| Phenol-acetone wastewater is a typical high-concentration toxic organic wastewater, whichshowed significant toxic effects on activated sludge and could be biologically treated at a lowloading rate with unstable operation. The objective of this study was to remove the toxicity of thewastewater. Firstly，the toxic substances against activated sludge in the wastewater were identified,through the application of both toxicity assays and substance analysis tools. Then, the technique fortoxic substances removal was selected and optimized. The effects of toxic substances removal on thefollowing biological treatment were investigated. The main conclusions were as follows.The monitoring results of phenol-acetone wastewater from a chemical factory indicated thatmost of the wastewater samples showed significant toxic effect on activated sludge with oxygenutilization rate (OUR) inhibition rate above50%. Cumene hydroperoxide (CHP) is one ofcharacteristic pollutants in phenol-acetone wastewater. It has a significant toxic effect on activatedsludge with a50%effective concentration (EC50) of255mg on OUR of activated sludge. It wasidentified as the main source of toxicity against activated sludge besides the salinity in thewastewater.Fe2+ions could catalyze the degradation of low concentration CHP in thewastewater with a high reaction rate at normal temperatures. The toxicity of thewastewater against activated sludge could be removed significantly. The higher the Fe2+dosage, the lower the residual CHP concentration and the higher reaction rate. Weakacid condition could facilitate the catalyzed degradation of CHP. When the CHPconcentration in the wastewater was0.6g/L, reaction of10min could remove CHPeffectively under optimized conditions of25℃，pH5，FeSO4·7H2O dosage of0.15g/L.After the pretreatment of Fe2+catalyzed degradation, activated sludge OURinhibition rate of phenol-acetone wastewater decreased to below10%. The followingbiological treatment loading rate was improved with a better effluent quality. |
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