Our BISCO^®concept combines the advantages of in-situ chemical oxidation (ISCO) and stimulated aerobic and/or anaerobic biological degradation (e.g. IRZ^®) raising their total efficiency. Different combinations are applicable. The animation shows one possible sequence. The pretreatment of the contamination by ISCO mineralizes the main part of the contamination and makes the residual contamination more bioavailable. Subsequently the contaminants are further degraded by stimulated biological activity. Low end concentrations are possible.