I think it highly depends on the type (chemical composition) of the applied waste. Therefore, you need to know the chemical composition of your solid waste.
If you have a freshwater pond with salinity more than required then the option left is the treatment of pond water with the help of bentomite or gypsum.
I think, adsorption is the dominant removal path in the case of using bentonite. In case of gypsum, I'm not quite sure as it has adequate levels of exchangeable ions.