循环冷却水系统中微生物的结垢特性

Fouling characteristics of microorganisms in circulating cooling water system

由生长在循环冷却水系统管道中的特异性细菌分泌的胞外聚合物(EPS)与循环冷却水的相互作用是导致工业循环冷却水系统产生生物污垢的主要原因。利用高通量生物测序分析循环冷却水系统中生物黏泥的优势菌种,以优势菌种分泌的EPS为研究对象,将其与矿物悬液混合进行平衡吸附实验。在传统化学分析的基础上,运用XRD、Raman、EDS、SEM等现代仪器分析技术,研究EPS与循环冷却水中离子经生化反应形成的矿物,以及EPS在主要矿物表面的吸附行为,以期为减少微生物污垢腐蚀提供重要的理论和实验依据。结果表明:循环冷却水中的微生物在高营养水平培养条件下,放线菌纲将逐渐成为冷却水中的优势菌;在与循环冷却水pH大致相同的偏中性(pH=7.78)环境下,EPS中的多糖(EPS-C)和蛋白质(EPS-N)更倾向于吸附在Fe_(2)O_(3)表面,但EPS中的核酸(EPS-P)更易吸附在SiO_(2)表面;EPS在矿物表面的吸附为物理吸附。

Some specific bacteria can grow in the industrial circulating cooling water piping and secrete extracellular polymeric substances(EPS).The interaction between EPS and circulating cooling water is the main cause of biological fouling in industrial circulating cooling water system.High-throughput biological sequencing was used to analyze the dominant bacteria of biological slime in the circulating cooling water system.EPS secreted by the dominant strains in slime was investigated,the equilibrium adsorption experiment was carried out by mixing EPS with mineral suspension.Based on the traditional chemical analysis,modern analytical technologies including XRD,Raman,EDS and SEM were applied to investigate the minerals formed by biochemical reaction between EPS and ions in circulating cooling water,and the adsorption behavior of EPS on the surface of main minerals.It provided an important theoretical and experimental basis for reducing microbial fouling corrosion.The results showed that when the microorganisms were incubated in circulating cooling water containing a higher concentration of nutrient,Actinomycetes gradually became the dominant bacteria in cooling water.In a neutral environment(pH=7.78)with roughly same pH of circulating cooling water,polysaccharides(EPS-C)and protein(EPS-N)in EPS were more likely to adsorb on Fe_(2)O_(3)surface,while nucleic acid(EPS-P)was more likely to adsorb on SiO_(2)surface.The adsorption of EPS on mineral surface was physical adsorption.