Abstract: The pollution restoration and treatment project of a waste slag backfill area in South China was taken as the research object, its waste residue belongs to the class II of general industrial solid waste. According to the hydrogeology, pollution risk, operation and maintenance characteristics, combined with its pollution characteristics, the in-situ risk control technology of“HDPE flexible vertical anti-seepage around + horizontal anti-seepage on pile surface + ecological phytoremediation”was adopted for pollution remediation, and the restoration effect was analyzed. The results showed that for weakly permeable aquifers such as moderately weathered layers, equivalent seepage control could be achieved by increasing the depth of vertical seepage by using the principle of controlling the total amount of pollutants. Engineering measures for foundation reinforcement should be implemented based on the lithology and geology of the strongly weathered layer in the middle of the site. Finally, the project through the anti-seepage testing and evaluation, and achieved good in-situ isolation effect by HDPE flexible vertical seepage geomembrane, which had certain reference significance for the treatment and restoration project of the same type of waste residue polluted site.

Key words: HDPE flexible vertical anti-seepage, equivalent anti-seepage, reinforcement of groove walls, in-situ risk management