The ozone/peroxymonosulfate (O3/PMS) system has attracted widespread attention from researchers owing to its ability to produce hydroxyl radicals (•OH) and sulfate radicals (SO4•−) simultaneously. The existing research has shown that the O3/PMS system significantly degrades refinery trace organic compounds (TrOCs) in highly concentrated organic wastewater. However, there is still a lack of systematic understanding of the O3/PMS system, which has created a significant loophole in its application in the treatment of highly concentrated organic wastewater. Hence, this paper reviewed the specific degradation effect, toxicity change, reaction mechanism, various influencing factors and the cause of oxidation byproducts (OBPs) of various TrOCs when the O3/PMS system is applied to the degradation of highly concentrated organic wastewater. In addition, the effects of different reaction conditions on the O3/PMS system were comprehensively evaluated. Furthermore, given the limited understanding of the O3/PMS system in the degradation of TrOCs and the formation of OBPs, an outlook on potential future research was presented. Finally, this paper comprehensively evaluated the degradation of TrOCs in highly concentrated organic wastewater by the O3/PMS system, filling the gaps in scale research, operation cost, sustainability and overall feasibility.

The widespread use of bisphenol A (BPA) in industry has resulted in BPA contamination of water bodies and even endocrine-disrupting effects on organisms and humans through water transmission. Advanced oxidation processes based on sulfate radicals have received increasing attention due to their ability to efficiently degrade endocrine disruptors (including BPA) in water. In this study, powdered iron (Fe(0)) and ferrous sulfate (Fe(II)) were used as activators to activate persulfate (PS) for the degradation of BPA. The effects of the dosage of the activator, the concentration of PS, the concentration of BPA, the initial solution pH, and the reaction temperature on the degradation efficiency of BPA in Fe(II)/PS and Fe(0)/PS systems were investigated, and the kinetics of BPA degradation under different reaction conditions were analyzed. The results showed that the optimal conditions were [Fe(II)] = 0.1 g/L, [PS] = 0.4 mM, [BPA] = 1 mg/L, T = 70 °C and pH = 5.0 for the Fe(II)/PS system and [Fe(0)] = 0.5 g/L, [PS] = 0.5 mM, [BPA] = 1 mg/L, T = 70 °C and pH = 5.0 for the Fe(0)/PS system; both systems were able to achieve equally good degradation of BPA. The degradation of BPA in the Fe(II)/PS system satisfied the pseudo-secondary kinetic equation under varying PS concentration conditions, otherwise the degradation of BPA in both systems conformed to the pseudo-first-order kinetic equation.

Based on the kinetics of the treatment process of the completely mixed reactor in series, this study reveals the relationship between the reactor stages and the treatment efficiency, and it was applied to the simultaneous nitrogen and phosphorus removal process. The strengthening effect of the reactor stages of the main anoxic sections on the anoxic phosphorus absorption efficiency and the contribution to improving the treatment effect were investigated. Using sewage with a low carbon-to-nitrogen ratio as the research object and keeping the operation parameters of the improved anaerobic–anoxic–oxic (A2O) process unchanged, the experimental research was carried out under the condition that reactor stages in series of the main anoxic section were one, two, three and four, respectively. The results showed an increase in the number of reactors in series in the main anoxic zone. The total phosphorus (TP) concentration in the effluent of the main anoxic stage decreased significantly, and the phosphorus uptake increased from 4.411 g/d (when n; the number of reactor stages in series was one) to 5.086 g/d when n was 4. Additionally, the nitrate nitrogen (NO3−–N) concentration in the effluent decreased, from 12.53 mg/L when n was one, to 9.62 mg/L when n was four, the removal rate of total nitrogen (TN) increased, from 56.86% when n was one to 65.98% when n was four, and the reduction power of nitrate nitrogen increased, and the denitrification rate increased. The increase in the number of reactors in series enhanced the anoxic phosphorus absorption and denitrification performance. Therefore, the main anoxic section of the synchronous nitrogen and phosphorus removal system can be designed and operated as reactors in series.

No abstract

No abstract