Environment ministry to hold first Daegu underflow-water trial review

The environment ministry said it will convene the first review panel for a Daegu underflow-water trial after initial tests found turbidity 89-95 percent lower than in Nakdong River water at Munsan Water Purification Plant in Dalseong-gun, Daegu.

After a June 16 launch ceremony, the Korean Society of Environmental Engineers led roughly a month of trial runs, which the panel will assess on Aug. 5. Against Nakdong River water, tests found reductions of 33-42 percent in total organic carbon, 66-69 percent in total phosphorus and 82-86 percent in microcystin-LR. The treated water was comparable to Andong Dam's 1b grade for total organic carbon.

Designed to reproduce conditions for an underflow-water intake, the facility operates two tanks with sand-and-gravel filter layers. It filters more than 30 tons of Nakdong River water daily to compare water quality and available volume.

The 10-member panel includes six water experts, three Daegu city representatives and one ministry official. It will meet monthly to assess results and weigh changes such as increasing operating flow or altering the filter-layer configuration. Starting Aug. 6, the ministry will publish daily, weekly and monthly testing data and the outcome of each monthly panel meeting on its website.

"If water filtered through the facility is supplied to the purification plant, treatment efficiency is expected to improve, and Daegu residents will be able to use cleaner tap water," Kim Ho-eun, the environment ministry's water-use policy director, said. "We will develop scientific and effective solutions to Daegu's water problem."

Daegu's search for a water solution has faced difficulties for more than three decades, with proposals to secure supplies from Gumi and Andong stalled by regional differences.

The ministry plans to bring key Nakdong River intake sources to Grade 1 water quality by 2030, using underflow and riverbank filtration to pre-filter raw water before introducing tailored purification processes. It will finalize policy direction with Daegu city based on the trial.