Residents outraged after sewage discharged into Mount Jiri stream used for drinking water

Improperly treated household sewage was discharged into a stream flowing from Mount Jiri into the Nakdong River last month, sparking outrage among residents in two provinces who rely on the waterway for drinking water.

Namwon city government on Monday said “partially treated wastewater” was discharged into the upper reaches of Ram Stream from the sewage treatment plant in its city on July 29 and 30. Ram Stream originates on Mount Jiri and flows through Namwon, North Jeolla, before joining the Nakdong River.

Drone footage taken above the Daejeong treatment plant on Aug. 3 by the environmental group Otter Friends showed cloudy water continuously pouring out of a discharge outlet near a patch of brush — household sewage, mixed with human waste and other contaminants, flowing straight into the stream. “Untreated sewage that hadn't even gone through a septic tank was discharged into Ram Stream,” it said. “The smell was severe.”

News of the discharge drew backlash from residents and environmental groups in Hamyang and Sancheong counties in South Gyeongsang, who rely on Ram Stream as a source of drinking water. Twenty-three groups from North Jeolla and South Gyeongsang jointly held a press conference in front of Namwon's city hall last Tuesday. “The pollution of the Ram Stream is an issue that goes beyond North Jeolla and directly affects South Gyeongsang, which relies on the stream as a source of drinking water,” they said, denouncing the city of Namwon.

The groups alleged that the plant skipped the normal treatment process, which should take at least four hours, and forcibly released untreated wastewater after just two hours.

They demanded that the city hold officials accountable, terminate its private outsourcing contract to bring the plant under direct municipal operation and have the North Jeolla and Nakdong River Basin environmental offices conduct a full inspection of sewage facilities in the area. They also called for Ram Stream and the Eomcheon River watershed to be upgraded to “national stream” status; for the establishment of a response manual for environmental pollution incidents and a reform of the 128 environmental hotline reporting system; the creation of a dedicated task force to manage the Namwon-Hamyang watershed jointly; and an expansion of the treatment plant's capacity.

The Daejeong plant was built by the city of Namwon but is operated by a private contractor. Other facilities managed by the same contractor have faced repeated allegations of wastewater discharge: in February, wastewater flowed into Ram Stream from a relay pump station in Inwol-myeon, Namwon; in April, wastewater backed up from a maintenance hole near the Daejeong plant; and between June and July, residents repeatedly reported wastewater backing up from maintenance holes near relay pump stations in Jusaeng-myeon and Ayeong-myeon in Namwon. The groups claim that despite repeated requests from residents to fix the sewage system, the Namwon city government has left the problem unaddressed.

Facing backlash, the municipal government apologized, saying the incident occurred because the plant's treatment capacity was overwhelmed by an influx of summer vacationers. The city said the Daejeong plant's daily treatment capacity is 130 tons, but more than 200 tons of household sewage flowed in. Increased use of the nearby valley's stream water over the weekend, combined with an influx of sewage from unidentified sources, also contributed, the city said.

The Daejeong plant operates using the Sequencing Batch Reactor (SBR) method, with an average daily treatment volume of around 100 tons, according to the city. Under the SBR method, micro-organisms break down pollutants in the wastewater, with aeration, settling and discharge all carried out sequentially in a single tank.

The city said that when sewage exceeding the plant's capacity flowed in on Aug. 3, the operator switched the control system to “high-water-level operation mode,” releasing the water after aeration and settling. However, the excess inflow reduced treatment efficiency, causing some sludge and debris to pass into the final treatment tank, which temporarily clouded the discharged water.

The city plans to redirect excess sewage to other treatment plants and expand the Daejeong plant's capacity over the long term. Inflow is currently being kept at 130 to 140 tons per day. It has also issued a stern warning to the outsourcing contractor and said it would take administrative action depending on the results of a discharge-water inspection by the Jeonbuk Regional Environmental Office.

The Jeonbuk Regional Environmental Office fined the city of Namwon 2 million won ($1,400) and issued a corrective order over the incident. It also plans to conduct emergency inspections of 27 public sewage treatment plants in the Nakdong River basin.

“We will use this incident as an opportunity to strengthen facility management and thoroughly implement distributed treatment of excess sewage,” said Ahn Seon-yeop, director of Namwon's Safety and Construction Bureau. “We will steadily carry out measures to reduce the inflow of unidentified wastewater to prevent further inconvenience to residents and pollution of the stream.”

BY KIM JUN-HEE [lee.jian@joongang.co.kr]