高级氧化法处理气田水中有机污染物的研究

气田水的产水量大,水质复杂,若直接排入水体,将造成环境污染。为此,采用气相色谱-质谱法(GC-MS)剖析了气田水的有机物组成,并单独采用臭氧(O_3)氧化技术和紫外光(UV)/H_2O_2氧化技术对气田水进行了深度氧化处理,考察了各氧化工艺条件下的影响因子对气田水处理效果的影响,研究了O_3氧化后水中的有机物特点,最终提出了O_3+UV/H_2O_2氧化技术。结果表明:气田水中的有机物种类复杂,含有各种难降解的含氮、含硫杂环有机化合物;当O_3投加量为7.5 g/h、pH值为11、氧化时间为90 min时,气田水中的有机物矿化程度最高,约为20%;O_3氧化后的有机物表征显示大部分物质被氧化为易于生物降解的酸类、醇类、酯类等简单化合物;UV/H_2O_2氧化过程中H_2O_2投加量为6 720 mg/L、pH值为3、反应时间为90 min时,可将TOC值由87.27 mg/L降到10 mg/L以下;最后,将两种氧化工艺联合使用,当H_2O_2投加量为4 880 mg/L、pH值为3、反应时间为60 min时,可将TOC值由87.27 mg/L降到20 mg/L以下,适当增加时间,可降为10 mg/L左右。对比两种氧化工艺,O_3+UV/H_2O_2氧化技术不仅减少了H_2O_2投加量,同时也缩短了UV/H_2O_2氧化的反应时间。

Investigation on the treatment of organic pollutants in gas field water by advanced oxidation

Because of the large yield and complex water quality of gas field water, if it is directly discharging into the water body, it will cause serious damage to the environment and human health. Combining with the water quality characteristics of gas field water, the advanced oxidation treatment of gas field wastewater was carried out by using seperate O₃ oxidation technology and UV/H₂O₂ oxidation technology respectively. The effect of the influencing factors on the treatment of gas field wastewater under various oxidation conditions was investigated, and the characteristics of organic substances in the water after ozonation were also studied. Finally, the technology of O₃ + UV/H₂O₂ oxidation was put forward. The results showed that the organic species in gas field wastewater were complex and contain various kinds of non-degradable nitrogen-containing and sulfur-containing heterocyclic organic compounds. When ozone dosage was 7.5 g/h, pH=11, and oxidation time was 90 min, the mineralization degree of organic matter in gas field water was the highest of 20%. The characterization of organic matter after ozone showed that most of the substances were oxidized to be easily degraded ones, such as acids, alcohols, esters, etc.; the dosage of H₂O₂ in the process of UV/H₂O₂ oxidation was 6 720 mg/L, pH=3, reaction time was 90 min, reducing TOC from 87.27 mg/L to less than 10 mg/L; finally, when the two oxidation processes were combined, under 60 min reaction time at a pH of 3 with 4 880 mg/L H₂O₂ dosage, TOC can be reduced from 87.27 mg/L to less than 20 mg/L. If the time increased appropriately to 90 min, it can be reduced to 10 mg/L. Compared with the two processes, the dosage of hydrogen peroxide was reduced and the reaction time was shortened.