Seoul City to spend W4.3tr to upgrade tap water

The Seoul Metropolitan Government announced Thursday plans to spend 4.32 trillion won ($3.28 billion) by 2040 to improve tap water quality.

Under the plans, dubbed Arisu 2.0, South Korea's capital city will employ a cutting-edge tap water purifying system, renew water pipes and increase water treatment capacity and storage, among other measures.

Seoul will invest 745.2 billion won to modernize water treatment facilities. Changes will be in place in two stages. Ozone will be employed instead of chlorine as an oxidizing agent to eliminate bacteria in water at a pre-oxidation stage. Also, at the post-filtration stage an additional layer of filters such as membranes for microfiltration or ultrafiltration will be set up.

According to the municipal government, ozone is a more efficient means of treating organic and inorganic compounds, as well as small living organisms like bacteria, than chlorine. Meanwhile, the enhanced post-filtration procedure will improve taste or smell of the tap water, it added.

Research is underway for a pilot implementation of the new technology by as early as 2025 in a water treatment plant in the Greater Seoul area, the city added. Seoul runs six treatment centers for its 9.6 million residents.

Water treatment facilities will not only modernize themselves, but also increase their capacity. In 2022 during the peak summer season, over 93 percent of the facility was operational, which Seoul deems beyond normal.

Separately, 2.7 trillion won of the city budget will be used to replace, mend or clean up over 3,400 kilometers of water supply pipes across the city regularly through 2040. Expansion of tap water storage will cost 138.5 billion won.

Seoul will also spend 255.7 billion won to modernize water meter sensors, leak detectors and freeze sensors, as well as the introduction of an electronic water billing system with technologies to allow each household to monitor potential problems remotely.

Promotions of Seoul's bottled tap water will also be included in the city's plan.

Of the total spending package, nearly 1 trillion won will be invested before the end of 2026, according to the city's blueprint.

Seoul began to introduce its tap water supply infrastructure some 115 years ago. The water is sourced from the Han River in the city.