–2011 Paldang BOD level: 1.1㎎/l, the lowest since the announcement of the Master Plan in 1998
-2011 Gyeongancheon Stream BOD level: 2.0㎎/l, the best since the start of water quality monitoring in 1992
 

The quality of the water in Paldang Lake is at its best since the announcement of a plan for comprehensive improvement in 1998.

According to data analyzed by Gyeonggi Province on January 25, the annual average BOD at Paldang Lake was 1.1mg/l, a significant improvement over the figure of 1.4㎎/l recorded in 1998, the year when the announcement was made to improve the quality of the water at Paldang.

Biochemical oxygen demand (BOD) is the amount of oxygen needed by aerobic biological organisms in a body of water to break down organic material in the water. It is principally used to judge the degree of pollution of a given water sample. Thus, the lower it is, the better.
 

The water quality of Gyeongan Stream, which was synonymous with filth and pollution until the end of the 1990s, also showed a considerable improvement. The province announced that the average BOD of the stream in 2011 was 2.0㎎/l, an improvement of more than 200% over the figure of 5.2㎎/l recorded in 2006.

Gyeongan Stream has been the focal point of the current administration’s efforts to improve water quality in Paldang since Governor Kim Moon-soo took office as the 4th governor of the province and announced a master plan to improve the water quality there in 2007. The latest BOD level of 2.0㎎/l is the lowest figure recorded since the monitoring of water quality at Gyeongan Stream began back in 1992.
 

Yu Yeong-bong, Director of the Gyeonggi Province Paldang Water Quality Improvement Headquarters, said, “The water quality at Paldang has improved for several reasons. First, an area of about 575ha along the stream has been transformed from farmland to grassland by the central government’s Four Major Rivers Restoration Project, thereby eliminating a serious source of pollution. Second, there was an increase in annual precipitation in 2011. Third, the provincial government has continued to increase and improve regional sewage pipes and plants.”

More specifically, according to the current regional government’s master plan announced in February 2007, Gyeonggi Province has reduced the flow of pollutants into Paldang Lake, expanded the sewer network, improved sewage pipes connecting to sewage treatment plants, expanded existing sewage treatment plants and constructed new sewage plants, and created a self-purifying eco-wetland along the waterways. By 2010, a total of KRW 875.9 billion had been used to improve the water quality of Paldang and Gyeongan, of which KRW 451.7 billion came from the central government, KRW 206.3 billion from the regional government, KRW 64.5 billion from the municipal and county governments, and KRW 153.4 billion from the Watershed Management Fund.

Consequently, the sewer installation rate rose from 66.5% in 2006 to 89.2% in 2010, the total length of sewage pipes increased from 3510km in 2006 to 5296km in 2010, and the daily sewage treatment quantity also increased from 453,295 tons in 120 sewage plants in 2006 to 731,500 tons in 180 plants in 2010.
The high-rate sewage treatment, which considers nitrogen and phosphorous in addition to BOD, was also improved from 82.5% in 2006 to 98.4% in 2010.

Governor Kim said, “This is the result of combined efforts on the part of the region’s government, residents and enterprises all along the water system. This will strongly affirm that it is more effective to actively engage in improving water quality rather than simply leaving streams and lakes as they are. I will continue to work hard to improve the quality of potable water for the 25 million people living in the metropolitan area.”

Regarding the question of how the water quality of Paldang Lake can now be at its best when, only last November, there was a dispute over a noxious odor emanating from green algae in the lake, an official of the province said, “The green algae appeared only in the North Hang River. Because the water quality of the South Han River and Gyeongan Stream is so good, the overall water quality of Paldang turned out to be better than ever.”

ⓒG-News Plus / Roh Soon-ik / rohsoon45@naver.com

http://gnews.gg.go.kr/news/news_detail.asp?number=201201261102457055C048&s_code=C048