Lotowater has performed well rehabilitation and pump maintenance work at several wells over the past year as part of the Regional Municipality of Waterloo’s 2008- 2009 Well Rehabilitation and Pump Maintenance contract. This project was awarded in a competitive bid process based on qualifications and price. Highlights of the work performed at some of the wells are presented below:
Preliminary work included a well performance test, casing thickness log and downhole video survey of the well to visually assess its condition. Results of the performance test showed a significant decline in well performance and the video showed extensive amounts of biological build-up across the screen and casing. Following rehabilitation, a hole was found in the well casing which allowed sand to enter and fill the screen. To repair the holes, a stainless steel liner was installed and the well was equipped with a discharge head and the original pump was serviced and re-installed. Testing confirmed satisfactory operation and sand free water.
The inspection of Well G8 included a multi-rate step test which demonstrated that well performance was relatively unchanged since the last rehabilitation and that no maintenance effort was required at this time. Additional inspections, including a video survey and acoustic televiewer log, were undertaken to evaluate the condition of the well and casing. This work did not reveal any structural issues. The original pump was determined to be in poor condition and was not suitable for continued use. Lotowater evaluated several replacement options and selected the most economical solution for the client. Several pumps which were available from recently decommissioned RMOW wells were assessed and a feasible replacement pump was chosen. The replacement pump was completely inspected, serviced and tested to confirm satisfactory operation.
The work at Well SC3 included a typical well performance test to evaluate performance and a complete inspection and service of all pump components. Following the initial inspection, it was determined that the well required rehabilitation to restore lost yield. The rehabilitation effort included injecting and mechanically surging an acid polymer solution followed by airlifting to remove any remaining material from the well. The pump was serviced by replacing worn components, and all column pipe was replaced due to excess corrosion. In addition, the pitless adapter was replaced due to damage observed on the original unit that allowed water to drain back into the well, potentially comprising the quality of the potable water supply. A final performance test was performed to assess the effectiveness of the rehabilitation effort and confirm satisfactory operation of the pump and motor.
This project is ongoing at this time.