Sewage Treatment System in Seoul
Oct 2016
Hunmo Jeong
Sewage Treatment Facilities Division
Seoul Metropolitan Government
e-mail : [email protected]
Development Plans2
Important Promotion Affairs in the Future3
Contents
Current Status of Sewage Treatment System1
Ⅰ. Current Status of Sewage Treatment System
Description of Sewerage System
• Area Served : 605.33 ㎢
• Population : 10.44 Million
• Drainage area : 4 big areas
• Sewer length : 10,297km
• Treatment Centers : 4
• Served ratio : 100%
Organization of Sewerage Management System
Sewerage Planning Division,Flood Control Division
25 Gu, 10 persons × eachJungnang Nanji Tancheon Seonam
Sewage TreatmentFacilities Division
Construction andTraffic Bureau
Seoul MetropolitanGovernment
25 District Offices
Water Recycle & Safety Bureau
Water ManagementPolicy Division
Water ReclamationPlanning Division
River ManagementDivision
4 Sewage Treatment Centers, 547 persons
Budget for Sewerage System
• Special account for sewerage works
• Budget (2015)
- Revenue : 733 billion won (USD 657 mil)
- Expenditure : 733 billion won (USD 657 mil)
Sewer Maintenance : 399 billion won (54.4%)
Operation and Maintenance of Sewage Treatment
Centers(STC) : 203 billion won (27.7%)
Facility Modernization and Others
: 131 billion won (17.8%)
Description of Sewerage System
• 85% area of Seoul is served by Combined sewer system.- During rainfall, runoff and domestic sewage are collected in the same sewer
until combined water volume comes to 3times of hourly maximum sewage flow.
Sewage Sewage
Sewage + Rainfall
Overflow Chamber
3Q
Q Q
Q
Q
2Q
3Q
Intercepting
Sewer
Intercepting
Sewer
1st
Sedimentation
Grit
Chamber
Pumping
Bioreactor 2nd Sedimentation
3rd T-P
Removal
3rd T-P
Removal
Sterilization TMS
Bypass line
Bypass Occurring
First Rainfall Treatment Facility
Other days
Rainy days
Description of Sewer in Seoul
2801151,1988,70410,297
U-shape gutterOpen channelRectangularCircularTotal Length
(Km)
• Length by Function
4475751,022(10%)8,819(86%)10,297
InterceptorSanitary sewerStorm sewerTotal
Separate sewer systemCombined sewer system
Total Length
• Subsidiary Facilities
1,340918486,767206,092
Storm water overflow chamberGrit chamberStorm water inletManhole
• Length by Type
(Km)
(EA)
456(4%)
Present Status of Sewage Treatment Plants
• Capacity : 4,980,000㎥/d
- Night soil & Septic : 12,500 ㎘/d
• Sludge Treatment : 1,950 t/d
- In Site : Sludge Drying 650, Incineration 300
- Other Site (Sudokwon Landfill Area) : 1000t/d
• Process
-Before Jan, 2012 : Standard Activated Sludge
- After Jan, 2012 : MLE + Chemical Treatment
• Total Man Power : 547 Persons
Jungnang Water Reclamation Center
• Site : Chajangteo 5-gil 10, Seongdong-gu
• Area : 791,000㎡
• Construction Period : 1970 ~ 1997
• Construction Cost : USD 370 million
• Sewage Treatment Capacity : 1,590,000㎥/d
• Night Soil & Septic : 4,000㎘/d
• Sludge Drying Furnace : 300t/d
• Man Power : 133 persons
• 2015 Budget : USD 57.1 million
Nanji Water Reclamation Center
• Site : Jayu-ro 116, Goyang-si, Kyeongki-Do
• Area : 929,000㎡
• Construction Period : 1984 ~ 1997
• Construction Cost : USD 214 million
• Sewage Treatment Capacity : 860,000㎥/d
• Night Soil & Septic : 4,500㎘/d
• Sludge Incinerator : 150t/d
Drying Furnace : 150t/d
• Man Power : 112 persons
• 2015 Budget : USD 37.7 million
Tancheon Water Reclamation Center
• Site : Nambusunhwan-ro 6610, Kangnamgu
• Area : 385,000㎡
• Construction Period : 1983 ~ 1998
• Construction Cost : USD 332 million
• Sewage Treatment Capacity : 900,000㎥/d
• Sludge Drying Furnace : 200t/d
• Man Power : 122 persons
(Private Sector Operation)
• 2015 Budget : USD 32.0 million
Seonam Water Reclamation Center
• Site : Yangcheon-gil 546, Kangseo-gu
• Area : 1,091,000㎡
• Construction Period : 1984 ~ 1999
• Construction Cost : USD 429 million
• Sewage Treatment Capacity : 2,000,000㎥/d
• Night Soil & Septic : 4,000㎘/d
• Sludge Incinerator : 150t/d
• Man Power : 176 persons
(Private Sector Operation)
• 2011 Budget : USD 54.3 milion
Present Status of Sewage Treatment (Average, 2015)
Food Leachate treatment
Digestion gas Generation
Operation
Total Night Soil &Septic
Others
Drying
Incineration
Solidification
Total
Sludge Treatme
nt Capacity(ton/day)
Effluent
InflowBOD
Operation
Total(㎥/day) Sewage Plant
Capacity
RemarksSeonamTancheonNanjiJungnangTotalDescription
63,92320,99645,171218,167(㎥/d)
3,268-4,1334,01011,411(㎘/day)
4000-4,5004,00012,500(㎘/day)
Reuse, Landfill, etc123121138
-140273587
125-125-250
Sugogueon Landfill, Incheon412125111292940
5493023885761,815
8.85.37.38.9<10(㎎/ℓ)
136128146173(㎎/ℓ)
1,520,000740,000530,0001,270,0004,370,000
1,630,000900,000860,0001,590,0004,980,000
174
88,072
170-474264908(㎥/day)
Development of Sewerage Management in Seoul
Before 1960
• National Income : under USD 80/capita as GNI
• Area : 268㎢, Population : 2.4million
• Reconstruction and extending of sewers (225km) built before Korean War (1950~1953)
• No treatment plants, sewage and night soil were discharged into streams and Han River
1961 ~ 1980
• National Income : USD 82 ~ 1,645/capita as GNI
• Area : enlarged to 605㎢ in 1973 Population : 2.5 ~ 8.3million
• Construction of 5,940km sewers in newly constructed areas (840 in 60s, 5096 in 70s)
- Service rate in 1980 : 64.8% with total 6,588km sewers
• Construction of 4 septic soil sanitary disposal plants (2,930t/d) during 1972~1976
• Completion of first sewage treatment plant (Jungnang, 360,000㎥/d) in 1979
- Sewage treatment rate of 1980 : 15% of total 2,400,000㎥/d sewage
Development of Sewerage Management in Seoul
1981 ~ 2000
2001 ~ 2015
• National Income : USD 1,800 ~ 10,841 as GNI Population : ~ 10.3million
• Construction of 4 sewage treatment plants (total 5,810,000㎥/d)
and intercepting sewers (413km) during 1984 ~ 1999
• Completion of 99.8% sewage treatment service in 1998
• National Income : USD 10,159 ~ 27,000 as GNI
• Construction of sludge treatment facilities (700t/d) in 2002
• Construction of offensive odor prevention facilities and parks, sports utilities, etc
• Construction of advanced treatment facilities(2009~2012) for nutrients removal
- Activated sludge process → MLE(Modified Ludzack-Ettinger) process
• CSO(Combined Sewer Overflow) Problem
- Seoul's sewers were mostly designed to overflow the mixture of sewage and storm
water into streams at 1,140 CSO discharge points when the flow volumes become over
3 times of hourly maximum flow of sewage in rainy weather.
- The runoff conditions and volumes of sewage generation have been changed largely
in some drainage area, and these areas need bigger intercepting sewers than already
installed one.
- Combined Sewer Overflows from discharge points in these areas usually contain a
lot of pollutants and result in public health threat. This bad impact of CSOs can be
minimized by installing pollutants reduction facilities with storm water detention facilities
at discharging points and enlarging capacity of intercepting sewer in some drainage area.
- However, these measures require huge expense (about USD 360 mil) and long time
for planning and execution.
Problems of Sewerage System in Seoul
• Sewer Repair & Replacement
- 18.8% of sewers in Seoul were constructed 30 years ago and 57.9% were 20 years
ago. Many of them have problems like decrepitude, leakage from bad joint and
insufficiency of discharge capacity. The total forecast expenditure during next 10-year
period for sewer repair and replacement purpose is over USD 4.4 billion.
• Strengthening of Effluent Standards
- For the purpose of preventing water pollution, the national effluent standards have
been strengthened continuously for 20years. BOD limitation became 10mg/l in 2008
from 20mg/l. Total phosphorus concentration limitation was 8, but it has been
strengthened to 2 in 2008 and 0.5 in 2012.
- In addition, total emission volume management system of water pollutants and first
flush control will be obligated to local governments sooner or later by national
environmental laws. These obligations will enforce local governments to secure not only
additional budget but also spaces for construction.
Problems of Sewerage System in Seoul
• Civil Complaints about Sewage Treatment Plants
- Three sewage treatment plants of Seoul are located in residential areas and a lot of
households are adjacent to the plants. Another one is located in the suburb of Seoul but
several small towns are located near the plant. Therefore, since their early operation
time, there were many complaints especially about offensive odor and depreciation of
value of their properties basically.
- Seoul Metropolitan Government have achieved large improvement of odor problems
but there are still civil complaints about inconvenience.
Problems of Sewerage System in Seoul
Ⅱ. Development Plans
Sewer Reconstruction Plan
Securing Watertightness
To protect environment against contamination of soil & stream and to prevent sewer from Infiltration/Inflow
Enhancing Durability
To extend sewer lifespan To prevent safety from negligent accident
Securing Optimal Flow
Velocity
To prevent sedimentation and bad smell
Securing Discharge Capacity
To protect civil safety and property against flooding
Purpose
Sewer Reconstruction Plan
• Construction Period : 2010 ~ 2020
• Budget : USD 4,460 million
• Target : 3,705㎞ (Sewers which are decrepitude, leaky from bad joint and insufficient
of discharge capacity)
Repair and Replacement Plan
Promotion Direction
• Planning by a drainage area unit - Working lower drainage areas first
• Citizen friendly construction
- Application of trenchless technology
- Lightweight lining with temporary facility for open-cut
• Following newly strengthened standard of phosphorus
• Safely treatment of phosphorus for prevention of eutrophication
• Construction Period : 2016 ~ 2018
• Budget : USD 180 million
• Target : 4 Centers
• Treatment Process and Efficiency : T-P 0.3mg/l
Construction of T-P Treatment Facilities
Background
Construction Plan
Description Jung-Nang
Process
• Echojet Green Pluss
- Kolong Engineering
• Fabric Disk Filter
- Yucheon enviro co.
Nan-Ji
• Fabric Disk Filter
- Yucheon enviro co.
Seo-Nam
•Actiflo Turbo
- Veolia Water Solution
• Fablic Disk Filter- Yucheon enviro co.
Tan-Cheon
• Echojet Green Pluss
- Kolong Engineering
• Actiflo Turbo
- Veolia WaterSolution
• Fabric Disk Filter
-Yucheon enviro co.
Construction of T-P Treatment Facilities
Echo-Jet Green Pluss
Fabric Disk Filter (YDF)
Stiring and
Coagulation Air-Flotation
Air Compressor
Fine Bubble
Rapid
Coagulation
Slow
Flocculation
Fabric Disk
Filter
Inorganic
CoagulantPolymer
Construction of T-P Treatment Facilities
ACTIFLO TURBO
Rapid
CoagulationFlocculation
Inclination
Plate Settler
Hydro
CycloneMicro Sand + Sludge Return
Sludge
Micro
Sand
Polymer
Modernization Plan for Jungnang & Seonam
• What is Modernization of Sewage Treatment Plants in Seoul?
- Compacting and laying facilities in underground
- Adopting advanced technology for new facilities
- Creating parks and recreation areas on the ground
• Target Centers : Jungnang, Seonam
- Constructing Facilities by 3 stages (2009~2030)
Modernization Plan for Jungnang & Seonam
• Modernization of Jungnang Center
- Scope of modernization : 1,130,000㎥/d (Extra 460,000㎥/day – Previously retrofitted)
- Period : 2009 ~ 2030 (20years)
- Budget : USD 853 million
[1st Stage Project (250,000 ㎥/d ]
- 2009 ~ 2016, USD 188 million
- Top of underground structures : Sports areas, Water museum, Ponds and garden
Modernization Plan for Jungnang & Seonam
• Modernization of Seonam Center
- Scope of modernization : 1,630,000㎥/d
- Period : 2009 ~ 2030 (20years)
- Budget : USD 1,210 million
[1st Stage Project (360,000 ㎥/d)]
- 2009 ~ 2018, USD 269 million
- Top of underground structures : Water science museum, Water garden
• Prohibition of ocean dumping with the Sea Contamination Prevention Law (from Feb. 2012)
• Preparation for increase of sludge from newly adopted phosphorus treatment process
• Prevention for interregional conflict created from sludge treatment in the other city
Background
Construction Plan
• Construction Period : 2017 ~ 2019
• Budget : USD 64 million
• Newly constructing facilities : 1,170t/d (present 950 → 2,120t/d)
- Jungnang : 370t/d, Drying facility
- Nanji : 160t/d, Drying facility
- Seonam : 520t/d, Drying facility
- Tancheon : 120t/d, Drying facility
Sludge Treatment Facilities Expansion
Sludge Treatment Facilities Expansion
Sudokwon Landfill FacilityDrying Facility
2015 (1,816 ton/day) 2019 (1,980 ton/day)
Sudogueon
Landfill, Dry
Others
Incineration
IncinerationOthers
Dry
- Digestion gas is being used for sludge drying . - All dried sludge is sold as fuel to thermoelectric power plants.
Ⅲ. Important Promotion Affairs in the Future
Purpose
1. Creation of Covered Parks at Tancheon Center
Resident-Friendly Sewage Treatment Center
: Build up “Resident-friendly facilities ”
by changing STCs to “Parks or Eco-friendly space”
• Site area : 392,671㎡, Covered area : 109,381㎡
• Project Cost : USD 63.3 billion
• Project Period : 1999~2016
- 1st stage : 1999~2004, 10283㎡, - 2nd : 2005~2007, 15600㎡, - 3rd : 2007~2010, 49700㎡
• Facilities : Park, Forest zone, Sports areas, Children’s playground, Parking lot, etc
• Ongoing Project : 4th Stage 33,798㎡ (2013~2016, about 33 billion won)
Tancheon Center Area View
Resident-Friendly Sewage Treatment Center
Covered park(3rd)
Covered park(2nd)
Tancheon Sewage Treatment Center
Covered park(1nd)
4th Stage
Covered Park
4th Stage
(Constructing)
2nd Stage 1st Stage
3rd Stage
2. Creation of Resident-Friendly Space around Seonam & Nanji
Resident-Friendly Sewage Treatment Center
• Forest park and Sports facilities at Seonam center
- Created Area : 188,500㎡
- Project Cost : USD 8.1 million
- Project Period : 2008 ~ 2011.6
- Facilities : Walking Way, Forest, Tennis Courts, Park Golf, etc.
• Sports Facilities at Nanji center
- Created Area : 10,000㎡
(Football Ground, Basketball Ground, etc)
- Project Cost : 1,000 million won, 2010~2011.2
3. Further Project
• Performing Nanji Modernization Plan
- Project Cost : USD 49.3 million
- Project Period : 2016 ~ 2020
- Facilities : Walking Way, Forest, Sports Facilities, etc
Use of New & Renewable Energy
• New & Renewable Energy
- Energy that comes from resources which are continually replenished such as sunlight,
wind, tides, waves and geothermal heat
• Use of New & Renewable Energy in STCs
- Sewage Treatment Systems are basically consisted of enormous energy consumption
facilities, however, they are also have huge potentialities of new & renewable energy
from digestion-gas, sewage heat recovery, photovoltaic power generation and etc.
Year 2015 2017
Goal of Energy Self-Sufficiency Rate for STCs
• 51% • 60%
Energy Con-sumption of 4STCs
•127,315 TOE/Year (mostly Electricity)
•127,315 TOE/Year
Energy Production of 4 STCs
• 65,775 TOE/Year(digestion gas, sewage heating pump and photovoltaics)
• 76,775 TOE/Year (digestion gas increase, construction of more sewage heating pump, etc)
Goal of Energy Self-Sufficiency Rate for 4 STCs in Seoul
Use of New & Renewable Energy
Photovoltaic power generation
• Construction of solar cells on the treatment tanks and grounds
- Plan : 2,000kw (2012, Jungnang 400, Nanji 100, Seonam 1,300)
→ 10,770kw (2 015, Tancheon 2,280, Jungnang 690, Seonam 6,000)
- Construction Cost : USD 46.6 million ( invested by Electricity Generation Enterprisers )
Seonam Photovoltaic Arrays(1,300kw)
Use of New & Renewable Energy
• Recovery of heat from treated water
※ 5℃-Thermal energy recovery can be achieved by heat-pump installation
- Plan : 19,000TOE (2014, Tancheon 19,000) → 30,000TOE (2017, Seonam 11,000)
- Construction Cost : USD 56.5 million (invested by Private sectors)
Sewage Heat Recovery
Use of New & Renewable Energy
Digestion Gas
• Increase of gasification rate and enhancement of utility value
- Plan : 210,000 ㎥/d (2015) → 260,000㎥/d(2020)
Cavitation and Ultrasonic Wave Treatment at the inlet line of sludge digester
Present Gas Usage : Digester Heating 23.3%, Sludge Dry 22%, Generation 32.5%,
Fuel for industry 7.7%, Burning 14.5%
⇒ By enhancing digestion gas values through refining and selling gas to cogeneration
enterprises, revenue over USD 4 million will be obtained annually
Creating 4 billion won revenue
95,600㎥/d
Electricity, Heat, City Gas
Seonam, Nanji, Jungnang
Seonam
4,800㎥/dFuel for 180 vehicles
Digestion Gas
20,000 Houses
Refining
Treated Water Re-use
Current: 4.8% ( 206,000 ㎡/d )
- Road Cleaning and
Cooling water
- Subway Train Washing
- Others
Future Goal: 10% of discharge
- Maintenance water
of stream
- Water for Landscape
- Cleaning water etc
Maintenance water of stream
Water for Landscape Cleaning water
The sewerage system of Seoul shall
largely contribute to safety and
comfortability of citizen, and
preserve environment of the Earth.