On 28 September, South Korea's Ministry of Climate, Environment and Energy signed a memorandum of understanding with Sejong city and Korea District Heating at Sejong City Hall in Boram-dong, Sejong, to build an energy self-sufficiency framework at sewage treatment facilities using biogas and sewage heat (헤럴드경제).
Key takeaways
- MOU signed 28 September between the Ministry of Climate, Environment and Energy, Sejong city and Korea District Heating at Sejong City Hall (헤럴드경제).
- Site is Sejong Water Quality Restoration Center A, with sewage heat and biogas power waste heat fed into the district heating network (헤럴드경제).
- Facility discharged about 59,000 tons of treated sewage per day last year, enough to recover roughly 105,000 Gcal of heat annually — equivalent to heating about 17,000 households a year (헤럴드경제).
- Combined sewage heat and waste heat from biogas generation will supply 1 Gcal of heat per hour to the district heating network (헤럴드경제).
- Sejong city expects direct and indirect annual benefits of around 450 million won ($333,000), with Korea District Heating projecting about 200 million won (헤럴드경제).
What was signed and where it runs
The agreement targets Sejong Water Quality Restoration Center A, the city's main sewage treatment facility, and is intended to unlock two untapped energy streams on a single site: sewage heat captured from treated effluent and waste heat from electricity generated by biogas (헤럴드경제). Under the MOU, Sejong city will provide the demonstration site, the biogas and the treated sewage water, and will handle permits and project approvals; Korea District Heating will connect the sewage heat and the biogas power waste heat to its district heating network and supply equipment and technical support; the ministry will provide policy and regulatory backing (헤럴드경제). The two organisations will work out project specifics through separate operational agreements.
Reported scale, benefits and policy backdrop
The centre's average daily discharge of about 59,000 tons last year, if fully exploited, could yield about 105,000 Gcal of recovered heat per year, enough to heat around 17,000 households annually (헤럴드경제). In the first phase, biogas will be used to generate electricity and the resulting waste heat will be combined with sewage heat to deliver 1 Gcal per hour into the district heating network (헤럴드경제). Sejong city puts expected direct and indirect annual benefits at around 450 million won ($333,000), while Korea District Heating estimates its own benefits at about 200 million won (헤럴드경제).
The MOU sits inside a wider regulatory push. Earlier in 2026, the ministry amended its basic sewage system improvement plan guidelines, making it mandatory for public sewage management authorities to assess sewage-heat feasibility at treatment plants with a daily processing capacity of 5,000 cubic metres or more, and to set energy self-sufficiency targets that count energy exported to district heating as well as on-site use (헤럴드경제). The ministry is also pursuing an amendment to the enforcement decree of the Act on the Promotion of the Development, Use and Diffusion of Renewable Energy to classify sewage heat as a water-source thermal renewable (헤럴드경제). "Sewage heat can be obtained close to urban centers and maintains a relatively stable water temperature throughout the year, making it an important heat source for achieving carbon neutrality," said Geum Han-seung, first vice minister of the Ministry of Climate, Environment and Energy, adding that the ministry "will continue to provide policy and regulatory support so that sewage heat can play a key role in building energy self-sufficiency at sewage treatment facilities" (헤럴드경제).
Specification read
Put the reported 59,000 tons/day (≈ 59,000 m³/day) of treated discharge in buyer units: that is roughly a 59 MLD municipal works. A facility of this throughput typically carries a screening → grit removal → primary sedimentation → biological stage (commonly A2O, MBR, MBBR or SBR) → tertiary nutrient removal → disinfection train; the stage this MOU bears on is downstream of the biological and tertiary steps, where the warm treated effluent leaves the works with a stable year-round water temperature, and the upstream anaerobic digester, which produces the biogas that the same project will burn for power and heat. On a flow of about 59 MLD, recovering 105,000 Gcal/year at a feed of 1 Gcal/hour implies the heat pump and heat-exchanger string runs on a continuous, baseload schedule tied directly to effluent flow and temperature. If your plant looks like a 50–70 MLD municipal works with BOD in the 150–250 mg/L range, primary sedimentation followed by a nutrient-removing biological stage, and you are now answering a regulator who has flagged energy self-sufficiency and renewable heat targets, this is what it means for you: the work is not new tankage, it is a sewage-source heat pump train on the treated-effluent line plus a combined-heat-and-power skid on the digester gas, and the deliverable to procurement is an integrated heat-export contract with the local district heating utility — the same scope covered in our Municipal sector hub and our Integrated Sewage Treatment product line. Comparable South Korea context for buyers sizing cooling and blowdown trains is laid out in our Data Center Cooling Blowdown Treatment in Busan, South Korea (2026 Guide).
FAQ
What capacity plant does the new sewage-heat rule actually apply to? Public sewage management authorities must assess sewage-heat feasibility at any treatment facility with a daily processing capacity of 5,000 cubic metres or more, under revised basic sewage system improvement plan guidelines issued earlier in 2026 (헤럴드경제).
How much heat can the Sejong site export once the project is running? The MOU targets 1 Gcal of heat per hour into the district heating network from combined sewage heat and biogas waste heat, with a long-term potential of about 105,000 Gcal per year from the 59,000 ton/day discharge (헤럴드경제).
What direct financial return is being quoted? Sejong city expects around 450 million won ($333,000) in annual direct and indirect benefits, and Korea District Heating expects about 200 million won (헤럴드경제). For a 50–60 MLD works, this is a planning-grade figure rather than a turnkey contract value (general industry range, not from the sources).
Is sewage heat being treated as a renewable for compliance? The ministry is pursuing an amendment to the enforcement decree of the Act on the Promotion of the Development, Use and Diffusion of Renewable Energy to define sewage heat as a water-source thermal renewable, and the revised plan guidelines already let facilities count heat exported to district heating toward energy self-sufficiency targets (헤럴드경제).
