The aim of this study was to investigate MTBE removal efficiency using sequencing batch airlift reactor (SBAR) and to determine the share of aeration and adsorption processes during the operation. The present study was conducted with a new design of the system (cubic area and embedded baffle). The reactor was applied in 4-h cycles, which included 2 min filling, 210 min aeration, 5 min sedimentation, 8 min draw, and 15 min idle time. One week after start-up, the initial brown granules were observed. During the operation, some granules were formed with the size of 2– 6 mm, average settling velocity and density of 0. 66 cm/s and 0. 06 g/mL, respectively. The results showed that COD removal efficiency was over 94 percent.

A bench scale aerobic Sequencing Batch Reactor (SBR) was investigated to treat the wastewater from an industrial milk factory. The reactor was constructed from plexi glass material and its volume was 22.5 L. The reactor was supplied with oxygen by fine bubble air diffuser. The reactor was fed with milk factory and synthetic wastewater under different operational conditions. The COD removal efficiency was achieved more than 90%, whereas COD concentration varied from 400 to 2500 mg/l. The optimum dissolved oxygen in the reactor was 2 to 3 mg/l and MLVSS was around 3000 mg/l. Easy operation, low cost and minimal sludge bulking condition make the SBR system an interesting option for the biological medium strength industrial wastewater treatment. The study demonstrated the capability of aerobic SBR for COD removal from dairy industrial wastewater.

Reactive dyes have been identified as problematic compounds in textile industries wastewater as they are water soluble and cannot be easily removed by conventional aerobic biological treatment systems. The treatability of a reactive dye (Brill Blue KN-R) by sequencing batch reactor and the influence of the dye concentration on system performance were investigated in this study. Brill Blue KN-R is one of the main dyes that are used in textile industries in Iran. Four cylindrical Plexiglas reactors were run for 36 days (5 days for acclimatization of sludge and 31 days for normal operation) at different initial dye concentrations. The dye concentrations were adjusted to be 20, 25, 30 and 40 mg/L in the reactors R1, R2, R3 and R4, respectively. In all reactors, effective volume, influent wastewater flowrate and sludge retention time were 5.5 L, 3.0 L/d and 10 d, respectively. According to the obtained data, average dye removal efficiencies of R1, R2, R3 and R4 were 57%±2, 50.18% ±3, 44.97% ± 3 and 30.98% ± 3, respectively. The average COD removal efficiencies of all reactors were 97% ± 1, 97.12% ± 1, 96.93% ± 1 and 97.22% ± 1, respectively. The dye removal efficiency was decreased by increasing the dye concentration with the correlation coefficient of 0.997.

Discharge of domestic and industrial wastewater to surface or groundwater is very dangerous to the environment. Therefore treatment of any kind of wastewater to produce effluent with good quality is necessary. In this regard choosing an effective treatment system is important. Sequencing batch reactor is a modification of activated sludge process which has been successfully used to treat municipal and industrial wastewater. The process could be applied for nutrients removal, high biochemical oxygen demand containing industrial wastewater, wastewater containing toxic materials such as cyanide, copper, chromium, lead and nickel, food industries effluents, landfill leachates and tannery wastewater. Of the process advantages are single-tank configuration, small foot print, easily expandable, simple operation and low capital costs. Many researches have been conducted on this treatment technology. The authors had been conducted some investigations on a modification of sequencing batch reactor. Their studies resulted in very high percentage removal of biochemical oxygen demand, chemical oxygen demand, total kjeldahl nitrogen, total nitrogen, total phosphorus and total suspended solids respectively. This paper reviews some of the published works in addition to experiences of the authors.

Polychlorinated Biphenyls are xenobiotic pollutants, commonly known as PCBs. PCBs could enter the food chain of biological organisms and accumulate in their fatty tissues. Thus, before the discharge of PCBs compounds in the environment, it is necessary to focus on processes and techniques for its removal at their sources. The objective of this research was to investigate the biodegradability of PCBs compounds by Sequencing Batch Biofilm Reactors (SBBR). Acetone and acetic acid were used as solvent in two separate reactors. Organic loading rates (OLRs) were from 0.04 to 0.75 g COD/l-d (maximum concentration of PCBs =0.7 mg/l). The SBBR was operated with four phases including fill, react (aeration), settle (sedimentation/clarification), and draw (decant) during different loading rates. The efficiency of COD and PCBs removal were evaluated. Maximum removal efficiencies of COD was 85% occurred in 0.2- 0.4 g /l-d in the reactor 1 (solvent acetone). Also, in reactor 2 (solvent acetic acid) maximum removal rates were recorded as% in OLR of 0.56g COD/ld. The maximum removal efficiency of PCBs was observed at 240 days after start-up of both reactors and was 99%. The results of this research showed that the concentration of priority organic pollutants can be decreased by using biological processes such as SBBR. This study can also indicated that biodegradation of high weight compounds by aerobic bioreactors is a time consuming processes.

As a result of penetration of water in landfills through precipitations and or by conducting some processes such as size reduction of waste materials as well as biodegradation of materials in composting process, leachate may be produced. High organic loading and containing complex and various compounds introduce leachate as a toxic wastewater and a risk for the environment. With respect to relatively high organic load and existing refractory organic compounds, a single process cannot remove all of the organic matters from leachate. Therefore, to meet discharge standards, additional treatment is required to remove the remaining materials from treated leachate. In addition, Sequencing Batch Reactor (SBR) is a reliable biological treatment applied to eliminate pollutant from leachate and spread in the worldwide. As a result post-treatment of composting leachate via SBR was chosen as the main objective of this study. This study was conducted in laboratory scale and in batch mode. The working volume of SBR reactor was 1. 3 L. A complete cycle of SBR is divided into five stages, include to fill, react (mixing & aeration), settle, draw, and idle. The SBR system and duration of five stages were automatically controlled. Sludge bulking is a common problem in biological treatment. For controlling of sludge bulking different parameters such as DO, pH and temperature were adjusted in a fixed range. Furthermore, due to better control of sludge bulking, sometimes H2O2 solution was injected to the reactor. In this study, performance of the SBR system were analyzed according to sludge retention time (SRT) and hydraulic retention time changes. SRT was adjusted to 3, 5 and 7 days and hydraulic retention time was increased from 4 hr. to 6, 8, 10 and 12 hr., respectively. The leachate samples were collected from the effluent of anaerobic biological reactor of a composting leachate treatment facility in north of Iran. The seed samples were supplied from a wastewater treatment plant in Tehran and acclimatized with diluted leachate. The SBR reactor operated with 1L of leachate and 300 ml of acclimatization seed. The mean initial COD and color were 2000 mg/L and 5. 7 Gardner, respectively. Performance of the SBR system was monitored by analyzing the COD and color removal efficiency, determining of MLSS and MLVSS changes and estimating the waste sludge production. In this research, optimum SRT and hydraulic retention time for SBR system were estimated to be 5 days and 12 hours, respectively. Based on the results, the maximum removal efficiency of COD and color in SBR process were estimated to be 90% and 44% respectively, that reduced the initial COD from 2184 mg/L to 215 mg/L and closed to the Iranian standard discharge limits for agricultural purpose. In this process, values of waste sludge production were also analysed respected different hydraulic retention times. The results revealed that by increasing the hydraulic retention time, waste sludge production was decreased. Finally, different kinetic models such as first order, Grau and Stover-Kincannon were examined for the optimal condition. The kinetics studies showed that post-treatment of leachate by SBR processes were in good agreement with the Grau and Stover-Kincannon kinetic models by a correlation coefficient of more than 97%.

Background and Objectives: Aerobic sludge granulation is an advanced phenomenonin which its mechanisms have not been understood. Granulation can be a promising and novel biological wastewater treatment technology to eliminate organic and inorganic materials in future. High salinity is a parameter which leads to plasmolisatian and reduction of the cell activity. This could be a problem for biological treatment of the saline wastewater. Aerobic granule was formed and investigated during this study.Materials and Methods: This study is an intervention study on the treatment of wastewater with 500-10000 mg/L concentration of NaCl by sequencing batch reactor. Asynthesized wastewater including nutrient required for microorganism’s growth was prepared. Input and output pH and EC were measured. Range of pH and DO varied between 7-8, and 2-5 mg/L, respectively. SEM technology was used to identify graduals properties.Results: In terms of color, granules divided into two groups of light brown and black.Granule ranged in 3-7mm with the sediment velocity of 0.9-1.35 m/s and density of 32-60 g/L. Properties of granules were varied. Filamentous bacteria and fungi were dominant in some granules. However non filamentous bacteria were dominant in others. EDX analysis indicated the presence of Ca and PO4.Conclusion: Granules with non filamentous bacterial were compact and settled faster. Presence of different concentrations of salinity leaded to plasmolysis of the bacterial cells and increased concentrations of EPS in the system as a result of which granulation accelerated.

This study was carried out for surveying the efficiency of biofilm sequencing batch reactor (SBR) for treatment of wastewater with high organic loading. A cylindrical lab scale biofilm SBR was used in this study. Primary microorganisms for startup of the reactor were obtained from return activated sludge of a municipal waste treatment plant. Reactor was feed with synthetic wastewater containing mono ethylene glycol as the main carbon source and NH4Cl and KH2PO4 as nutrients. Following startup and acclimation of microorganisms, organic loading was increased via influent COD concentrations of 500, 1000, 1500 and 2000 mg/L in constant hydraulic retention time. The most removal efficiency of 94% was achieved in influent COD concentration of 100 mg/L. According to data obtained in this work, it can be concluded that biofilm SBR has acceptable efficiency for high strength wastewaters.