Thông tư 15/2021/TT-BXD hướng dẫn về công trình hạ tầng kỹ thuật thu gom, thoát nước thải đô thị, khu dân cư tập trung

CIRCULAR

Providing guidance on technical infrastructure facilities for wastewater collection and drainage in urban areas and concentrated residential areas^[1]

Pursuant to the June 18, 2014 Construction Law; and the June 17, 2020 Law Amending and Supplementing a Number of Articles of the Construction Law;

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

Pursuant to the Government’s Decree No. 81/2017/ND-CP of July 17, 2017, defining the functions, tasks, powers and organizational structure of the Ministry of Construction;

Pursuant to the Government’s Decree No. 80/2014/ND-CP of August 6, 2014, on water drainage and wastewater treatment; and the Government’s Decree No. 98/2019/ND-CP of December 27, 2019, amending and supplementing a number of articles of the Decrees regulating the field of technical infrastructure;

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

The Minister of Construction promulgates the Circular providing guidance on technical infrastructure facilities for wastewater collection and drainage in urban areas and concentrated residential areas.

Article 1. Scope of regulation

This Circular guides a number of provisions on facilities for wastewater collection and drainage in urban areas and concentrated residential areas, covering requirements to be satisfied in the construction, management and operation of these facilities.

Article 2. Subjects of application 

This Circular applies to agencies, organizations, individuals and households involved in the construction, management and operation of technical infrastructure facilities for wastewater collection and drainage in urban areas and concentrated residential areas.

Article 3. Interpretation of terms

In this Circular, the terms below are construed as follows:

1. Technical infrastructure facilities for wastewater collection and drainage in urban areas and concentrated residential areas (below referred to as wastewater collection and drainage facilities) include connection boxes, grade-3 sewers, grade-2 sewers, grade-1 sewers, water drainage pumping stations, wastewater separator wells, probe wells, sluicegates, etc., and other auxiliary facilities for use for collecting, conveying and treating wastewater up to national technical regulations on environment for discharge into receiving waters.

2. Connection box means an equipment or a test well or a probe well built at a connection point for connecting wastewater or rainwater plumbing of a water draining household to the drainage system, and arranged to help perform the connection and serve the maintenance, repair, blow-cleaning and dredging.

3. Connection to the drainage system means connection of drainage sewers from water-draining households to the drainage system.

4. Sewers of water-draining households means a system of drainage plumbing, sewers, ditches, gutters or canals built within land areas of water-draining households in order to collect and convey wastewater and rainwater to connection points.

5. Grade-1 sewers means a main sewer system for collecting and conveying wastewater from drainage basins to a wastewater treatment plant.

6. Grade-2 sewers means a sewer system for conveying wastewater for drainage areas or sub-basins to grade-1 sewers.

7. Grade-3 sewers means a sewer system for collecting and conveying wastewater from water-draining households to grade-2 or grade-1 sewers.  

8. Collector sewers means a grade-1 or grade-2 sewer system of a common drainage system for collecting the whole volume of wastewater when it is not rainy and a fixed portion of rainwater mixed with wastewater when it is rainy and conveying it to a pumping station and then to a wastewater treatment plant.

9. Rainwater overflow (or wastewater separator well) means a facility arranged in a common drainage system for separating and conveying wastewater to a concentrated wastewater treatment plant, and concurrently for overflowing the rainwater and wastewater mixture into receiving waters during a heavy rain.  

10. Specialized agency in charge of water drainage means an agency advising and assisting local People’s Committees at all levels in performing the state management of water drainage and wastewater treatment; and performing tasks and exercising powers as assigned and delegated by a superior state agency.

11. Concentrated residential area referred to in this Circular means a rural residential area as defined in the Construction Law or another residential area outside urban development zones formed under a master plan approved by a competent authority.

Article 4. Principles of management and construction of wastewater collection and drainage facilities

1. Investment in the construction of wastewater collection and drainage facilities in urban areas and concentrated residential areas must comply with urban master plans, construction master plans and master plans on wastewater drainage in urban areas (if any) in each drainage basin.

2. The construction and repair or renovation of wastewater collection and drainage facilities shall be carried out in a synchronous manner, ensuring connection with facilities in the water drainage and wastewater treatment network, and with an appropriate conveyance and treatment capacity for wastewater volumes of urban areas and concentrated residential areas, taking into account reserve capacity for  unexpectedly generated wastewater volumes in order to ensure treatment of such volumes up to national technical regulations on environment before being discharged into receiving waters. It is encouraged to apply solutions that do not require open-digging of drainage sewers, particularly grade-1 sewers in old urban quarters with busy traffic.   

3. For existing urban areas and concentrated residential areas with common water drainage networks, People’s Committees at all levels shall formulate and approve plans on and roadmaps for investment in construction, upgrading, renovation and expansion of such networks into private or semi-private ones (construction of rainwater overflows, and surrounding sewer and collector sewer systems to collect and convey wastewater to concentrated wastewater treatment plants).

4. New urban areas and concentrated residential areas are required to construct their wastewater collection and treatment systems separate from rainwater drainage systems in order to make connections, collect and convey wastewater meeting the demand for water drainage in their areas, except special cases specified by the Government.

Article 5. Wastewater collection and drainage facilities

1. Rainwater overflows in a common water drainage system:

a/ Locations for construction of rainwater overflows shall be determined based on the practical situation of water drainage, and topographic, geological and hydrological characteristics. Locations for construction of rainwater overflows must be accessible in the course of their management, operation and supervision and convenient for discharge of rainwater into receiving waters and must not affect other technical infrastructure facilities;

b/ The management and operation of rainwater overflows must comply with management and operation processes according to designs approved by competent agencies;

c/ Rainwater overflows must be dredged, repaired and maintained on a regular basis to ensure their smooth operation. 

2. Surrounding sewers and collector sewers for conveyance of wastewater to treatment plants:

a/ Positions and underground depth of surrounding sewers and wastewater collector sewers must ensure convenient management and operation and conformity with national technical regulations on technical infrastructure facilities for water drainage;

b/ Diameters, flow speed and slope of wastewater surrounding sewers and wastewater collector sewers shall be calculated and checked in order to ensure an appropriate flow of wastewater collection and conveyance to concentrated wastewater treatment plants, and avoid leakage of wastewater into the environment;

c/ Surrounding sewers and collector sewers must be durable, air-tight and stable under the impacts of carriage load, natural conditions and corrosion of the environment during their use period.

3. Sluicegates for discharging treated wastewater into receiving waters shall be constructed at appropriate positions so that wastewater can be mixed with water in the receiving waters and cause neither bank erosion nor impacts on the surrounding environment, landscape and facilities and traffic activities in water bodies.

4. Probe wells of wastewater sluicegates shall be constructed at positions convenient for access to, inspection and control of wastewater sources and sampling before wastewater is discharged into receiving waters.

5. For common water drainage systems connected to detention reservoirs, before being discharged into such detention reservoirs, rainwater must go through overflows. The storage of water and regulation of water level of detention reservoirs must ensure the rainwater regulation.

Article 6. Connection of water drainage systems

1. Performance of connection of water drainage systems:

a/ Before implementing agreements on connection, water drainage units shall check the drainage capacity of existing water drainage systems and ensure that the construction of wastewater collection and drainage facilities does not affect the drainage capacity of existing areas;

b/ For water-draining households in basins of common drainage systems, water drainage units shall provide at least one connection point for both wastewater and rainwater. For water-draining households in basins of private drainage systems, water drainage units shall provide at least one point of connection to wastewater sewers and at least one point of connection to rainwater sewers;

c/ The elevation of a connection point at a connection box must be lower than that of facilities of water-draining households. By the time of construction of a facility, if a fixed connection point is available, the facility owner shall ensure the base elevation of the provided connection box and slope, preventing wastewater from flowing from collector sewers back to facilities of water-draining households;

d/ In case the elevation of a wastewater discharge point inside the facility of a water-draining household is lower than that of the connection box due to the situation of the facility or local terrain, the water drainage unit shall guide the water-draining household in taking remedial measures so that its wastewater can be connected to the drainage system, meeting requirements on connection technique;

e/ Connection boxes shall be constructed at fixed positions of connection points, ensuring stability, safety and convenience for inspection, supervision and maintenance and avoiding wastewater leakage.

2. Requirements on connection of water drainage systems:

a/ Urban areas and concentrated residential areas may have their private water drainage systems and concentrated municipal wastewater treatment plants with domestic wastewater of water-draining households directly connected to connection boxes. In case of upgrading or renovation of common water drainage systems into private water drainage systems, drainage facility owners shall base themselves on the water drainage situation and conditions in areas with upgraded or renovated facilities to decide on maintenance of septic tanks;

b/ Wastewater sewers of water-draining households shall be connected to connection boxes or other wastewater drainage facilities in areas where no connection boxes are available. Rainwater sewers of water-draining households must be connected at fixed positions of connection boxes for rainwater drainage, canals, gutters or rainwater sewers in such areas;

c/ Untreated wastewater shall be connected to collector sewers of the water drainage system, ensuring that it is not permeated into underground soil or does not flow into other water sources;

d/ Wastewater of production, business or service establishments in urban areas and concentrated residential areas shall be collected and preliminarily treated in accordance with regulations of such urban areas or local administrations before being connected to wastewater collection and drainage facilities;

e/ After being treated on the spot, wastewater of production, business or service establishments in urban areas and concentrated residential areas must meet technical regulations on environment or environmental protection requirements for each type of wastewater before being connected to wastewater collection and drainage facilities.

Article 7. Responsibility to manage wastewater collection and drainage facilities and connection of water drainage systems

1. Responsibilities of water drainage units:

a/ To develop the process of technical management and operation, formulate plans on prevention of and response to environmental incidents in the course of operation of the drainage systems, and propose solutions to develop the drainage network for basins under their management to specialized agencies in charge of water drainage;

b/ To regularly maintain wastewater and rainwater collection and drainage facilities and other facilities of the drainage system, ensuring that these facilities are always in smooth operation;

c/ To monitor, supervise and regulate water levels of detention reservoirs, drainage canals, gutters and sewers, ensuring the maximum rainwater drainage and drainage regulation capacity and preventing inundation;

d/ To manage elevations of main sewers and wastewater and rainwater collector sewers; to provide information on elevations of connection points of drainage systems to organizations and individuals that so request in areas under their management.

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

a/ To formulate and approve plans on and roadmaps for investment in the construction, upgrading, renovation and expansion of private rainwater collection facility systems and wastewater collection and treatment facilities;

b/ To direct specialized agencies in charge of water drainage in guiding and inspecting the implementation of this Circular in their localities.

Article 8. Implementation provisions             

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

2. Any problems arising in the course of implementation of this Circular should be promptly reported to the Ministry of Construction for study, guidance and settlement.-

For the Minister of Construction
Deputy Minister
LE QUANG HUNG