Depends on what you call ...

Depends on what you call pretreating. Allowing nature's microbes to biodegrade grey and black water in an enclosed setting may be considered pretreatment. But usually people think CHLORINE is a pretreat item.  When using the Archaea group of microbes all organic compounds are reduced to their elemental/nutritional form. It eliminate odor, will not allow methane production, and chelates any and all toxins into their non toxic state.  This way the water will  be potable and ready for reuse in your water storage home system. (in addition a biogenerator can be connected to the biodigesters to collect loose electrons to make electricity for your residential needs.  Catch rain water, install water cistern ,  make a home garden, green house, food storage program.  Drought passes you by, food quality and quantity increases, zero waste, and allows you to work towards being 100% off the grid and 100% sustainable.