The problem
What was the problem that you experienced?
During recent filter inspections at the Winneke treatment Plant, the need arose to extract media samples for analysis from various levels within the media bed. This meant that samples were to be extracted from a depth of up to 1 metre from the sand media.
Previous media sampling has often required the use of shoring to ensure the excavation would not collapse during the sampling. This could often mean the removal of up to 1m3 of media to ensure the appropriate sample could be taken.
How did the problem impact you or your work situation?
The previous method relied on using a shovel to dig down to the appropriate depth. This was a very onerous task as the area excavated needed to be quite large to ensure the media did not collapse into the excavation and that the sample taken was indeed representative of the particular level within the media. This required a high level of patience and perseverance from our operations team as there was the potential to extract samples from at least six different locations within each of the 16 media filters
at the Winneke plant.
How long had the problem been occurring?
The Winneke Plant has been in operation since 1980, so any previous media sample extraction over the past 42 years has required the use of a shovel to dig down to the appropriate depth.
The solution
How did you come up with the solution?
After taking the first few samples by shovel and experiencing our excavation collapse in on itself before we could extract the sample, the team knew it was time to come up with an easier solution. This idea came about after a short brainstorming session whilst undertaking sampling from Filter no 2 at Winneke.
Who helped work on the solution?
All the Winneke Operations team assisted with the development and trial of the tool, with particular input and support from operators Yong Tee Goh, Greta Pullen and Alan Abbott.
Describe the solution.
The media extraction tool is quite simple and consists of a 1 metre section of 90mm PVC pipe with a cutting edge on one end and a separate 1 metre long auger which fits neatly inside the PVC pipe. The PVC pipe is first twisted down into the media until the supporting gravel layer is reached. The auger is then placed inside the PVC pipe and twisted down into the media to the required sample depth. The auger can then simply be lifted out of the pipe to extract the media sample. Once the sample is
extracted, The PVC pipe can be removed and the hole backfilled.
The overall length of the tool is also limited to ensure it cannot be screwed in too far, to prevent potential damage to the filter nozzles.
How has it helped you at work?
This tool has made media sampling a simple, one person task with each sample taking no more than a few minutes to extract with very little physical effort required.
Suggest improvements, if time or financial limitations were not a factor.
In the future I would like to experiment with a smaller diameter version of this tool to allow smaller volume samples to be extracted which should simplify this process even further.
Any other comments.
I would like to acknowledge the support and assistance of the Winneke Operations team with the development and trial of this prototype tool.