A Large Lavatory with a Structure Similar to the Modern Septic Tank Discovered in Gyeongbokgung Palace

[경향신문]
An excavation team discovered the ruins of a large lavatory that had a facility similar to a septic tank.

On July 8, the National Research Institute of Cultural Heritage, an affiliate of the Cultural Heritage Administration of Korea announced, “We excavated the ruins of a lavatory located south of Donggung (Palace of the Crown Prince) in Gyeongbokgung Palace. This is the first time that we have discovered the remains of a lavatory inside a palace.”

Size and structure of the lavatory in Gyeongbokgung Palace. Courtesy of the Cultural Heritage Administration of Korea

The lavatory was a stone structure in the shape of a narrow rectangular hole 10.4 m long, 1.4 m wide, and 1.8 m deep. From the floor to the walls, everything was made of stone. There was one inlet through which water flowed into this facility and two outlets through which the water flowed out. The inlet in the north was higher than the outlets.

Complete view after the excavation of the lavatory in Gyeongbokgung Palace. Courtesy of the Cultural Heritage Administration of Korea

According to the National Research Institute of Cultural Heritage, the water flowed in and mixed with the excrement in the lavatory accelerating the fermentation of the excrements and reducing their volume. “This resulted in the deposition of the sludge on the bottom and the effluence of the wastewater out of the palace.” The institute explained that the structure was similar to the modern septic tank (Add water to sediments of excrements  fermentation and sedimentation effluence of wastewater).

The water inlet on the north side of the lavatory in Gyeongbokgung Palace. Courtesy of the Cultural Heritage Administration of Korea

Lee Jang-hun, director of the Korean Institute of Odor Studies said, “There are no cases worldwide of a large-scale lavatory with a septic system from 150 years ago like the one in Gyeongbokgung Palace.” He further said, “The system of using water to accelerate the fermentation of excrements and treating the wastewater before releasing it outside was a significantly advanced technology compared to previous structures.”

The National Research Institute of Cultural Heritage also found parasitic eggs (18,000 eggs per gram) and seeds (cucumber, eggplant, and perilla) in the organic matters recovered from soil samples. The institute further explained, “On the basis of the records of the Gyeongbokgung Yeonggeonilgi (The Daily Log of the Construction Works of the Gyeongbokgung Palace), the determined accelerator mass spectrometry (AMS) radiocarbon dates of the samples, and the stratigraphic profile of the feature, it is postulated that this lavatory was built in 1868 when the reconstruction of the palace was completed and was used for about 20 years.”

The outlet on the east side of the lavatory in Gyeongbokgung Palace. Courtesy of the Cultural Heritage Administration of Korea

According to the institute, the lavatory was 4-5 kan in dimension, with a capacity of ten people max. Based on the average daily amount of excrement per person and considering the measure of capacity of the structure (16.22m2), the institute believes the lavatory could cover about 150 people a day, about five times higher than the lavatory without a septic system.

An estimated ground plan of the lavatory in the Donggung Palace grounds in Gyeongbokgung Palace. Courtesy of the Cultural Heritage Administration of Korea

The location of the structure indicates that it was used by people serving the Donggung Palace, such as low-ranking officials, court ladies, and gatekeepers. The buildings around Donggung Palace were completed in 1868 (5th year of King Gojong’s reign), but they were severely damaged in 1915, when Japan cleared the site to hold the Joseon Local Products Expo to justify its annexation of Joseon.

Records of the lavatory at Gyeongbokgung Palace can be found in Gyeongbokgungbaechido (Plan of the Gyeongbokgung Palace), Bukgweoldohyeong (Figure of the Northern Palace), and Gunggweolji (Records of the Royal Palace). According to these records, the biggest lavatory in Gyeongbokgung Palace was 75.5 kan. The institute explained, “Most were located in the densely populated area in the palace. In particular, many lavatories were situated close to the Geolnaegaksa Office south of Gyeonghoeru (Royal Banquet Hall), Donggung Palace, and the area of the National Folk Museum of Korea.”