around 4142 mg L-1) from matured landfill leachate through a novel combination of humic acid extraction and coagulation with natural oil palm trunk starch (OPTS) was investigated in this study. Central composite design from response surface methodology of Design Expert-10 software executed the experimental design to correlate experimental factors with desired responses. Analysis of variance developed the quadratic model for four factors (e.g. coagulant dosage, slow mixing speed and time and centrifugation duration) and two responses (% removal of colour, COD). The model confirmed the highest colour (84.96%) and COD (48.84%) removal with a desirability function of 0.836 at the optimum condition of 1.68 g L-1 coagulant dose, 19.11 rpm slow mixing speed, 16.43 minutes for mixing time and 35.75 minutes for centrifugation duration. Better results of correlation coefficient (R2 = 0.98 and 0.96) and predicted R2 (0.94 and 0.84) indicates the model significance. Electron microscopic images display the amalgamation of flocs through bridging. Fourier transforms infrared spectra confirmed the existence of selected organic groups in OPTS, which eventually signifies the applied method.

Efficient treatment of mature landfill leachate with a novel composite biological trickle reactor developed using refractory domestic waste and aged refuse

Municipal solid waste classification is a major livelihood project, while the classified materials are deficiently utilized, especially the inert waste. In this study, a composite biological trickle reactor, packed with foam concrete, waste textile, animal bone and aged refuse, was developed for the treatment of mature landfill leachate, and the function of reaction factors were investigated systematically. Results indicated that under the optimum conditions with mixed filler, temperature of 30 °C, hydraulic loading of 40 L/(m3·d), and aeration rate of 1.8 L/(h·L), the average removal rates of chemical oxygen demand, total nitrogen, ammonia nitrogen and total phosphorus were 85.02%, 76.00%, 99.90% and 96.83%. The reactor presented well buffering performance after 100 days operation, with a slightly accumulation of organic and nitrogen substances. Biological analysis showed that the main phyla in all fillers were Actinobacteria and Proteobacteria. The microbial diversity and richness of waste textile were inferior to those of animal bone, aged refuse and foam concrete. In the operation system, the alternate aerobic–anoxic–anaerobic environment was structured, and the contaminants removal was due to the comprehensive function of adsorption, promotional biotreatment and chemical precipitation. All the results demonstrated that this novel trickle reactor was an excellent choice for leachate treatment because of the low cost and superior efficiency.

Efficient and advanced nitrogen removal from mature landfill leachate via combining nitritation and denitritation with Anammox in a single sequencing batch biofilm reactor

A novel combined partial nitrification-Anammox and partial denitrification-Anammox (PnA/PdA) single sequencing batch biofilm reactor (SBBR) was established to realize efficient and advanced nitrogen removal from mature landfill leachate with low biodegradability. Nitrogen removal rate and nitrogen removal efficiency were increased to 2.83 ± 0.06 kgN/(m3∙d) and 98.6 ± 0.2% by stepwise increase of dissolved oxygen (DO, from 0.5 to 3.5 mg/L) and continuous carbon source feeding. Comparable activities of ammonia oxidation bacteria and Anammox bacteria were realized during aerobic period. More organic carbon was redirected from complete denitrification to partial denitrification during anoxic period. The main pathway PnA jointly synergized with PdA, which contributed to 76.04% and 19.44% nitrogen removal, respectively. Nitrosomonas, Thauera, and Kuenenia dominated in floc sludge (0.78%, 5.38%, and 1.14%, respectively) and biofilm (0.34%, 5.18%, and 0.98%, respectively). Overall, this study provides new insight into the high-efficiency treatment of landfill leachate at full-scale landfill sites.

Solar photo-Fenton oxidation of mature landfill leachate: empirical model and chemical inferences

ABSTRACT In this study, a stochastic model was applied to investigate the degradation of landfill leachate by solar photo-Fenton processes. The coefficient of determination (R 2) between experimental and predicted data ranged from 0.9958–0.9995. The optimal conditions for the initial phase (lasting 5–22 min) were high Fe2+ level, low pH level, and intermediate H2O2 level. For the second phase, optimal leachate degradation percentages were obtained by maintaining the pH, increasing H2O2, and decreasing Fe2+ to the lowest level. Determination of optimal reaction conditions (such as pH, Fe2+, and H2O2 values) for both degradation phases is of paramount importance for process scale-up. The major contribution of this study was the development of a tool that considers the effects of one or more reactions on organic carbon degradation. This was achieved by assessing the significance of the effects of experimental conditions on model parameters for the fast and slow steps of leachate degradation by advanced oxidation processes.

Pollutant Removal Efficiency of Different Units Along a Mature Landfill Leachate Treatment Process in a Membrane Biological Reactor-Nanofiltration Combined Facility

Properties of landfill leachate are complex. Therefore, leachate should be treated by combined processes with both biological and advanced methods. Due to the shortage of engineering-scale assessment data about the pollutant treatment contribution of individual process units, existing optimization methods still lack theoretical support. Here, a membrane biological reactor (MBR)+nanofiltration (NF) system with a capacity of 800 m3·d-1 was examined. Conventional physiochemical parameters and fluorescent parameters were examined to analyze the contribution of each process unit to treating mature landfill leachate. Furthermore, the transformation of dissolved organic matter (DOM) was evaluated using excitation emission matrix fluorescence spectroscopy-parallel factor (EEMs-PARAFAC). Results showed that the biological treatment removed soluble nitrogen (dissolved nitrogen, DN) by 74.7%, 54.6% occurred in the first-stage denitrification unit. The external ultrafiltration unit reduced dissolved chemical oxygen demand (COD) and dissolved organic carbon (DOC) by 92.2% and 93.3%, respectively. The nanofiltration unit effectively removed heavy metals and salts. Based on the tracking of DOM using fluorescent parameters, the first-stage denitrification unit was found to remove 75.4% of protein-like substances. The ultrafiltration unit mainly retained DOM with high hydrophilicity, while humus with high aromaticity was mainly retained by nanofiltration. The higher the degree of humification, the better the interception effect that was obtained. This indicates that biological treatment using the MBR process can be simplified, and ultrafiltration should prove reliable at preventing clogging during the treatment of mature landfill leachate.

New insights into co-treatment of mature landfill leachate with municipal sewage via integrated partial nitrification, Anammox and denitratation

As a low consumption and high efficiency process, Partial Nitrification-Anammox/denitratation (PNAD) was applied to co-treat mature landfill leachate with municipal sewage for 300 days. Specifically, ammonia (670.2 ± 63.7 mg N/L) contained in mature landfill leachate was firstly oxidized to nitrite (611.5 ± 28.1 mg N/L) in sequence batch reactor (SBRPN); meanwhile, organic matter in municipal sewage was partially removed in another reactor (SBROMR); finally, nitrite produced (611.5 ± 28.1 mg N/L) in SBRPN and ammonia (53.1 ± 6.4 mg N/L) residing in pretreated municipal sewage were simultaneously degraded through combined Anammox-denitratation process in an up-flow anaerobic sludge bed (UASBAD). A satisfactory effluent quality of 10.3 mg/L TN was obtained after long-term operation, with Anammox and denitrification contributing to 86.2% and 5.8% nitrogen removal efficiency, respectively. Mass balance confirmed 67.2% nitrate generated from Anammox could be reduced to nitrite and in-situ reused. Anammox bacteria genes and nitrate reductase/nitrite reductase ratio were highly detected, accelerating combined Anammox-denitratation. Further, Ca. Brocadia triumph among various Anammox bacteria groups, increasing from 1.2% (day 120) to 3.6% (day 280).