In my experience, most ...

In my experience, most soluble COD is actually biodegradable after acclimation of waste treatment organisms.  Verify P and N levels. Running a series of tests in a respirometer can be a simple way to initially assess biodegradabiity. If results are promising, do a flow through treatability test.  If the waste is found to be not biodegradable, physicochemical treatment should be considered.