油田污水中碳钢表面生物膜的生长监测与控制

Monitoring and Controlling Growth of Biofilm on Carbon Steel Surface in Oilfield Sewage

金属表面硫酸盐还原菌微生物膜内的反应影响金属腐蚀的机理和速度,杀灭膜内微生物是控制微生物膜腐蚀金属的重要措施。采用丝束电极技术,研究了油田污水中生物膜在Q345碳钢表面的生长规律;通过投加3种杀菌剂来灭杀生物膜内细菌,并对其杀菌效果进行了比较,获得了杀菌剂对细菌的抑制周期及最低有效浓度。结果表明:油田污水中微生物首先在Q345碳钢表面大量附着、生长,至216 h时生长完整,至360 h时开始脱落;生物膜对Q345钢的腐蚀呈现不均匀性,微生物的存在可在局部范围内降低Q345碳钢表面的腐蚀电流密度,但有促进其腐蚀的倾向;杀菌剂HGY-B1的杀菌效果优于KD-24及LC-3,投添加量为300 mg/L时,对生物膜内细菌抑制周期可达8 d,最低杀菌浓度为40 mg/L。

A wire beam electrode( WBE) was applied to study the growth rule of the sulfate reducing bacteria biofilm on Q345 carbon steel surface in oilfield sewage. Three kinds of bactericide were added into the sewage to kill the bacteria in the biofilm. The antibacterial efficacy of the bactericides was comparatively evaluated,and their inhibition period as well as the lowest effective concentration towards bacteria was established. Results showed that abundant microorganisms in oilfield sewage were attached on the surface of the steel and grew thereon. A complete biofilm was formed upon 216 h of growth, and the biofilm began to fall off upon 360 h of growth. Besides, the biofilm caused uneven corrosion of the steel; and the existence of microorganisms could reduce the corrosion current density in a certain region but led to accelerated corrosion of the steel. Moreover,broad-spectrum bactericide BGY-B1 exhibitted better antibacterial performance than KD-24 and LC-3; and in particular,at a dosage of 300 mg / L,BGY-B1 was able to inhibit the bacteria in the biofilm up to a period of 8 days,with the lowest antibacterial concentration being 40 mg / L.