South Korea unveils multi-front strategy to improve water quality in the Nakdong River

The Government of South Korea has set out a multi-layered plan to improve the water quality of the Nakdong River, aiming to achieve Grade 1 standards by 2030. The river supplies drinking water to approximately 13 million people in the Yeongnam region, making its ecological condition a matter of national importance.

The Nakdong River Water Quality Improvement Measures, announced on 25 February by the Ministry of Climate, Energy and Environment, focus on reducing total phosphorus discharges by 30%. Total phosphorus is identified as the decisive factor behind the recurring proliferation of green algae, which has continued despite notable long-term improvements in conventional water quality indicators. In addition, the measures place greater emphasis on the control of trace pollutants in industrial wastewater, reinforcing safeguards for drinking water quality.

While total phosphorus concentrations have fallen by more than 70% over the past three decades and biological oxygen demand has also declined, the Nakdong River has still accounted for around 80% of all nationwide green algae alerts during the last five years. The government attributes this to the dominance of non-point source pollution, which represents more than 80% of the phosphorus load entering the river system.

Addressing non-point source pollution

As of 2023, an estimated 12,498 kg of total phosphorus flows into the Nakdong River basin each day. Almost half originates from farmland, with a further 39.9% linked to livestock manure. To address these diffuse sources, the government plans to expand soil-testing-based fertilisation and promote best management practices in agriculture. These include the use of controlled-release fertilisers and physical measures such as field dikes to limit nutrient runoff during rainfall events. In addition, improved paddy water management is expected to reduce agricultural water use by up to 12%, indirectly limiting phosphorus transport to waterways.

Livestock waste represents a parallel challenge. Currently, around 85% of manure is applied to land as compost or liquid fertiliser, often in excess of crop requirements. Under the new strategy, half of this surplus application will be diverted to energy production, including solid fuel and biogas. This shift is expected not only to reduce nutrient loading but also to cut greenhouse gas emissions by about 620,000 tonnes annually while generating 706 GWh of electricity.

Upgrading wastewater treatment plants

Municipal wastewater remains another key front. Domestic sewage accounts for just over 12% of daily phosphorus inflows, yet its impact is concentrated near intake points. The ministry will tighten phosphorus discharge standards for public sewage treatment plants and expand village-scale sewage retention facilities in rural areas. A total of 32 plants across the Nakdong River system are scheduled for phased construction or expansion (5 new plants and 27 expansions), alongside 33 village sewage systems. These measures are intended to ensure that even during summer conditions, phosphorus concentrations at major abstraction points remain at or below 0.037 mg/L.

Stronger control of industrial pollution

Industrial wastewater management forms the third pillar of the plan. Approximately 470,000 tonnes of industrial effluent enter the river each day, much of it generated in the Gumi and Daegu areas. Large public treatment facilities will adopt advanced processes combining ozone and activated carbon, which the ministry estimates can remove more than 90% of trace pollutants, including PFAS. Monitoring coverage for unregulated substances will expand significantly, supported by additional automatic stations downstream of industrial complexes and reinforced 24-hour surveillance.