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Study of Capability a Fixed-bed Anaerobic-aerobic System to Remove Phosphorus from Wastewater

Barzinmehr, Hossein | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49032 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Borghei, Mehdi
  7. Abstract:
  8. Discharge of Raw wastewater or effluent of Treatment plants into the natural bodies of water, in the case of high nutrients may cause serious problems such as algae bloom which results in a reduction in concentration of dissolved oxygen. Among the nutrients, phosphorous is known as a limiting factor in growth and intensification (intensifier) of eutrophication. Therefore, elimination of phosphorus from wastewater prior to the discharge point is highly important. Phosphorus can be removed chemically as well as biologically. Chemical methods are known, efficient and reliable but Problems like operational and maintenance costs and chemical sludge production cause tendency to use biological methods. Biological phosphorus removal was investigated in an anaerobic-aerobic system. It was tried to design a high-rate and reliable system. The anaerobic reactor used in experiments was a modified Anaerobic baffled reactor (ABR) which includes fixed-bed carriers and each compartment is disconnected from the previous one due to stage formation. A submerged aerated fixed-bed bioreactor was used for aerobic zone. The scope of this study was to investigate the capability of an anaerobic-aerobic process for phosphorus and COD removal. Synthetic wastewater (COD=1000 mg/L) under variant phosphorus concentrations and the effect of effluent recycle were investigated. It was observed that increasing phosphorus concentration up to 25 mg/L caused positive effects on P-removal. But concentrations above the 25¬ mg/L caused reduction in removal efficiency. It was observed that increasing phosphorus concentration caused reduction in efficiency of COD removal. Best condition in P-removal was observed when phosphorus concentration was 25 mg/L with 92.04% in P-removal and 95.03% of COD removal. Considerable effect on COD removal and P-Removal was observed during study of return flow. Best result in COD removal was obtained in no return-flow case with 96.25% COD removal. Best results in P-removal was obtained when return flow discharged to 3rd compartment and 96.07% P-removal was observed. Aerobic Reactor was separately investigated and it was found that with the same hydraulic retention time of anaerobic-aerobic system, it has no capability of phosphorus and COD removal in comparison with the two sequential reactors
  9. Keywords:
  10. Wastewater Treatment Plant ; Submerged Aerated Filter (SAF) ; Anaerobic Baffled Reactor (ABR) ; Biological Phosphorus Removal ; Biofilm ; Pumice Stone ; Submersible Fixed Bed Reactor

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