Circular No. 15/2021/TT-BXD guiding urban and concentrated residential area wastewater collection and drainage infrastructure projects.

CIRCULAR

Guidelines on urban and concentrated residential area wastewater collection and drainage infrastructure works

Pursuant to the Law on Construction promulgated on June 18, 2014; The Law Amending and Supplementing Certain Provisions of the Construction Law on June 17, 2020;

Pursuant to the Environmental Protection Law dated November 17, 2020;

Pursuant to Decree No. 81/2017/NĐ-CP dated July 17, 2017 of the Government stipulating the functions, tasks, powers, and organizational structure of the Ministry of Construction;

Pursuant to the Government Decree No. 80/2014/NĐ-CP dated August 6, 2014 on Drainage and Wastewater Treatment; Government Decree No. 98/2019/NĐ-CP dated 27 the 12 Article 2. The receipt, handling of reflections and petitions from individuals and organizations concerning administrative regulations shall be carried out in accordance with Decree No. 20/2008/NĐ-CP dated February 14, 2008 of the Government on the receipt, handling of reflections and petitions from individuals and organizations concerning administrative regulations (amended and supplemented by Decree No. 48/2013/NĐ-CP dated May 14, 2013 on amending and supplementing certain articles of decrees related to administrative procedure control and Decree No. 92/2017/NĐ-CP dated August 7, 2017 on amending and supplementing certain articles of decrees related to administrative procedure control).9 of the Government on amending and supplementing certain provisions of decrees within the technical infrastructure sector;

At the proposal of the Director of the Technical Infrastructure Department;

The Minister of Construction issues this Circular guiding on urban and concentrated residential area wastewater collection and drainage infrastructure works.

Article 1. Scope of Regulation

These Guidelines provide guidance on certain aspects of urban and concentrated residential area wastewater collection and drainage infrastructure works including requirements that must be met in construction, management, and operation activities.

Article 2. Applicability

These Guidelines apply to agencies, organizations, individuals, and households related to construction, management, and operation activities of urban and concentrated residential area wastewater collection and drainage infrastructure works.

Article 3. Explanation of Terms

In this Circular, the following terms shall be understood as follows:

1. Urban and concentrated residential area wastewater collection and drainage infrastructure works (hereinafter referred to as wastewater collection and drainage works) include connection boxes, tertiary sewers, secondary sewers, primary sewers, pumping stations, sewage separation wells, inspection wells, discharge outlets, and other auxiliary works aimed at collecting, conveying, and treating wastewater to meet national environmental technical standards for discharge into receiving water bodies.

2. Connection box is a device or inspection well constructed at the point of connection to link household sewage and stormwater pipes to the drainage system, arranged to facilitate connection and maintenance, repair, cleaning, and dredging.

3. Connecting the drainage system is linking the household drainage sewer to the drainage system.

4. Household drainage sewer is a pipeline, sewer, ditch, or canal drainage system built within the household's land area to collect sewage and stormwater and convey them to the connection point.

5. Primary sewer is the main sewer line collecting sewage from drainage catchment areas to the wastewater treatment plant.

6. Secondary sewer is the sewer transporting sewage from a drainage sub-catchment area to the primary sewer.

7. Tertiary sewer is the sewer collecting sewage from households to the secondary sewer or primary sewer.

8. Collector sewer is the primary or secondary sewer line of the common drainage system collecting all sewage during non-rainfall periods and a fixed portion of stormwater mixed with sewage during rainfall, and conveying it to the pumping station for delivery to the wastewater treatment plant.

9. Stormwater overflow well (or sewage separation well) is a facility located on the common drainage system to separate sewage for centralized wastewater treatment plants, while allowing a mixture of stormwater and sewage to overflow into receiving water bodies during heavy rainfall.

10. Specialized agency for drainage is an advisory body assisting local People's Committees at various levels in performing state management functions in the drainage and wastewater treatment sector; implementing tasks and powers delegated by higher-level state authorities.

11. Concentrated residential area mentioned herein refers to rural settlement points as defined in the Construction Law and other residential areas outside urban development zones established according to approved planning.

Article 4. Principles for managing and constructing wastewater collection and drainage works

1. Investment in constructing urban and concentrated residential area wastewater collection and drainage works must comply with urban planning, construction planning, and urban wastewater drainage planning (if available) according to each drainage basin.

2. The construction, repair, and renovation of wastewater collection and drainage works must be synchronized, ensuring connection with other works on the drainage network and wastewater treatment system; ensuring capacity to transport and treat the volume of wastewater from the area, with reserve capacity for generated wastewater volumes and achieving national technical standards for environmental quality before discharge into receiving water bodies. Encouragement is given to using trenchless construction solutions for drainage pipes, especially primary drainage pipes in old urban areas with high traffic density.

3. Existing urban and concentrated residential areas that have a common drainage network, People's Committees at all levels according to their management hierarchy are responsible for establishing and approving plans and timelines for investment, construction, upgrading, renovation, and expansion into separate or semi-separate drainage systems (constructing stormwater overflow wells, encircling sewers, and collection sewers to collect and transport wastewater to centralized wastewater treatment plants).

4. New urban and concentrated residential areas must construct separate systems for wastewater collection and treatment from stormwater drainage systems to organize connections, collection, and transportation of wastewater, meeting the drainage needs within the area, except in special cases prescribed by the Government.

Article 5. Wastewater Collection and Drainage Works

1. Stormwater Overflow Wells on Common Drainage Systems:

a) Based on current drainage conditions, topography, geology, and hydrology, determine the location for constructing stormwater overflow wells. The location for stormwater overflow wells must ensure accessibility during management, operation, and monitoring of the works, facilitate stormwater discharge into receiving water bodies, and not affect other infrastructure works;

b) Management and operation of stormwater overflow wells must comply with management and operation procedures approved by competent authorities;

c) Stormwater overflow wells must be regularly cleaned, maintained, and serviced to ensure normal operation of the works.

2. Encircling Sewers and Collection Sewers for Transporting Wastewater to Treatment Plants:

a) The location and depth of encircling sewers and collection sewers for wastewater must ensure convenience in management and operation and comply with national technical standards for infrastructure works in drainage systems;

b) The diameter, velocity, and slope of encircling sewers and collection sewers for wastewater must be calculated and checked to ensure the flow rate for collecting and transporting wastewater to centralized wastewater treatment plants without leakage into the environment;

c) Encircling sewers and collection sewers must ensure durability, tightness, and stability under load, natural conditions, and environmental corrosion over the service life of the works.

3. Discharge Outlets for Treated Wastewater into Receiving Water Bodies must be constructed in suitable locations to allow wastewater to mix with receiving water bodies without causing erosion of banks, affecting the surrounding landscape, structures, and waterway traffic activities.

4. Inspection Wells for Discharge Outlets must be constructed in convenient locations for accessing, inspecting, controlling discharges, and sampling before discharge into receiving water bodies.

5. Common Drainage Systems with Flood Control Reservoirs, stormwater must pass through stormwater overflow wells when discharged into flood control reservoirs. Water storage and level regulation in flood control reservoirs must ensure stormwater regulation tasks.

Article 6. Connection to Sewage Systems

1. Implementation of connection to sewage systems:

a) Prior to implementing the connection agreement, the drainage unit shall be responsible for inspecting the drainage capacity of the existing drainage system, ensuring that the construction of collection and drainage facilities does not affect the drainage capacity of the existing area;

b) For households connected to the drainage system within the watershed of the common drainage system, the drainage unit must provide at least one common connection point for both wastewater and stormwater. For households connected to the drainage system within the watershed of the individual drainage system, the drainage unit must provide at least one connection point to the wastewater drain and at least one connection point to the stormwater drain;

c) The height of the connection point at the connection box must be lower than the height of the household's drainage facilities. In cases where the construction project has already installed a fixed connection point, the construction project investor must comply with the foundation height of the provided connection box, ensuring the slope, ensuring that wastewater from the collection drain does not flow back into the household's facilities;

d) In cases where due to the current status of the facility or terrain, the wastewater discharge point inside the household's facility is lower than the connection box, the drainage unit shall guide the household to implement remediation measures to ensure that the household's wastewater can be connected to the drainage system in accordance with technical connection requirements;

e) The connection box must be constructed as a fixed structure at the connection point, ensuring stability, safety, and convenience for inspection, monitoring, and maintenance, preventing leakage of wastewater.

2. Requirements for connecting to the drainage system:

a) Urban areas and concentrated residential areas with their own drainage systems and centralized urban wastewater treatment plants, household wastewater must be directly connected to the connection box. In cases where upgrading and renovating the common drainage system into an individual drainage system, the owner of the drainage works shall base on the current status and drainage conditions in the upgraded and renovated area to decide on maintaining septic tanks;

b) Household wastewater drains must be connected to the connection box or other drainage facilities in areas without a connection box. Household stormwater drains must be permanently connected to the stormwater connection box, canal, ditch, or stormwater drain in the area;

c) Untreated wastewater must be connected to the collection drain of the drainage system, it must not seep into the ground or flow into other water sources;

d) Wastewater from production, business, and service establishments in urban areas and concentrated residential areas must be collected and preliminarily treated to meet urban regulations or local government regulations before being connected to the collection and drainage facilities;

e) On-site treated wastewater from production, business, and service establishments in urban areas and concentrated residential areas must meet environmental technical standards or environmental protection requirements for each type of wastewater before being connected to the collection and drainage facilities.

Article 7. Responsibilities for Managing Collection and Drainage Facilities and Connecting to Drainage Systems

1. Responsibilities of the Drainage Unit:

a) Develop technical management procedures, operation plans, and emergency response plans during the operation of the drainage system, and propose development solutions for the network according to the watershed management with specialized drainage agencies;

b) Regularly maintain collection and drainage facilities, stormwater facilities, and other facilities of the drainage system, ensuring that the facilities are always maintained in normal operation;

c) Monitor and regulate the water level of reservoirs, canals, ditches, and stormwater drains, ensuring maximum drainage and stormwater regulation capabilities, preventing flooding;

d) Manage the elevation of main drainage lines and wastewater collection drains; provide the elevation of drainage system connection points to organizations and individuals within the management area upon request.

2. Responsibilities of People's Committees at all levels:

a) People's Committees at all levels, based on their management hierarchy, are responsible for establishing and approving investment plans and timelines for upgrading, expanding, and constructing separate stormwater collection facilities and wastewater collection and treatment facilities;

b) People's Committees at all levels direct specialized drainage agencies to be responsible for guiding and inspecting the implementation of this Circular in their respective localities.

Article 8. Implementation clause

1. This Circular takes effect from February 10, 2022.

2. During the implementation of this Circular, if any issues arise, relevant agencies, organizations, and individuals shall promptly report them to the Ministry of Construction for research, guidance, and resolution./.