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The discharge of wastewater from various industries such as petroleum and petrochemical, pollute water resources. The presence of these pollutants in water resources will cause disorders in the ecosystem and it has various risks to human health. The effluent usually contains organic matter, including phenol and its derivatives. In this study, three different types of reactors were used in the activated sludge process to study the biological removal of o-nitrophenol from the petrochemical industrial effluent. These reactors include Continuous Moving-Bed Sequencing Batch Reactor, Moving-Bed Sequencing Batch Reactor and conventional sequencing batch reactor. For this purpose, the operational indicators of each reactor were investigated and optimized. For MSBR, active sludge volume ratio (30%), aeration flowrate (18 L/min), operation time (4h), pH (7), filler to reactor volume ratio (4.7 %) and SVI (89 ml/g) were considered. Also, For C-MSBR indicators such as initial volumetric flowrate (20 ml/min), aeration flowrate (12 L/min), filler to reactor volume ratio (5.8 %) and SVI (98 ml/g) were optimized. As SBR is structurally similar to the other reactors, only initial volumetric flowrate was considered (40 ml/min) and based on the results, this reactor has better SVI (88 ml/g) than the other two reactors. Finally, based on the optimized parameters, percentage removal of ortho nitrophenol from a synthesized effluent, analogous to Karoon Petrochemical company effluent, was investigated by C-MSBR. In addition to o-nitrophenol, other chemicals such as Toluene and Benzene were also present. The results show the indicators including ortho nitrophenol percentage removal (84.7%), Chemical Oxidation Demand (COD) (94%), Biochemical Oxidation Demand (94.8%), BOD5/COD (0.57) and SVI (74.45 ml/g) comply with environmental standards and the treated effluent can be used in irrigation and agriculture by addition of one more processing step.

The concept of Molten Salt Reactor use Th to breed fissile 233U, where an initial source of fissile material needs to be provided. However, there is no available 233U and so; the fissile fuel supply is one of the unresolved problems. Thus, it is necessary to use existing fissile materials such as 235U or Pu to produce 233U. Current studies analyze the fuel transition from 235U/Th or Pu/Th to 233U/Th and, in this context, the present work evaluates the criticality and the neutron flux of MSBR (Molten Salt Breeder Reactor) considering the fuel: (i) mix of Th and enriched U; (ii) the combination of Th and reprocessed Pu; and (iii) matrix of reprocessed Pu/minor actinides (MAs) and Th. The goal is to verify which of these fuels can be used as initial fissile supply. The MSBR core was simulated by MCNPX 2.6.0 code and the criticality model presents similar behavior of previous studies. The results show that reprocessed fuels could have a potential to be used as initial fissile supply, but these fuels present a neutron flux profile less flattens than traditional 233U/Th. It is possible that a new distribution of fuel elements may improve this profile and future simulations will be performed to evaluate this behavior. The uranium, must has high enrichment value to be used as initial seed. Other studies need be performed to evaluates the uranium enrichment and the U/Th ratio that produces similar core criticality to traditional fuel.

Preliminary results of the dynamic analysis of a two-fluid molten-salt breeder reactor (MSBR) system are presented. Based on an earlier work on the preliminary dynamic model of the concept, the model presented here is nonlinear and has been revised to accurately reflect the design exemplified in ORNL-4528. A brief overview of the model followed by results from simulations performed to validate the model is presented. Simulations illustrate stable behavior of the reactor dynamics and temperature feedback effects to reactivity excursions. Stable and smooth changes at various nodal temperatures are also observed. Control strategies for molten-salt reactor operation are discussed, followed by an illustration of the open-loop load-following capability of the molten-salt breeder reactor system. It is observed that the molten-salt breeder reactor system exhibits “self-regulating” behavior, minimizing the need for external controller action for load-following maneuvers.

A lab-scale SBR equipped with a flat sheet membrane in submerged configuration that is named MSBR was used for the treatment of composting leachate. It was fed by biologically treated leachate with overall 70-1360 mg/L Chemical Oxygen Demand (COD). The values of pH, Electrical Conductivity (EC), and Dissolved Oxygen (DO) were monitored routinely. However, analysis of total COD, Soluble COD (SCOD), Biological Oxygen Demand (BOD5), Total Suspended Solids (TSS) and Volatile Suspended Solids (VSS) was done in feed and filtrate, whenever the system reached steady state twice a week for about 6 months.In all loading rate, BOD5 concentration was less than standard limit. The removal efficiency of total COD increased in the bioreactor with time in all experiments was up to 80%.Influent SCOD varied spectacularly (50-1050mg/L) due to the leachate collection during different seasons but in the effluent, it remained relatively stable. About 60% of the feed SCOD was the non biodegradable type that was separated by the membrane.Up to 99 % further solids was removed with micropore membrane which might be mainly included in colloidal solids. The value of EC for the leachate sample was 0.86-4 mS/cm at 22 °C which decreased by membrane significantly.It was concluded that MSBR as a versatile technology with high throughput could treat composting leachate belowthe standard limit if used after proper processes.

Abstract: The start-up of an Anammox process was studied in a membrane sequencing batch reactor (MSBR) in which a submerged hollow fibre membrane module was used to retain the biomass. The reactor was seed with Anammox biomass and fed using the Van de Graaf medium. During a first operating stage, salt precipitation was observed and interfered with microbial activity and caused a decrease of the nitrogen removal rate of the reactor from 100 to only 10mgl−1 per day. Salt precipitation was avoided by diminishing adequately the Ca and P concentrations of the Van de Graaf medium during the last operating stage. This action increased quickly the activity of the system, and nitrogen removal rate reached up to 710mgl−1 per day with almost full nitrite removal. Sporadic flotation of the sludge was observed in the MSBR. The use of the membrane avoided biomass wash-out from the system. Moreover, a surprising fact was that Anammox biomass did not grow in flocs in the MSBR, but in granules. This fact showed that this kind of microorganisms have a trend to grow in aggregates. Results indicated that the use of the MSBR could be a suitable system for nitrogen removal by using the Anammox reaction. [Copyright &y& Elsevier]