User:Sewer oder/sandbox

= Sewage Odors in Seoul Korea =

General
Seoul Metropolitan Government is a big city with an area of 605.19㎢ and a population of 10,413,000, and operates four water recycling centers that treat sewage of 4,390,000㎥ per day with sewers extending 10,392㎞. Sewers are operating under the Combined Sewer System with 9,104㎞ (87.6%), Separate Sanitary & Storm water Sewer System 820㎞ (7.9%), and Collection Pipe Line of 468㎞ (4.5%). Unlike other cities in foreign countries, Seoul has about 600,000 septic tanks, and an individual waste water treatment system. This sewage treatment and conduit system are essential social infrastructure for the safety and pleasant lives of citizens, but they have created a sewage odor resulting in many public complaints, as well as disturbing the comfort for citizens. The number of complaints about the sewage odor in Seoul has been rising every year with 1,753 complaints in 2010, 2,567 in 2011, 3,135 in 2012, and 3,079 in 2013. 78 percent of the complaints about sewage odor are related to sewers. In addition, complaints are widespread throughout the city, meaning a countermeasure to reduce the odor is urgently needed.



Cause of sewage odor
When sewage water is pumped from the septic tanks in buildings, apartment houses, and drainage tanks, overflows happen, producing a stinking smell of waste water on the streets. Additionally, due to a lack of slopes in the sewers, especially in traditional marketplaces or low-lying lands, organic matters accumulate and decay, and at the stepped cones of sewers, hydrogen sulfide (H2S) inside the water evaporates into the air. Also, the odor is spreading near the conduit pipe line where the waste water gathers.

Efforts in Seoul to reduce sewage water odor
By installing an aerial supply unit to the septic tanks and drainage tanks of large buildings, the cause of the odor is relieved, and by regularly repairing old, malfunctioning sewers to prevent sediments from accumulating in the sewer, the minimum speed of sewage is maintained. Sediments within the pipes were removed to eliminate the source of the odor. In addition, in order to prevent sewage odor from leaking out of the sewers, the structure of the street inlet)was improved. Moreover, a device to cut off nasty smells was installed and a fence screen was set up before the conduit pipe line. Despite these efforts, the waste water odor has not been reduced and continues to be an issue.

Expert opinions on the reduction of sewage water odor
Complaints about sewage water odor in Seoul are increasing, and 78% of the odor occurs in sewers), and in particular, with the pumping of waste water in septic tanks, manholes and the street inlets in the combined sewer system generate a bad smell. Experts recommend that in order to reduce sewage odor, the installation of an aerial supply device on septic tanks – currently being implemented by Seoul City -- needs to be accelerated and a law should be created which requires building owners to mandatorily clean and maintain their drainage facilities.

The limitations and difficulties faced by the Seoul Metropolitan Government with sewage water odor control
Most of the sewers were built under the combined sewer system, and about 600,000 septic tanks are distributed among residential and commercial areas throughout Seoul. Accordingly, an odor is always present everywhere in our daily lives. To solve this, the present Combined Sewer System can be transformed into a Separate Sanitary & Stormwater Sewer System, which would need)significant cost and time. Additionally, private individual drainage facilities like septic tanks should be repaired as well, which would make seoul more difficulty with reducing odors. Accordingly, your wisdom and ideas to reduce sewage odor are invited, and we look forward to having your earnest contribution to make the pleasant city of Seoul free of odor.