Extraction & Injection Well Rehabilitation and Repair

Client: 
Regional Municipality of Peel
Contact: 
Dallas Stinson, C.E.T., Supervisor - Water Treatment Regional Municipality of Peel Phone: 905-791-9400
Brief: 
Landfill Leachate Treatment System Maintenance
Year: 
2002-Ongoing
Project: 

Groundwater at the Region of Peel Caledon Landfill is collected from 3 extraction wells which is subsequently treated by air stripping to remove VOCs and precipitate dissolved iron. Water is then re-injected into 7 wells.

Annual Injection Well Chemical Rehabilitation 

Lotowater Technical Services Inc. performs regular chemical rehabilitation of 7 injection wells at the Region of Peel Caledon landfill.  High levels of dissolved oxygen in the water cause the precipitation of calcite and promotes aerobic bacteria growth in the injection wells.  A site specific chemical rehabilitation program was designed by Lotowater that consists of mechanical agitation, jetting, chemical injection and airlift pumping.    Prior to Lotowaters involvement the system was hampered with regular shut downs and was not meeting minimum injection rates necessary to provide plume containment.   Since Lotowaters involvement well injection rates have been maintained at or above original design levels, meeting all MOE and hydrogeologic requirements to provide plume containment.

Injection Well Repair

Lotowater has repaired several wells with breaks in the casing, allowing the entry of fine sand. The PVC well casings were repaired with an epoxy patching system and the fine sand fill was airlifted from the wells.  The repair was successful in completely restoring the wells functionality and saved the Region 10’s of thousands of dollars in drilling new replacement wells.  

Treatment System Pipeline Chemical Cleaning and Flushing

The main treatment system pipeline has been cleaned and flushed to remove mineral and biological growth restricting well flow by employing similar rehabilitative techniques used on the injection wells.  This included injecting the line with a chemical solution followed by surging and flushing.

Extraction & Injection Well Annual  Performance Testing

Lotowater Technical Services regularly monitors production well and injection well performance.  When well performance drops below pre-established threshold values rehabilitation is performed.  This criteria based determination has saved the Region thousands by reducing the number of unnecessary rehabilitation efforts and has helped optimize system resources.