Bioconversion of soluble and suspended organics from storm water runoff comprises: (a) introducing the runoff stream, comprising insoluble debris, inorganic materials and an aqueous component (AC) containing suspended and soluble materials both containing potassium, phosphorus and nitrogen values, into a bioreactor (BR) having an aerobic zone (AEZ) and an anaerobic zone (ANZ); (b) settling inorganic materials and insoluble debris in ANZ; (c) treating AC with a metal salt to form a precipitatable P complex; (d) conditioning AC in AEZ to enhance the formation of facultative bacteria (FB); (e) forming, in AEZ and ANZ, a biomass containing sufficient enhanced FB to actively bio-convert soluble P, K and N materials contained in AC; (f) transporting AC, containing enhanced FB, bio-converted, complexed and precipitatable and suspended P and suspended, precipitatable and bio-converted K and N materials, to an eco-reactor (ER); (g) bio-converting AC and precipitating a beneficial humus material (HM) containing complexed and bio-converted P, K and N containing organics, and (h) recovering or discharging from ER water containing P, K and N values in reduced amounts cf. those in the stream introduced into BR. Also claimed is HM produced by the process, where HM contains &gt; 0.5% N and &gt; 0.2% P and K and constitutes a potting soil, topsoil or other all naturally produced material suitable for soil amendment or plant production.    ADVANTAGE -   Biologically active, ecologically stable HM and a biologically active and/or nutrient-rich organic soil are produced from storm water runoff, together with clean, low nutrient water which can safely enter fresh water aquifers. Ecological problems associated with e.g. the migration of nutrients and BOD are resolved by the efficient bioconversion of polluting materials at, or adjacent to, the offending site into stable, economically and/or ecologically beneficial materials. Nutrients, BOD, toxins or other waste materials in the runoff water are biologically transformed.