Sequencing Batch Reactor System Research Articles

Efficiency of Attached-Growth Sequencing Batch Reactor in the Treatment of Recycled Paper Mill Wastewater

In this study, an attached-growth bioreactor was operated using granular activated carbon (GAC) with additional biomass; and evaluatedits performance in the treatment of real recycled paper mill effluent at chemical oxygen demand (COD) level in the range of 800-1300 mg/L, a fixed hydraulic retention time of 24 hours and COD:N:P ratio of about 100:5:1. A laboratory-scale aerobic sequencing batch reactor (SBR) was used. The efficiency of this biological treatment processwas studiedover a 300-day period, in order to evaluate their performance, especially for the removal of nitrogen compound and of biodegradable organic matter. It has been found that this process was able to remove organic matter (expressed as COD; 91-99%) and turbidity (89-99%) almost completely and simultaneously; the removal of nitrogen (expressed as NH3-N; 70-94%), phosphorus (expressed as PO43-P; 42-71%), suspended solid (81-99%) and colour (72-91%) were sufficiently achieved. The overall performance confirmed that an attached-growth SBR system using additional biomass on GAC is a promising configuration for wastewater treatment in terms of the performance efficiency and process stability under fluctuations of organic load.

The effect of loess addition on the settling ability of activated sludge

In this research, loess addition was investigated as a possible means of controlling the bulking sludge generated from a sequencing batch reactor (SBR) system treating a synthetic wastewater. The specific objective was to investigate whether loess changed the morphology of the sludge (i.e., influenced the relative abundance of filamentous species), as opposed to improving settling simply because the clay portion of the loess acted as a flocculating agent. To this end, two sets of batch tests were performed using 1 L reactors filled with bulking sludge from the SBR. The first set of batch tests investigated the effect of different loess concentration on the settling properties of the sludge; thus loess was added in concentrations of 0.0, 0.4, 2.0 and 5.0 g L−1. The 5.0 g L−1 loess concentration exhibited the most positive results on settling, bringing the modified sludge volume index (SVI) down into the target range of 150 mL g−1. The second set of batch tests investigated filament length along with the modified SVI. It appeared that at the microbial level, 5.0 g L−1of loess caused no reduction in filament length, suggesting no reduction in the amount of filamentous microorganisms. This means that adding loess to a system after it has bulked has the potential to mask the bulking problem by improving settling, while not fixing the problem microbiologically.

Effect of sludge reduction in oxic-settling-anaerobic (OSA) systems with different anaerobic hydraulic retention times (HRTs)

The performance of an oxic-settling-anaerobic (OSA) system in terms of sludge reduction was investigated for various anaerobic hydraulic retention times (HRTs) (7 d, 5 d, 3 d, 1 d, 12 h, and 6 h) for a sequencing batch reactor (SBR)-OSA system. Compared to the traditional SBR system, the rates of sludge reduction in the 7d, 5d-1, 5d-2, 3d, and 1d OSA systems were observed to be 66.6, 57.7, 52.5, 50.0, and 48.5%, respectively. In terms of the apparent yield and actual yield of sludge, the OSA systems with longer HRTs exhibited lower sludge yields and better sludge reduction performance. The systems with an HRT > 1 d achieved a considerable increase in sludge reduction, whereas those with an HRT < 1 d did not. The anaerobic HRT was observed to be an important factor in determining the sludge reduction of OSA systems.

Accumulation and isolation of simultaneous denitrifying polyphosphate-accumulating organisms in an improved sequencing batch reactor system at low temperature

The paper studied accumulation of denitrifying polyphosphate-accumulating organisms (DNPAOs) by using an improved sequencing batch reactor (SBR) system in which anaerobic-aerobic-anoxic (A-O-A) and anaerobic-anoxic (A–A) are at low temperature (15 °C). Results indicated that it was feasible to accumulate DNPAOs with nitrogen (N) and phosphorus (P) removals concurrently in an improved SBR system. Moreover, a DNPAOs strain was isolated from the accumulation and was identified as Acinetobacter sp. J6. Important factors that affect N and P removal efficiency of strain J6 were investigated, including temperature, pH and total phosphate (TP) concentration. Strain J6 had the highest N and P removal rates under original pH 8.0, TP concentration 4.16 mg L−1 and 15 °C. The purification culture of strain J6 contributed to the germplasm resources for a full-scale biological N and P removal system to denitrify and remove phosphate simultaneously.

Studies on the interactions of Ca2+ and Mg2+ with EPS and their role in determining the physicochemical characteristics of granular sludges in SBR system

The main objectives of the present study were to investigate the interactions of divalent metals (Ca2+ and Mg2+) with protein and polysaccharide components of extracellular polymeric substances (EPS) and to deduce their role in imparting different physicochemical characteristics to aerobic granules in sequencing batch reactor (SBR) system. Three reactors were run for 60 days; R-1 functioned as a control reactor, whereas R-2 and R-3 were operated by dosing 25mg/L of Ca2+ and Mg2+, respectively, and the other operating conditions were similar in all of the SBRs. The granulation rate, particle size and sludge settleability were rapidly increased by Ca2+ addition, whereas the sludge dewaterability was significantly enhanced by Mg2+ augmentation. During the investigations, R-1, R-2 and R-3 had 1.31, 2.98 and 1.58 times higher quantities of polysaccharides, whereas proteins were 1.28, 1.74 and 2.41 times, respectively, more abundant than seed sludge. The divalent metals profoundly changed the composition of EPS, but their total contents were almost similar. XPS and FTIR results showed that Ca2+ bonded strongly with hydroxyl groups of polysaccharides due to there being less steric hindrance than proteins, and Mg2+ preferably bonded with amide groups of proteins and found no such hindrance due to its smaller size and thus changed the composition of EPS, which eventually altered the granular sludge characteristics.

Biological decolorization of reactive azo dye by anaerobic/aerobic-sequencing batch reactor system

&lt;div&gt; &lt;p&gt;This study aims to investigate the removal of a reactive azo dye (Reactive Red 198) in anaerobic/aerobic sequencing batch reactors (SBR). The total volume of the SBR system used in the study was 10 l. Sludge age was selected as 15 days. The color removal efficiencies varied between 76 to 98% with initial color concentrations of about 20 and 50 mg l&lt;sup&gt;-1&lt;/sup&gt;. The effluent color concentration changed between 0.4-6.0 mg l&lt;sup&gt;-1&lt;/sup&gt;. The maximum dye removal efficiencies of the SBR system under 20 mg l&lt;sup&gt;-1&lt;/sup&gt; dye concentration with 16/4 hours anaerobic/aerobic phases respectively were %98. The increase of anaerobic contact times had improved dye removal efficiency. The COD removal was also high during this period (81-94 %). The increase of organic loading rate from 500 to 1000 mg COD l&lt;sup&gt;-1&lt;/sup&gt; day&lt;sup&gt;-1&lt;/sup&gt; had improved the dye removal efficiency (from 88% to 96%) but deteriorated the COD removal efficiency to 81% from 88% in SBR systems.&lt;/p&gt; &lt;/div&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Simultaneous removal of nutrients from milking parlor wastewater using an AO2 sequencing batch reactor (SBR) system

The feasibility of using a lab-scale, anaerobic-aerobic-anoxic-aerobic sequencing batch reactor ((AO)2 SBR) to simultaneously remove biological organics, nitrogen and phosphorus from dairy milking parlor wastewater was investigated in this study. Three hydraulic retention times (HRT = 2.1, 2.7, and 3.5 days) and three mixing-to-process time ratios (TM/TP = 0.43, 0.57, and 0.68) were evaluated as two controlling factors using a 3 × 3 experimental design to determine the optimal combination. Results showed that the HRT of 2.7 days with TM/TP = 0.57 was the best to achieve simultaneous nutrients removal for the influent with initial soluble chemical oxygen demand (SCOD) of about 2000 mg L−1 (only 0.55 mg L−1 NH4-N, < 0.1 mg L−1 nitrate, and 0.14 mg L−1 soluble phosphorus in the effluent). Good correlations between pH and ORP, and ORP and DO, were also obtained with correlation coefficients all higher than or equal to 0.975. These relationships could be used to develop real-time control strategies to optimize the duration of each operating phase in the (AO)2 SBR system to save energy and enhance treatment efficiency.

Integrating sequencing batch reactor with bio-electrochemical treatment for augmenting remediation efficiency of complex petrochemical wastewater

The present study evaluates the sequential integration of two advanced biological treatment methods viz., sequencing batch reactor (SBR) and bioelectrochemical treatment systems (BET) for the treatment of real-field petrochemical wastewater (PCW). Initially two SBR reactors were operated in aerobic (SBRAe) and anoxic (SBRAx) microenvironments with an organic loading rate (OLR) of 9.68kg COD/m3-day. Relatively, SBRAx showed higher substrate degradation (3.34kg COD/m3-day) compared to SBRAe (2.9kg COD/m3-day). To further improve treatment efficiency, the effluents from SBR process were fed to BET reactors. BETAx depicted higher SDR (1.92kg COD/m3-day) with simultaneous power generation (17.12mW/m2) followed by BETAe (1.80kg COD/m3-day; 14.25mW/m2). Integrating both the processes documented significant improvement in COD removal efficiency due to the flexibility of combining multiple microenvironments sequentially. Results were supported with GC–MS and FTIR, which confirmed the increment in biodegradability of wastewater.

The effects of continuous Cu(II) exposure compared with a shock dosage of Cu(II) on pollutant removal in activated sludge

In order to determine how Cu(II) exposure affects activated sludge, we investigated pollutant removal and recovery of removal efficiency after continuous exposure to Cu(II) or a shock dosage of Cu(II) in a sequencing batch reactor (SBR) system. The continuous exposure experiment, involving 20 mg L−1 Cu(II), showed that the removal efficiency for chemical oxygen demand (COD) initially decreased rapidly to 7%, but conspicuously recovered to 78% by the 50th day and then dropped to nearly zero by the 160th day. The removal of NH3-N was even more conspicuously inhibited and failed to recover during the experimental period. The continuous dosage of activated sludge with 20 mg L−1 of Cu(II) for nearly 160 d rendered the SBR almost completely unable to remove pollutants. In the shock dosage (batch) experiment, the removal of both COD and NH3-N was inhibited after shock dosages of 10, 20, and 40 mg L−1 Cu(II). However, after 24 h, the removal efficiency of COD at each shock dosage recovered to 81, 60, and 52%, respectively; NH3-N removal efficiency recovered to 78, 74, and 45%, respectively.

Effect of Cr+3 on the efficiency and performance of the sequencing batch reactor (SBR) system for treatment of tannery industrial wastewater

The study focused on the treatment of tannery industrial wastewater (TIW); TIW containing 10 mg/L Cr3+ (TIW + 10 Cr3+) and synthetic tannery industrial wastewater (STIW) containing Cr+3 concentrations of 0, 5, 10, 20, 30 and 40 mg/L using a sequencing batch reactor (SBR) system at hydraulic retention times (HRT) of 1.5, 3 and 5.0 d and concentrations of mixed liquor suspended solids (MLSS) of 1,000, 2,000, 3,000, 4,000 and 5,000 mg/L removal efficiency were determined. The highest Cr+3, COD, BOD5, TKN and TN removal efficiencies of 87.5 ± 0.2, 96 ± 0, 96 ± 1, 88.5±0.1 and 61.0 ± 0.5%, respectively, were detected with STIW + 5 Cr+3 at MLSS of 5,000 mg/L and HRT of 3 d. Cr+3 gave a strong repression effect to the growth and activity of young bio-sludge, and the effect increased with increase in Cr+3concentration or loading. However, older bio-sludge showed strong resistance to Cr+3 toxicity and had higher Cr+3 adsorption yield than younger bio-sludge. The SBR system with raw TIW showed the highest Cr3+, COD, BOD5, TKN and TN removal efficiencies of 96.9 ± 0.2, 98 ± 1, 99 ± 0, 69.2±0.0 and 60.3 ± 0.1%, respectively, at HRT of 5 d and MLSS of 5,000 mg/L. Efficiency with TIW was reduced by addition of Cr+3. However, the efficiency was recovered with increase in HRT. The system containing TIW + 10 Cr3+ showed the highest Cr+3, COD, BOD5, TKN and TN removal efficiencies of 95.6 ± 0.3, 98 ± 1, 99 ± 0, 68.6±0.0 and 60.0 ± 0.1%, respectively, with SVI less than 100 mL/g at HRT of 5 d and MLSS of 5,000 m/L.

Characterization of Nitrifying Bacterial Community in a Mariculture Wastewater Treatment Using SBR System

Sequencing batch reactors (SBR) have been used in the biological treatment of aquaculture wastewater. In this study, we investigated the microbial community of a SBR that used diatomite earth (20 g/L) as the sludge carrier material. Marine wastewater in which ammonia content was 42.08 to 55.88 mg/L was supplied to the SBR every 12 h over a treatment period of 65 days. During the first 20 days, the concentration of NH4-N decreased gradually, while nitrite (NO2-N) became the major nitrogen compound, reminiscent of the development of an ammonia-oxidizing process. Over the next 20 days, the concentration of NH4-N decreased further due to conversion to NO3-N. More than 99% of the NH4-N was converted to NO3-N over a period of 40-65 days. Denaturing gradient gel electrophoresis (DGGE) assay showed that bacteria of the genus Flavobacterium were present during the entire treatment period, while α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, and Sphingobacteriia started to accumulate after the first 20 days. Fluorescence in situ hybridization (FISH) assay identified Nitrobacter and Nitrosomonas as the main bacteria involved in the conversion of NH4-N to NO3-N. Diatomite earth therefore acted as an efficient sludge carrier by shortening the settling time and facilitating bacterial colonization. This SBR was capable of rapid removal of NH4-N. This warrants further investigation at the pilot-scale in an actual mariculture farm

Characterization of Nitrifying Bacterial Community in a Mariculture Wastewater Treatment Using SBR System

Sequencing batch reactors (SBR) have been used in the biological treatment of aquaculture wastewater. In this study, we investigated the microbial community of a SBR that used diatomite earth (20 g/L) as the sludge carrier material. Marine wastewater in which ammonia content was 42.08 to 55.88 mg/L was supplied to the SBR every 12 h over a treatment period of 65 days. During the first 20 days, the concentration of NH4-N decreased gradually, while nitrite (NO2-N) became the major nitrogen compound, reminiscent of the development of an ammonia-oxidizing process. Over the next 20 days, the concentration of NH4-N decreased further due to conversion to NO3-N. More than 99% of the NH4-N was converted to NO3-N over a period of 40-65 days. Denaturing gradient gel electrophoresis (DGGE) assay showed that bacteria of the genus Flavobacterium were present during the entire treatment period, while α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, and Sphingobacteriia started to accumulate after the first 20 days. Fluorescence in situ hybridization (FISH) assay identified Nitrobacter and Nitrosomonas as the main bacteria involved in the conversion of NH4-N to NO3-N. Diatomite earth therefore acted as an efficient sludge carrier by shortening the settling time and facilitating bacterial colonization. This SBR was capable of rapid removal of NH4-N. This warrants further investigation at the pilot-scale in an actual mariculture farm.

BM 미생물제제를 이용한 선박 오·폐수 내 유해물질처리

본 연구에서는 선박에서 발생하는 오 폐수의 처리를 위하여 SBR공정에 유효미생물을 주입하는 변법을 이용하여 Lab scale 실험을 수행하였다. 유해물질 유입에 따른 생물학적 처리 장치의 효율 저하 문제를 해결하기 위하여 SBR공정에 유효미생물을 주입하는 변법은 크루즈선이라는 특수 환경과의 접목성과 생물학적 처리 시 야기될 수 있는 문제를 대비하기 위한 대안으로 선박환경에 매우 적합한 공정으로 평가되었다. 슬러지 관찰 결과 기존의 활성슬러지에 유효미생물의 주입함으로써 슬러지의 안정성을 확보할 수 있었으며, 슬러지의 EPS 함량도 40% 이상 높아진 것을 확인할 수 있었다. 또한 슬러지의 미생물 분석 결과 유효미생물 주입으로 인해 수처리에 유리한 미생물종이 다수 출현하여 휘발성 유기화합물과 같은 유기 유해물질이 생분해되어 안전한 물질로 전환되는 것을 확인할 수 있었으며. 중금속과 같은 무기 유해물질도 중금속의 종류와 유입농도에 영향을 받지 않고 70% 이상의 안정적인 처리 효율도 확보할 수 있는 것으로 확인되었다. Lab scale experiment study was carried out for biological treatment process development in shipboard. SBR(Sequence Batch Reactor) process with BM(Beneficial Microorganisms) was investigated for practical application on shipboard sewage treatment. From the results it was suggested that SBR process with BM might be a suitable process in terms of harmful materials removal. By adding BM to SBR system, the useful species of microorganisms and EPS(Extracellar Polymetric Substances) in sludge was increased. It was found that the biodegrability and harmful organic compounds like VOCs and harmful inorganic compounds like heavy metals. was reduced over 70%. As far as reclamation water is considered, this process is very advantageous to special environments such as cruise ships, because the method of adding BM makes it unnecessary to add other facilities on the SBR system.

Hybrid of Fenton and sequencing batch reactor for petroleum refinery wastewater treatment

The treatment of high-strength petroleum refinery effluent (PRE) with [BOD5]/[COD]0=0.14 was investigated using combined Fenton–sequencing batch reactor (SBR). The effect of [H2O2]:[COD]0 molar ratio on biodegradability enhancement was investigated. Fenton optimal conditions were: [H2O2]:[COD]0 of 6, [H2O2]:[Fe0] of 10 and pH=3.0 that could remove 76.5%, 45% and 96% of COD, TOC and phenol and increased biodegradability ratio to 0.37. The pretreated PRE subjected to SBR for one single cycle of 10h. The results revealed the effectiveness of hybrid Fenton–SBR system in treating PRE where the complete treatment of the PRE was attained by this system.

The role of microorganisms in a full-scale sequencing batch reactor under low aeration and different cycle times.

This study describes the role of microorganisms in a full-scale step-feed sequencing batch reactor (SBR) system for urban wastewater treatment. Chemical profiles for three different cycle times were measured under low aeration conditions with a high carbon-to-nitrogen ratio. The applied organic load was above 1.0 g chemical oxygen demand (COD)/L x d. The removal efficiencies were higher than 81%, 93%, and 76% for soluble COD, N-NH4+, and total Kjeldahl nitrogen, respectively. The ratio of volatile suspended solids (VSS) to total suspended solids was 78%, and the food-to-microorganism ratio was an average of 1.41 g COD/g VSS x d. The active biomass was comprised of 87.8% heterotrophic and 12.2% autotrophic organisms. Nitrifying organisms were found with a low amount of ammonia-oxidizing bacteria (5%) and a much higher amount of nitrite-oxidizing bacteria. Polyphosphate-accumulating organisms (PAOs) were found at high amounts (25%) compared to glycogen-accumulating organisms, even in a system with a high carbon to phosphorus ratio. The activity of denitrifying PAOs was 72%.

The Use of Redox Mediators for Enhancing the Decolourisation of Orange G in a Sequencing Batch Reactor (SBR)

The declorization of the acid azo dye, Orange G (Acid Orange 10) in an anaerobic phase of the anaerobic-aerobic sequencing batch reactor feed by synthetic wastewater was investigated. Moreover, the impact of a redox mediator (AQS) on the color removal was studied. it is for the first time that the decolorization of Orange G is investigated in SBR system with activated sludge. The redox mediator was really effective for cleavage the azo band and increased the efficiency of the reactor. When 20 mg/l of Orange G was added to the sysnthetic wastewater, the decolorization efficiency was 50 % without the addition of AQS. The decolorization efficiency increased up to 75% when the small quantity of AQS, 0.05nM, was added to the wastewater. The high COD removal of synthetic dye wastewater was observed during the operation. The COD removal was always in the range of 80-90 %.

Long term experiences of sequencing batch reactor-system and wetland treatment from a municipal wastewater treatment plant in Sweden, operated with low temperature wastewater

A biological wastewater treatment plant, Nynäshamn treating municipal wastewater and septic sludge operated with a combination of sequencing batch reactor (SBR) units and constructed wetland is presented in this paper. The plant has to treat low temperature wastewater in winter time, still with demands for a biological nitrogen removal. Treatment results from a 13 year operation period are presented. Special attention was given to the nutrient removal during low temperature conditions. The combination of a SBR system along with classical chemical precipitation and a polishing step based on ‘natural’ extensive treatment has been a sustainable way to keep the discharge levels low. The combined treatment with SBR and the wetland at the Nynäshamn plant has resulted in improved discharge levels typically as follows (annual mean values); BOD7 3 mg/l, to be compared with the formal consent value of &amp;lt;15 mg/l, total P &amp;lt; 0.1 mg/l, to be compared with the formal consent value of &amp;lt;0.5 mg/l and total N 7 mg/l, to be compared with the formal consent value of &amp;lt;15 mg/l. It is also important to underline that the change of process train has resulted in a substantial saving of the precipitant agent for phosphorus removal. The needed dosage is now 50% of the previous dose, before the implementation of the SBR-units.

Removal performance and changes in the microbial communities of SBRs under aerobic and anoxic conditions with trace tetracycline pressure

The reactor performance and microbial community composition of sequencing batch reactor (SBR) under aerobic and anoxic conditions were investigated in this study. The experimental results showed high chemical oxygen demand (COD) removal efficiency. The tetracycline (TC) removal efficiencies were not obviously affected by aerobic and anoxic conditions, and were 64–97 and 60–87%, respectively. Aerobic condition was observed to be more suitable for decreasing tetracycline‐resistant bacteria (TRB) than anoxic condition in synthetic and real wastewater. Denaturing gradient gel electrophoresis (DGGE) and clone library analysis revealed that Chlorobaculumthiosulfatiphilum was the dominant species in the tested SBR systems. TC significantly influenced the relative numbers of TRB‐ and TC‐resistant genes, and the microbial community diversity changed with the addition of 250 μg L−1 of TC. The genes of tetA and tetC, tetM and tetS, tetA and tetM, tetS and tetA showed significant correlation with each other (P < 0.05).

Effects of chemical phosphate precipitation in the sidestream process on biological phosphorus removal at the anaerobic stage in an anaerobic—aerobic sequencing batch reactor

This study investigates the effects of chemical phosphate precipitation on the performance of a sequencing batch reactor (SBR) operated in anaerobic—aerobic mode. Supernatants enriched with 50% phosphorus were removed from the SBR (i.e. sidestream) system at the end of the anaerobic stage and were placed into a reaction-sedimentation basin to recover the phosphorus. Results indicate that phosphorus removal efficiency increased from 95.26 to 97.22% during the first 40 d and then declined over the next 20 d. Intracellular polyphosphate (poly-P) storage remained low during sidestream stripping. The sludge was not dominated by organisms that accumulate poly-P, as confirmed by the low anaerobic phosphorusrelease/HAcuptake ratios, the phosphorus content in the sludge, and the high ratios of volatile suspended solids of mixed liquor to suspended solids of mixed liquor. These results imply the possibility of changes in population structure given the low level of intracellular poly-P storage during long-term stripping. Intracellular poly-P content may be considered a factor that affects biological phosphorus removal in the future work.

Characteristics and performance of aerobic granular sludge treating rubber wastewater at different hydraulic retention time

The influence of hydraulic retention time (HRT, 24, 12, and 6h) on the physical characteristics of granules and performance of a sequencing batch reactor (SBR) treating rubber wastewater was investigated. Results showed larger granular sludge formation at HRT of 6h with a mean size of 2.0±0.1mm, sludge volume index of 20.1mLg(-1), settling velocity of 61mh(-1), density of 78.2gL(-1) and integrity coefficient of 9.54. Scanning electron microscope analyses revealed different morphology of microorganisms and structural features of granules when operated at various HRT. The results also demonstrated that up to 98.4% COD reduction was achieved when the reactor was operated at low HRT (6h). Around 92.7% and 89.5% removal efficiency was noted for ammonia and total nitrogen in the granular SBR system during the treatment of rubber wastewater.