Some standard content:
National Standard of the People's Republic of China
Outdoor Drainage Design Code
GBI14-87
(1997 Edition)
Editor: Shanghai Construction Commission
Approval Department: State Planning Commission of the People's Republic of China Effective Date: December 1, 1987
5-2—1
Announcement No. 12 on Partial Revision of National Standards for Engineering Construction
National Standard "Outdoor Drainage Design Code" GBJ14—87 has been partially revised by Shanghai Municipal Engineering Design Institute in conjunction with relevant units. It has been reviewed by relevant departments and the partially revised provisions are now approved for implementation on March 1, 1996. The provisions of the corresponding provisions in the code are repealed at the same time. This is hereby announced.
Notice on Issuing the "Outdoor Drainage Design Code" No. 666 of the Ministry of Construction of the People's Republic of China (1987)
According to the "Notice on Issuing the Compilation and Revision Plan of National Standards for Engineering Construction from 1982 to 1985" (No. 546 of the former State Construction Commission (81) Construction Development and Construction), the "Outdoor Drainage Design Code" TJ14-74 (Trial) revised by the Shanghai Construction Commission and relevant departments has been revised and has been reviewed by relevant departments. The revised "Outdoor Drainage Design Code" GBJ14-87 is now approved as a national standard and will be implemented from December 1987. The original "Outdoor Drainage Design Code" T14-74 (Trial) was abolished by the Ministry of Construction of the People's Republic of China on December 5, 1997.
This code is managed by the Shanghai Construction Commission, and the specific interpretation work is the responsibility of the Shanghai Municipal Engineering Design Institute. The publication and distribution is organized by the Basic Construction Standards and Quotas Research Institute of our Commission.
National Planning Commission
April 28, 1987
Revision Notes
This specification is based on the Notice No. 546 of the former National Capital Construction Commission (81), edited by the Shanghai Municipal Construction Commission, and specifically published by the Shanghai Municipal Engineering Design Institute in conjunction with design, colleges and universities and other relevant units, to revise the "Outdoor Drainage Design Specification" TJ14-74 (Trial).
Since the original specification was put into trial use in 1974, the specification management group has organized relevant units across the country to carry out scientific research cooperation according to the unified plan, and conducted investigations and necessary scientific experimental research. On the basis of the above work, in the process of revising this specification, the specification compilation group further conducted relatively extensive investigations and key tests, carefully summarized domestic and foreign scientific research results and engineering practice experience, referred to and learned from relevant foreign standards and materials, and widely solicited opinions from relevant units across the country. After several discussions and revisions, it was finally reviewed and finalized by our commission and relevant departments.
This specification is divided into eight chapters and five appendices. The main contents of this revision include: adding two chapters on site selection and overall layout of sewage treatment plants and sludge treatment structures, and five sections on drainage of grade-separated roads, channels, biofilm method, oxygen supply facilities and sludge return facilities; modifying the statistical method of the rainstorm intensity formula and the selection of the recurrence period, the minimum design flow rate, pipe diameter and slope of the drainage pipe, the water quality index of domestic sewage, and the design parameters of treatment structures such as digestion tanks; deleting the formula for calculating the rainstorm intensity by the humidity saturation difference method, acid-magnetic sewage: cyanide-containing sewage, chromium-containing sewage, mixing tank, reaction tank, domestic sewage fish farming and flat-plate surface mechanical heaters.
During the implementation of this specification, if you find that there is a need for modification or supplementation, please send your opinions and relevant information to the National Standard Management Group of the Outdoor Water Supply and Drainage Design Specification of Shanghai Municipal Engineering Design Institute for reference when revising it.
Shanghai Construction Committee
February 4, 1987
Parameters of the rainstorm intensity formula
Parameters of the rainstorm intensity formula
Parameters of the rainstorm intensity formula
Catchment area
BODs of aeration tanksVolume load
BODs of aeration tanksSludge load
Flow depth
Hydraulic gradient
Rainfall intensity
Influent BODs
Reduction factor
Average concentration of suspended solids in mixed liquor in aeration tankParameters of the rainstorm intensity formula
Roughness coefficient
Interception multiple
Design recurrence period
Design flow Quantity
Industrial wastewater in the combined pipe
Dry flow sewage before the overflow well
Domestic sewage in the combined pipe
Designed rainwater in the combined pipe
Total design flow of the combined pipe
Dry flow sewage after the overflow well
Designed rainwater volume of the catchment area after the overflow well Flow of the pipe section after the clear flow
Designed rainstorm intensity
Hydraulic radius
Rainfall duration
Ground water collection time
Rainwater prevalence time in the pipe
Volume of aeration tank
Runoff coefficient
5-—2--3
Chapter I General Provisions
Chapter II Discharge|| tt||Section 1 Quantity of domestic sewage and industrial wastewater Section 3 Rainwater
Section 1
Section 3
Section 4
Section 5
Section 6
Section 7
Section 8
Section 9
Section 10
Combined flow
Drainage pipes and their ancillary
Structures
General provisions
Hydraulic calculation
Inspection well
Drop well
Water seal well
Water outlet
Grasscross road drainage
Inverted siphon
Section 12
Chapter 4
Section 1| |tt||Section 3
Chapter 5
Chapter 6
Section 3
Section 4
Pipeline Integration
Drainage Pumping Station
·General Provisions
Collection Tank
1 Electric 1
Site Selection and
Overall Layout of Sewage Treatment Plant
Sewage Treatment Structures
·General Provisions
Grit Tank
Sedimentation Tank
·General Provisions
(H) Sedimentation Tank
(II) Inclined Plate (Tube) Sedimentation Tank
(N) Double-layer Sedimentation Tank
Section 5 Biofilm Method
·General Provisions
5—2 ---4
2—-5
-2—6
5—2-6
5—2—7
-2—8
5—2—8
5-2—8
5--2—8||t t||5—2—9
5—2—9
2—10
2—10
-2—10
-2—11
-2—11
5—2-11
5— 2-11
5--2--12
5-2-12
5—2-12
(II) Biological filter
(III) Biological rotary table
(IV) Biological contact oxidation tank
Section VI
Activated sludge process
(I) General provisions
(II) Aeration tank
Section VII
Oxygen supply facilities
General provisions
(I) Blower room
Section VIII
Section 9
Section 10
Return sludge and excess sludge
Stabilization pond
Irrigation field
Section 10
Chapter 7
Section 1
Section 2
Section 3
Section 4
Section 5
Sludge treatment structures
General provisions
-2—12
5--2—13
5-2—13
-2-—13
5-- 2-13
5-2—13
-2—-13
-2—14
5--2-14
2—-14
-2—15
5—215
Sludge thickening tank and wet sludge tank5-2—15
Digestion tank…
Sludge drying field
Sludge mechanical dewatering
(I) General provisions
(II) Vacuum filter,
(III) Filter press
+* 5--2-—15
....5—2—15
.... 5-215
.... 5--2—15
...... 5--2-16
....... 5--2-16
Chapter VIII Oily Wastewater and Phenol-Containing Wastewater. 5--2—16 Appendix
Appendix III
Appendix III
Appendix IV
Compilation Method of Rainstorm Intensity Formula
Minimum Clearance Distance between Drainage Pipes and Other Underground Pipelines
5--2—16
(Structures)
..... 5-2-16
Permissible Concentration of Hazardous Substances in the Influent of Biological Treatment Structures
...... 5—2-16
The conversion relationship between commonly used non-legal measurement units and legal measurement units:
Appendix 5 Explanation of terms used in this code
Additional notes List of the editorial unit, participating units and main
drafting persons of this code
52--17
5—2—17
5---217
Chapter 1 General
Article 1.0.1 This code is specially formulated to ensure that the design of drainage projects in my country complies with national guidelines, policies and laws and meets the requirements of preventing water pollution, improving and protecting the environment and improving people's health.
Article 1.0.2 This specification applies to the design of permanent outdoor drainage projects in newly built, expanded and renovated towns, industrial enterprises and residential areas. Article 1.0.3 The design of drainage projects should be based on the approved local town (region) master plan and drainage project master plan. From the overall perspective, according to the planning period, project scale, economic benefits, environmental benefits and social benefits, the relationship between towns, industry and agriculture, concentration and dispersion, treatment and utilization, short-term and long-term should be properly handled. Through comprehensive demonstration, it can be ensured that the environment can be protected, the technology is advanced, the economy is reasonable, and it is safe and applicable.
Article 1.0.4
The choice of drainage system (divided flow system or combined flow system) should be determined based on the planning of towns and industrial enterprises, local rainfall conditions and emission standards, existing drainage facilities, sewage treatment and utilization conditions, terrain and water bodies, etc. Different drainage systems can be adopted in different areas of the same town. The drainage system in the newly built area should adopt the diverted flow system.
Article 1.0.5 The design of drainage system shall comprehensively consider the following factors: 1. Coordinate with the treatment and disposal of sewage and sludge in the adjacent areas. 2. Comprehensively utilize or reasonably dispose of sewage and sludge. 3. Coordinate with the water supply system, flood and water removal system in the adjacent areas and regions.
4. The possibility of accepting industrial wastewater and conducting centralized treatment and disposal. 5. Appropriately transform the original drainage engineering facilities to give full play to their engineering efficiency. Article 1.0.6 The water quality of industrial waste ice connected to the urban drainage system shall not affect the normal operation of urban drainage pipes and sewage treatment plants; shall not cause harm to maintenance and management personnel; shall not affect the discharge and utilization of treated effluent and sludge, and its water quality shall be implemented in accordance with relevant standards.
Article 1.0.7
When the industrial wastewater pipeline is connected to the urban drainage system, it must be connected to the corresponding urban drainage pipeline according to the water quality. The sewage pipeline should minimize the outlets, and the quantity detection facilities should be installed before connecting to the urban drainage pipeline. Article 1.0.8 The design of drainage engineering should actively adopt the new technologies, processes, materials and equipment that have been verified and are effective, based on the continuous summary of scientific research and production practice experience. Article 1.0.9 The degree of mechanization and automation of drainage engineering equipment should be determined through comprehensive technical and economic comparisons based on the needs of management, the quality and supply of equipment and materials, and the specific local conditions. For the main processes that are heavy to operate, affect safety and endanger health, mechanized and automated equipment should be used first. Article 1.0.10 In addition to being implemented in accordance with this code, the design of drainage engineering should also comply with the relevant standards, specifications and regulations currently in force in the country. Article 1.0.11 When designing drainage engineering in earthquake-prone areas, collapsible loess, expansive soil, permafrost and other special areas, the provisions of the current relevant special specifications should also be met.
Chapter 2 Drainage
Section 1 Domestic Sewage and Industrial Heating Water Article 2.1.1 The domestic sewage quota and comprehensive domestic sewage quota shall be determined based on the local water quota, combined with the level of water supply and drainage facilities inside the building and the degree of popularization of the drainage system. It can be adopted at 80%~90% of the local water quota. Article 2.1.2 The total variation coefficient of domestic sewage volume should be adopted according to Table 2.1.2. The determination of the amount of domestic sewage and shower sewage in industrial enterprises shall be coordinated with the relevant provisions of the current "Outdoor Water Supply Design Code" in China. Average daily flow of sewage (1/s)
Total variation coefficient
Total variation coefficient of domestic sewage
Table 2.1.2
1100| 200 | 500 /≥1000
2.32.01.81.71.61.51.4
Note, ①When the average daily flow of sewage is an intermediate value. The total variation coefficient is obtained by internal elimination 2) When there is actual data on the variation of domestic sewage in the residential area, it can be adopted according to the actual data, 1.3
Article 2.1.4 The industrial wastewater volume of industrial enterprises and its total variation coefficient should be determined according to the process characteristics and coordinated with the relevant provisions of the current national industrial water consumption. Article 2.1.5 In areas with high groundwater levels, it is appropriate to consider the amount of groundwater infiltration.
Section 2 Rainwater Quantity
Article 2.2.1 The design flow of rainwater shall be calculated according to the following formula: Q = q4F
Design flow of rainwater (L/s);
Design rainstorm intensity (L/s·ha);
Runoff coefficient;
Catchment area (ha).
Note: When there is production burst water discharged into the toilet water pipe, its water volume shall be included in the calculation. (2. 2. 1)
Article 2. 2. 2 The runoff coefficient can be adopted according to Table 2. 2. 2-1. The average runoff coefficient of the catchment area is calculated by weighted average according to the ground type: the comprehensive runoff coefficient of the region can be adopted according to Table 2.2.2-2.
Runoff coefficient
Ground types
Various roofs, concrete and asphalt pavement
Phase-free pavement with large stone and asphalt surfacesGraded gravel pavement
Dry masonry and gravel pavement
Unpaved ground
Public or green space
Comprehensive runoff coefficient
Regional conditions
0. 5 ~ 0. 8
0. 4 ~ 0. 6
The design rainfall intensity shall be calculated according to the following formula Article 2.2.3
167A,(1 + Clg P)
(t +b)n
Formula China
Design rainstorm intensity (L/s·ha);
-Rainfall duration (min);
Design recurrence period (a);
Table 2. 2. 2-1
Table 2. 2. 2-2
a parameter, calculated according to statistical methods. In areas with Ar, C, n, b-
automatic rainfall records for more than ten years, the rainstorm intensity formula can be compiled according to the relevant provisions of Appendix 1 of this specification.
Note that in areas with less than ten years of automatic rainfall records, data from nearby areas with similar meteorological conditions can be used. Article 2. 2. 4
The design recurrence period of rainwater pipes and canals should be determined based on factors such as the nature of the catchment area (square, road, factory area, residential area), terrain characteristics and meteorological characteristics. In the same drainage system, a double recurrence period or different recurrence periods can be used. The recurrence period is generally selected as 0.5 to 3 years. For major roads, major areas or areas where short-term waterlogging can cause serious consequences, it is generally selected as 2 to 5 years, and it should be coordinated with the road design. Note: The particularly important areas and secondary areas can be increased or decreased according to the situation. Article 2.2.5 The design rain release duration of the rainwater pipe should be calculated according to the following formula: t = t + mt2
5—2—5
Rainfall duration (min);
Surface water collection time (min), depending on the distance, terrain slope and ground coverage,
\-Generally 5~15 min:
Reduction coefficient, concealed pipe reduction coefficient m=2, open channel reduction coefficient m=1.2:
Rainwater prevalence time in the pipe (min).
Note: In the area of broken slopes. When using the omission pipe, the reduction coefficient m-1.2 ~ 2. The total design flow of the combined pipe should be calculated according to the following formula: Article 2.3.1
Q, = Q, + Q, + Q, = Q: + Q,
-total design flow (L/s);
Q. ---design domestic sewage volume (L/s),
-assuming T. industrial water volume (1./s);
-design rainwater volume (L/s);
dry flow sewage volume before the overflow well (L/s). (2.3.1)
Article 2.3.2 The flow rate of the overflow and the start-up pipe section shall be calculated according to the following formula: (2.3.2)
Q' = (n. + 1Q + Q, +Q
Q\, the flow rate of the pipe section after the overflow well (L/s) Wuzhong
n. ·Interception multiple, that is, the ratio of the amount of water intercepted at the beginning of overflow to the amount of dry flow sewage:
The design rainwater volume of the catchment area after the overflow well (L/s), the amount of dry flow sewage after overflow and (1. /s). Article 2.3.3 The interception multiple n. shall be determined by calculation based on the water quality and water volume of early flow sewage and its total variation coefficient, water body hygiene requirements, hydrological and meteorological conditions, etc., and generally adopts 1 to 5.
Article 2.3. 4. The rainwater design recurrence period of the flow pipe can be appropriately higher than the rainwater design recurrence period of the rainwater pipe under the same conditions.
Section 3
Drainage pipes and their ancillary structures
Section 1 General Provisions
Article 3.1.1 The drainage pipe system shall be uniformly arranged and constructed in phases according to urban planning and difficult construction conditions. The drainage channel shall be designed according to the long-term water volume. Article 3.1.2 The plane position and elevation of the pipe shall be determined based on comprehensive consideration of factors such as topography, road construction conditions, soil quality, groundwater level, existing and planned underground facilities, and construction conditions.
Article 3.1.3 The materials of the pipe and its ancillary structures, pipe joints and foundations shall be selected based on factors such as drainage water quality, water temperature, freezing conditions, cross-sectional dimensions, pressure inside and outside the pipe, soil quality, groundwater level, groundwater erosion and construction conditions, and shall be sourced locally as much as possible.
Article 3. Article 1.4 Pipes and canals for conveying corrosive sewage must be made of corrosion-resistant materials, and their joints and adjacent structures must take corresponding anti-corrosion measures. Article 3.1.5 When conveying sewage that is prone to precipitation in the pipe, the determination of the pipe nest form and cross-section must take into account the convenience of maintenance and inspection. Article 3.1.6 Production sewage within the factory area should be equipped with dedicated sewage pipes according to its different recycling, utilization and treatment methods. Rainwater from sites that are often contaminated by harmful substances should be connected to the corresponding sewage pipes after pretreatment. Article 3.1.7 The design of rainwater pipes and combined pipes should take into account gravity discharge as much as possible. When calculating the water level of a water body, the water level changes caused by existing and planned reservoirs and other water conservancy facilities should be considered at the same time. When the water level is supported by the water body, tidal gates, vents or pumping stations should be installed according to the regional oxygen demand and the consequences of water accumulation. Article 3.1. 8. When designing sewer pipes, it is possible to combine urban planning and use lakes and ponds to store rainwater. Article 3.1.9 An emergency outlet should be set on the sewage pipe system. Article 3.1.10 A flow connecting pipe can be set between water pipe systems or between combined pipe systems as needed. If necessary, a shut-off valve or gate can be set at the connecting pipe. The connecting pipe and the attached gate should also be convenient for maintenance and management. Article 3.1.11 When designing sewage pipes, for each independent system or pipeline with a heavy pumping station, a flow metering facility should be set at the total outlet. Section 2 Hydraulic Calculation
Article 3.2.1 The flow velocity of drainage pipes and canals shall be calculated according to the following formula: VElRtt
Wherein, v=
-flow velocity (m/s); R—-hydraulic radius (m); 1—hydraulic gradient, and roughness coefficient. The roughness coefficient of the pipe and canal should be adopted according to Table 3.2.2. Article 3.2.2 Pipeline composition coefficient Pipeline type Asbestos cement pipe, copper pipe Commercial soil, iron pipe Concrete pipe, concrete pipe Water-mixed mortar plastering Coefficient 0.D120.014 0.013~ 0.014 Pipeline type Brick road Block stone road Dry foundation block stone road (including with turf) Table 3.2.2 Composition coefficient 0.020~0. 025
0. 0250. 030
Case 3. 2. 3 The maximum design filling degree and super height of the drainage pipe shall comply with the following provisions:
1. The sewage pipe shall be calculated based on the non-full flow, and its maximum design filling degree shall be adopted according to Table 3.2.3.
2. The rainwater pipe and combined pipe shall be calculated based on the full flow. Maximum design filling degree
Diameter of pipe height (mm)
200~300
350~450
50~900
Table 3. 2. 3
Maximum design filling degree
Note: When calculating the filling degree of the sewage pipe, the water volume that suddenly increases due to excess or in a short period of time is not included. However, when the pipe diameter is less than or equal to 300 m, it shall be reviewed according to the full flow. 3. The height of the open channel shall not be less than 0.2 m. Article 3.2.4 The maximum design flow rate of the drainage pipe shall comply with the following provisions: 1. Metal pipe: 10 m/sl
2. Non-metal pipe: 5 m/s.
The maximum design flow rate of the drainage open channel shall comply with the following provisions Article 3.2.5
1. When the water flow depth is 0.4 ~1.0 m, it is advisable to adopt according to Table 3.2.5. Design flow concept of open channel
Coarse sand
Silty clay
Lime or medium sandstone
Turf surface
Dry-turned boulders
Mortar iodine boulders acid mortar
Concrete
Table 3.2.5
Maximum design flow rate (m/s)
2. When the water flow depth is outside the range of 0.4~~1.0 m, the maximum design flow rate listed in Table 3.2.5 should be multiplied by the following coefficients:
1.0h<2.0 m
h≥2.0 m
where: h is the water density.
Article 3.2.6 The minimum design flow rate of drainage pipes and canals shall comply with the following provisions: 1. The design flow rate of sewage pipes is 0.6 m/s at the design fullness. For the management of production wastewater with full-scale, mine-exposed or heavy-duty licenses. The minimum design flow rate should be appropriately increased.
The design flow rate of rainwater pipes and combined pipes is 0.75 m/s at full flow. 2.
3. The design flow rate of open channels is 0.4 m/s.
Note: When the flow rate in the starting sewage pipe section is not sufficient to meet the above requirements, it shall comply with the requirements of Article 3.2.9 of this Regulation.
(When the designed flow rate is not sufficient to meet the minimum design requirements, additional cleaning measures shall be provided.
The design flow rate of the pressure sludge pipe for domestic sewage can generally be adopted according to the minimum design flow rate of the pressure sludge pipe.
Water content of sewage (%)
Article 3.2.8
Article 3.2.9
3.2.9.
Seawater pipe
Water pipe and combined pipe
Two-inlet connecting pipe
Pressure mixing pipe
Table 3.2. 7
Minimum design velocity (m/a)
Diameter 300 ~ 400 mm
Diameter 15~~250mm
The design velocity of the pressure pipeline should be 0.7~1.5m/s. The minimum pipe diameter and minimum design slope of the pipeline shall be in accordance with the table Minimum equal diameter and minimum design slope
In the neighborhood and factory area
Under the road
Minimum pipe diameter (mm)
Table 3. 2. 9
Minimum design slope
Note: 1> If the pipeline slope does not meet the above requirements, it can be reduced. However, there should be anti-vibration and silt removal values. ② The minimum design slope of the gravity pipeline is 0.01 Article 3.2.10
At the place where the slope of the pipeline becomes steeper, its diameter can be changed from large to small according to hydraulic calculation, but it shall not exceed 2 levels and shall not be less than the minimum diameter. Section 3 Pipeline
Article 3.3.1 Inspection and connection of pipelines of different diameters should be connected by water surface or pipe top flat connection.
Article 3.3.2 At the turning and intersection of pipelines, the water flow angle shall not be less than 90°. Note: When the pipe diameter is less than or equal to 300 mm and the water head is greater than 0.3 m, this restriction can be exempted. Article 3.3.3 The foundation of the pipeline should be determined according to the geological conditions. For areas with soft foundation or uneven settlement, reinforcement measures shall be taken for the foundation or foundation, and flexible interfaces shall be used for pipeline interfaces.
Article 3.3.4 When designing combined pipes, backflow of household pipes should be prevented under pressure flow conditions.
Article 3.3.5
Article 3.3.6
Sewage pipes and combined pipes should be equipped with ventilation facilities as required. The minimum soil cover thickness on the top of the pipe should be determined based on external loads, pipe strength, soil freezing conditions, and other conditions, combined with local pipe burial experience. Under the roadway, it should generally not be less than 0.7m
Note: When the freezing line of the soil is very high (or the freezing line is obvious but there are insulation measures), and the pipeline is guaranteed not to be damaged by external loads, the soil cover thickness can be reduced. Article 3.3.7 The buried depth of sewage pipes in the frozen layer shall be determined according to factors such as flow rate, water temperature, water flow conditions and laying location, and shall generally comply with the following provisions:
For domestic sewage pipes without insulation measures or industrial water pipes with water temperature close to that of domestic sewage, the bottom of the pipe can be buried 0.15m above the freezing line. For pipes with insulation measures or higher water temperature, the distance above the freezing line can be increased, and its value shall be determined based on the experience of the region or regions with similar conditions. Article 3.3.8 When burying Lishui pipes in the frozen layer, if there are measures to prevent freezing expansion from damaging the pipes, they shall be buried above the freezing line. Article 3.3.9 When designing pressure pipes, the influence of water hammer shall be considered. Exhaust devices shall be installed at the high points of the pipelines and at regular intervals; emptying devices shall be installed at the low points of the pipelines and at regular intervals. Article 3.3.10 The socket-and-spigot pressure pipe shall be designed to determine whether to set a buttress at the bend in the vertical or horizontal direction according to factors such as pipe diameter, turning angle, pressure test standard and friction of the interface. Article 3.3.11 When the pressure pipe is connected to the gravity pipe channel, there shall be energy dissipation facilities. The location of the four-section inspection well shall be set at the intersection of the channel, the turning point, the change of pipe diameter or slope, the waterfall and a certain distance on the straight pipe section. Note: In combination with regional planning, reserve a branch pipe near the planned building. Add a branch pipe, and the maximum spacing of the straight pipe section shall be determined according to the specific situation. Generally, it is recommended to adopt it according to Table 3.4.2.
Article 3.4.3 Inspection and the dimensions of each part shall meet the following requirements: ", parallel, the dimensions of the well casing and well chamber shall be convenient for maintenance and inspection, the dimensions and positions of the ladder and footrest shall be convenient for maintenance and up and down safety: 2. The height of the inspection room is generally 1.8 m when the pipeline burial depth permits. The sewage inspection well is calculated from the top of the flow channel, and the rainwater (combined) inspection well is calculated from the bottom of the pipe. Inspection and maximum spacing
Pipe diameter or clear height
200~-400
500700
8001000
1100~1500
>1500, and ≤2 000
Sewage pipeline
Table 3. 4.2
Maximum spacing (ml)
Rainwater (combined) pipe construction
Note; When the pipe diameter or the clear height of the channel is greater than 200 mm. The maximum spacing of the inspection wells can be appropriately increased. Article 3.4.4
A flow channel should be set at the bottom of the inspection well. The flow head of the sewage inspection well can be level with 0.85 times the diameter of the large pipe, and the flow channel of the rainwater (combined) inspection well can be level with 0.5 times the diameter of the large pipe. The width of the flow channel head should meet the maintenance requirements. Article 3.4.5 At the turning point of the pipe, the bending radius of the center line of the flow channel in the inspection well should be determined according to the size of the corner and the diameter of the pipe, but should not be less than the diameter of the large pipe. Article 3.4.6 For inspection wells located near the vehicle and frequently opened and closed, iron and steel covers should be used. When outside the road, it can be higher than the ground according to the specific situation. Article 3.4.7
A measurement channel can be set.
Article 3.4. 8
More than 3.
In the inspection wells at appropriate intervals in the sewage main pipe. When necessary, the number of branch pipes (household pipes or connecting pipes) connected to the inspection well should not be more than Section 5 Waterfall Wells
When the water head of the pipeline waterfall is 1 to 2 m, it is advisable to set up a waterfall. When the water head is greater than 2.0m, a waterfall well must be set up. Waterfall wells should not be set up at the pipe turning point. Section 3.5.2
When the diameter of the water inlet pipe of the waterfall well is not greater than 200mm, the height of the water head of the waterfall shall not be greater than 6m; when the pipe diameter is 300~400mm, it should not be greater than 4 at a time. Tn. The water drop can generally be in the form of a vertical or rectangular trough. When the pipe diameter is greater than 400mm, the water head height and water drop method of the first drop shall be determined according to hydraulic calculation. Section 6 Water Seal WellsWww.bzxZ.net
Article 3.6.1 Element
When the production sewage can produce gas that can cause explosion or fire! A water seal well must be set up in its pipeline system. The water seal should be located at the outlet where the above sewage is produced and at appropriate intervals on the main pipe. Article 3.6.2 The water seal depth should be 0.25m, and ventilation facilities should be installed on it. A sludge tank should be installed at the bottom of the well.
Water seal wells and other inspection wells in the pipeline system should not be located on the roadway or in areas with a large number of pedestrians, and should be appropriately away from places where open flames are generated. Article 3.6.3
Section 7 Rainwater Inlets
Article 3.7.1 The type, quantity and layout of rainwater inlets shall be determined according to the flow generated by the catchment area, the drainage capacity of the rainwater gate and the road type! Article 3.7.2 The distance between rainwater inlets should be 25~50 m. The number of rainwater inlets connected in series by connecting pipes should not exceed 3. The length of the rainwater inlet connecting pipe should not exceed 25 m. Note: In low-injection and waterlogging areas, two water inlets should be appropriately increased as needed. Article 3.7.3 When the longitudinal slope of the road is greater than 0.02, the distance between rainwater inlets can be greater than 50 m, and its type, quantity and layout should be determined according to specific conditions and calculations. When the slope section is short, water can be collected at the lowest point, and the number or area of rainwater inlets should be appropriately increased. Article 3.7.4 The depth of the rainwater inlet should not be greater than 1m, and a sedimentation trough should be set as needed. When shallow burial is required in special circumstances, reinforcement measures should be taken. The depth of the Lishui outlet in areas affected by frost heave can be determined based on local experience. Section 8 Water Outlet
Article 3.8.1 The location, type and outlet flow rate of the drainage pipe outlet should be determined based on drainage water quality, downstream water use, water flow and water level change amplitude, dilution and self-purification capacity, water flow direction, wave conditions, terrain changes and meteorological factors. Article 3.8.2 The outlet should take measures such as anti-scouring, energy dissipation and reinforcement; when extending into the river, signs should be set up.
Article 3. 8. 3 The outlet in areas affected by frost heave should be built with frost-resistant materials, and the foundation of the outlet must be set below the freezing line. Section 9 Drainage of Grade Separation Roads
Article 3.9.1 Drainage of grade separation roads shall exclude surface runoff water in the catchment area and groundwater that affects the function of the road. Its form shall be determined according to local planning, on-site hydrogeological conditions, interchange type and other engineering characteristics. Article 3.9.2 Calculation of surface runoff volume of grade separation drainage shall comply with the following provisions:
1. The design volume recurrence period is 1~5 years, and a higher value shall be adopted for important parts. Different parts of the same grade separation project may adopt different recurrence periods; 2. The surface water collection time shall be 5~10 minutes; 3. The runoff coefficient shall be 0.8~1.01
4. The catchment area shall be reasonably determined, and a system with high water and high drainage and low water and low drainage that are not connected to each other shall be adopted, and reliable measures shall be taken to prevent high water from entering the low water system. Article 3.9.3 Drainage of grade separation tunnels shall be equipped with an independent drainage system, and its outlet shall be reliable.
Article 3.9.4
When the lowest point of the grade separation tunnel project is below the groundwater level, measures should be taken to drain water or lower the groundwater level. Section 10 Example of siphon
Article 3.10.1
Inverted siphons passing through rivers should generally not be less than two. One inverted siphon can be used for siphons passing through valleys, early ditches or small rivers. Note: Siphons passing through obstacles should also comply with relevant regulations on intersections with the obstacles. Article 3.10.2 The design of inverted siphons should meet the following requirements: 5-2 8
1. The minimum pipe diameter should be 200mm;
2. The design flow velocity in the pipe should be greater than 0.9 m/s and should be greater than the flow velocity in the water inlet pipe. When the design flow velocity in the pipe cannot meet the above requirements, regular flushing measures should be added, and the flow velocity during flushing should not be less than 1.2 m/s. 3. The distance between the top of the inverted siphon and the planned riverbed should generally not be less than 0.5m. When passing through a navigation channel, its position and the distance between the top of the pipe and the planned riverbed should be determined in consultation with the local shipping management department, and signs should be set up. Anti-scouring measures should be considered to avoid scouring the riverbed; 4. Inverted siphons should be equipped with accident discharge outlets. Article 3.10.3 When a combined sewer is equipped with an inverted siphon, the flow rate shall be calibrated according to the amount of dry-flow sewage.
Article 3.10.4 The net height of the inspection room of the inlet and outlet of the inverted siphon should be 2 m. When the inlet and outlet are deep, an inspection platform should be set inside the well, and its width should meet the inspection requirements. When the inverted siphon is a double line, the center of the manhole cover should be set on the center line of each pipe. Article 3.10.5 A sluice or gate should be set in the inlet and outlet well of the inverted siphon. Article 3.10.6
A sludge trough should be set in the inspection well before the inlet and outlet of the inverted siphon. Section 11 Channels
Article 3.11.1 In areas with flat terrain, limited burial depth or outlet depth, nest channels (open channels or cover nests) can be used to drain Lishui. Yiban Channels should be made of local materials, and the structure should be easy to maintain. The channel wall can be built together with the roadside stone. Article 3.11.2 The bottom width of open channels and covered channels should not be less than 0.3m. The side slope of unpaved open channels should be adopted according to Table 3.11.2 according to different geology: the side slope of open channels paved with bricks or concrete blocks can be 1.075~1.11. Article 3.11.3 When channels are connected to culverts, the following requirements should be met: 1. When channels are connected to culverts, the influence of cross-section contraction, flow velocity changes and other factors on the water surface of the open channel caused by the blockage should be considered; 2. The cross-section of the culvert should be calculated according to the discharge volume when the channel water surface reaches the design super height; 3. Retaining walls, slope protection and bottom protection should be set at both ends of the culvert; 4. The culvert should be made into a square shape. If it is a round pipe, the bottom of the pipe can be appropriately lower than the bottom of the channel, and the lowered part will not be included in the water-passing section.
Open slope
Loose fine sand, medium sand and coarse sand
Dense fine sand, medium sand, coarse sand or clayey silt Silty clay or claystone or quartz
Semi-lithic soil
Weathered rock
Table 3. 11. 2
1 + 3~1 : 3. 5
11 2 ~1+ 2. 5
1 + 1.5 ~112
1 + 1. 25~1 + 1: 5
1 : 0. 5~1 -1
1 + 0. 25 ~3 + 0. 5
11 0. ~ 1 + 0. 25
3. 11. 4 Retaining walls and other connection facilities should be installed at the connection between the channel and the pipeline. Grilles should be installed at the connection between the channel and the pipeline. Article 3.11.5 The bending radius of the center line of the open bend should generally not be less than 5 times the design water surface width; the open channel of the Yaoban Canal and the Tangyan Canal can adopt a radius not less than 2.5 times the design water surface width. Section 12 Pipeline General Article 3.12.1 The position of the drainage pipeline and other underground pipelines and buildings and structures should meet the following requirements: 1. When laying and repairing the pipeline, they should not affect each other; 2. When the drainage pipeline is damaged, it should not affect the foundation of nearby buildings and structures or pollute drinking water; 3. The drainage pipeline should be laid parallel to the center line of the road and should be placed outside the expressway as much as possible. Article 3.12.2 When the sewage pipeline and combined pipeline intersect with the domestic water supply pipeline, they should be placed below the domestic water supply pipeline.
Note: If the above requirements cannot be met, there must be a trap to prevent pollution. The increase of sugar in the water supply pipeline. Article 3.12.3 The horizontal and vertical minimum clearance between the drainage pipeline and other underground pipelines (or structures) should be determined according to the comprehensive design of the local city or industrial enterprise pipelines based on factors such as the type, elevation, construction sequence and consequences of pipeline damage. It can also be adopted according to Appendix 2 of this specification.
Chapter 4 Drainage Pump Station
Section 1 General Provisions
Article 4.1.1 Drainage pump stations should be designed according to long-term scale, and water pump units can be configured according to short-term water volume.
Article 4.1.2
Drainage pump stations should be designed as separate buildings. Sewage pump stations that pump and produce flammable, explosive and toxic gases must be designed as separate buildings, and corresponding protective measures should be taken.
Article 4.1.3 For pump stations installed separately, according to the pollution degree of wastewater to the atmosphere, the noise of the unit, etc., combined with local environmental conditions, the necessary distance should be maintained from residential houses and public buildings, and a fence should be set up around them, and greening should be done. Article 4.1.4 For pump stations in flood-affected areas, the designed ground elevation at the entrance should be more than 0.5㎡ higher than the designed flood level. When the above requirements cannot be met, temporary flood prevention measures such as troughs can be set up at the entrance. Article 4.1.5
An emergency discharge outlet should be set up in front of the pump station.
Article 4.1.6 The power supply of the pump station should be designed according to the secondary load. The recording stations in important areas such as grade-separated roads must be designed according to the secondary load. When the above requirements cannot be met, the power facilities used should be equipped.
Article 3.1.7 The standards for heating, ventilation, noise and fire protection of the pump room should comply with the provisions of the current relevant specifications.
Article 4.1.8 The pump room should have at least one door that can accommodate the largest equipment or parts.
Article 4.1.9 For pumping stations that pump corrosive sewage, the pumps and pipe fittings must take corresponding anti-corrosion measures.
Article 4.1.10 The drainage pump station of the grade-separated intersection should appropriately consider the facilities for pumping groundwater according to the water level and flow of local groundwater. Article 4.1.11 In the pump room that is often managed by people, there should be a soundproof working room with ventilation and communication facilities. For pumping stations far away from residential areas, living facilities for staff should be appropriately set up according to needs.
Section 2 Water Collection Tank
Article 4.2.1
The volume of the water collection tank should be determined based on factors such as water volume, water pump capacity and water pump working conditions. Generally, the following requirements should be met: 1. The volume of the water collection tank in the sewage pump room should not be less than the water output of the largest water pump for 5 minutes.
Note. If the water step unit is automatically controlled, the chain should not be started more than 6 times per hour. 2. The volume of the water collection tank in the sewage pump room should not be less than the water output of the largest water pump for 30 seconds.
3. The volume of the water collection tank in the primary sludge and digested sludge pump room should be calculated according to the amount of sludge discharged at one time and the pumping capacity of the sludge pump. The volume of the water collection tank in the activated sludge pump room should be calculated according to the amount of return sludge discharged, the amount of residual sludge and the pumping capacity of the sludge pump. Article 4.2.2 The sewage and rainwater flowing into the water collection tank should pass through the grille. Article 4.2.3 The water collection tank in the sewage pump room should be equipped with facilities such as sludge flushing and sludge cleaning. When pumping production sewage containing tar, heating facilities should be provided. 4.2.4 Element
A gate or gate slot shall be installed in front of the water collection tank of the pump room. The layout of the water collection tank shall consider improving the hydraulic conditions of the water system suction pipe and reducing the flow or vortex.
Section 3 Pump Room
Article 4.3.1 The selection of water pumps shall be determined based on factors such as water volume, water quality and required head, and shall meet the following requirements:
1. Water pumps shall be of the same model. When the water volume changes greatly, the matching of water pump sizes shall be considered, but the models shall not be too many, or adjustable speed motors shall be used. 2. There should be no less than 2 working pumps in the pump room. The number of spare pumps in the sewage pump room shall be determined based on factors such as regional importance, pump room characteristics, working pump model and number. But it shall not be less than 1. Rainwater pump room may not have spare pumps. 3. Energy saving measures shall be taken.
4. When conditions permit, a submersible pump should be used to pump rainwater, sewage or sludge. Section 4.3.2 The flow rate of the water pump suction pipe and outlet pipe should meet the following requirements: 1. The flow rate of the suction pipe is 0.7~1.5 m/s1 2. The flow rate of the outlet pressure pipe is 0.8~2.5 m/s. Section 4.3.3 The lifting equipment in the pump room can be selected according to the weight of the heaviest part of the pump or the motor according to the following provisions
, the lifting weight is less than 0.5t ground-type pump room, use fixed hook or mobile hanger:
2. When the lifting weight is less than 1t, use manual monorail single-beam lifting equipment: 3. When the lifting weight is 1~3t, use manual or electric monorail single-beam lifting equipment! 4. When the lifting weight is more than 3t, use electric single-beam bridge lifting equipment. Note: For systems with large lifting height, long transportation distance or many lifting times, the mechanical level of the lifting can be appropriately raised.
The layout of the main units and the width of the passage shall meet the following requirements: Article 4.3.4
1. The clear distance between the foundations of two adjacent units t
1. When the motor capacity is less than or equal to 55 kW, it shall not be less than 0.8m2. When the motor capacity is greater than 55 kW, it shall not be less than 1.2m.2. In a pump room without crane lifting equipment, there shall generally be a passage 0.5m larger than the width of the unit on one side of each unit, but shall not be less than the provisions of one paragraph of this article. 3. The distance between the protruding foundation parts of two adjacent units, as well as the distance between the protruding parts of the unit and the wall, shall ensure that the water pump shaft or the motor rotor can be disassembled during maintenance, and shall not be less than 0.8m. If the motor capacity is greater than 55 kW, it shall not be less than 1.0m. The width of the main passage shall not be less than 1.2m. 4. The width of the passage in front of the distribution box shall not be less than 1.5 m for low-voltage distribution and not less than 2.0 m for high-voltage distribution. When maintenance is carried out behind the distribution box, the distance from the back to the wall should not be less than 1.0 m.
5. In the pump room with bridge-type lifting equipment, there should be a passage for lifting equipment. Article 4.3.5 When it is necessary to repair equipment in the pump room, a space for repair equipment should be reserved. Its area should be determined according to the external dimensions of the largest equipment (or component), and a passage with a width of not less than 0.7 m should be set around. Article 4.3.6 The height of the pump room shall comply with the following provisions: 1. If there is no crane lifting equipment, the effective height above the indoor ground shall not be less than 3.0 mt
2. If there is a car lifting equipment, it should be ensured that there is a clearance of not less than 0.5 m between the bottom of the hoisted object and the top of the fixed object passed over; 3. The height of the house with high-voltage distribution equipment shall be determined according to the external dimensions of the electrical equipment.
There should be facilities for draining accumulated water in the pump room.
Article 4.3.7
Element 4.3.8
Maintenance workbench.
When the transmission shaft of the vertical water system is equipped with an intermediate bearing, a maintenance workbench should be provided. When the pipeline is laid on the ground in the pump room, a crossing facility should be provided as needed.
Element 4.3.9
If it is laid overhead, it shall not cross over electrical equipment and obstruction passages, and the bottom of the pipe at the passage shall not be less than 2.0 m from the ground.
Element 4.3.10 When two or more water pumps share one outlet pipe, a check valve shall be provided on the outlet pipe of each water pump, and a check valve shall be provided between the check valve and the water system; if the individual outlet pipe is free flow, generally no check valve and check valve are required. Article 4.3.11 The drainage pump room should be designed to be self-priming and should meet the following requirements: 1. A smell valve should be installed on the suction pipe; 2. The operation should be automatically controlled according to the changes in the liquid level of the sump. Section 4.3.12 In the pump room of non-self-priming water pumps, water diversion equipment should be installed and the equipment should be suitable. 5-2-9 Site selection of sewage treatment plant Chapter V and overall layout Article 5.0.1 The location of the sewage treatment plant shall comply with the requirements of the overall urban planning and drainage engineering planning, and shall be determined comprehensively based on the following factors: downstream of urban water bodies; on the upwind side of the minimum frequency wind direction in the city in summer. 2. 3. Good engineering geological conditions; 4. Less demolition, less occupation of farmland, and a certain sanitary protection distance. 5. Possibility of expansion. 6. Convenient for the discharge and utilization of sewage and sludge; 7. The terrain of the plant area is not affected by water filtration and has good drainage conditions; 8. Convenient traffic, transportation and water and electricity conditions. Article 5.0.2 The plant area of the sewage treatment plant shall be determined according to the long-term scale and the phased construction shall be arranged. Article 5.0.3 The overall layout of the sewage treatment plant shall be determined according to the functions and process requirements of the buildings and structures in the plant, combined with the topography, meteorology and geological conditions of the plant site, after technical and economic comparison, and shall be convenient for construction, maintenance and management. Article 5.0.4 The shapes of the buildings in the sewage treatment plant shall be simple and beautiful, the materials shall be appropriate, and the effect of the group of buildings and structures shall be coordinated with the surrounding environment. Article 5.0.5 The production and management buildings and living facilities shall be arranged in a centralized manner, and their location and orientation shall be reasonable, and they shall be kept at a certain distance from the treatment structures. Article 5.0.6 The treatment structures of sewage and sludge shall be arranged in a centralized manner as much as possible according to the situation. The spacing between the treatment structures shall be continuous and reasonable, and shall meet the requirements of the construction, equipment installation, burial of various pipelines, and maintenance and repair management of each structure. Article 5.0.7 The process flow and vertical design of the sewage treatment plant should make full use of the original terrain and meet the requirements of unobstructed drainage, reduced energy consumption and balanced earthwork. Article 5.0.8 The location and design of the plant fire protection and digestion tank, gas storage tank, residual gas combustion capacity, sludge gas pipeline and other dangerous goods warehouses should meet the requirements of the current "Building Design Fire Protection Code". Article 5.0.9 According to needs, the sewage treatment plant can set up a place for stacking materials, spare parts, fuel or waste residue and parking at an appropriate location. Article 5.0.10 The green area of the sewage treatment plant should not be less than 30% of the total area of the plant.
Article 5.0.11 The sewage treatment plant shall be provided with necessary passages leading to various structures and ancillary buildings. The design of the passages shall meet the following requirements: 1. The width of the main carriageway shall be 3.5 m for a single lane and 6~~7 m for a double lane, and there shall be a return lane.
The turning radius of the carriageway shall not be less than 6 ml; 2.
3. The width of the sidewalk shall be 1.5~2 m; 4. The inclination angle of the escalator leading to the elevated structure shall not be greater than 45 degrees, and the width of the overpass shall not be less than 1 m.
Article 5.0.12 The sewage treatment plant shall be provided with a fence, and its height shall not be less than 2 m. The protection of the sewage treatment plant of industrial enterprises can be determined according to specific requirements. Article 5.0.13 The gate size of the sewage treatment plant shall be able to accommodate the largest equipment or parts, and a side door for transporting and removing slag shall be set up separately. Article 5.0.14 The parallel-operated treatment structures of the sewage treatment plant should be equipped with an equalizing water distribution device, and the systems of each treatment structure should be equipped with switchable connecting pipes and canals. Article 5.0.15 The various pipes and canals in the sewage treatment plant should be arranged comprehensively to avoid mutual interference. When the pipelines are complex, it is advisable to set up a pipe gallery. The layout of the water, mud and gas pipelines between the treatment structures should make the pipes and canals short, with small head loss, smooth flow, not easy to be blocked and easy to clear. When conditions are appropriate, the connection between the sewage treatment structures should use open channels.
Article 5.0.16 The sewage treatment plant should reasonably arrange the bypass pipes of the treatment structures. Article 5.0.17
The treatment structures should be equipped with emptying facilities, and the discharged water should be returned for treatment.
Article 5.0.18 When the water supply system of the sewage treatment plant is connected to the treatment device, measures must be taken to prevent the pollution of the water supply system.
Article 5.0.19 The power supply of the sewage treatment plant should be designed according to the secondary load. The power supply of the main equipment to maintain the minimum operating level of the sewage treatment plant must be the secondary load. When the above requirements cannot be met, a backup power facility should be installed. Note: The power supply level of the industrial enterprise sewage station should be connected to the main sewage treatment workshop. Article 5.0.20
The sewage treatment plant should be equipped with sewage, sludge and gas metering devices according to the requirements of the treatment process, and may be equipped with necessary instruments and control equipment. Article 5.0.21 The composition and area of the ancillary buildings of the sewage treatment plant should be determined according to the scale, process flow and management system of the sewage treatment plant in combination with the local actual situation, and should comply with the current relevant regulations.
The ancillary buildings of industrial sewage treatment plants should be built together with the relevant buildings of the industrial enterprise.
Article 5.0.22
Sewage treatment plants located in cold areas should have insulation and anti-freezing measures.
According to the needs of maintenance and management, distribution boxes, lighting, contact telephones, flushing faucets, bathrooms, toilets and other facilities should be installed at appropriate locations within the plant area. Article 5.0.24
Article 25
Elevated treatment structures shall be equipped with appropriate safety measures such as handrails, anti-slip ladders and needle avoidance.
Chapter VI
Sewage Treatment Structures
Section 1 General Provisions
Article 6.1.1 When urban sewage is discharged into a water body, its treatment degree and method shall be determined in accordance with the current national and local relevant regulations, as well as the release and self-purification capacity of the water body, the utilization of upstream and downstream water bodies, the water quality and quantity of sewage, the seasonal impact of sewage utilization and other conditions. The treatment efficiency of urban sewage treatment plants can generally be adopted according to Table 6.1.2.
6.1.2.
Bypass treatment treatment efficiency
Treatment type
Treatment method
Sedimentation method
Biofilm method
Cyclic mixing method
Main process
Primary sedimentation. Biofilm method,
Secondary anti-liquid
Primary sedimentation is the most gas, secondary sedimentation
Treatment efficiency (%)
40~5520~30
Note: In the table, SS represents the surface area, BDD represents the five-day biochemical sugar content. ②Activated sewage treatment method According to the water quality, process flow, etc., the primary sedimentation, 65~90
Article 6-1.3 In sewage treatment plants with large changes in water quality and (or) water volume, facilities for adjusting water quality and (or) waterscape can be set up. Article 6.1.4 The design flow of sewage treatment structures shall be calculated according to the phased construction. When sewage enters by gravity, it shall be calculated according to the maximum daily maximum design flow of each phase. When sewage enters by lifting, it shall be calculated according to the maximum combined flow of the working water system of each phase. The design reduction of the maximum gasification shall be determined according to the gasification difficulty and gasification time. When the maximum gasification time is long, the design flow may be reduced. In addition to the design of the combined system treatment structure in accordance with the relevant provisions of this Article 6.1.5, the design of the combined system treatment structure shall be in accordance with the relevant provisions of this Article. The impact of Lishui entering should also be considered. Generally, the following requirements can be adopted: 1. Grid cabinets and sand filters are calculated according to the combined design flow rate. 2. Primary sedimentation tanks are generally designed according to the early flow sewage volume and verified according to the combined design flow rate. The verified sedimentation time should not be less than 30 minutes. 3. Second-level treatment system, one is calculated according to the early flow sewage volume. If necessary, a certain combined water volume can be considered.
4. The volume of sludge thickening tanks, wet sludge tanks and digestion tanks, as well as the area of sludge incubation area, can generally be increased by 10% according to the single flow situation. ~20% calculation; 5. The pipe rack should be calculated according to the corresponding maximum daily maximum design flow. Article 6.1.6 The design water quality of urban sewage, when there is no data, should generally be adopted according to the following requirements:
, the five-day biochemical oxygen demand of domestic sewage should be calculated at 20~35 per person per day;
2. The suspended solids volume of domestic sewage should be calculated at 35~50g per person per day. 3. The design water quality of domestic sewage can be adopted by referring to the existing data of the same type of industry, and its suspended solids content and five-day biochemical oxygen demand can be calculated by converting the population equivalent; 4. In the case of combined system, the suspended solids content and five-day biochemical oxygen demand in the combined sewage entering the sewage treatment plant should adopt the actual measured values. 5. The water temperature of the biological treatment structure should be 10-40℃, the pH value should be 6.5-9.5, the harmful substances should not exceed the allowable concentration specified in Appendix III of this specification, and the nutrient combination ratio (5-day biochemical oxygen demand: nitrogen: phosphorus) can be 100:5:11. Article 6.1.7 The number of each treatment structure (grid) should not be less than 2 (grids), and it is advisable to design in parallel series.
Note. When the amount of water is small. Among them, 1 (grid) can be considered for use. Article 6.1.8 Rectification measures should be taken at the inlet and outlet of the treatment structure. Article 6.1.9 Urban sewage treatment plants should consider setting up water quality and water quality facilities according to the discharge water conditions and water quality requirements.
Section 2
Article 6.2.1 Before the sewage treatment system or water pump, a water quality grid must be set up.
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.