生物通风法修复柴油污染土壤模拟实验研究

Simulation Experiment for Remediating Diesel Fuel Contaminated Soil by Bio-venting Technology

通过生物通风技术修复不同柴油浓度污染土壤的土柱模拟实验,研究了各土柱中土壤总石油烃(total petroleum hydrocarbon,TPH)的去除规律,并对影响柴油去除效果的因素进行了分析,结果表明:①经过3个月的生物通风后,初始柴油浓度为5(柱Ⅰ)、10(柱Ⅱ)、20(柱Ⅲ)、40(柱Ⅳ)g/kg的土柱柴油去除率为Ⅱ>Ⅰ>Ⅳ>Ⅲ,柱Ⅱ的修复效果最佳,半衰期为60.05天,TPH最终去除率达65.3%;②挥发和生物降解作用影响土柱中柴油的去除,由于重力引起的向下迁移作用只对柴油在土柱中的空间分布产生影响,三者共同作用决定各土柱不同取样口柴油的去除规律;③在实验过程中,各土柱土壤pH变化不大,初始柴油浓度越高土柱水分损失率越小;有效磷和速效氮含量均有所降低,柱Ⅲ降低率最大,分别为58.27%和31.87%,柱Ⅰ最小;土柱上层土壤中的酶活性要低于下层,过氧化氢酶和脱氢酶活性均呈现出先升高后降低的趋势。实验结果为研究各土柱中柴油的生物降解规律提供了依据。

The bio-venting experiment was investigated in the laboratory using diesel as a model contaminant, performed in columns filled with soils. The removal of TPH and the factors in affecting the efficiency of diesel degradation were studied. The results showed that： 1） after three month bio-venting, the removal rate of the four different columns was II 〉 I 〉 N 〉 III, the initial diesel concentration was 5 g/kg （Column I）, 10 g/kg （Column II ） , 20 g/kg （Column III） and 40 g/kg （Column III）, respectively. The optimal bio-venting velocity was column II, whose half life was 60.05 d, the removal rate of TPH was 65.3%. 2） The diesel removal in the column was influenced by volatilization and biodegradation. The downward migration impact which caused by the gravity influenced the diesel＇s distribution on the space in column. The removal rule of diesel columns with different sampling port was decided by the three actions together. 3） The change of pH was very little in the process of experiment; the loss of water was less when the initial diesel concentration was higher. Available phosphorus and available nitrogen contents were reduced, but the degrees varied from each other. The reduction rate of column III was maximum, they were 58.27% and 31.87% respectively. The column I was least. The soil enzyme activities in upper soils were less than those in lower soils, the activities of catalase and dehydrogenase increased firstly and then decreased, which provided an important basis for the research of the diesel biodegradation in each column.