CDR: underestimated potential for wastewater and waste
CDR (Carbon Dioxide Removal) refers to the removal of CO₂ from the atmosphere followed by long-term storage. CDR technologies, which generate so-called negative emissions, are considered essential for achieving global climate targets. A new publication by Carbon Gap highlights the potential for CDR applications in wastewater and waste treatment.
In April 2026, Carbon Gap published the study ‘No wasted opportunities – Embedding carbon removal in the management of wastewater, concrete and mine waste’, produced in collaboration with Deloitte North and South Europe. This report outlines the significant and, to date, underutilized potential of the three sectors – wastewater treatment, concrete recycling and the treatment of mining waste – for the implementation of CDR technologies.
CDR: Distinction from CCS and CCU
CDR technologies involve human-initiated measures designed to capture CO2 from the atmosphere and store it permanently in geological reservoirs, in the ground or in the oceans – or in long-lasting products. Whilst direct CO2 capture from the atmosphere is certainly part of this, it often also involves treating biomass in such a way as to prevent CO2 release into the atmosphere in the long term, i.e. over centuries, if not millennia. In any case, there is a clear distinction between CDR and other carbon management practices, foremost among them CCS and CCU (carbon capture and storage and utilisation, respectively). A detailed overview of which measures are classified as CDR is also provided in the policy paper “Scaling up carbon dioxide removals”, published in February 2026 by the European Scientific Advisory Board on Climate Change.
CDR potential of the three sectors in figures
Wastewater management: Around 40 billion m3 of wastewater is treated annually in the EU, and 380 billion m3 worldwide. Direct greenhouse gas emissions (CH4, N2O and biogenic CO2) account for a significant proportion of the total emissions from wastewater treatment plants. The theoretically storable amount of CO2 is 16.6 Mt per year in the EU; globally, the figure is 116 Mt/a.
Concrete recycling: With an annual waste volume of 230 Mt in the EU and 1.5 Gt worldwide, this results in a theoretically storable amount of CO2 of 2.3–5.7 Mt in the EU and 7.6–18.9 Mt worldwide.
Treatment of mining waste: This concerns, in particular, waste from the extraction of nickel and platinum group metals (PGMs). Waste streams from these mines consist of mafic and ultramafic rocks that are rich in magnesium and calcium silicates. When exposed to air and water, these are capable of binding CO₂ and storing it in the form of stable carbonates. Globally, around 384–621 Mt of rock waste is generated annually in nickel mining. The extraction of PGM metals produces 53–89 Mt of waste per year. The potential for CDR technologies is estimated at 136–221 Mt of CO2 per year by 2030.
All figures mentioned in this section are taken from the study. Links to the sources used are provided there.
What is needed to establish CDR technologies across these sectors?
This document provides an overview of CDR processes that can be used in sewage treatment plants, in concrete recycling and in the treatment of mining waste. Not all of these options have already reached a technology readiness level of 8 or 9.
In addition, however, the current challenges facing the scaling up of CDR technologies are also highlighted. These include, for example, knowledge gaps, a lack of data, and the fact that standards for GHG accounting and reporting have not yet been adapted.
Furthermore, recommendations are made for policymakers, who should drive the scaling up of CDR technologies by establishing a legal framework, funding pilot and first-of-a-kind (FOAK) projects, integrating CDR into public procurement and, last but not least, expanding infrastructure and standards.
Further articles on the possibilities for implementing CDR in individual sectors will be published on this website in the near future.