Performance Of Sequencing Batch Reactor Research Articles

Performance evaluation and metagenomic analysis of sequencing batch reactor under transient 2,4,6-trichlorophenol shock

The transient chlorophenol shock under some emergency conditions might directly affect the pollutant removal of bioreactor. Therefore, the recovery of bioreactor performance after transient chlorophenol shock is a noteworthy issue. In the present research, the performance, antioxidant response, microbial succession and functional genes of sequencing batch reactor (SBR) were evaluated under transient 2,4,6-trichlorophenol (2,4,6-TCP) shock. The chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) removal efficiencies decreased sharply in the first 4 days after 60 mg/L 2,4,6-TCP shock for 24 h and gradually recovered to normal in the subsequent 8 days. The nitrogen removal rates and their corresponding enzymatic activities rapidly decreased after transient 2,4,6-TCP shock and then gradually increased to normal. The increase of antioxidant enzymatic activity, Cu-Zn SOD genes and Fe-Mn SOD genes contributed to the recovery of SBR performance. The abundance of genes encoding ammonia monooxygenase and hydroxylamine dehydrogenase decreased after transient 2,4,6-TCP shock, including amoA, amoC and nxrA. Thauera, Dechloromonas and Candidatus_Competibacter played key roles in the restorative process, which provided stable abundances of narG, norB , norC and nosZ. The results will deeply understand into the effect of transient 2,4,6-TCP shock on bioreactor performance and provide theoretical basis to build promising recoveries strategy of bioreactor performance.

Copper oxide nanoparticles influence on the performance of sequencing batch reactor and the transfer of antibiotic resistance genes by regulating bacterial quorum sensing system

The environmental pollution caused by copper oxide nanoparticles (CuO NPs) has attracted widespread attention. In this study, microbial community, key metabolic pathways and quorum sensing (QS) were investigated to reveal the impact of copper oxide nanoparticles (CuO NPs) on the performance of sequencing batch reactor (SBR) and the transfer of antibiotic resistance genes (ARGs). Results showed that under CuO NPs impact, the removal efficiency of COD, ammonium nitrogen (NH4+-N) and total nitrogen (TN) was stable at around 90%, 96% and 60%, respectively. However, removal efficiency of total phosphorus (TP) was reduced to below 60% under 0.1 mg/L and 1 mg/L CuO NPs exposure. Microbial community analysis showed CuO NPs was advantageous to the growth of key functional bacterial phyla Bacteroidetes, Proteobacteria and Patescibacteria. The relative abundance of Candidatus Accumulibacter genus and ppX gene were decreased, which then lower the TP removal efficiency. Besides, CuO NPs might trigger QS system, affecting Candidatus Accumulibacter, Aeromonas genus and ppX gene, and then regulated the removal of TP in the SBR system. The co-occurrence network analysis revealed a correlation among core ARGs, signaling molecule, QS-related microbial community and ARGs’ hosts, suggesting that the spread of ARGs might be driven by QS system under selective pressure of CuO NP. These findings could reveal the effect of CuO NPs on the performance of activated sludge system and provides new ideas for ARGs control through regulating the QS system.

Chloroxylenol positively affects the aerobic sequencing batch reactor performance and reshapes microbial communities and antibiotic resistance genes

The antibacterial ingredient chloroxylenol (PCMX) has been frequently detected in various environments, raising increasing concerns about its potential risks to organisms and ecosystems. Herein, the impacts of PCMX on the performance and microbial communities of aerobic sequencing batch reactors were investigated. The results demonstrated that 0.1 and 1.0 mg/L PCMX did not affect the removal performance of COD and NH4+-N, as well as the production of extracellular polymeric substances. However, a notable enhancement in these performances was observed when the concentration of PCMX reached 10 mg/L. Analysis of microbial community revealed that exposure to PCMX did not alter α diversity but significantly shifted the community structure. Spirosoma and Ferruginibacter were identified as dominant genera across all stages in the sludge, with Ferruginibacter being inhibited by 10 mg/L PCMX (from 20.3 % to 11.1 %). Network analysis revealed that PCMX had a diminishing effect on the interaction and complexity of microbial. High throughput qPCR analysis indicated that PCMX reshaped the antibiotic resistance genes (ARGs). The relative gene copy number increased from 0.23 to 0.29 at a concentration of 0.1 mg/L PCMX, while it decreased from 0.51 to 0.40 by 10 mg/L PCMX. Genes tetX and sul2 were identified as dominant genes unaffected by 0.1 and 1.0 mg/L but significantly inhibited by 10 mg/L PCMX. These findings suggested that environmental levels of PCMX might promote the enrichment of ARGs, while higher concentrations impeded gene propagation. This study provides new information regarding the roles, potential risks, and removal strategies of PCMX in wastewater treatment processes.

Effect of hydraulic retention time on the performance of sequencing batch reactor under combined stress of ibuprofen and ciprofloxacin

The impacts of changes in hydraulic retention time (HRT) on nitrogen elimination, the activity of sludge and the structure of microbial communities in a sequencing batch reactor under the joint stress of ibuprofen (IBP) and ciprofloxacin (CIP) were investigated. Under the combined stress of IBP (belonged to nonsteroidal anti-inflammatory drugs) and CIP (belonged to antibiotics), the elimination level of ammonia nitrogen, chemical oxygen demand, and the rate of specific ammonia oxidation, specific nitrite oxidation, specific nitrate reduction in activated sludge declined with the shortening of HRT. Under the joint stress of IBP and CIP, the content of polysaccharide (PS) and protein (PN) together with the ratio of PN to PS in the extracellular polymeric substances grew with the shortening of HRT, and the content of aromatic proteins increased significantly, which indicated that aromatic proteins were the major protective response substances to the shortening of HRT. Under the joint stress of IBP and CIP, with the reduction of HRT, and the reduction rate of relative abundance of nitrifying bacteria was more evident than that of denitrifying bacteria. This exploration gives novel thoughts for understanding the impacts of HRT on biological nitrogen removal of wastewater under combined stress of IBP and CIP.

Effects of zinc ion concentrations on the performance of SBR treating livestock wastewater and analysis of microbial community

Zinc ion (Zn2+) is a frequently occurring heavy metal in livestock wastewater. The effects of Zn2+ on the physicochemical properties and the microbial distribution of activated sludge are essential to controlling nitrogen removal performance. Nevertheless, there are raw studies on the effects of Zn2+ on nitrogen removal. This study investigated the effect of Zn2+ on the treatment performance of livestock wastewater in a sequencing batch reactor (SBR). The results indicated the low Zn2+ concentrations could improve nitrogen removal performance. However, as the Zn2+ concentration increased, the total nitrogen (TN) removal performance of the reactor gradually deteriorated. When the Zn2+ concentration was 90.00 mg/L, the TN removal efficiency was the lowest, only 2.40%. The contents of the Extracellular polymeric substance (EPS) presented a trend of first increasing and then decreasing with the increase of Zn2+ concentration, and the main reason was the decrease of protein-like and tryptophan-like. The 16SrRNA analysis indicated that Zn2+ within a specific concentration could increase the operational taxonomic units (OTUs) number, microbial richness, and diversity of microorganisms in the SBR. However, with Zn2+ concentration exceeding 10.00 mg/L, the relative abundance of denitrification functional bacteria (Dechloromonas, Nitrospira, and Thauera) decreased.

Responses of activated sludge under a short-term exposure to facial scrub microbeads: implications from treatment performance and higher-life microbial population dynamics.

In this study, four identical laboratory-scale sequencing batch reactors (SBRs) were continuously operated with different concentrations of microbeads (MBs) (5,000-15,000 MBs/L) to investigate the stress-responses of activated sludge under the MB exposure. It was found that the overall treatment performance (organic removal) of SBRs was fairly affected by short-term exposure to low levels of MBs; however, it was adversely affected as the concentration of MBs increased. The average concentration of mixed liquor suspended solids and heterotrophic bacteria in the reactor fed with 15,000 MBs/L were 16 and 30% less than in the pristine control reactor, respectively. Batch experiments further demonstrated that fairly low concentrations of MBs favored the development of dense microbial structures. Further increasing the MB concentrations to 15,000 MBs/L, however, distinctly weakened the settling performance of sludge. Morphological observations revealed suppressed uniformity, strength, and integrity of flocs reactors with the addition of MBs. Microbial community analyses revealed that the abundance of protozoan species declined 37.5, 58, and 64%, respectively, when SBRs were exposed to 5,000; 10,000; and 15,000 MBs/L as compared with the control reactor. The present work provided new insight into the possible effects of MBs on the performances and operational parameters of activated sludge.

Effects of sponge iron dosage on nitrogen removal performance and microbial community structure in sequencing batch reactors

The application of sponge iron (SI) carriers can improve the biochemical treatment performance of sequencing batch reactors (SBR) during wastewater treatment. This study used SBR reactors to explore the effects of SI dosage on the nitrogen removal performance and reactor stability and microbial community structure under low temperature and ultra-low load. In contrast to conventional SBR, the average removal rate of total nitrogen (TN) in the biological sponge iron system (BSIS) was increased by 5.38 % for 45 g/L, 18.93 % for 90 g/L, and 13.52 % for 135 g/L, respectively. The nitrogen removal performance and reactor stability showed the best performance under the SI dosage of 90 g/L. The addition of SI formed the anaerobic-anoxic-aerobic microenvironments, which facilitate the propagation of denitrifying bacteria (Saccharimonadales, Hydrogenophaga) and iron bacteria (Rhodoferax and Acinetobacter) in the BSIS. This study provides a new insight on the application of SI in the wastewater treatment.

Wastewater treatment and simultaneous production of algal lipids in sequencing batch reactors containing a microalgal-bacterial consortium

The use of microalgal-bacterial consortiums has attracted interest owing to their potential in sewage treatment. However, the performance of sequencing batch reactor (SBR) coupled with microalgal-bacterial consortiums has not been investigated extensively. The present study investigates two SBRs namely R1 and R2, operated for 60 d; R1 was supplemented with microalgal-bacterial consortium, while R2 contained conventional activated sludge. The average removal efficiency for chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorus in R1 were 91.7%, 98.8%, 69.9%, and 64.3%, which improved by 4.9%, 3.4%, 10.1%, and 8.6% compared to R2, respectively. The maximum chlorophyll content was 345.77 mg L−1 and the maximum lipid content was 340 mg L−1 in R1 which indicates the potential of algal biomass production. Microbial analysis showed the community characteristics and the population dynamics in R1 and R2 at different stages, and revealed the influence of the microalgal-bacterial consortium on microbial community evolution. These results suggest that microalgal-bacterial consortium-based systems can be used to treat wastewater and efficiently utilize sewage as a source of high-value compounds.

Sequencing Batch Reactor Performance Evaluation on Orthophosphates and COD Removal from Brewery Wastewater

The discharge of industrial effluent constituting high orthophosphates and organic pollutants in water receiving bodies compromises freshwater quality and perpetuates eutrophication. In this study, an anaerobic–aerobic sequencing batch reactor (SBR) under activated sludge was investigated for orthophosphates and chemical oxygen demand (COD) removal from brewery wastewater. Raw brewery wastewater samples were collected on a daily basis for a period of 4 weeks. The findings of the study are reported based on overall removal efficiencies recording 69% for orthophosphates and 54% for total COD for a sludge retention time (SRT) of 7 days and hydraulic retention time of 18 h at mesophilic temperature conditions of ±25 °C. Moreover, the SBR system showed stability on orthophosphate removal at a SRT ranging from 3 to 7 days with a variation in organic volumetric loading rate ranging from 1.14 to 4.83 kg COD/m3.day. The anaerobic reaction period was experimentally found to be 4 h with the aerobic phase lasting for 14 h. The SBR system demonstrated feasibility on orthophosphates and COD removal with variation in organic loading rate.

Performance of sequencing batch reactor for the removal of chemical oxygen demand from waste cooking oil

Performance of sequencing batch reactor for the removal of chemical oxygen demand from waste cooking oil

Performance and bacterial community profiles of sequencing batch reactors during long-term exposure to polyethylene terephthalate and polyethylene microplastics

Microplastics (MPs) are ubiquitous in wastewater treatment plants (WWTPs), but much remains to be learned about their roles in WWTPs. Herein, polyethylene terephthalate (PET) and polyethylene (PE) particles were added into sequencing batch reactors (SBRs), and the sole impacts and co-impacts of MPs with other pollutants (phenol and Cu2+) on wastewater treatment processes were evaluated. Results indicated that MPs did not significantly affect SBR performance, either alone or co-occurrence with phenol, but the co-exposure to MPs and Cu2+ severely suppressed COD removal efficiency by 37.02%-64.70%. The functional groups of activated sludge had no changes after receiving MPs, but the MPs-Cu2+ co-exposure could greatly promote the secretion of extracellular polymeric substances. Furthermore, MPs had no negative impacts on diversity, richness and structure of bacterial communities, and PET and PE showed different preferences for enrichment of bacterial populations. Moreover, the MPs-Cu2+ co-exposure obviously reduced the overall abundances of Cu-related genes in SBRs.

Effect of operational time on the chemical oxygen demand performance of sequencing batch reactor treating disperse dye synthetic wastewater

This work examines the effect of operational time of 6 hours on the removal of disperse dye from synthetic textile wastewater. Experiments were conducted daily at fill, react, settle, draw, and idle phase at 1 h, 1 h, 2 h, 1 h, 1 h respectively. The results showed that the highest removal efficiency of COD reached 77 %. Short operational time resulted in low COD removal efficiencies of disperse dye. The findings also revealed that when applying optimum operational time, sequencing batch reactor will achieve the highest growth of the bacteria responsible for the degradation of COD. When operational time increases, degradation becomes the dominant removal mechanisms of COD.

Kinetic characterization of a low-dissolved‑oxygen oxic-anoxic process treating low COD/N tropical wastewater revealed selection of nitrifiers with high substrate affinity

The design of wastewater treatment plants in the tropics is largely based on default parameters from the studies in temperate climates. This may lead to suboptimal design, such as the intensive aeration required for biological nitrogen removal. To reduce the aeration energy, a low-dissolved‑oxygen oxic-anoxic (low-DO OA) process was developed for treating low chemical oxygen demand-to‑nitrogen (COD/N) tropical wastewater. This study calibrated the growth kinetic parameters of microbes in a conventional anoxic-oxic (AO) and a low-DO OA sequencing batch reactors (SBRs) based on a modified version of Activated Sludge Model No. 1 (ASM1). We selected three parameters to be calibrated, namely the maximum growth rate of heterotrophs (μH), maximum growth rate of nitrifiers (μA) and nitrifiers' affinity towards ammoniacal nitrogen (NH4+−N) (KNH). The low-DO OA SBR selected for microbes with a low μH (2.2 d−1), μA (1.49 d−1) and KNH (0.035 mgNH4+−NL−1), which supported the observed proliferation of K-strategist Nitrospira at low-DO condition (0.4 ± 0.2 mg O2 L−1). The calibrated parameters for the AO SBR (1.7 ± 0.2 mg O2 L−1) were significantly higher (μH=9.3 d−1, μA=4.49 d−1, KNH=6.3 mgNH4+−NL−1) than the low-DO OA SBR. The calibrated ASM1 adequately simulated the low-DO OA SBR performance under different sludge retention times. The findings demonstrated a kinetic insight into the unique K-strategist nitrifiers in a low-DO OA process. Moreover, this study reinforced the importance of using parameters for tropical wastewater rather than relying on default values from studies in temperate climates.

A comparative examination of MBR and SBR performance for municipal wastewater treatment

Abstract In this study, the performance of the membrane bioreactor (MBR) and anoxic–aerobic sequencing batch reactor (SBR) are compared in treating municipal wastewater. The aim of the work was to determine the feasibility of these systems for the removal of organics matter and nutriments from the municipal wastewater. The MBR displayed a superior performance with removal efficiencies exceeding 99% for TSS, 94% for chemical oxygen demand (COD) and an improvement on SBR efficiencies was found. In the same way, the MBR produced an effluent with much better quality than SBR in terms of total nitrogen (TN) and total phosphorus (TP) removal efficiencies. Combining membrane separation and biodegradation processes or the membrane bioreactor (MBR) technology improved pollution removal efficiencies significantly.

Waste nutrient solutions from full-scale open hydroponic cultivation: Dynamics of effluent quality and removal of nitrogen and phosphorus using a pilot-scale sequencing batch reactor

Hydroponic cultivation is revolutionizing agricultural crop production techniques all over the world owing to its minimal environmental footprint, enhanced pest control, and high crop yield. However, waste nutrient solutions (WNS) generated from hydroponic systems contain high concentrations of N and P; moreover, they are discharged into surface and subsurface environments, leading to eutrophication and subsequent ecosystem degradation. In this study, the nutrient concentrations in WNS from 10 hydroponic indoor tomato, capsicum, and strawberry farms (greenhouses) were monitored for up to six months. The concentrations of N and P in WNS discharged from these farms were 48.0–494.0 mg L−1 and 12.7–96.9 mg L−1, respectively, which exceeded the Korean water quality guidelines (40.0 mg L−1 N and 4.0 mg L−1 P) for effluents. These concentrations were varied and dependent on the supplied nutrient concentrations, crop types, and growth stages. In general, the concentrations of N and P were in the following order: tomato > capsicum > strawberry. High N as NO3− and P as PO43− but low organic C in WNS warrant subsequent treatment before discharge. Therefore, this study tested a pilot-scale sequencing batch reactor (SBR) system as a potential technology for WNS treatment. The SBR system had BOD, COD, nitrate, and phosphate removal efficiency of 100, 100, 89.5, and 99.8%, respectively. In addition, the SBR system removed other cations such as Ca2+, dissolved Fe, K+, Mg2+, and Na+ and the removal efficiencies of those ions were 48, 67, 18, 14 and 15%, respectively. Lower methanol addition (0.63 mg L−1) and extended aeration (~30 min) improved SBR performance efficiency of C, N, and P removal. Thus, SBR showed significant promise as a treatment alternative to WNS pollutants originating from hydroponic systems.

Long-term effect of graphene oxide on the aerobic granular sludge wastewater treatment process

This study investigated the bioreactor performance, production of extracellular polymeric substance (EPS), and microbial activity of a granulated sequencing batch reactor (SBR) by increasing the graphene oxide nanoparticle (GO NP) concentration stepwise. The GO NPs reduced the removal of chemical oxygen demand (COD), ammonia, and phosphorus, whereas the nitrite and nitrate contents of the effluent were kept stable during the experiment. The ammonia-nitrogen (NH4-N) and COD removal rates were deceased considerably from 99% and 95–96.2% and 78.6% at 55 mg/L GO NPs; furthermore, at 115 mg/L GO NPs, the NH4-N and COD removal rates further decreased to 88.5% and 59.3%. The removal of phosphorus decreased even at small concentrations of graphene oxide (GO), and the inhibitory effect enhanced with an increase in the GO NP content. The increased amounts of nanoparticles significantly influenced the microbial activity of aerobic granular sludge (AGS). The specific oxygen uptake rate (SOUR) decreased from 42.04 to 33.14 mg O2/g MLVSS*h, specific ammonia oxidation rate (SAOR) declined from 4.84 to 4.12 mg N/g MLVSS*h, specific phosphorus uptake rate (SPUR), and specific phosphorus release rate (SPRR) significantly decreased from 13.1 and 10.05–8.2 and 8.7 mg P/g MLVSS*h after 98 days. However, the specific nitrite and nitrate reduction rate (SNIRR and SNRR), and the specific nitrite oxidation rate (SNOR) remained relatively stable. The EPS content of sludge was initially 5.95 mg/g MLVSS, but the presence of GO up a concentration of 55 mg/L promoted the secretion of EPS and increased to 11.86 mg/g MLVSS. At higher GO concentrations, the secretion of EPS was inhibited. After 14 days, when the influent synthetic wastewater (SWW) did not contain GO NP, the AGS SBR performance showed a remarkable recovery capability.

Ancillary palm oil fuel ash (POFA) in sequencing batch reactor for enhancing recalcitrant pollutants removal from domestic wastewater

Domestic wastewater has been generated massively along with rapid growth of population and economic. Biological treatment using sequencing batch reactor (SBR) augmented with palm oil fuel ash (POFA) was investigated for the first time. The performance of POFA in enhancing biological treatment of wastewater has not been tested. The porosity property of POFA can improve SBR efficiency by promoting growth of mixed liquor suspended solids (MLSS) and formation of larger flocs for settling and facilitating attachment of microorganisms and pollutants onto POFA surfaces. The properties of POFA were tested to identify morphological properties, particle size, surface area, chemical compositions. Four SBRs, namely SBR1, SBR2, SBR3 and SBR4 were provided with aeration rate of 1, 2, 3 and 4 L/min, respectively. Each reactor was augmented with different dosages of POFA. Optimum aeration rate and POFA concentration were identified by the performance of SBRs in removing chemical oxygen demand (COD), ammoniacal nitrogen (NH3–N) and colour from domestic wastewater. The results showed the most efficient COD (97.8%), NH3–N (99.4%) and colour (98.8%) removals were achieved at optimum POFA concentration of 4 g/L in SBR and aeration rate of 1 L/min. The study also found that higher aeration rate would contribute to the smaller specific size of flocs and decrease the pollutant removal efficiency.

Effect of increasing organic loading rate on the performance of conventional and modified sequencing batch reactors. (Dept. C)

A modified sequencing batch reactor (MSBR) was developed by installing six fiber vertical plates of specific surface area of 180 cm2/ L in conventional sequencing batch reactor (SBR), which designed for supporting the biofilm formation and increasing the system efficiency. In this study, the effect of increasing the organic loading rate of 281.25 g COD/m3. d by 33%, 67%, and 100 % on the performance of SBR and MSBR was investigated. The effluent BOD5, COD and TSS of the MSBR at high organic loading rate was 20, 32 and 27 mg /L, respectively, while for conventional SBR was 34, 58 and 45 mg /L, respectively. The total bio-sludge of MSBR was more than that of conventional SBR by about 30% resulting in a reduction of the F/M value. The sludge volume index (SVI) in MSBR was lower than that of conventional SBR by about 33%. MSBR system was able to treat municipal wastewater with high performance.

Effect of temperature shifts and anammox biomass immobilization on sequencing batch reactor performance and bacterial genes abundance

Implementation of anaerobic ammonium oxidation (anammox) below its optimal temperature, known as “cold anammox”, may lead to its common use in wastewater treatment plants, reducing the operational costs of wastewater treatment. Thus, we investigated the effects of immobilization in polyvinyl alcohol–sodium alginate gel beads on anammox performance at temperatures of 30 °C, 23 °C, and 15 °C in laboratory-scale sequencing batch reactors. We determined the relative gene abundance of the nitrogen removal bacterial groups, which are considered as the key functional microbes of nitrogen cycle in activated sludge: denitrifies, ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, and anammox bacteria. Nitrogen removal efficiency was higher for immobilized anammox sludge in comparison with non-immobilized anammox biomass at each investigated temperature. At 30 °C, nitrogen removal efficiency was 83.7 ± 6.46% for immobilized reactor, and 79.4 ± 7.83% for the control reactor, while at 15 °C was remained at the level of 50 ± 2.5% for immobilized reactor, and fluctuated from 13.2 to 45.3% for the control one. During temperature shifts, the process was also more stable in the case of the reactor with immobilized biomass. A statistically significant correlation was found between nitrogen removal efficiency and hydrazine oxidoreductase gene abundance.

Effect of F/M Ratio on the Performance of Sequencing Batch Reactor for Dairy Wastewater Treatment

Indian economy has huge contribution of dairy industry. About one fourth of nation’s income is contributed by dairy. Milk processing involves various operations starting from receiving point to disposal end. This whole process demands fresh water leading to wastewater generation and this quantity is highest amongst all industries. Dairy wastewater is composed of organic matter, nutrients, suspended & dissolved solids and high COD, BOD. So it becomes necessary to remove the pollution load before its disposal. Some advanced treatments like SBR, gas stripping, surface filtration show better results and are effective than conventional treatments. In this study, SBR process was used to treat dairy wastewater. SBR process has flexibility, minimal footprint and it conducts all operations like equalization, primary clarification, biological treatment and secondary settling in a single reactor. Time phased Fill and draw type lab scale SBR model was operated with 12 liter total volume and 10 liter working volume. Before loading dairy wastewater to the reactor, loading of sewage was done for acclimatization of microorganisms. Dairy wastewater was collected from equalization tank of an Effluent Treatment Plant of dairy industry. It was analysed for various parameters for 15 days to know the variations in characteristics. For the treatment of dairy wastewater reactor was operated under varying MLSS from 6000 to 8000 mg/L thereby under varying F/M ratio and named as phase 1, phase 2, and phase 3 with 20% Volume Exchange Ratio. Total cycle time provided was 6 hour in which fill was instantaneous, aeration for 5 hour 30 minutes, settling for 25 minutes and 5 minute decant. By keeping all the remaining parameters constant, only F/M ratio was varied. Maximum removal efficiencies for parameters like COD, BOD, TDS, and TSS were determined for each phase. For phase 1, 2 and 3 maximum removal efficiencies were achieved at F/M 0.16, 0.14 and 0.13 per day respectively. But among all three phases, 3rd phase gave maximum removal efficiency at F/M 0.13. Hence it was concluded that SBR performs better at higher MLSS concentration or at lower F/M ratio in order to achieve disposal standards.