填埋场HDPE膜漏洞靶向电动修补技术影响因素

The influencing factors of targeted electric repair technology for HDPE membrane leakage in landfill

为突破当前HDPE膜漏洞修补技术操作复杂、成本高,且具有安全隐患的难题,探究靶向电动修补技术的工艺参数对修补效果的影响规律,开展了电极类型、电压大小、运行时间、膨润土浓度与分散剂/膨润土投加比例等单因素实验,并探索达到修补效果的最低工艺条件.结果表明,漏洞直径为5mm时,选用石墨电极、电压大小为50V、运行时间为2d、膨润土浓度为10g/L、分散剂/膨润土比例为30%时,修复后HDPE膜漏洞处的渗透系数达到9.41×10^(-6)cm/s,具有较好的修补效果;此外,通过建立修补溶液体系的Zeta电位与电动修补后漏洞处渗透系数的数学表征模型,为实际场景下的应用提供依据,当渗透系数达到1×10^(-6)cm/s所对应修补溶液的Zeta电位至少应为-42.11mV.

The timely repair of HDPE membrane leakage in landfill is an important means of environmental risk control,which is of great significance to prevent leachate from polluting groundwater and soil environment.In order to solve the problems of complex operation,high cost and security risks during the operation period and after closure of landfill,the single factor experiments on the main influencing factors such as electrode type,voltage,operation time,bentonite concentration and dispersant/bentonite dosage ratio were carried out so as to analyze their impacts on repair effect and explore the best technological.The results showed that the accumulation at the leakage(5mm diameter)possessed good repair effect with the permeability coefficient of 9.41×10^(-6) cm/s,when graphite electrode adopted,the control voltage was 50V,the shortest operation time was 2days,the optimal bentonite concentration was 10g/L,and dispersant/bentonite ratio was 30%.In addition,the mathematical characterization model between the Zeta potential of solution system and the permeability coefficient of accumulation at the leakage were established,which can provide basis for the application in practical scenarios.In order to meet the impermeability requirements,the permeability coefficient needs to reach 1×10^(-6)cm/s,the Zeta potential of the corresponding repair solution should be at least-42.11mV.