White Rock North Dump Extraction Wells

Cost effective remediation and fouling prevention of extraction wells

Sierra West successfully designed, constructed, and operated multiple control systems at a remote site while maintaining stringent health and safety protocols due to the existence of hazardous chemicals in the groundwater.

Sierra West performed preliminary pollution investigation evaluations to understand the nature of the biological growth in five groundwater extraction wells located downgradient from the former White Rock North Dump landfill, and designed and constructed a cost-effective chemical addition system to mitigate significant biological fouling and prevent future fouling of the wells.

Bench-scale tests indicated that a Nalco biocide would control the bacteria better than chlorine. However, due to cost considerations, chlorine was selected as the preferred biocide. Sierra West cleaned the wells and pipelines, including pigging nearly 4,000 lineal feet of transmission pipeline. For optimal biocide distribution management of distribution of biocide, Sierra West designed and constructed a centrally located chlorine storage building with five chemical feed pumps into each well.

Sierra West used side-by-side ATP biological-based field tests to monitor the performance of chlorine and an on-site generated mixed-oxidant using equipment supplied by MIOX Corporation at varying application rates. The results of the rigorous pilot tests indicated that the mixed-oxidant performed better than and should be used instead of chlorine. Sierra West’s critical operations support and other services have now brought the biological growth under control.