Recycling of Discarded 'Leaked Groundwater'... Seoul City Creates First 'Guideline'

Water Quality Standards by Usable Purposes such as Cleaning, Landscaping, and Construction, Location-Based Usage Guidance, and Case Studies Introduced
Increase of 18% in Seoul's Underground Water Discharge over 10 Years Due to Underground Space Development... Promoting Water Resource Recycling

[Asia Economy Reporter Lim Cheol-young] On the 14th, the Seoul Metropolitan Government announced that it has created the 'Seoul City Guidelines for Utilizing Discharged Groundwater' to increase the utilization of 'discharged groundwater' generated when constructing buildings or developing underground spaces such as subway construction. The guidelines were completed after consulting domestic groundwater experts, the Ministry of Environment which oversees the 'Groundwater Act,' and local districts.

'Discharged groundwater' can be used for cooling and heating or landscaping water, but it is often discarded into the sewage system due to lack of knowledge on how to utilize it. According to the Groundwater Act, if a certain amount of discharged groundwater is generated, building owners must establish a utilization plan, but there has been no related manual or water quality standards for usable discharged groundwater.

As underground space development increases, the amount of 'discharged groundwater' generated in Seoul has increased by about 18% over the past 10 years. If the discharged groundwater that was discarded into the sewage system last year had been utilized, sewage fees could have been reduced by 9.6 billion KRW and sewage treatment costs by 25.9 billion KRW.

Seoul plans to strengthen the recycling of wasted water resources in the era of climate crisis by guiding public and private sectors, which have not been able to properly utilize discharged groundwater due to lack of manuals, to increase its utilization.

The Seoul City Guidelines for Utilizing Discharged Groundwater systematically include the procedures required to use discharged groundwater, the standards, methods, and related laws on how it can be utilized. In particular, the city independently established water quality standards by usage to prevent confusion when applying these standards in the field.

The guidelines also present the usage purposes of discharged groundwater and water quality standards for each purpose. Drinking, domestic, agricultural and fishery, and industrial uses follow the groundwater quality standards by usage under the Groundwater Act, while water for maintaining rivers is recommended to meet the clean area discharge standards under the Sewerage Act and the Water Environment Conservation Act.

Utilization plans are also provided according to discharge volume and surrounding location. If the daily amount is 50 tons or less, it can be used as domestic water; for 51 to 100 tons, it can be used for firefighting and road cleaning water. If within 500 meters of a river, it can be used as river maintenance water; near large buildings, for building cooling and heating water; and in large-scale development areas, for construction water.

Additionally, the guidelines include considerations that building owners and others should take into account when establishing utilization plans at each construction stage. Compliance with related laws and management plans for safe use can be self-checked in advance according to site conditions.

The Seoul Metropolitan Government also introduced detailed cases of utilizing discharged groundwater for reference. Last year, as a pilot project, discharged groundwater was recycled as small streams and green space water in Yangcheon Park. Discharged groundwater generated at Seonam Hospital was designated as a civil defense emergency water supply facility (drinking water) for use in emergencies, among various other cases.

Choi Jin-seok, Director of the Water Circulation Safety Bureau of Seoul, said, "The Seoul City Guidelines for Utilizing Discharged Groundwater are the result of long deliberation and effort by experts in related fields," adding, "This year, Seoul plans to diversify discharged groundwater utilization projects into clean roads, cooling fog, ecological water landscapes, and river maintenance water."