The present invention provides a method for treating wastewater in which the majority of solids and biological oxygen demand compounds are separated from the wastewater feed using a primary separation process, to produce a solids phase and a water phase. The solids phase is irradiated to reduce the level of pathogens such that it is safe to use as a soil substitute and/or additive so that the solids can thus be disposed of in an environmentally-friendly manner. In additional embodiments, the solids that have been disinfected by radiation are mixed with a suitable inert filler material to produce a soil substitute, fertilizer, compost, or other soil additive. The liquid phase is treated in a substantially smaller system than would be required for treating the full-strength wastewater that can include a suspended media biological regeneration reactor system. The liquid treatment system can include a high flux adsorbent material treatment system integrated with a low flux adsorbent material biological regeneration reactor.