Showing papers on "Enhanced biological phosphorus removal published in 2023"
TL;DR: In this paper , de novo granulation of sewage-borne microorganisms without using activated sludge (AS) inoculum was investigated in bench-scale sequencing batch reactors (SBR).
Abstract: Long start-up periods for granulating activated sludge and concerns on granular stability are the bottlenecks reported during implementation of novel aerobic granular sludge (AGS) technology in municipal wastewater treatment plants. Here, de novo granulation of sewage-borne microorganisms without using activated sludge (AS) inoculum was investigated in bench-scale sequencing batch reactors (SBR). Data showed that formation of AGS from sewage-borne microorganisms was rapid and first granules appeared within one week. Granulation was indicated by appearance of biomass particles (size >0.12 mm), high biomass levels (∼8 g/L) and superior settling properties (SVI30 min: 30 mL/g). Granulation process involved distinct stages like formation of aggregates, retention of aggregates, and growth of millimetre sized granules. Simultaneous COD, nitrogen and phosphorous removal was established within 10 days of start-up in the SBR without using AS inoculum. However, phosphorus removal became stable after 50 days of start-up. Total nitrogen (TN) and total phosphorus (TP) removals of 92% and 70%, respectively, were achieved from real domestic wastewater. Furthermore, addition of granular activated carbon (GAC) had improved both granulation and biological nutrient removals. Interestingly, phosphorus removal became quite stable within 10 days of start-up in the SBR operated with GAC particles. TN and TP removals were found to be higher at >98% and >94%, respectively, in GAC-augmented SBR. Removal of ammonia and phosphorus were mediated by nitritation-denitritation and enhanced biological phosphorus removal (EBPR) pathways, respectively. The bacterial diversity of AGS was lower than that of sewage. Quantitative PCR indicated enrichment of ammonia oxidizing bacteria, denitrifying bacteria and polyphosphate accumulating organisms during granulation. De novo granulation of sewage-borne microorganisms is a promising approach for rapidly cultivating AGS and establishing biological nutrient removal in sewage treatment plants.
4 citations
TL;DR: In this paper , a two-stage aerobic granular sludge (AGS) system was developed to treat municipal wastewater, which achieved high removal efficiencies of phosphorus and nitrogen under a low influent carbon/nitrogen ratio of 5.4.
3 citations
TL;DR: In this paper , a review compiles the production method of SAFL and the progress of its application as a biological nutrient removal (BNR) carbon source, which can significantly improve the nutrient removal efficiency of the BNR process.
2 citations
TL;DR: In this paper , a comparative study was conducted for the AAO process and its two upgrading processes, five-stage Bardenpho and AAO coupling moving bed bioreactors (AAO + MBBR), using long-term operation data of six full-scale wastewater treatment plants.
2 citations
TL;DR: In this article , the authors examined the impact of pH on a Tetrasphaera PAO enriched culture, over a pH range from 6.0 to 8.0 under both anaerobic and aerobic conditions, and found that pH has a substantial impact on the P release and uptake kinetics of PAOs.
2 citations
TL;DR: In this paper , polyphosphate accumulating organisms (PAOs) were introduced to an established photogranular culture and operated in sequencing batch mode with six cycles per day and alternating anaerobic (dark) and aerobic (light) phases.
2 citations
TL;DR: In this paper , a novel process for integrated partial nitritation/anammox (PN/A) and enhanced biological phosphorus removal (EBPR) in a single reactor employing integrated fixed film activated sludge was tested.
2 citations
TL;DR: In this paper , the authors focused on optimizing the SBR designs (selector and non-selector based) for EBPR and identifying the relationships between wastewater characteristics and phosphorus removal governed by typical microbial functions with the perspective of optimizing decentralized treatment systems of India.
Abstract: Enhanced biological phosphorus removal (EBPR) is a growing, succeeding, and recognized process for removing phosphorus biologically from wastewater. Four sequencing batch reactor (SBR) plants with capacities of 120, 87.5, 50, and 3 million L per day (MLD) from different Indian locations were analyzed for EBPR. The 120 MLD Varanasi, 87.5 MLD Mumbai, and 50 MLD Gurgaon plants were working effectively for EBPR; >75% total phosphorus (TP) removal was observed at milligrams of readily biodegradable chemical oxygen demand (rbCOD) per milligram TPremoved of 12.0, 14.4, and 18.6, respectively; however, the 3 MLD Roorkee SBR was working mainly as adequate nitrogen removing technology at milligrams rbCOD/mg TPremoved<8. The linear increasing trend was observed between rbCOD/COD (%) and EBPR (%) at R2=0.99 (p<0.05 and r=0.99) in plants. Optical microscopic examinations were performed to identify the intracellular polymers [poly-β-hydroxybutyrate (PHB) and polyphosphates] in the EBPR sludge. This study focuses on optimizing the SBR designs (selector and non-selector based) for EBPR and identifying the relationships between wastewater characteristics and phosphorus removal governed by typical microbial functions with the perspective of optimizing decentralized treatment systems of India.
1 citations
TL;DR: In this article , the role of bacteria in the acidogenic phosphorus release (APR) process was investigated and it was proved that bacteria-mediating metal reductive dissolution approach could efficiently release the reducible metal compounds (such as Fe-P) from complex mixture, which can be extended to many other scenarios regarding resource extraction and recovery.
1 citations
TL;DR: In this paper , a pair of 3 L/h lab-scale continuous flow A²/O and S2EBPR reactors were synchronously started and operated for 150 days, and the sludge volume index and the microbial richness were investigated in different operating conditions to obtain some rules of sludge bulking.
Abstract: Side-stream EBPR (S2EBPR) process was regarded as a promising innovative modification and emerging alternative to EBPR configurations, and the research on controlling and preventing its sludge bulking should also be paid more attention to. In this study, a pair of 3 L/h lab-scale continuous flow A²/O and S2EBPR reactors were synchronously started and operated for 150 days. After 54 days of adjustment and maintenance, the reactors were successfully started. However, considering that the sludge bulking problem in the reactors occurred successively, the desired phosphorus removal parameters were not secured. By comparing the performance and stability of A²/O and S2EBPR reactors, the sludge ex situ EBPR metabolic activity, EPS, fluorescent matter, and microbial community were analyzed in detail. Besides, the sludge volume index and the microbial richness were investigated in different operating conditions to obtain some rules of sludge bulking. The experimental results showed that within the same operating parameters, the system stability was ordered sequentially as: side-stream ratio of 6.7% S2EBPR > side-stream ratio of 10.0% S2EBPR > A²/O > side-stream ratio of 13.3% S2EBPR due to limited sludge bulking. The study of sludge bulking in the 3 L/h lab-scale continuous flow reactors demonstrated that the parameter adjustment of S2EBPR could be used as an effective strategy to control or prevent sludge bulking.
1 citations
TL;DR: In this article , the metabolic changes and subsequent recovery of polyphosphate accumulating organisms and glycogen accumulating organisms (GAOs) were investigated at different sulfide concentrations, and the results showed that the metabolic activity of PAOs and GAOs was mainly related to H2S concentration.
TL;DR: In this article , the turnover of proteins and polysaccharides in an enrichment culture of polymeric substances (EPSs) relative to internal proteins was analyzed. And the authors showed that EPS is not preferentially consumed by flanking populations under stable EBPR process conditions.
Abstract: Abstract Polyphosphate accumulating organisms (PAOs) are responsible for enhanced biological phosphate removal (EBPR) from wastewater, where they grow embedded in a matrix of extracellular polymeric substances (EPS). EPSs comprise a mixture of biopolymers like polysaccharides or (glyco)proteins. Despite previous studies, little is known about the dynamics of EPS in mixed cultures, and their production by PAOs and potential consumption by flanking microbes. EPSs are biodegradable and have been suggested to be a substrate for other organisms in the community. Studying EPS turnover can help elucidate their biosynthesis and biodegradation cycles. We analyzed the turnover of proteins and polysaccharides in the EPS of an enrichment culture of PAOs relative to the turnover of internal proteins. An anaerobic-aerobic sequencing batch reactor (SBR) simulating EBPR conditions was operated to enrich for PAOs. After achieving a stable culture, carbon source was switched to uniformly 13 C-labeled acetate. Samples were collected at the end of each aerobic phase. EPSs were extracted by alkaline treatment. 13 C enrichment in proteins and sugars (after hydrolysis of polysaccharides) in the extracted EPS were measured by mass spectrometry. The average turnover rate of sugars and proteins (0.167 and 0.192 d −1 respectively) was higher than the expected value based on the solid removal rate (0.132 d −1 ), and no significant difference was observed between intracellular and extracellular proteins. This indicates that EPS from the PAO enriched community is not selectively degraded by flanking populations under stable EBPR process conditions. Instead, we observed general decay of biomass, which corresponds to a value of 0.048 d −1 . Key Points • Proteins showed a higher turnover rate than carbohydrates. • Turnover of EPS was similar to the turnover of intracellular proteins. • EPS is not preferentially consumed by flanking populations.
TL;DR: In this article , the authors review the different perspectives of mainstream and side-stream EBPR processes and particularly target contrasting views on hydrolysis and fermentation rates as well as anaerobic condition implementation and magnitude.
TL;DR: In this article , a side stream anaerobic reactor was used for enhanced sludge and phosphorus removal in an A2O SBR with a pre-anoxic chamber and an influent receiving inlet anaerodynamic reactor, which was operated at the average and lowest range of prevailing C/P ratio of 50 and 15 in the sewage.
TL;DR: In this paper , the authors investigated the establishment and stable operation of enhanced biological phosphorus removal (EBPR) by aerobic granular sludge (AGS) under mixed stress conditions induced by tetracycline (TC), sulfamethoxazole (SMX), ofloxacin (OFL), and roxithromycin (ROX).
TL;DR: In this paper , a new clade of Tetrasphaera-PAO was identified as the dominant PAO in a lab-scale phosphorus removal reactor and both phosphorus release and uptake by Tetrasphara-PAOs were more efficient with acetate than with glycerol and glucose.
Abstract: Tetrasphaera are polyphosphate-accumulating organisms (PAOs) prevalent in wastewater phosphorus removal systems. However, their metabolic versatility on carbon sources and correlations between carbon and phosphorus metabolism have not been fully elucidated. In this study, we identified a new clade of Tetrasphaera as the dominant PAO in a lab-scale phosphorus removal reactor. Both phosphorus release and uptake by Tetrasphaera-PAOs were more efficient with acetate than with glycerol and glucose. Fermentation of glycerol and glucose provided 4 and 1.7 times more energy than poly-P hydrolysis, and the trade-off between the two processes resulted in poor phosphorus release. Raman-fluorescence in situ hybridization suggested that polyhydroxyalkanoates (PHA) were synthesized from acetate. Glycogen, on the other hand, was the key energy storage compound formed using glycerol and glucose. Aerobic phosphorus uptake with acetate was 4.4 and 1.8 times more efficient than glycerol and glucose due to the additional energy supplied by PHA hydrolysis. The metabolic versatility and fermentation capability of Tetrasphaera-PAOs supported their prevalence in EBPR and underlined their potential metabolic interactions with other populations in the community. This work adds to our understanding of the genetic and metabolic divergence of Tetrasphaera-PAOs, providing useful information for the optimization of wastewater phosphorus removal under varied carbon source conditions.
TL;DR: In this article , ferrihydrite and magnetite were respectively dosed into bio-flocculation organic carbon capture system to comprehensively evaluate their potential improvements on phosphorus recovery from municipal wastewater.
TL;DR: In this article , a novel process was proposed for simultaneous denitrification and phosphorus (P) recovery, which facilitated the activity of denitrifying P removal (DPR) in P enrichment, which stimulated P uptake and storage, making P more readily accessible for release into the recirculated stream.
TL;DR: In this article , the effects of different influent ammonia nitrogen (NH3-N) concentrations (stage I to IV: 20, 40, 60 and 80 mg/L) on the phosphorus removal process were studied in an aerobic granular sludge (AGS) reactor under anaerobic/aerobic operating conditions.
Abstract: The effects of different influent ammonia nitrogen (NH3-N) concentrations (stage I to IV: 20, 40, 60 and 80 mg/L) on the phosphorus (P) removal process were studied in an aerobic granular sludge (AGS) reactor under anaerobic/aerobic operating conditions. The phosphorous removal performance kept stable at first (stage I and II) and then significantly deteriorated at further increase of influent NH3-N concentration (stage III and IV). On the process of microbial metabolism, further increase of NH3-N aggravated the competition between phosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) for carbon sources in the anaerobic phase, and weakened the P absorption capacity of PAOs in the aerobic phase. Denitrifying phosphate accumulating organisms (DPAOs) showed higher resistance to the increase of NH3-N concentration than traditional PAOs. On the functional structure of the system, microorganisms related to phosphorus removal in the system were mainly enriched in the granules, while microorganisms with heterotrophic denitrifying function dominated the sludge flocs to obtain higher growth advantage at high ammonia nitrogen concentration. The results of this study provide more insight into the biological stability of AGS systems.
TL;DR: In this paper , the denitrifying phosphorus removal process coupled with anaerobic/aerobic denitrification was started in a single-stage Membrane Aeration Biofilm Reactor (MABR).
Abstract: In the study, the denitrifying phosphorus removal process coupled with anaerobic/aerobic denitrification was started in a single-stage Membrane Aeration Biofilm Reactor (MABR). When the influent NO3−-N was 50.2 mg/L and the total phosphorus (TP) was 30.5 mg/L, the maximum Total Inorganic Nitrogen Removal Efficiency (TINRE) can reach 99.79 % and the Total Phosphorus Removal Efficiency (TPRE) can reach 82.62 % without the addition of any flocculant or precipitant. The phosphorus content in the substrate sludge was 4.10 %–6.15 %, which was higher than that in the initial biofilm or activated sludge (1.27 %–1.83 %). Based on 16S rRNA sequencing technology, it was found that Phosphorus-Accumulating Organisms (PAOs, Acinetobacter, relative abundance 0.02 % to 1.92 %) and Denitrifying Phosphorus-Accumulating Organisms (DPAOs, Flavobacterium (0.26 % to 5.39 %), Bdellovibrio (0.12 % to 1.48 %), and Pseudomonas (2.29 % to 1.28 %)) played pivotal roles in phosphorus removal. The enzyme gene reads of Complex I and Complex V processes were much more than that of Complex II- Complex IV, which indicated that Complex I and Complex V can be the main process for oxidative phosphorylation in the MABR. Moreover, four inorganic nitrogen metabolic processes, Dissimilatory Nitrate Reduction to Ammonium (DNRA), Assimilatory Nitrate Reduction Ammonium (ANRA), nitrification, and denitrification were found. Nitrifiers (Nitrosomonas (0.09 % to 0.19 %), Nitrospira (2.48 % to 0.06 %)), denitrifiers (Dokdonella (6.95 % to 2.11 %), Denitratisoma (0.42 % to1.48 %)), and aerobic denitrifiers (Pseudomonas (2.29 % to 1.28 %) and Thauera (4.75 % to 1.78 %)) contributed to nitrogen removal in the MABR. This study provided insights into the removal mechanism of nitrogen and phosphorus in a single-stage MABR.
TL;DR: In this article , the external sludge was first collected and fermented under a sludge retention time of 10 days, then introduced into SBR with a 1:15 sewage ratio, which revealed a gradual increase in the nitrite accumulation ratio to 34.7% in the SBR at the end of the oxic stage after 64 days of adding fermented sludge products.
Abstract: Although the addition of excess sludge fermentation products to improve nutrient removal from sewage is cost‐effective, its application has rarely been demonstrated. In this study, the external sludge was first collected and fermented under a sludge retention time of 10 days, then introduced into SBR with a 1:15 sewage ratio. The results revealed a gradual increase in the nitrite accumulation ratio to 34.7% in the SBR at the end of the oxic stage after 64 days of adding fermented sludge products. In addition, the average effluent total nitrogen and phosphorous decreased to 7.3 and 0.5 mg/L, corresponding to removal efficiencies of 86.7% and 95.5%, respectively. On the other hand, the use of the fermented sludge products as external organic carbon sources in the SBR increased the external sludge reduction ratio to 42.5%. High‐throughput sequencing demonstrated that the increase in the endogenous denitrifier community, polyphosphate‐accumulating organisms, and fermentation bacteria were the main factors contributing to the increase in nutrient removal and excess sludge reduction. The economic evaluation indicated that the operational cost of the pilot‐scale system saves 0.011$/m3 of sewage treated.
TL;DR: In this paper , the effect of high DCF concentrations (1.04 mg/dm3-12.5 mg/DM3; 0.25 mg/gTS-3.0 mg/GTS) on the efficiency of nitrifying, denitrifying and phosphate-accumulating organisms in the wastewater treatment cycle was discussed.
Abstract: Significant quantities of pharmaceutical substances enter biological wastewater treatment plants, where they interact with activated sludge microorganisms. An example of a pharmaceutical commonly used is the non-steroidal anti-inflammatory drug diclofenac (DCF). The presence of high concentrations of DCF in wastewater can disrupt nutrient removal processes, which are highly sensitive to external environmental factors. This paper discusses the effect of high DCF concentrations (1.04 mg/dm3–12.5 mg/dm3; 0.25 mg/gTS–3.0 mg/gTS) on the efficiency of nitrifying, denitrifying and phosphate-accumulating organisms in the wastewater treatment cycle. The condition of the activated sludge was assessed on the basis of the oxygen and nitrogen uptake rates values and the ability to biologically remove phosphorus compounds from the wastewater. The effect of DCF on the ability of methane-forming bacteria to produce biogas in the anaerobic digester was also investigated. None of the biochemical reactions of activated sludge were inhibited at applied DCF concentrations. A 33% reduction in biogas production was observed at a DCF dose of 0.0391 mg/gTS. Slight deviations from the typical course of biochemical transformation of ammonium compounds were recorded at a DCF concentration of 3 mg/gTS of sludge. However, in the concentration range studied, no negative effect of DCF, on the operation of the activated sludge, was found.
TL;DR: In this paper , the role of a denitrifying glycogen accumulating organisms, Candidatus_Competibacter, was re-explored given its overwhelming dominance.
TL;DR: In this article , the performance of the anaerobic/anoxic sequencing batch reactor (A2SBR) process was investigated to explore the microbial community structures of activated sludge systems.
Abstract: ABSTRACTAcclimatization of short-cut denitrifying polyphosphate accumulating organisms (SDPAOs), metabolic mechanism, and operating parameters were analyzed to investigate the performance of the anaerobic/anoxic sequencing batch reactor (A2SBR) process. The high-throughput sequencing technology was employed to explore the microbial community structures of activated sludge systems. The experimental results illustrated that SDPAOs were successfully enriched with three-phase inoculation for 36 days. The removal rates of TP and NO2--N were 93.22% and 91.36%, respectively, under the optimal parameters of a pH of 7.5, an SRT of 26 days, a temperature of 24 ℃ and a COD of 200.00 mg·L-1 using acetate as the carbon source. In the anaerobic stage, 82.20% external carbon source was converted into 88.78 mg·g-1 PHB, and the removal rate of NO2--N in the anoxic stage was characterized by ΔNO2--N/ΔPHB, anoxic ΔP/ΔPHBeffective was 0.289, which was higher than anaerobic ΔP/ΔCODeffective of 0.203. Ignavibacterium and Povalibacter with significant phosphorus removal ability were the dominant bacterial genera. The nitrogen and phosphorus removal could be realized simultaneously in an anaerobic/anoxic sequencing batch reactor. Therefore, this study provided an important understanding of the removal of nitrogen and phosphorus from low-carbon nitrogen wastewater.
TL;DR: In this article , the authors investigated AGS formation and BNR pathways while treating real domestic wastewater in a 2 m3 pilot-scale granular sequencing batch reactor (gSBR) operated without and with granular activated carbon (GAC) particles.
TL;DR: Wang et al. as discussed by the authors analyzed the species and fractions, and characterization of phosphorus during the sludge treatment process and discussed the nutritional value of phosphorus in the sludgery treatment process.
Abstract: Sludge treatment is an important part of wastewater treatment and the recovery and utilization of phosphorus from wastewater treatment plant (WWTP) is a challenge for sludge treatment and product disposal. In this paper, eight Chinese typical sludge treatment projects were selected to analyze the species and fractions, and characterization of phosphorus during the sludge treatment process. Furthermore, the nutritional value of phosphorus in the sludge treatment process and the land resource utilization value of phosphorus in the sludge treatment product were discussed. The results showed that the insufficient release of phosphorus to supernatant during anaerobic digestion (AD) of sludge is an important factor restricting phosphorus recovery. Phosphorus in sludge aerobic composting treatment products is mainly in the solid phase, and the concentration effect is beneficial for the phosphorus recovery potential. Phosphorus in sludge treatment products mainly exists in the form of non-apatite inorganic phosphorus, which indicates that improving the bioavailability of phosphorus in sludge treatment products is the key to realizing the nutritional value of the sludge products.
TL;DR: Zhang et al. as mentioned in this paper proposed a plant-biofilm oxidation ditch (PBOD) with different aeration conditions and plant types to investigate the parameter optimization of PBOD and internal mechanism of accelerated phosphorus removal.
TL;DR: In this paper , two lab-scale sequencing batch reactors (SBRs) with different sludge retention times (SRTs) were assessed for their EE2 and TP removal rates.
Abstract: Sewage treatment systems can prevent the direct discharge of endocrine disruptors, such as 17α-ethinylestradiol (EE2), into the environment. Treatment systems capable of promoting total phosphorus (TP) removal, such as sequencing batch reactors (SBRs), are promising in this regard. Two lab-scale SBRs with different sludge retention times (SRTs) were assessed for their EE2 and TP removal rates. Anaerobic/aerobic/anoxic phases with cycles of 6 h were used to treat sewage containing EE2 at a concentration of 5 μg L-1. The removal rates of chemical oxygen demand and TP were approximately 80% for both the SBRs. Partial nitrification was observed in the SBRs. Initially, concentrations of EE2 above 1.0 μg L-1 in the treated sewage were measured. These concentrations were smaller in SBR 1, which used lower SRTs; EE2 was removed by sludge sorption. After the 56th cycle, the concentrations of EE2 in the treated sewage were below 0.1 μg L-1 in both the SBRs, indicating that its removal may have occurred by biodegradation due to acclimation to the process. Therefore, both TP removal and nitrification seem to play an important role in EE2 removal by SBRs.
Keywords: A2O SBR, EE2 and TP removal, sewage treatments.
19 Apr 2023