SEWERAGE SYSTEM IN ULAANBAATAR Brief introduction of Ulaanbaatar city Ulaanbaatar is the capital of Mongolia. Population - 1.35 million citizens /2015/ Elevation-1351m above sea level Occupies the area of 4704 sq.km Lowest temperature -40C Highest temperature +35C
Current situation of wastewater treatment Assessment of current situation Strong urban growth in Ulaanbaatar Establishment of industries in the city Lack of industrial pollution control Existing wastewater treatment plant outdated and obsolete
2,000,000 1,800,000 1,600,000 1,400,000 1,200,000 1,000,000 800,000 600,000 400,000 200,000 0 Current situation of wastewater treatment Forecasted population growth 1,763,000 1,534,000 1,161,785 952,400 2005 2010 2015 2020 2025 2030
Current situation of wastewater treatment The central wastewater treatment plant; The plant was constructed at 1964 with capacity of 45000m3/day. During 1979-1986, it was expended with biological treatment and capacity was increased up to 200000m3/day. The CWWTP treats domestic waste water from about 0.6 million inhabitants and waste water from industries.
Current situation of wastewater treatment Actual flow rate: 165000m3/day. The method of sewage treatment is the mechanical and activated sludge process. Total length of sewage main networks -152km Total employes-155 Annual operation cost- 5.3 billion MNT /4.3mln$/ Total electro consumption-21mln kwt (1.4mln$)/year Cost for 1m3 ww-mnt86.09 (0.06USD/m3)
Flow diagram of the CWWTP
BOD5, COD, SS in influent. /mg/l/ mg/l мг/л 1800 1600 1400 1200 1000 800 600 400 200 0 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 BOD, mg/l 280 440 414.53 408.99 314 261.1 292 265 296.03 330.71 345.64 337.29 COD, mg/l 339.6 866.3 676.03 622.92 534 730 805 823 935.1 1195.92 998.47 942.57 SS, mg/l 161.9 358.6 478.43 293.03 357 357.5 426 377 463.6 720.83 556.49 1709.98
mg/l 1600 Current situation of wastewater treatment Significant increase of the pollution 1400 1200 Evolution of inlet concentration at the CWWTP BOD 1000 800 600 400 200 0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
Current situation of wastewater treatment Inlet Pumping Station The plant have two pumping stations which are working in parallel. In front of both Pumping stations, there are five screens to protect the pumps from large particles that could damage the pumps. The waste water from 2 pumping stations through 4 pipes of 1000mm diameter collected to the mixing zone.
Current situation of wastewater treatment Screens and Grit chamber Waste water from the mixing basin flows into fine screens and grit chamber. In the grit chamber sand and solids settle to the bottom and are removed by hydro- elevator to the sand drying beds.
Current situation of wastewater treatment Primary Sedimentation Tank The waste water flows slowly in a primary sedimentation tanks and where organic solids gradually settle to the bottom. The plant using 4 settlers with diameter 40 meter.
Current situation of wastewater treatment Aeration tank The major role of the aeration tank is to clear away the soluble BOD and suspended solids. The plant using 5 aeration tanks with dimension 36x105x6 meter.
Current situation of wastewater treatment Secondary sedimentation tank The mixed liquor from the aeration tank flows slowly in a secondary sedimentation tank, the biological solids are separated from the mixed liquor and returned to the aeration tank. Excess biological solids are sent to the sludge thickener. The plant using 5 settlers with D40m
Current situation of wastewater treatment Disinfecting unit The treated water is disinfected by UV rays and discharged to the Tuul river.
Current situation of wastewater treatment Sludge processing The sludge which is produced of the plant is pumped to the sludge thickener and belt filter press for dewatering. The plant have 44 sludge drying beds. After dewatering the sludge is disposed to the special area. There is no re-use.
Current situation of wastewater Existing plant outdated treatment Significant environmental impact Existing structures heavily damaged Low treatment performance Problems with sludge treatment Poor influent wastewater quality Important odour nuisance Major pollution of the Tuul River
m3/d Development strategy Future increase of capacity 290,000 Required additional capacity from 2030 270,000 250,000 New CWWTP 250,000 m3/jour 230,000 210,000 Flow to be treated at the existing plant 190,000 170,000 150,000 2015 2020 2025 2030 2035
Development strategy Phasing of the implementation Short term rehabilitation of the existing CWWTP to optimise the performance until the new plant is operational / to increase the plant capacity, to implement new treatment technology / Implementation and enforcement of industrial pollution control Construction of a new CWWTP, 250,000 m 3 /d, in operation from 2020 Extension works for additional capacity from approximately year 2030
Treatment technology for the new CWWTP Trough the eye of the architect
29/09/2016 ARTELIA 20
Rehabilitation measures of existing CWWTP Objectives of rehabilitation Purpose: to ensure best possible efficiency before the commissioning of the new CWWTP in year 2020 No additional structures to be constructed optimise the operation of the existing facilities Measures shall be implemented rapidly