When you say 'organic', do you mean that you wish to grow certified organic produce for sale? If so, then I think that most certifications systems ban the use of sewage, no matter how it is treated. Or do you mean that you wish to treat your own community's sewage in a way that is suitable for use to grow food?
If you are talking about treating your own, what system are you currently using to treat it? If you are thinking of importing it, do you know about what treatments it has been subjected to?