You can use the sludge tested for your culture medium to monitor the activity of existing bacteria or use it as a culture medium after incubating the sludge.

Erfan Jamshidi, the thing is that the sewage sludge would contain a large variety of microorganisms and I would like to isolate just the electrochemically active ones. I just don’t know how I’d do that

Sa’Adatu Ocheni First, kill all the bacteria in the sludge by physical methods (uv), then enter the bacteria you want to enter.

To increase the quality, you can analyze the material in the sludge before sterilizing the medium.

Hope it helped you.