2
2011
How to Measure Septic Tank Sludge Depth
In a recent post, you have learned that there is no way to know for certain when to exactly pump your septic tank other than an actual measurement of accumulated sludge and scum. When the scum and sludge layer take up 30% of the volume of the tank the tank should be pumped .
As an example, if the liquid depth is 48”, when the combined scum and sludge reach 14 ½”the tank should be pumped (48” X 0.30).
The proper way to use the sludge judge is as follows:
To measure the scum layer:
- Push the sludge judge through the scum layer until it just breaks through the layer.
- Make a visible note of the relationship between the top of the scum layer and the location on the tube.
- Pull the tube up and measure the length on the tube. Many times you will see some of the scum layer stuck to the tube to identify the location.
To measure the sludge at the bottom:
- Lower the tube slowly into the tank until it stops at the tank bottom.
- Quickly jerk the tube upward closing the check valve. This will capture the solid/liquid profile of the water in the septic tank. The sludge layer thickness is then measured.
Reviewing the pumping records indicate that this septic tank was last pumped 26 months ago. Based on this date, the septic tank should be pumped within 43 months of the last septic tank pump out (0.18 / 26 months X 0.30 = 43 months). Because the rate of scum/sludge accumulation can change over time, it is suggested that this measurement be made annually, especially if the number of people living in the home changes or a different family moves into the home.
To measure the scum layer, push the stick cheesecloth side down through the scum layer until it just breaks through the layer. Note of the relationship between the top of the scum layer and the location on the stick. Pull the stick up and measure the length on the stick. Many times you will see some of the scum layer stuck to the stick to identify the location.
In many cases the pumping frequency can be reduced if a Aero-Stream Remediation system is installed. The aerobic process digests the scum layer eliminating that portion of the combined scum and solids measurement. Keep your system functioning for a long time with Aero-Stream!
great info…..thank you
excellent info, can’t find the $75 plus sludge judge or even the sludge sampler, if any body knows where please let me know or i’ll have to take this advise and make my own, thanks
Bill: NASCO sells the Sludge Judge. Current price is about $93.
http://www.enasco.com/product/C09247WA/