地下水人工回灌水化学因素对生物堵塞的影响

通过室内砂柱实验及扫描电镜，红外光谱，光电子能谱等技术，研究回灌水中离子强度及回灌过程中水-岩作用对细菌在饱和多孔介质中迁移及滞留的影响，揭示回灌过程中离子强度对介质生物堵塞演化规律及其作用机理的影响.结果表明，适宜的离子强度刺激细菌的生长及胞外聚合物（EPS）的生成，导致介质渗透性下降幅度达到99%，离子强度过高或过低都会抑制微生物的生长；Na⁺可以中和介质与细菌表面的负电荷，通过压缩双电层及减少静电斥力，进而增强细菌在介质表面的附着能力；介质中的碳酸盐矿物水解可导致环境pH值升高，诱导介质中的微量SiO₂，Al₂O₃等矿物溶解，促使介质孔隙度增大，延缓生物堵塞的发生时间并缓解堵塞程度；外源Na⁺及内源介质溶解产生的Ca²⁺，Mg²⁺，Al （III），刺激细菌产生更多的EPS，同时化学离子与EPS的官能团以新的官能团和化学键结合，形成新的物质，对堵塞的发生和演化起促进作用；溶解产生的Mg²⁺，Ca²⁺与细菌呼吸产生的CO₂，在微碱性条件下反应形成新的沉淀，也对堵塞产生促进作用.

Effect of hydrochemical factors on bio-clogging during artificial recharge of groundwater

In this study, the effects of ionic strength in recharging water and water-rock interaction during recharging on the migration and retention of bacteria in saturated porous media were studied through column experiments in laboratory, Scanning Electron Microscopy, infrared spectroscopy, photoelectron spectroscopy and other technologies were used reveal the influence of ionic strength on the evolution of biological clogging and its mechanism during artificial recharging. The results shown that, Suitable ionic strength stimulates the growth of bacteria and the production of extracellular polymers (EPS), which resulted in the hydraulic conductivity decreased by 99%. Excessive or low ionic strength inhibited the growth of microorganisms; Na⁺ from NaCl, neutralized the negative charge of sand and bacteria, enhanced the attachment of bacteria on the surface of the sand through compressed the electric double layers and reduced electrostatic repulsion; The hydrolysis of carbonate in the medium led to an increase of pH in environmental, which might induce the trace amounts of SiO₂, Al₂O₃ dissolved in the medium, increased the porosity of the medium, delayed the occurrence time of biological clogging and relieve the clogging degree; In turn, ions such as exogenous Na⁺ and endogenous Ca²⁺, Al(III), Mg²⁺enhanced biomass production by stimulating the bacteria to produce more EPS, at the same time, chemical ions combined with the functional groups of EPS by new functional groups and chemical bonds to form new substances, which promoted the occurrence and evolution of clogging; The Mg²⁺, Ca²⁺ reacted with CO₂ produced by bacterial respiration and formed new precipitate under slightly alkaline conditions and promoted clogging evolution.