Design Standard TCVN 7957: 2008 of MOC. Building code of Vietnam, volume 1, 2, 3.
Standard and design planning of urban construction 20 TCN 82-81.
The socio-economic development plan of District 2 and the drainage & sewage network master planning of HCMC to 2025.
Reference to criteria and requirement of drainage & sewage system in nationwide urban areas such as Hanoi, Haiphong, Danang and other surrounding areas in HCMC.
2. Wastewater standards
Dirty water flow in an urban area is related to the water demand. According to a study result under the HCMC Revised Master Construction Plan (in period of 2010 – 2025) and the Revised Construction Plant of District 2 by HCMC Planning Institute, the norm for water consumption in the study area in accordance with the HCMC water supply planning to 2025 is as follows:
Table 15. Norm for water supply in accordance with the proposal of the city
No. Water supply demand Norm of water consumption
To 2015 To 2020
1 Domestic water 180 l/person/day 180 l/person/day
2 Public services 40 l/person/day 40 l/person/day
3 Visitors 30 l/person/day 30 l/person/day
4 Handicraft 15 l/person/day 15 l/person/day
5 Public work at under management of the
city 40 m
3 /ha/day 40 m3 /ha/day
6 Industrial areas 40 m3 /ha/day 40 m3 /ha/day
7 Daily coefficient of non-regulation 1,2 1,2
8 Hourly coefficient of non-regulation 1,5 1,5
3. Estimation of population scale
The total population of District 2 in the revised master planning of District 2 approved by HCMC PC is estimated at 650,000 persons.
The estimated population density is 118 persons/ ha. In the district area, the population is rather high (160 person/ ha), excluding the functional areas of the city (Thu Thiem New Urban area, Rach Chiec Sport Center, Cat Lai and Thanh My Loi Industrial Zone), higher than the average density of the city (65 person/ ha in 2020) and little lower than the density of Block A – Phu My Hung Urban Area in District 7 (230 persons/ ha)
Table 18. Estimated population scale in District 2 to 2020
No. Items Unit Estimated
population 1 Population scale
- Year 2015 Persons 370,000
- Year 2020 Persons 650,000
2 Annual growth rate of population
- 2011 ÷ 2015 % 3,0
4. Estimation about wastewater amount in District 2.
Table 19. Daily Wastewater flow in District 2
No. Water usage
Present time To 2020 Norm of water consumption Population (persons) Wastewater flow (m3/day) Norm of water consumption Population (persons) Wastewater flow (m3/day) I Domestic wastewater 140,629 650,000
1 Domestic usage 180 l/person 22,781.9 180 l/person 105,300.0
2 Public services 40 l/person 5,062.6 40 l/person 23,400.0
3 Visitors (25% of population) 30 l/person 35,157 949.3 30 l/person 162,500 4,387.5
4 Penetration amount: 10% (1+2+3) 2,879.4 13,308.8
5 Daily coefficient of non-regulation 1.2 1.2
Highest flow 38,007.8 175,675.5
6 Hourly coefficient of non-regulation 1.5 1.5
Highest flow 2,375.5 10,979.7
II Production wastewater 10,9111.6 10,9111.6
Industrial zones 40 m3/ha 272,79 ha 10,911.6 40 m3/ha 272.79 ha 10,911.6
Therefore the total domestic wastewater flow in District 2 at the present is from 31,673.4 m3/day to 38,007.8 m3/day. To 2020, the total
domestic wastewater flow in the district will be from 146,396.3 m3/day ÷ 175,675.5 m3/day.
5. Development orientation of sewage system in District 2.
The sewage system includes the sewer network and wastewater treatment plant. a. Industrial wastewater:
- The industrial wastewater is collected to the sewer into the local treatment plant in industrial zones.
- The industrial wastewater after treatment must comply with QCVN 40:2011/BTNMT before discharging to the environment.
b. Wastewater from residential areas:
- The sewer system collecting wastewater from residential areas:
+ The main sewer route shall transfer the wastewater to the transition pumping station and to the central wastewater treatment plant of the city.
+ The branch sewer route is a separate sewer. The sewer shall collect wastewater from the discharging sources to the wastewater collection point.
- Orientation for domestic wastewater treatment:
+ Step 1 (serving for the period prior to 2020): The residential projects having wastewater flow Q ≥ 1000 m3/day must construct local wastewater treatment plant. The wastewater after
treatment must meet TCVN 7222- 2002 (for permanent wastewater treatment plants) and QCVN 14:2008/ BTNMT (for temporary treatment plants) before discharging to the environment. The project having wastewater amount Q ≤ 1.000 m3/day, the wastewater shall be transported to a
collection point (regulation tank) for easier checking wastewater quality and connection with the main sewer.
+ Step 2 (after 2020): In the future (after 20 years, the operation time of local treatment plant shall be expired), the central wastewater treatment plant of city will be completed and operated. Then the wastewater of the planned area (from the collecting point or local temporary treatment plant) shall be conveyed to the main sewer route of the city and to the central wastewater treatment plant of the city.
c. Local treatment system:
Regarding new residential areas, the sewage system shall be invested by the project investor. In order to meet regulations on environmental sanitary, the wastewater shall be collected to local treatment plant and shall meet Class B in accordance TCVN 5945-1995 before discharging to the environment. After the interceptor and Nhieu Loc – Thi Nghe wastewater treatment plant are completed, the local treatment plant shall be rehabilitated to wastewater pumping station and transported wastewater to the main sewer of the city and to Nhieu Loc – Thi Nghe WTP.
Regarding industrial zones, the wastewater shall be treated in at the local WTPs invested by project investors. The wastewater after treatment must meet Class B in accordance with TCVN 5945-1995 before discharging the environment.
The areas having new residential areas are: - Thu Thiem Residential Area,
- Residential Area of An Phu Ward, along Luong Dinh Cua Street,
- Sport – Residential area of An Phu Ward, on the East of Dong Van Cong Street, - Residential Area of Thanh My Loi Ward (on the West of Dong Van Cong Street), - Thanh My Loi – Cat Lai Residential Area (on the South of the Ring Road no. 2) d. Central WTPs:
In accordance with the Revised Master Plan of District 2, the sewage system is separated. The wastewater is collected and transported to Nhieu Loc – Thi Nghe WTP.
6. Wastewater Discharging Basins
The wastewater discharging basins are divided similar to the rainwater discharge basins. Regarding the wastewater discharge of the study area, it is possible to classify into 3 types: - Basins for existing area.
- Basins for new urban areas.
- Basins for wastewater discharge in the future.
The following criteria are used to define areas which are suitable to construct a wastewater discharge system, i.e.:
- The areas cannot be applied with in-situ treatment methods. - The areas have completed transport infrastructures.
- The industrial, commercial and administrative areas.
- The planned areas have growth rate of population density at medium and high level (> 150 persons / ha), located in the designed areas.
7. Hydraulic Calculation
The hydraulic calculation is done based on the drainage route identification. Discharge basins are defined to specify the discharge area which is covered by the sewer. The principle for route identification and basin division is based on the actual discharge direction and different cells, which are divided from a basin. From the cells, it is possible to calculate the discharge area and select the coefficient of coverage, etc. In the feasibility report, the preliminary calculation shall be made for the new construction and presented in the statement for the basic design.
Calculate the drainage flow in accordance with Manning formula: /s) (m A xV Q 3 (m/s) S x R n 1 V 2/3 1/2 In which: Q - calculated flow(m3/s)
A - cross-section area of the flow (m2)
V - average flow velocity (m/s)
n - roughness coefficient, depending on the nature of river bed surface R - Hydraulic radius (m)
S - hydraulic gradient(m/m)
Pipes connected in accordance with water-level measure Coefficient of non-regulation Kng max: Kng-max=1.2 Coefficient Kh-max = 1.8
Calculated slope imin=1/D(mm) in accordance with TCVN:7957-2008
8. Calculation results of WTP scale. a. Main sewer route with grade 2.
+ Basin 1 - on the north of Hanoi Highway: The wastewater shall be collected to the main sewer route with grade 2 as follows:
- Sewer Ø400 on Xuan Thuy Street, connecting with Sewer Ø500 on Nguyen Van Huong Street
- Sewer Ø500 on Nguyen Van Huong Street along Sai Gon River
- Sewer Ø400, Ø500 on Thao Dien Street connecting with Sewer Ø500 on Hanoi Highway. - Sewer Ø500 on Hanoi Highway and Sewer Ø500 on Nguyen Van Huong Street are connected to the Sewer Ø1000 on the transport junction from Sai Gon Bridge to Tran Nao Street
+ Basin 2 in Binh An Ward along Tran Nao Street: the wastewater is collected to the main routes with grade II as follows:
- Sewer Ø1000, Ø1200 on Tran Nao Street connecting with the Well G5 on Nhieu Loc – Thi Nghe Interceptor.
+ Basin 3 – Thu Thiem Urban area: the sewer network shall collect wastewater to the local pumping station near Well G7 of the interceptor and then the wastewater shall be pumped to the local WTP of Thu Thiem Urban Area located nearby Sai Gon river and road on the bank of Sai Gon River, Binh Trung Tay Ward. The wastewater will be treated preliminary to meet Class B in the first phase (when the interceptors and Nhieu Loc – Thi Nghe WTP are not completed). In a next phase when Nhieu Loc – Thi Nghe WTP is completed, the local WTP shall convey the wastewater to Nhieu Loc – Thi Nghe Interceptor.
+ Basin 4 – Residential Area in An Phu Ward along Luong Dinh Cua Street
- The pipeline Ø500 in An Phu Residential Area with 132 ha connects with pipeline Ø500, Ø600 in Nguyen Quy Duc Street (Street no. 5).
- The pipeline Ø500, Ø600 in Nguyen Quy Duc Street (Street no. 5) connects with pipeline Ø600, Ø800 in Luong Dinh Cua Street.
- The pipeline Ø600, Ø800 in Luong Dinh Cua Street connect with the pipeline Ø1000 in Tran Hung Dao Street toward Well G5 on Nhieu Loc – Thi Nghe Interceptor.
- The pipeline Ø500 in Nguyen Chi Tho Street connect with the route G9
+ Basin 5 - Sport Center in An Phu Ward (on the east of Dong Van Cong Street): the wastewater is collected to the pipeline Ø400, Ø500 in Dong Van Cong Street, to the pipeline Ø400, Ø500 in Sai Gon – Long Thanh – Dau Giay Expressway.
+ Basin 6: the existing area on the East of Dong Van Cong Street (Inter-provincial Road 25B): the wastewater is collected to main pipeline Ø800, Ø1000 in Nguyen Thi Dinh Street to the pipeline Ø1200 on the East Ring Road.
Besides, there are some main routes in the existing residential areas as follows:
- The pipeline Ø600 in Nguyen Duy Trinh Street connects with the pipeline Ø800 in Nguyen Thi Dinh Street.
- The pipeline Ø600 in Nguyen Van Thinh Street connect with the pipeline Ø1200 in Nguyen Thi Dinh Street.
- The pipelines Ø400, Ø500 on the main street of Binh Trung Dong Street
+ Basin 7 - Thanh My Loi Residential Area on the West of Dong Van Cong (Interprovincial Road no 25B): The wastewater is collected to the local treatment plant in residential areas. The wastewater will be treated preliminary to meet Class B in the first phase (when the interceptors and Nhieu Loc – Thi Nghe WTP are not completed). In a next phase when Nhieu Loc – Thi Nghe WTP is completed, the local WTP shall convey the wastewater to Nhieu Loc – Thi Nghe Interceptor.
+ Basin 8 - Thanh My Loi – Cat Lai Residential area on the South of Ring Road no. 2: the wastewater from the industrial zone and Cat Lai Port shall be treated in the industrial zone and at the port in accordance with Class A in TCVN 5945-1995 before discharging to Sai Gon River.
The wastewater from Thanh My Loi – Cat Lai Residential Area shall be treated at local WTPs at the first phase (when the interceptors and Nhieu Loc – Thi Nghe WTP are not completed). In a next phase when Nhieu Loc – Thi Nghe WTP is completed, the wastewater shall be conveyed by the pipeline Ø1200 on the East Ring Road.
b. Pipeline network with grade 3.
Zoning for investment of sewer network with grade 3: As district 2 is a new urban area of the city in the developing process, including both existing and new residential area with many projects for new residential area development. The existing common system should be rehabilitated. The investment in a separated system will require a huge investment. In order to implement the project effectively, it is necessary to define the areas for investment, clarify the responsibilities of the developers in the residential areas and of state budget in association with World Bank funds for rehabilitation of existing residential areas.
The zoning for investment shall be made according to the existing condition of residential areas and planning orientation for land use and topography. The areas to be invested with the pipeline network with grade 3 coincides with the proposed areas for investment with the drainage system.
The proposed areas for investment by funds of World Bank and State Budget are: - Basin 1: On the north of Hanoi Highway
- Basin 2: basin along Tran Nao Street
- Basin 6: the existing area on the East of Dong Van Cong Street (Inter-provincial Road 25B).
Water pumping station: The water pumping stations are constructed to reduce the depth of pipeline installation and pressure increase to convey water to the WTP. It is estimated to invest in 3 pumping stations.
Station 1is located in Nguyen Van Huong Street and junction at Sai Gon Bridge in Thao Dien Ward.
Station 2 is located in Nguyen Thi Dinh Street and Nguyen Duy Trinh Street in Binh Trung Dong Ward.
Station 2 is looted in East Ring Road and in Nguyen Thi Dinh Street. Regarding location of the pumping stations:
- Select relatively independent positions in the area
- Put in the position between road and discharging sources
- Install underground to reduce pollution and create good view for the city. 9. Scale of the sewage system in District 2.
Table 20. The scale of the sewage system in District 2
No. Area Network Items Unit Quantity
I Thao Dien Grade 2 Pipeline
- Pipeline 500 m 7.663
- Pipeline 400 m 2.836
No. Area Network Items Unit Quantity Cross section with the existing
facilities point 18 Manhole - Manhole 500 pcs 143 - Manhole 400 pcs 56 Grade 3 Pipeline - Pipeline 300 m 29.882
Cross section with the existing facilities point 176 Manhole - Manhole 300 pcs 872 II Nam Thao Dien Grade 2 Pipeline - Pipeline 1000 m 2.199 - Pipeline 800 m 1.241
- Pipeline crossing channels m 62
Cross section with the existing facilities point 6 Manhole - Manhole 1000 pcs 44 - Manhole 800 pcs 26 Grade 3 Pipeline - Pipeline 300 m 12.413
Cross section with the existing facilities point 23 Manhole - Manhole 300 pcs 436 III Binh Trung Dong - Binh Trung Tay - Cat lai Grade 2 Pipeline - Pipeline 1200 m 1.623 - Pipeline 1000 m 1.340 - Pipeline 600 m 3.190 - Pipeline 500 m 1.946
- Pipeline crossing channels m 80
Cross section with the existing facilities point 30 Manhole - Manhole 1200 pcs 34 - Manhole 1000 pcs 26 - Manhole 600 pcs 66 - Manhole 500 pcs 42 Grade 3 Pipeline - Pipeline 300 m 41.165
No. Area Network Items Unit Quantity Cross section with the existing
facilities
point 102
Manhole
- Manhole 300 pcs 1.196
IV Other areas Grade 2
Pipeline - Pipeline 1500 m 1.679 - Pipeline 1200 m 3.528 - Pipeline 800 m 607 - Pipeline 600 m 1.201 - Pipeline 500 m 5.985 - Pipeline 400 m 3.740
- Pipeline crossing channels m 840
Manhole - Manhole 1500 pcs 41 - Manhole 1200 pcs 84 - Manhole 800 pcs 16 - Manhole 600 pcs 30 - Manhole 500 pcs 142 - Manhole 400 pcs 89
V Transition pumping station station 2