its mostly the biological ...

its mostly the biological inhibitors that give problems.  mainly Ammonia and phenolics.   metals are mostly sorted out and though a few are left, its not material.  so odor is an issue, but the bod, cod and ammonia.  the phenols is best under 100.   Ammonia over 480 can kill almost all microbes,  and phenols over 100 kill the microbes that treat ammonia.  after these two are taken cared of, the leachate treatment becomes easy.    best of luck, Eduardo.