It is impossible to treat the semiconductor cleaning wastewater biologically without pre-treatment, since it is mixed with high concentrations of NH4+-N, F-, and isopropyl alcohol(IPA), So, the purpose of this study is to treat the semiconductor cleaning wastewater biologically after determining som...
It is impossible to treat the semiconductor cleaning wastewater biologically without pre-treatment, since it is mixed with high concentrations of NH4+-N, F-, and isopropyl alcohol(IPA), So, the purpose of this study is to treat the semiconductor cleaning wastewater biologically after determining some influence factors such as proper injection molar ratio, pH and stirring intensity during the pre-treatment of crystallization through lab scale experiment.
Wastewater of buffered oxide echant(BOE) was treated with struvite crystallization. In this process, optimum injection molar ratios of NH4+ : Mg2+ : PO43-, and pH were 1 : 1 : 1, pH 9 and G·td value was more than 2 × 105, respectively. Mixed wastewater with high concentration of F- was treated with CaF2 crystallization. In this process, optimum molar ratios of F- : Ca2+ and pH were 1 : 2 and pH 6, respectively.
In biological treatment, high concentration of IPA among the influence factors of mixed wastewater shows organic toxicity to activated sludge, which makes direct biological treatment impossible. Therefore, activated sludge needed to be appropriately adapted to IPA. MLE process was also applied to this biological treatment. In this process, two reaction tanks, one is filled with plastic flow media coated with activated carbon and the other is not filled with plastic flow media, have been tested. Experimental results showed that the removal efficiencies of IPA(CODCr) in each tank were 98.9%(filled with media) and 97.6%(non-filled with media) and the removal efficiencies of NH4+-N, were 94.3% and 95.8%, respectively, and effluent concentration of NO3—-N was close to 0 mg/L.
Consequently, it can be confirmed that biological treatment is possible even for high concentration of IPA in semiconductor cleaning wastewater if activated sludge is being adapted to IPA, and that activated sludge also could be used as a denitrification organic source.
It is impossible to treat the semiconductor cleaning wastewater biologically without pre-treatment, since it is mixed with high concentrations of NH4+-N, F-, and isopropyl alcohol(IPA), So, the purpose of this study is to treat the semiconductor cleaning wastewater biologically after determining some influence factors such as proper injection molar ratio, pH and stirring intensity during the pre-treatment of crystallization through lab scale experiment.
Wastewater of buffered oxide echant(BOE) was treated with struvite crystallization. In this process, optimum injection molar ratios of NH4+ : Mg2+ : PO43-, and pH were 1 : 1 : 1, pH 9 and G·td value was more than 2 × 105, respectively. Mixed wastewater with high concentration of F- was treated with CaF2 crystallization. In this process, optimum molar ratios of F- : Ca2+ and pH were 1 : 2 and pH 6, respectively.
In biological treatment, high concentration of IPA among the influence factors of mixed wastewater shows organic toxicity to activated sludge, which makes direct biological treatment impossible. Therefore, activated sludge needed to be appropriately adapted to IPA. MLE process was also applied to this biological treatment. In this process, two reaction tanks, one is filled with plastic flow media coated with activated carbon and the other is not filled with plastic flow media, have been tested. Experimental results showed that the removal efficiencies of IPA(CODCr) in each tank were 98.9%(filled with media) and 97.6%(non-filled with media) and the removal efficiencies of NH4+-N, were 94.3% and 95.8%, respectively, and effluent concentration of NO3—-N was close to 0 mg/L.
Consequently, it can be confirmed that biological treatment is possible even for high concentration of IPA in semiconductor cleaning wastewater if activated sludge is being adapted to IPA, and that activated sludge also could be used as a denitrification organic source.
주제어
#semiconductor cleaning wastewater,struvite CaF2 IPA BOE MLE
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