不同臭氧催化氧化体系处理老龄垃圾渗滤液的效果及能耗分析

老龄垃圾渗滤液因其成分复杂且可生化性差,故传统技术无法对其进行有效降解,且利用臭氧催化氧化体系处理垃圾渗滤液缺乏系统性评估报道。为解决上述问题,采用臭氧/过二硫酸盐(${{rm{S}}_2}{{rm{O}}_8^{2 - }}$,PS)、臭氧/过一硫酸盐(${rm{HS}}{{rm{O}}_5^ -} $,PMS)和臭氧/过氧化氢(H₂O₂)氧化体系,探讨了处理老龄垃圾渗滤液的可行性,考察了初始pH、温度、O₃及H₂O₂、Na₂S₂O₈、KHSO₅的投加量等因素对其处理效果的影响,并对其能源效率进行了分析。结果表明,优化条件下,O₃/PMS、O₃/H₂O₂和O₃/PS的单位数量级能耗(electrical energy per order,EE/O)分别为1 007.5、1 233.7、662.6 kWh·m⁻³,O₃/PMS氧化体系处理老龄垃圾渗滤液的效果与O₃/H₂O₂氧化体系相似,且优于O₃/PS。
由综合处理效果与能耗评估结果可知,O₃/H₂O₂氧化体系最佳,在温度为25 ℃,pH=6,O₃和H₂O₂投加量分别为3 g·h⁻¹和2 125 mg·L⁻¹,反应时间为60 min条件下,能耗最低,EE/O降至443.9 kWh·m⁻³,且TOC去除率和反应速率常数分别为27.1%和0.005 3 min⁻¹,BOD₅/COD也由0.18增至0.26。综合上述结果,基于臭氧体系的高级氧化法能耗较高,可将臭氧催化氧化与低成本的生物处理技术相结合,从而实现对污染物高效经济降解。上述研究结果可为臭氧高级氧化技术的工程化应用提供参考。

Effect and energy consumption analysis of aged landfill leachate treatment by different catalytic ozonation

Aged landfill leachate was hardly degraded by traditional water treatment due to its highly complex composition and low biodegradability. There are few systematic evaluations on the landfill leachate treatment by ozone-based advanced oxidation processes (O3-based AOPs). This study investigated the feasibility of aged landfill leachate treated by O3/PS (peroxydisulfate, ${{rm{S}}_2}{{rm{O}}_8^{2 - }}$), O3/PMS (peroxymonosulfate, ${rm{HS}}{{rm{O}}_5^ -} $) and O3/H2O2 systems based on treatment efficiency and energy efficiency under different initial pH, temperature, O3, Na2S2O8, KHSO5 or H2O2 dosages. The results showed that the EE/O (electrical energy per order) of O3/PS, O3/PMS and O3/H2O2 systems were 662.6, 1 007.5 and 1 233.7 kWh·m−3, respectively, under the optimum conditions. The treatment efficiency of O3/PMS systems was similar to O3/H2O2 and was higher than O3/PS systems. In consideration of treatment efficiency and energy consumption, the optimum treatment was observed with the O3/H2O2 systems at 25 ℃, initial pH of 6.0, O3 dosage of 3 g·h−1, H2O2 dosage of 2 125 mg·L−1 and reaction time of 60 min, the EE/O was reduced to 443.
9 kWh·m−3. The removal efficiency of total organic carbon (TOC) and the reaction rate constant were 27.1% and 0.005 3 min−1, respectively. And the BOD5/COD value also increased from 0.18 to 0.26. The analysis showed that O3-based AOPs were energy-intensive, the combination of catalytic ozonation and low-cost biological treatment technologies might achieve efficient and economic degradation of pollutants. This study can be considered as a reference for the engineering application of O3-based AOPs.