Two-stage Sequencing Batch Reactor Research Articles

Removals of endocrine disrupting compounds during landfill leachate treatment in two-stage aerobic sequential batch reactor: Effect of Alcaligenes faecalis no.4 bio-augmentation

The effect of Alcaligenes faecalis no.4 (A. faecalis no.4) in two-stage sequencing batch reactor (SBR) treatment of endocrine disrupting compounds (EDCs), i.e., bisphenol A (BPA), di-n-butyl phthalate (DBP) and bis-2-ethyl hexyl phthalate (DEHP) containing in landfill leachate was investigated. Two aerobic SBRs were operated without (C-SBR) and with A. faecalis no.4 bio-augmentation (B-SBR) at a hydraulic retention time (HRT) and solid retention time (SRT) of 3 and 30 days over 280 days. The removals of BPA, DBP, and DEHP were significantly improved to 91.1%, 84.5%, and 80.9% from their average influent concentrations of 185, 244, and 532 μg/l under the presence of A. faecalis no.4 through their enhanced biodegradation. The A. faecalis no.4 bio-augmentation helped promote a strong consortium of bacterial genera reported as BPA, DBP, and DEHP degraders in microbial sludge. This study demonstrated the technical feasibility of applying SBR with A. faecalis no.4 in landfill leachate treatment with effective EDC removals.

Avaliação de desempenho de uma estação de tratamento de esgoto movida a energia solar (SBR de dois estágios) operada em regiões de clima tropical

ABSTRACT This article investigates the performance behaviour of a small decentralized wastewater treatment plant with a capacity of up to 50 population equivalents powered by solar energy. The two-stage sequencing batch reactor (SBR) consists of a photovoltaic (PV) system to deliver energy, a battery storage for night operation and two reactor tanks. In the experimental period of 157 days, the wastewater inflow was increased from 3 to 4.5 and 6 m3.d−1, with sludge ages of 32 ± 2 d in the beginning and 21 ± 2 d in the end. The results corresponding to the different phases indicated high efficiency and stability of the system with domestic wastewater, reaching efficiencies of the test periods of 93 ± 2%, 86 ± 4% and 93 ± 6% for removal of chemical oxygen demand, nitrogen and phosphorus, respectively. In the last 51 days, aeration in the night was interrupted for three hours to save energy and study the behaviour of extended non-aerated phases. A shortening of the aeration phases can help to extend the lifetime of batteries and reduce operational costs, while limiting values in the outlet are still met.

Evaluation of Greenhouse Gas Emission from Municipal Solid Waste Leachate by two-stage Sequencing Batch Reactor

This work investigated greenhouse gas emission during the treatment of municipal solid waste leachate by two-stage Sequencing Batch Reactor (SBR). The SBR was carried out by anaerobic reactor followed by aerobic reactor. The system was operated at hydraulic retention times (HRT) of 4 and 2 days during 130 operating days. At steady state, the organic removal efficiencies were found to be 67.0% and 62.7% for 4 and 2 days of HRT. The organic carbon and nitrogen were mainly removed in aerobic reactor. The surface emission rates of methane in anaerobic reactor were 0.181 and 0.292 g/m2.d under HRT of 4 and 2 days, respectively. The emission factors of CH4 at HRT 4 and 2 days were 0.297 and 0.238 gCH4/gCOD, respectively while those of N2O were 0.25 and 0.19 gN2O/gN for HRT of 4 and 2 days, respectively. The PCR technique confirmed that the microbial group was methonogenic bacteria which corresponded to the emission of greenhouse gas. Type of Paper: Empirical Keywords: Greenhouse gas; leachate; methane emission; microbial communities; sequencing batch reactor

Application of the central composite design for the treatment of soft drink factory wastewater in two-stage aerobic sequencing batch reactors combined with ozonation

AbstractIn current study, a two-stage aerobic sequencing batch reactor (SBR) at laboratory scale was used to investigate the removal of chemical oxygen demand (COD) of a soft drink factory wastewater. The experiment was settled in series and has been combined with ozonation unit as a middle step. We evaluated the effect of three significant independent variables on the process including: mixed liquor suspended solids in both SBRs (MLSS1 and MLSS2) and feed-gas/off-gas ozone concentrations. MLSS was limited to the 3,000, 4,500, and 6,000 mg/L, for both SBRs. Central composite design matrix (CCD) was used for the experimental design and response surface methodology (RSM) was employed to optimize the experiments. The results showed that using ozonation as a middle stage between two-stage SBR significantly affects COD removal of the soft drink factory effluent. In addition, multi-stage biological process revealed that MLSS in the first-stage SBR (i.e. MLSS1) influences the COD removal efficiency. We also foun...

Startup operation and process control of a two-stage sequencing batch reactor (TSSBR) for biological nitrogen removal via nitrite

The startup operation and process control of a two-stage sequencing batch reactor (TSSBR) was investigated to improve the efficiencies of organic substrate degradation and nitrification via nitrite from a chemical industrial wastewater with high COD and nitrogen concentrations. A control strategy using process variables as dissolved oxygen (DO), oxidation-reduction potential (ORP) and pH was implemented. The conventional SBR test results showed that based on DO and pH breakpoints at the transition of COD removal and nitrification, organic substrate degradation and nitrification could be separated and occurred in two different reactors termed TSSBR. For the purpose of improving the process flexibility and saving aeration energy, the variations of DO, ORP and pH in TSSBR were characterized. The developed control strategy for TSSBR was that in the SBR1, DO and ORP breakpoints indicated the end of COD removal; in the SBR2, the DO breakpoint and ammonia valley on the pH profile represented the end of nitrifica...

Treatment of low carbon-to-nitrogen wastewater using two-stage sequencing batch reactor with independent nitrification

Two-stage sequencing batch reactor (SBR) with independent nitrification was evaluated for simultaneous removal of COD, nitrogen, and phosphorus from a low carbon-to-nitrogen wastewater (C/N ratio ranged from 1.1 to 7.4). Independent nitrification proceeded by incorporating the contact period within the system and the nitrification period in the external reactor, which was an outsourcing resource dedicated to enhancing nitrification activity. The contact period enabled the fraction of organic substrate in the influent. Ammonia nitrogen was then able to be decanted to the external nitrification reactor, in which ammonia nitrogen was nitrified as much as 70%. During the nitrification period, dominate microbial group was an ammonia oxidizing bacteria such as Nitrosomonas sp. JL21, Nitrosomonas sp. JL2, and Nitrosolobus multiformis. During the react period, the nitrogen nitrified was not only denitrified, but organic matters were also biodegraded. It was revealed that the effective and preferential use of organic substrate enhanced the overall performance of the system without the supplement of any external carbon sources. Removal efficiencies of COD, nitrogen, and phosphorus were as high as 87% at the loading rate of 0.06–4.79 kg COD/m 3 day, 81% at the loading rate of 0.05–0.84 kg N/m 3 day, and 60% at the loading rate of 0.01–0.09 kg P/m 3 day, respectively.

Two-stage SBR for treatment of oil refinery wastewater

A two-stage sequencing batch reactor (SBR) system was used for treatment of oily wastewater with COD and oil and grease (O&G) concentrations ranging from 1,722-7,826 mg/L and 5,365-13,350 mg/L, respectively. A suitable start-up protocol was developed using gradual increase in oily wastewater composition with methanol as the co-substrate. This strategy enabled a short acclimation period of 12 days for the sludge in the two-stage SBR to adapt to the oily wastewater. After acclimation, the 1st stage and 2nd stage SBRs were able to achieve COD removals of 47.0+/-2.4% and 95.3+/-0.5%, respectively. The 1st stage SBR was able to achieve 99.8+/-0.1% of O&G removal and effluent O&G from the 1st stage SBR was only 6+/-2 mg/L. The 2nd stage SBR was used to further remove COD in the effluent from the 1st stage SBR. The final effluent from the 2nd stage SBR had a COD concentration of 97+/-16 mg/L with no detectable O&G content. Thus, a two-stage SBR system was shown to be feasible for treating high strength oily wastewater to meet the local discharge standards.

Aerobic treatment of dairy wastewater with sequencing batch reactor systems.

Performances of single-stage and two-stage sequencing batch reactor (SBR) systems were investigated for treating dairy wastewater. A single-stage SBR system was tested with 10,000 mg/l chemical oxygen demand (COD) influent at three hydraulic retention times (HRTs) of 1, 2, and 3 days and 20,000 mg/l COD influent at four HRTs of 1, 2, 3, and 4 days. A 1-day HRT was found sufficient for treating 10,000-mg/l COD wastewater, with the removal efficiency of 80.2% COD, 63.4% total solids, 66.2% volatile solids, 75% total Kjeldahl nitrogen, and 38.3% total nitrogen from the liquid effluent. Two-day HRT was believed sufficient for treating 20,000-mg/l COD dairy wastewater if complete ammonia oxidation is not desired. However, 4-day HRT needs to be used for achieving complete ammonia oxidation. A two-stage system consisting of an SBR and a complete-mix biofilm reactor was capable of achieving complete ammonia oxidation and comparable carbon, solids, and nitrogen removal while using at least 1/3 less HRT as compared to the single SBR system.

Swine wastewater treatment in a two stage sequencing batch reactor using real‐time control

A laboratory scale two‐stage sequencing batch reactor (TSSBR) was used to study the effectiveness of pH as a real‐time control parameter in swine wastewater treatment. A Ringlace media was inserted into the A/O (Anoxic/Oxic) reactor for bacteria immobilization. The TSSBR was subjected to three levels of organic loading. The pH and ORP (Oxidation Reduction Potential) patterns obtained were consistent with distinct features, enabling the real‐time control strategy to effectively set a flexible aeration time pending on influent concentration, hence resulting in flexible cycle time and HRT (Hydraulic Retention Time) for the system. The real‐time process ensured a removal efficiency of over 99% and 95%, respectively, for ammonia and TOC (Total Organic Carbon). For NO3 ‐‐N and PO4 ‐3, the run with influent TOC = 4,000 mg/L yielded the most efficient removal of 61% and 95%, respectively. Test results suggest that pH can be a viable tool for on‐line real‐time control of a biological treatment process.

Real-Time Control of Two-Stage Sequencing Batch Reactor System for the Treatment of Animal Wastewater

An evaluation of the use of ORP as a real-time control parameter was conducted. A newly developed real-time control strategy, using ORP, was successfully applied, without a supplemental carbon source, to a new type of bench-scale two-stage SBR process for the treatment of swine wastewater. With real-time control, consistently high system performances were obtained, despite the fluctuation of influent quality; removal efficiencies for BOD5, COD, NH4-N, TKN, Ortho-P, Total Phosphorus (TP) averaged approximately 99.6%, 97%, 98%, 96%, 95% and 94%, respectively. Also, effective denitrification could be achieved without the addition of an external carbon source; the average NOx-N level on final effluent was 11 mg l−1. The data from this study reveal that both the ORP and pH can be used as successful process control parameters in the optimization of nutrient removal and treatment system capacity. Feasible real-time control strategies using dynamic ORP and pH change are established through this research.