Potential reasons for my package Sewage Treatment Plant not meeting consent

Here at The Tank Sampling Company, we have encountered many reasons as to why sewage treatment plants do not meet their permitted discharge consent. Before you consider spending money on possible remedial works, take a look at the list below to see if you are doing any of these!

  • Desludging too infrequently (not sticking to the operating and maintenance manual instructions)
  • Desludging too often (not giving the biological processes time to establish)
  • Incorrect desludging (the correct chambers within the plant are not being emptied in accordance with the O&M manual)
  • Mechanical parts breaking (many types of plant have moving parts – these crucial items will wear and break over time)
  • Excessive use of household cleaning products (most are OK if used in the stated amounts – read the instructions). A good sign that this is the case is when there is no crust build up in the primary chamber(s) and there is a noticeable sewage smell.
  • Non-household chemicals and liquids entering the STP (We have seen major issues caused by engine oil and white spirit being placed down the drain)
  • STP alarm ignored (If it is on, there is probably a problem, so it needs checking!)
  • Insufficient air being introduced into the effluent. Normal operation will either see bubbles rising from the bottom of the tank in the biozone chamber, or effluent being sprayed over or dropped onto the media through ‘distributor heads’ or arms)
  • The volume of waste entering the system is either insufficient or exceeding the plant’s size.
  • Loss of power to the plant. The bacteria need oxygen to survive so if the blowers, compressors, rotational discs are not working, the bacteria will start to diminish.

By using this checklist, we hope you can resolve the problem before calling in a specialist engineer. Alternatively, give The Tank Sampling Company a call and we will be happy to help.