In summary
- Our client requested a water quality assessment of their live service reservoir after detecting bacteriological deterioration following an installation of a new compliance sample point tap
- Panton McLeod was employed to conduct a Remote Operated Vehicle (ROV) scope, sampling all areas at varying depths of the tank over a selection of times during a 24 hour period
- The scope identified areas of low turnover water and informed changes to improve water quality
Project in numbers
60 the number of samples obtained by the end of the scope
0 coliform bacteria detected
The need
DWI regulations stipulate that water companies must provide good wholesome water to customers and must therefore undertake regular sampling to monitor water quality. Our client required a method to assess the water quality throughout the body of the service reservoir, not just at outlet pipes.
The method had to be able to collect samples of water at various locations and depths within the main body of the reservoir without mixing or disturbing the water. This would facilitate an accurate assessment of water quality and confirm that the location of a new compliance sample point was representative of the water in the reservoir.
The solution
To identify areas of the tank where water movement was low and therefore carried the highest potential risk of bacterial growth and low chlorine levels, our client enlisted Panton McLeod to conduct an ROV spot sample survey. After identifying sampling locations within the tank, the ROV abstracted water from these various points in the tank to enable sampling and analysis for bacteria, turbidity and chlorine throughout a 24-hour period.
The results of the ROV survey revealed there were no coliforms detected in any of the samples. Low chlorine levels and elevated plate counts for bacteria were identified in some areas of the tank – while these were harmless bacteria, the numbers signified a deterioration in water quality and concluded low turnover in that area. The information helped our client to make necessary adjustments to water flow dynamics within the tank and identify long term investment.
The benefits
- ROV spot sampling enabled the monitoring of water from hard-to-reach areas within a live tank; a highly effective way to assess the quality of drinking water in the reservoir as it’s being supplied to consumers.
- The method avoided the need to drain the tank to gain insights about areas of low water turnover and potential water quality deterioration, allowing our client to consider improvements while the reservoir remained operational.
Project gallery
