That parameter is the ratio of the cationic polymer to the anionic coupling agent. As a result, flocculent formation in the RDP method depends totally on when the coupling agent is added to the system. For example, if a dye is flocced out of solution and the floc is agitated, the dye can go back into solution as a contaminant. In the RDP method, the contaminant is encapsulated and will not leach. This is important since a sludge that leaches cannot be put into a non-hazardous landfill.
Cationic polymers tend to be toxic to wastewater and activated sludges.
Any cationic polymer that does not floc will remain in the wastewater and be a potential toxic substance.