This document provides guidance on key aspects of remediation techniques and their implementation. It briefly describes principles, the main characteristics and the advantages and limitations to be considered in the selection within an option appraisal of individual or combinations of in-situ and onsite remediation techniques, including: the type of contaminants to be dealt with; current and/or intended site use; local legal, policy, socio-economic and environmental contexts It follows the principles for sustainable remediation in ISO 18504. The scope of this document is restricted to the remediation of contaminated sites, i.e. where soil, or soil gas, ambient air or groundwater are contaminated. It identifies which phase/matrix can be targeted by a technique, e.g. fluid, (groundwater, gas, non-aqueous phase) or solid and which contaminant it can applied to. The document also provides information on hazards that can be associated with the implementation of a remediation. This document does not provide: an exhaustive list of remediation techniques; guidance on sites contaminated with radioactive substances, pathogenic or infectious agents, or pyrotechnic devices (e.g. unexploded ordnances) ; guidance on ex-situ techniques that are set up off-site; a framework that covers all individual situations; or prescribe which technique(s) to use in a specific context.