Suspected Larvae Found at Bupyeong Water Purification Plant's 'Advanced Water Treatment Facility'

Incheon Mayor Park Nam-chun (right) is inspecting the Cheongna Reservoir in Seo-gu in relation to the occurrence of larvae in tap water. July 17, 2020.
[Photo by Incheon City]

[Asia Economy Reporter Park Hyesook] Regarding the Incheon tap water larvae incident, in addition to the initial outbreak site, Gongchon Water Purification Plant, objects presumed to be chironomid larvae were also found at Bupyeong Water Purification Plant, prompting calls for a more detailed investigation into the cause.

On the 19th, Incheon City and the Ministry of Environment announced that objects presumed to be dead chironomid larvae were found at Bupyeong Water Purification Plant and three water reservoirs in the Bupyeong area, which supply tap water to Bupyeong-gu and Gyeyang-gu.

Until now, larvae had only been found at Seo-gu Gongchon Water Purification Plant and the reservoirs and households supplied by it, leading authorities to strengthen monitoring centered on the Gongchon Water Purification Plant water system.

Bupyeong Water Purification Plant had not confirmed larvae in the previous two investigations. However, after objects presumed to be larvae were identified at a Bupyeong area reservoir on the 17th, further detailed investigations were conducted, discovering objects presumed to be dead larvae.

Additionally, field investigations found five cases of objects presumed to be larvae in households in Gyeyang-gu and Bupyeong-gu, where tap water is supplied from Bupyeong Water Purification Plant.

The number of complaints related to tap water larvae totaled 580 from the 9th to the 18th (as of 6 p.m.), of which 149 cases involved actual discovery of objects presumed to be larvae after on-site investigations.

Excluding the five cases in Bupyeong and Gyeyang areas, 144 cases were found in Seo-gu, Ganghwa-gun, Yeongjongdo, and other areas supplied by Gongchon Water Purification Plant.

Experts have voiced the need for a detailed cause investigation and countermeasures as objects presumed to be larvae were found even at Bupyeong Water Purification Plant, which has an advanced water treatment facility using closed ozone treatment.

The advanced water treatment process is a water purification system that adds ozone and granular activated carbon processes to the existing standard water treatment process to remove trace organic substances that cannot be eliminated by the standard process.

In the case of Gongchon Water Purification Plant, where larvae were previously found, it was put into early operation in September last year without complete sealing such as ozone treatment facilities, raising the possibility that flying insects laid eggs on the plant’s activated carbon filter, causing larvae to appear.

The city announced that based on genetic analysis results of tap water larvae the previous day, "The genes of one larva first found in the activated carbon filter of Gongchon Water Purification Plant and three larvae from a household in Wondang-dong, Seo-gu, were all identified as species of Chironomus plumosus and Chironomus anthracinus," and "It is presumed that the larvae leaked from the Gongchon Water Purification Plant pipelines to households."

Incheon City has temporarily switched the advanced water treatment process at Bupyeong Water Purification Plant to the standard process, similar to Gongchon Water Purification Plant. Other plants are strengthening water treatment processes (ozone increased from 0.5 to 0.7 ppm, cleaning cycle shortened from 10 days to 2 days).

They are also conducting water drainage through pipelines and fire hydrants to discharge foreign substances and plan to complete cleaning of four reservoirs by the 22nd.

Incheon City and the Ministry of Environment have formed a "Joint Expert Detailed Investigation Team on Tap Water Larvae," led by Professor Emeritus Hyun Inhwan of Dankook University, to identify the cause of larvae occurrence and prepare measures to prevent recurrence.

An Incheon City official stated, "Monitoring is also being conducted at Namdong Water Purification Plant, Susan Water Purification Plant, and nine reservoirs in the respective areas besides Gongchon and Bupyeong, but no larvae have been found so far," and added, "We will work with the Ministry of Environment and related agencies to ensure that tap water can be supplied normally as soon as possible."

This content was produced with the assistance of AI translation services.