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Developing Optimal Operating Parameters for Wastewater Treatment Units of A Paper Manufacture Factory- By Tagachi Qualitative Engineering Assessment Model
Abstract Traditionally, the operation parameters of wastewater treatment units were generally determined by laboratory experimental analyses and personal experiences on sites. They generally could not be operated under the best conditions for these wastewater treatment units due to the properties and flowrate wastewater changed quite often or due to after a long time of operation of wastewater treatment plants. Especially, the raw material for paper manufacture factory was depended on the recycled wastepaper and its prosperities were different frequently. This results in the quality of process wastewater changed frequently. It is necessary to establish a fast and systematical simulating model that can adjust the operation parameters of wastewater treatment units in a possibly shortest period. Thus, the main objective of this study was to establish the optimal operating parameters for wastewater treatment unites from a paper manufacture factory with Tagachi qualitative engineering assessment model. Both physical and biological wastewater treatment unit operations were investigated as examples. Meanwhile, to establish the wastewater recycling operation was another purpose for this investigation. Several information and analytic skills such as orthogonal tables, effect tables, effect figures, average process data assessment, and variation analyses is generally applied by Tagachi model. The analytic results indicated that the dosage of PAC and polymer, air/water ratio, and water quality of influent wastewater would affect the removal efficiencies of the flotation wastewater treatment units. Using this model, we developed the optimal operating parameters and achieved the enhancement of 30 % in the COD removal efficiency. Another advantage of the analytic procedures also showed that the recovery period could be reduced from 3 day to 4 hours from failing operation of the floatation operation units. In addition, for biological wastewater treatment units (oxidation ditch), we developed the optimal operated parameter and achieved 10% of increase in COD removal efficiency. Several parameters were important for achieve better removal efficiencies of biological treatment units. They were properties of wastewater, rotating frequencies of air purging machine, the amount of dosage of bio-adds, and cycling biological sludge ratios. The study results also indicated that the reuse of wastewater could be recycled up 87 %. This ratio was much higher than the average recycling ratios of wastewater water for most paper manufacture factories in Taiwan.
Keywords: Tagachi model; system analyses, wastewater treatment, optimization, floatation, oxidation ditch, operational parameters
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