I have encountered a lot of 'dead' decanted sludge in an industrial activated sludge treatment plant that has experienced mixing and aeration problems.
I have taken samples and analyzed them and found volatile solids averaging 51%. So there is a high mineral content, but can you confirm whether this indicates the sludge is actually dead and that it would be better to perform a wash rather than incorporate it into the return activated sludge, thereby contaminating the existing biology?
It is an industrial wastewater treatment plant. It may have a high mineral content anyway in the water. If the sludge is septic I would definitely not put it back into the RAS.
Indeed, I forgot to specify that the sludge is totally black and smelly. That is why I referred to it as "dead" (septic) sludge.
Today the aeration basin is working, but on an initial volume of 3000 m3, there is only 500 m3 that is usable, the rest being this black sludge. It looks like there is going to be a big cleaning job ahead!
Not much information to go by. You don't mention what you are treating. I assume you are operating as an extended aeration?
What is the design loading for the system?
What is the current pounds per day feed rate?
What is your current DO levels?
What are your wasting rates?
Do you have any influent information?
Where is the effluent discharged to and what are the limits?