Outdoor storm sewer snip. Snip external sewerage networks

Heavy rains and spring thaw for many homeowners are becoming a real problem. After all, the area after the rain turns into a kind of swamp, and regular flooding of the foundation and walls contribute to their destruction. Consider the main points of the construction of such a device as storm sewers - SNiP, GOST and other requirements that should be taken into account.

What is storm sewer? Storm sewers are called complex engineering networks that serve to collect and discharge moisture from the drained territory, which falls in the form of precipitation. For the construction of these schemes should be guided by the requirements of SNiP, which addressed the construction of external sewage networks.

The SNiP, which regulates the norms that external sewage networks must comply with, contains the necessary formulas for calculations during the design of the system, the requirements for materials, the depth of the pipes and other important aspects of construction are indicated.

Types of storm sewer

There are two types of storms:

• Point system.
• Linear system.

Point type stormwater drainage

Point schemes are networks of storm water inlets and pipes connecting them. In order for the assembled circuit to be durable, safe and efficient, the technical conditions for storm sewers include the installation of protective gratings on storm water inlets, as well as the installation of special filters - sand traps.

Sewer storm linear type

A linear diagram is a network of channels that are designed to collect and transport water. According to the requirements of SNiP - storm sewage is mounted so that there is a bias towards the main collector.

Closed type storm sewers consist of a network of storm water inlets connected by pipes laid at a depth, through which water is discharged into the collector. For maintenance and monitoring of the system, it includes inspection wells with a diameter of 1 meter.

Advice! All aspects that will need to be taken into account during the development of the project and the construction of storm sewers are described in the normative document SNiP 2.04.01-85.

If, for some reason, when laying pipes, it is not possible to maintain a minimum slope, then pumps for pumping liquid are included in the system, since it cannot be moved by gravity.

Elements of storm sewers

As a rule, the following elements are included in the sewage network:

• Storm water inlets. This is one of the important elements of the system, the main function of which is the local collection of water from the surface of the earth.
• Door pallets. This is an analogue of storm water inlets, which are installed in front of the entrance groups at home or at the gate.
• Trays or gutters. Elements installed in ditches for water drainage. To allow water to move through them by gravity, a small slope of storm sewers is provided, directed towards the collector.

• Pipes. This element performs the same function as the trays, but is not laid in surface trenches, but underground.
• Sand traps. These are filter elements that prevent debris and soil particles from entering the drainage system.
• Viewing wells. Elements necessary to control the operation of the system.

Calculation of storm sewers

Before the start of the construction of the stormwater, you need to make the correct calculation of the storm sewer, for this you need to know:

• The average rainfall in this area.
• The drain area, that is, the area of \u200b\u200broofs, platforms and walkways with a waterproof coating.
• Soil properties on the site.
• Location of already built underground utilities on the site.

You can calculate what the diameter of the storm sewer should be according to the formula:

Q \u003d q20 x F x Ψ

Designations in the formula:

Q - the amount of water that the system will have to divert.
  q20 - precipitation intensity.

Advice! This value depends on the climatic conditions of the area, you can find its value in the tables on SNiP 2.04.03 - 85.

F is the surface area from which it is planned to discharge water.
  Ψ - correction factor, which depends on the coating material of the site with which the water is collected.

Advice! The correction factor for the roof is 1.0, for paved areas and paths - 0.95, for concrete pavements - 0.85, for crushed stone coatings - 0.4 (and if the crushed stone is treated with bitumen, the coefficient will be 0.6).

Pipe Depth

The question of what should be the depth of the laying of storm sewers is widely discussed at building forums. Meanwhile, a quite understandable answer is given in SNiP 2.04.03-85 - the minimum depth of a storm sewer is determined by the experience of operating systems in this area.

Advice! As a rule, when operating in the middle lane and using pipes with diameters up to 500 mm, 30 cm is taken as the minimum depth. If pipes of larger diameter are used to build a system such as storm sewers, the depth of their laying should not be less than 70 cm.

In order not to make complicated calculations and not worry about possible mistakes, it is best to find out what the depth of the people who are involved in the construction of storm sewers in practice should be. You can ask your neighbors if they have already finished building external drainage and stormwater drainage networks, or inquire with construction organizations working in this area.

Slope of storm pipes

In order to find out the minimum slope of storm sewers, you need to consider:

• Type of drainage;
• Pipe diameter;
• Surface coating.

When using pipes with a diameter of 200 mm, the slope should be 0.7 cm per meter of pipe length. If pipes with a cross section of 150 mm were used, the slope should be 0.8 cm per meter. In case of urgent need, SNiP 2.04.03-85 has a direct indication that in certain sections of the network the minimum slope can be slightly reduced:

• up to 0.5 cm per meter when using pipes with a size of 200 mm;
• up to 0.7 cm per meter for pipes with a diameter of 150 mm.

Thus, if local conditions force this to be done, it is possible to “save” up to 2 mm per meter of pipeline length. Do not forget that SNiP regulates not only the minimum, but also maximum slope  the pipeline. It should not exceed 1.5 cm per meter of pipe.

If you exceed this indicator, then the risk of clogging the structure will increase. The fact is that if the slope is greater than normal, the water quickly leaves, and the sand contained in it settles, as a result, the inner surface of the pipe quickly silts.

Construction of storm sewers

In general, installation work on the installation of storm storms takes place in the same way as when laying the outer pipelines of ordinary sewers.

The choice of pipes for the underground part of the pipeline

If external stormwater networks are mounted, SNiP allows the use of the following types of pipes:

• Asbestos-cement;
• Steel;
• Plastic

Asbestos cement is a traditional material used for the construction of external sewage pipelines, including stormwater. The disadvantages of the material include its high fragility and considerable weight (a meter of a pipe with a diameter of 100 mm weighs more than 24 kg). Steel tubes they have much less weight (a meter of pipe weighs about 10 kg), but they are prone to corrosion, so it is unprofitable to use them for the construction of stormwater.

Recently, plastic pipes have been used to construct stormwater. They are light (a meter weighs no more than 5 kg), but are durable and resistant to corrosion. In addition, they are easy to connect, no welding required. Can be used:

• PVC pipes, if external networks are mounted, then for their construction you need to use a special type of pipe, they are painted in orange;
• Multilayer polymer pipes. Today is the best option. These pipes have a smooth inner surface, so hydraulic resistance does not occur.

Roof installation

The work goes like this:

• In the ceilings, holes are arranged for installing storm water inlets, all junctions are carefully sealed.
• Outflow pipes are strengthened during the construction of a point system or trays - during the installation of a linear stormwater system.
• Install sewage risers or pipes.
• A water discharge unit is going to the collector or discharge into the tray systems.
• All devices are attached to walls and ceilings with clamps. Places for installing clamps are planned in advance, not forgetting to observe the recommended values \u200b\u200bof the slopes.

Underground installation

• Installation begins with the installation of trenches. During the construction of systems such as storm sewers, the depth of laying is most often determined not by the freezing depth, but by the experience of operating the systems at the construction site.
• The trenches are excavated with a slope, that is, their depth should gradually increase.
• At the bottom of the trenches, a sand pillow is made, the layer height is 20 cm.
• The foundation pit is being prepared for installing the collector.
• Pipes should be laid in the prepared ditches; pipe connections to each other and their connection to the collector are carried out using conventional fittings.
• If the sewer network consists of a single branch with a length of more than 10 meters, then in the middle it is worth planning to install a viewing well. Such wells should be placed at the branching points of networks.
• Sand collectors are installed at the junction of the water inlets and the storm pipe systems.
• Now it remains to backfill the trenches and cover the open structures (trays) with trellises on top.

The need to create security zones

Few people know that there is such a thing as a sewage protection zone, including a storm, and meanwhile, SNiP stipulate that a security zone of a certain size be organized near the pipes. So, the storm protection zone provides an indent from the walls of the pipe in each direction for 5 meters. The security zone is a place where it is prohibited:

• Build permanent or temporary structures.
• Dispose of landfills.
• Arrange parking.
• Plant trees or bushes less than three meters from the pipe.
• Block free access to manholes.

So, the installation of a rainwater drainage system is a necessary measure in the improvement of the site. When constructing such systems, it is necessary to strictly comply with the requirements and rules that are formulated in regulatory documents - construction and sanitary rules.

Approved and enforced
Order of the Ministry
regional development
Russian Federation
(Ministry of Regional Development of Russia)
dated December 29, 2011 N 635/11

SET OF RULES

SEWERAGE. EXTERNAL NETWORKS AND STRUCTURES

UPDATED EDITORIAL
SNiP 2.04.03-85

Seewerage. Pipelines and wastewater treatment plants

SP 32.13330.2012

Date of introduction
January 1, 2013

Foreword

The goals and principles of standardization in the Russian Federation are established by the Federal Law of December 27, 2002 N 184-ФЗ "On Technical Regulation", and the development rules - by the Decree of the Government of the Russian Federation of November 19, 2008 N 858 "On the procedure for the development and approval of codes of practice "

Rule Set Information

1. Contractors - LLC "ROSEKOSTROY", OJSC "Research Center" Construction ".
2. Submitted by the Technical Committee for Standardization TC 465 "Construction".
3. Prepared for approval by the Department of Architecture, Construction and Urban Policy.
4. Approved by Order of the Ministry of Regional Development of the Russian Federation (Ministry of Regional Development of Russia) dated December 29, 2011 N 635/11 and entered into force on January 1, 2013.
5. Registered by the Federal Agency for Technical Regulation and Metrology (Rosstandart). Revision of SP 32.13330.2010 "SNiP 2.04.03-85. Sewerage. External networks and structures."

Information on amendments to this set of rules is published in the annually published information index "National Standards", and the text of the changes and amendments is published in the monthly published information signs "National Standards". In case of revision (replacement) or cancellation of this set of rules, the corresponding notification will be published in the monthly published information index "National Standards". Relevant information, notification and texts are also posted in the public information system - on the official website of the developer (Ministry of Regional Development of Russia) on the Internet.

Introduction

Updating performed by ROSEKOSTROY 000 and SIC Construction, responsible executors: G.M. Mironchik, A.O. Dushko, L.L. Menkov, E.N. Zhirov, S.A. Kudryavtsev (LLC "ROSEKOSTROY"), M.I. Alekseev (SPbGASU), D.A. Danilovich (OJSC MosvodokanalNIIProekt), R.Sh. Neparidze (LLC Giprokommunvodokanal), M.N. Orphan (TsNIIEP Engineering Equipment OJSC), V.N. Shvetsov (NII VODGEO OJSC).

1 area of \u200b\u200buse

This set of rules establishes design standards for newly built and reconstructed systems outdoor sewage  permanent use of urban and close to them in the composition of industrial wastewater, as well as rain sewage.
This set of rules does not apply to sewage systems of greater capacity (more than 300 thousand m3 / day).

This set of rules provides links to the following regulatory documents:
SP 5.13130.2009. Fire protection systems. Automatic fire alarm and fire extinguishing installations. Norms and design rules
SP 12.13130.2009. Definition of the category of premises, buildings and outdoor installations for explosion and fire hazard
SP 14.13330.2011 "SNiP II-7-81 *. Construction in seismic areas"
SP 21.13330.2012 "SNiP 2.01.09-91. Buildings and structures in the developed areas and subsidence soils"
SP 25.13330.2012 "SNiP 2.02.04-88. Foundations and foundations on permafrost soils"
SP 28.13330.2012 "SNiP 2.03.11-85. Protection of building structures from corrosion"
SP 30.13330.2012 "SNiP 2.04.01-85 *. Internal water supply and sewerage of buildings"
SP 31.13330.2012 "SNiP 2.04.02-84 *. Water supply. External networks and structures"
SP 38.13330.2012 "SNiP 2.06.04-82 *. Loads and impacts on hydraulic structures (wave, ice and from ships)"
SP 42.13330.2011 "SNiP 2.07.01-89 *. Urban planning. Planning and development of urban and rural settlements"
SP 43.13330.2012 SNiP 2.09.03-85. Construction of industrial enterprises
SP 44.13330.2011 "SNiP 2.09.04-87 *. Administrative and domestic buildings"
SP 62.13330.2011 "SNiP 42-01-2002. Gas distribution systems"
SP 72.13330.2012 "SNiP 3.04.03-85. Protection of building structures and structures from corrosion"
SP 104.13330.2011 "SNiP 2.06.15-85. Engineering protection of territories from flooding and flooding"

Consultant Plus: note.
JV 131.13330.2011, referred to in this document, was subsequently approved and published with the number of JV 131.13330.2012.

SP 131.13330.2011 "SNiP 23-01-99 *. Construction climatology"
GOST R 50571.1-2009. Low voltage electrical installations
GOST R 50571.13-96. Electrical installations of buildings. Part 7. Requirements for special electrical installations. Section 706. Cramped Rooms with Conductive Floors, Walls, and Ceilings
GOST R 50571.15-97. Electrical installations of buildings. Part 5. Selection and installation of electrical equipment. Chapter 52. Electrical Wiring
GOST 12.1.005-88. Occupational safety standards system. General hygiene requirements for workplace air
GOST 17.1.1.01-77. Protection of Nature. Hydrosphere. Use and protection of water. Key Terms and Definitions
GOST 14254-96. Degrees of protection provided by enclosures (IP code)
GOST 15150-69 *. Machines, devices and other technical products. Versions for different climatic regions. Categories, operating conditions, storage and transportation regarding the impact of climatic environmental factors
GOST 19179-73. Hydrology of sushi. Terms and Definitions
GOST 25150-82. Sewerage. Terms and Definitions.
Note. When using this set of rules, it is advisable to check the validity of reference standards and classifiers in the public information system - on the official website of the national standardization body of the Russian Federation on the Internet or on the annually published information index "National Standards", which is published as of January 1 of this year , and according to the corresponding monthly published information indexes published in the current year. If the referenced document is replaced (changed), then when using this set of rules should be guided by the replaced (changed) document. If the referenced material is canceled without replacement, the provision in which the link to it is given applies to the extent not affecting this link.

3. Terms and definitions

In this set of rules, terms and definitions are used in accordance with GOST 17.1.1.01, GOST 25150, GOST 19179, as well as terms with the corresponding definitions given in Appendix A.

4. General

4.1. The selection of schemes and systems of sewage facilities should be made taking into account the requirements for wastewater treatment, climatic conditions, terrain, geological and hydrological conditions, the current situation in the drainage system and other factors.
4.2. When designing, it is necessary to consider the feasibility of cooperating with sewage systems of objects, take into account the economic and sanitary assessments of existing structures, provide for the possibility of their use and the intensification of their work.
4.3. Treatment of industrial and municipal wastewater is allowed to be carried out jointly or separately, depending on their nature and subject to maximum reuse.
4.4. Projects of sewage facilities, as a rule, should be linked to the scheme of their water supply, with a mandatory consideration of the possibility of using treated wastewater and rainwater for industrial water supply and irrigation.
4.5. When choosing a sewage scheme for industrial enterprises, it is necessary to consider:
the possibility of reducing the volume of polluted wastewater generated in technological processes due to the introduction of non-waste and waterless production, the installation of closed water systems, the use of air cooling methods, etc .;
the possibility of local treatment of wastewater flows in order to extract individual components;
the possibility of consistent use of water in various technological processes with different requirements for its quality;
conditions for the discharge of industrial wastewater into water bodies or into the sewage system of a settlement or other water user;
conditions for the disposal and use of sludge and waste generated during wastewater treatment.
4.6. Combining the flows of industrial wastewater with various pollutants is allowed when it is advisable to co-treat them.
In this case, it is necessary to take into account the possibility of chemical processes in the communications with the formation of gaseous or solid products.
4.7. When connecting sewer networks of subscribers that are not related to the housing stock to the networks of a settlement, it is necessary to provide releases with control wells located outside the territory of subscribers.
It is necessary to provide devices for measuring the discharge of wastewater from each enterprise, if the subscriber has a substantially open water balance, at least in the following cases:
if the subscriber is not connected to a centralized water supply system or has (or may have) water supply from several sources;
if during the production process more than 5% of the water consumption consumed from the water supply is added or withdrawn.
Combining the production wastewater of several enterprises is allowed after the control well of each enterprise.
4.8. Industrial wastewater to be disposed of and treated together with household wastewater of a settlement must meet current requirements for the composition and properties of wastewater taken into the sewage system of a settlement.
Industrial waste water that does not meet the specified requirements must be pre-treated. The degree of such treatment should be agreed upon with the organization (organizations) operating the sewage system and treatment facilities of the settlement (or, in the absence thereof, with the organization designing this sewage system).
4.9. It is forbidden to discharge into water bodies untreated to the established standards rain, melt and irrigation water, which is organized away from residential areas and sites of enterprises.
4.10. When designing treatment facilities for general-alloy and semi-divided sewage systems, which carry out joint diversion of all types of wastewater for treatment, including surface runoff from residential areas and enterprise sites, one should be guided by the instructions of this set of rules, as well as other regulatory documents governing the operation of these systems, including including regional ones.
4.11. The most polluted part of the surface runoff, which is formed during periods of rainfall, snowmelt and from washing of road surfaces, in the amount of not less than 70% of the annual runoff volume for residential areas and sites of enterprises close to them in terms of pollution, and all the volume of runoff from the sites of enterprises whose territory may be contaminated with specific substances with toxic properties or a significant amount of organic substances.
For most settlements of the Russian Federation, these conditions are met when calculating the treatment plant for receiving runoff from low-intensity, often repeated rains with a period of one-time excess of the calculated rain intensity of 0.05 - 0.1 years.
4.12. Surface wastewater from industrial areas, construction sites, warehouses, car farms, as well as highly polluted areas located in residential areas of cities and towns (gas stations, car parks, bus stations, shopping centers), before being discharged into a rain sewer or centralized The municipal sewage system must be cleaned at local treatment facilities.
4.13. When determining the conditions for the release of surface runoff from residential areas and enterprise sites into water bodies, one should be guided by the standards of the Russian Federation for the conditions for the discharge of urban wastewater.
The choice of the scheme of diversion and treatment of surface runoff, as well as the design of treatment facilities, is determined by its qualitative and quantitative characteristics, conditions of disposal and is carried out on the basis of assessing the technical feasibility of implementing a particular option and comparing technical and economic indicators.
4.14. When designing rainwater drainage facilities in populated areas and industrial sites, it is necessary to consider the option of using treated wastewater for industrial water supply, irrigation or irrigation.
4.15. The main technical solutions used in the projects, the sequence of their implementation should be justified by a technical and economic comparison of possible options, taking into account sanitary and hygienic and environmental requirements.
4.16. When designing sewage networks and structures, advanced technical solutions, mechanization of labor-intensive work, automation of technological processes, industrialization of construction and installation works through the use of structures, structures and factory-made products, etc. should be provided.
It should also include measures for energy conservation, as well as for the maximum possible use of secondary energy resources of wastewater treatment plants, the disposal of treated water and sludge.
It is necessary to ensure appropriate safety and sanitary-hygienic working conditions during the operation and implementation of preventive and repair work.
4.17. The location of the sewage system and the passage of communications, as well as the conditions and places for the release of treated wastewater and surface runoff to water bodies, must be agreed with local authorities, organizations that carry out state sanitary supervision and protection of fish stocks, as well as with other bodies, in accordance with the legislation of the Russian Federation, and the places of release into navigable water bodies and seas - with the relevant authorities of the river and sea fleet.
4.18. The reliability of the sewage system is characterized by the preservation of the required estimated throughput and the degree of wastewater treatment when the wastewater costs and composition of pollutants change (within certain limits), conditions for their discharge into water bodies, in the event of power outages, possible accidents in communications, equipment and structures, production of scheduled repair work, situations related to special environmental conditions (seismic, subsidence of soils, permafrost, etc.).
4.19. To ensure uninterrupted operation of the sewage system, the following measures should be provided:
appropriate reliability of power supply of sewage facilities (two independent sources, stand-alone autonomous power station, storage batteries, etc.);
duplication of communications, arrangement of bypass lines and bypasses, switching on parallel pipelines, etc .;
arrangement of emergency (buffer) tanks with subsequent pumping out of them in normal mode;
sectioning of parallel working structures, with the number of sections providing the necessary and sufficient effectiveness of the action when one of them is disconnected for repair or maintenance;
reservation of working equipment for one purpose;
providing the necessary margin of power, throughput, capacity, strength, etc. equipment and facilities (determined by technical and economic calculations);
determination of the allowable reduction in system capacity or the efficiency of wastewater treatment in emergency situations (as agreed with the supervisory authorities).
The application of the above measures should be studied during the design, taking into account the responsibility of the object.
4.20. Sanitary protection zones from sewage structures to the borders of residential buildings, sections of public buildings and food industry enterprises, taking into account their prospective expansion, should be taken in accordance with sanitary standards, and cases of deviation from them should be agreed with the sanitary and epidemiological surveillance authorities.

5. The estimated costs of urban wastewater.
Hydraulic calculation of sewer networks.
Unit costs, unevenness coefficients
and estimated wastewater costs

5.1. General directions

5.1.1. When designing sewage systems in settlements, the calculated specific average daily (for the year) water disposal of domestic wastewater from residential buildings should be taken equal to the calculated specific average daily (for the year) water consumption according to SP 31.13330, excluding water consumption for irrigation of territories and green spaces.
5.1.2. Specific wastewater to determine the estimated costs of wastewater from individual residential and public buildings, if necessary, account for concentrated costs should be taken in accordance with SP 30.13330.
5.1.3. The amount of wastewater from industrial enterprises and the coefficients of unevenness of their inflow should be determined by technological data with an analysis of the water balance in terms of possible water circulation and reuse of wastewater, in the absence of data - by the integrated norms of water consumption per unit of output or raw materials or according to similar enterprises.
From the total amount of wastewater of enterprises, it is necessary to single out the costs accepted in the sewers of a settlement or other water user.
5.1.4. Specific drainage in non-canalized areas should be taken 25 l / day per inhabitant.
5.1.5. The estimated average daily wastewater flow rate in the village should be determined as the sum of the costs established in 5.1.1 - 5.1.4.
The amount of wastewater from local industrial enterprises serving the population, as well as unaccounted expenses, may (if justified) be additionally accepted in the amount of 6 - 12% and 4 - 8% of the total average daily drainage of the settlement (if justified).
5.1.6. Estimated daily wastewater costs should be taken as the product of the average daily (for the year) consumption according to 5.1.5 by the daily unevenness coefficients, adopted in accordance with SP 31.13330.
5.1.7. Estimated total maximum and minimum wastewater costs, taking into account daily, hourly and intra-hourly irregularities, should be determined by computer simulation of water disposal systems that take into account the schedule of wastewater inflow from buildings, residential areas, industrial enterprises, the length and configuration of networks, the availability of pumping stations, etc. d., or according to the actual water supply schedule during the operation of similar facilities.
In the absence of these data, it is allowed to take general coefficients (maximum and minimum) according to table 1.

Table 1

Estimated total maximum and minimum costs
sewage, taking into account daily, hourly
and intra-hourly unevenness

Total ratio
  flow irregularities
  wastewater Average wastewater consumption, l / s
5 10 20 50 100 300 500 1000 5000
and more
Maximum at 1%
security 3.0 2.7 2.5 2.2 2.0 1.8 1.75 1.7 1.6
Minimum at 1%
security 0.2 0.23 0.26 0.3 0.35 0.4 0.45 0.51 0.56
Maximum at 5%
security 2.5 2.1 1.9 1.7 1.6 1.55 1.5 1.47 1.44
Minimum at 5%
security 0.38 0.46 0.5 0.55 0.59 0.62 0.66 0.69 0.71
  Notes. 1. General wastewater inflow rates given in
table, it is allowed to take with the number of production
water not exceeding 45% of the total flow.
  2. With an average wastewater flow rate of less than 5 l / s, the maximum
non-uniformity coefficient is accepted 3.
  3. 5% security implies a possible increase
(decrease) in consumption on average 1 time per day, 1% - 1 time per
during 5-6 days.

5.1.8. The estimated costs for networks and structures for the supply of sewage by pumps should be taken equal to the productivity of pumping stations.
5.1.9. When designing drainage communications and facilities for wastewater treatment, one should consider the feasibility and sanitary-hygienic possibility of averaging the estimated costs of wastewater.
5.1.10. Sewerage facilities should be designed to allow the passage of the total estimated maximum flow rate (determined by 5.1.7) and the additional influx of surface and groundwater, disorganized into gravity sewer networks through leaks in manhole covers and due to groundwater infiltration.
The magnitude of the additional inflow, l / s, is determined on the basis of special surveys or data on the operation of similar facilities, and in their absence, by the formula

where L is the total length of gravity pipelines to the calculated structure (pipeline alignment), km;
- the value of the maximum daily amount of precipitation, mm (according to SP 131.13330).
Verification calculation of gravity pipelines and channels with a cross-section of any shape for the passage of increased flow should be carried out when filling 0.95 height.

5.2. Hydraulic calculation of sewer networks

5.2.1. Hydraulic calculation of gravity sewer pipelines (trays, channels) should be performed at the estimated maximum second flow rate of wastewater according to tables, graphs and nomograms. The main requirement in the design of gravity collectors is to pass the estimated costs at self-cleaning speeds of the transported wastewater.
5.2.2. Hydraulic calculation of pressure sewer pipelines should be made in accordance with SP 31.13330.
5.2.3. Hydraulic calculation of pressure pipelines transporting raw and fermented sludge, as well as activated sludge, should be carried out taking into account the mode of movement, physical properties and characteristics of the composition of the sediments. At a moisture content of 99% or more, the sediment obeys the laws of movement of the waste fluid.
5.2.4. The hydraulic slope i when calculating pressure head sludge pipes with a diameter of 150 - 400 mm is determined by the formula

where is the moisture content of the sediment,%;
V is the sediment speed, m / s;
D is the diameter of the pipeline, m;
  - diameter of the pipeline, cm;
  - coefficient of resistance to friction along the length, determined by the formula

For pipelines with a diameter of 150 mm, the value should be increased by 0.01.

5.3. Smallest pipe diameters

5.3.1. The smallest pipe diameters of gravity networks should be taken, mm:
for a street network - 200, an intra-quarter network, a network of domestic and industrial sewage - 150;
for rain street network - 250, intra-quarter - 200.
The smallest diameter of pressure pipes is 150 mm.
Notes. 1. In settlements with a wastewater flow rate of up to 300 m3 / day for the street network, the use of pipes with a diameter of 150 mm is allowed.
2. For the production network, with appropriate justification, the use of pipes with a diameter of less than 150 mm is allowed.

5.4. Estimated speeds and filling of pipes and channels

5.4.1. In order to avoid siltation of sewer networks, the estimated speed of the wastewater should be taken depending on the degree of filling of pipes and channels and the size of suspended solids contained in the wastewater.
The minimum speed of movement of wastewater in domestic and rainwater networks with the highest estimated filling of pipes should be taken according to table 2.

table 2

Estimated minimum wastewater speeds
depending on the highest degree of tube filling
in domestic and rainwater networks

│ Diameter, mm │ Velocity V, m / s, when filling H / D │
│ │ min │
│ ├───────────┬───────────┬───────────┬───────────┤
│ │ 0,6 │ 0,7 │ 0,75 │ 0,8 │

│150 - 250 │ 0,7 │ - │ - │ - │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│300 - 400 │ - │ 0,8 │ - │ - │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│450 - 500 │ - │ - │ 0,9 │ - │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│600 - 800 │ - │ - │ 1,0 │ - │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│900 │ - │ - │ 1,10 │ - │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│1000 - 1200 │ - │ - │ - │ 1,20 │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│1500 │ - │ - │ - │ 1,30 │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│St. 1500 │ - │ - │ - │ 1.50 │
├─────────────────────────┴───────────┴───────────┴───────────┴───────────┤
│ Notes. 1. For production wastewater, the lowest speeds│
│ Accept in accordance with the guidelines for building design │
│ enterprises of individual industries or operational │
│ data. │
│ 2. For industrial wastewater similar in nature to suspended │
│ substances to household, take the lowest speeds as for domestic sewage │
Water. │
│ 3. For rain sewage at P \u003d 0.33 years, the lowest speed│
│ Take 0.6 m / s. │

5.4.2. The minimum estimated speed of clarified or biologically treated wastewater in trays and pipes is allowed to take 0.4 m / s.
The highest estimated speed of wastewater should be taken, m / s: for metal and plastic pipes - 8 m / s, for non-metal (concrete, reinforced concrete and chrysotile cement) - 4 m / s, for rain sewage - 10 and 7 m / s, respectively .
5.4.3. The estimated speed of movement of unclarified wastewater in the siphons must be taken at least 1 m / s, while in places where the wastewater approaches the siphon, the speed should be no more than the speeds in the siphon.
5.4.4. The lowest calculated speeds of movement of raw and fermented sediments, as well as compacted activated sludge in pressure pipes, should be taken according to table 3.

Table 3

Estimated minimum raw speeds
and fermented sediments as well as compacted
activated sludge in pressure pipes

┌─────────────────────────┬───────────────────────────────────────────────┐
│ Sediment humidity,% │ V, m / s, at │
│ │ min │
│ ├───────────────────────┬───────────────────────┤
│ │ D \u003d 150 - 200 mm │ D \u003d 250 - 400 mm │

│ 98 │ 0,8 │ 0,9 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 97 │ 0,9 │ 1,0 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 96 │ 1,0 │ 1,1 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 95 │ 1,1 │ 1,2 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 94 │ 1,2 │ 1,3 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 93 │ 1,3 │ 1,4 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 92 │ 1,4 │ 1,5 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 91 │ 1,7 │ 1,8 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 90 │ 1,9 │ 2,1 │
└─────────────────────────┴───────────────────────┴───────────────────────┘

5.4.5. The highest speeds of rainfall and allowed to be discharged into the reservoirs of industrial wastewater in canals should be taken according to table 4.

Table 4

The highest speeds of rain and permissible
to drain into the reservoirs of industrial wastewater in canals

┌────────────────────────────────┬────────────────────────────────────────┐
│ Ground or type of channel attachment │ Maximum speed in the channels, │
│ │ m / s, with a flow depth of 0.4 to 1 m │

│ Fastening with concrete slabs │ 4 │
├────────────────────────────────┼────────────────────────────────────────┤
│Limestones, medium sandstones │ 4 │
├────────────────────────────────┼────────────────────────────────────────┤
│Option: │ │
│ flat │ 1 │
│ about the wall │ 1.6 │
├────────────────────────────────┼────────────────────────────────────────┤
│ Paving: │ │
│ single │ 2 │
│ double │ 3 - 3,5 │
├────────────────────────────────┴────────────────────────────────────────┤
│ Note. With a flow depth of less than 0.4 m, the velocity values│
Принимать accept wastewater movements with a coefficient of 0.85; with depth over│
│1 m - with a coefficient of 1.24. │
└─────────────────────────────────────────────────────────────────────────┘

5.4.6. The calculated filling of pipelines and channels of any section (except rectangular) should be taken no more than 0.7 diameter (height).
The estimated filling of the channels of rectangular cross-section is allowed to take no more than 0.75 height.
For rain sewer pipelines, it is allowed to accept full filling, including with short-term wastewater discharges.

5.5. Slopes of pipelines, channels and trays

5.5.1. The smallest slopes of pipelines and channels should be taken depending on the permissible minimum wastewater speeds.
The smallest slopes of pipelines for all sewerage systems should be taken for pipes with diameters: 150 mm - 0.008; 200 mm - 0.007.
Depending on local conditions, with appropriate justification, for individual sections of the network it is allowed to accept slopes for pipes with diameters: 200 mm - 0.005; 150 mm - 0.007.
The slope of the connection from the storm water inlets should be 0.02.
5.5.2. In an open rain network, the smallest slopes of the roadway trays, ditches and drainage ditches should be taken according to table 5.

Table 5

The smallest slopes of the carriageway trays,
ditches and drainage ditches

Name Least bias
Asphalt concrete trays 0.003
Trays coated with pavers or gravel 0.004
Cobblestone pavement 0.005
Single trays and ditches 0.006
Gutter Ditches 0.003
Polymer, polymer concrete trays 0.001 - 0.005

5.5.3. The smallest sizes of cuvettes and ditches of a trapezoidal section should be taken: width along the bottom - 0.3 m; depth - 0.4 m.

6. Sewer networks and structures on them

6.1. General directions

6.1.1. Gravity-free (non-pressure) sewerage networks are designed, as a rule, in one line.
Notes. 1. In parallel laying of gravity sewer collectors, it is necessary to consider the arrangement of bypass pipelines in separate sections (where possible) to ensure their repair in emergency situations.
2. It is allowed to transfer to emergency tanks (with subsequent pumping) or, in agreement with the Sanitary and Epidemiological Supervision authorities, to rain collectors equipped with treatment facilities at the outlets. At bypasses to rain collectors, gates to be sealed must be provided.

6.1.2. The reliability of the operation of pressureless networks (collectors) of sewage is determined by the corrosion resistance of the material of the pipes (channels) and butt joints both to the transported wastewater and to the gaseous medium in the surface area.
6.1.3. The location of the networks on the master plans, as well as the minimum distances in the plan and at intersections from the outer surface of the pipes to the structures and utilities, should be taken in accordance with SP 42.13330.
6.1.4. Sewage pressure pipelines should be designed taking into account the characteristics of the transported waste fluid (aggressiveness, high content of suspended particles, etc.). It is necessary to provide for additional measures and constructive solutions that ensure prompt repair or replacement of pipeline sections during operation, as well as the use of appropriate non-clogging pipeline valves.
The drainage of the wastewater from the emptied area during the repair should be provided without discharge into a water body - in a special tank with subsequent transfer to the sewer network or removal of a tanker truck.
6.1.5. The design of deep-laid collectors, laid by paneling or mining, must be performed in accordance with SP 43.13330.
6.1.6. Ground and elevated laying of sewer pipelines in the territory of settlements is not allowed.
When laying sewer pipelines outside populated areas and on the sites of industrial enterprises, surface or elevated pipelines are allowed to meet the necessary operational reliability and safety requirements, taking into account the strength characteristics of the pipe when exposed to wind supports, etc.
6.1.7. The material of pipes and channels used in sewage systems must be resistant to the influence of both transported waste fluid and gas corrosion in the upper part of the collectors.
In order to prevent gas corrosion, appropriate protection of pipes and measures to prevent the formation of aggressive media (ventilation of the network, exclusion of stagnant zones, etc.) should be provided.
6.1.8. The type of pipe base must be taken depending on the bearing capacity of soils and loads, as well as the strength characteristics of the pipe. Backfilling of pipelines should take into account the bearing capacity and deformation of the pipe.

6.2. Pivots, connections and piping depth

6.2.1. Accessions and turns on the collectors should be provided in the wells.
The radius of the curve of rotation of the tray must be taken at least the diameter of the pipe, on collectors with a diameter of 1200 mm or more - at least five diameters with the installation of inspection wells at the beginning and end of the curve.
6.2.2. The angle between the connected and the outlet pipe must be at least 90 °.
Note. When connecting with a differential, any angle between the connected and outlet pipelines is allowed.

6.2.3. Connections of pipelines of different diameters in wells should be provided for along pipe hoses. When substantiating, it is allowed to connect the pipes at the calculated water level.
6.2.4. The smallest depth of the laying of sewer pipelines must be determined by heat engineering calculation or taken based on the experience of operating networks in the area.
In the absence of data, the minimum depth of the pipeline tray can be accepted for pipes with a diameter of up to 500 mm - 0.3 m, and for pipes of larger diameter - 0.5 m less than the greater penetration depth of zero temperature into the ground, but not less than 0.7 m to the top pipes, counting from the surface of the earth or planning (to avoid damage by land transport).
6.2.5. The maximum pipe laying depth is determined by calculation depending on the pipe material, their diameter, soil conditions, method of work.

A properly designed and installed external sewage system will not create unnecessary trouble in its operation, it will provide not only comfort and all kinds of conveniences for residents of various houses, office workers and other buildings, but also a full guarantee of sanitary and hygienic safety of human health.

That is why it is very important to follow all sanitary norms and rules (SNiP) established at the state level.

SNiP provide complete relevant information on how to accurately calculate and create a project of external sewage networks in order to avoid epidemics, contamination of drinking water and soil areas as a result of sewage emissions, breakthrough of sewer pipes and other emergency situations in their future operation.

Unlike internal sewer networks, which are located inside residential and non-residential premises, the external ones are communications that stretch from the house to the reservoirs, which store wastewater.

Such sewer installations are installed both for city-wide building objects, and for private houses, where there is a slope for gravity sewage or pressure networks are installed with pumping stations or sewage pumps.

City-wide buildings relate, as a rule, to the department and maintenance of municipal utilities, while private buildings are serviced autonomously and independently.

And in both cases, when building or laying and installing an external sewage system, strict adherence to specially developed state sanitary and hygienic standards and rules is required.

According to the structure of the installation and installation method, sewer external networks are divided into such systems:

• separate  - the drain of domestic and fecal wastewater is separated from rainwater and melt, it flows through different pipes and is collected in different containers;
• semi-separate  - in this case, rain, melt and domestic water flowing through separate pipes are collected in one sewer, where they are stored for some time and then disposed of;

  Photo: half-divided sewer networks

• general alloy  - according to this scheme, drains of all types flow down the same pipeline into the same sewer tank.

  Photo: Alloy Sewer Networks

According to the type of location and purpose, there is a sewerage system for its outdoor use in such places:

• intra-yard and intra-quarter networks  - tracing (laying the pipeline by vectors from point A to point B) of the entire sewage system is carried out along the walls of buildings at a distance of 3 m from their outer walls, using the shortest path to collectors located on the streets. Such a concept as a courtyard network is applicable only to sewers that connect to centralized urban systems, but does not apply to autonomous sewers;
• street  - This is a whole system of pipelines and wells, branched out in various ways, which runs directly along the streets and ensures the transportation of wastewater to the center of the entire external sewer system - city sewers;
• collectors  - their role is to collect wastewater and, if necessary, redirect it to other collectors. For the most part, sewer collectors are located both in the territory of the sewage basin and on its outskirts. Sewerage basin is a part of the territory limited by watersheds where sewer pipes run and sewage is transported either by gravity or pressure method;

  Photo: sewer network collectors

• treatment facilities  - the final point of wastewater dispatch is treatment facilities where the water is treated and the treated water is discharged into the reservoir, or for the use of industrial and economic needs of large and small production facilities.

  Photo: Wastewater Treatment Plant

There are also some options for the location and arrangement of the schemes for laying the external sewage pipeline themselves.

Differences in schemes are formed due to the diversity of the terrain where sewer pipes are laid.

Indeed, it can depend on turns and bends on the lines of passing pipes, the level of groundwater, which means supplying the system with inspection, drainage or revision wells and other specific subtleties.

The most basic schemes of external sewers can be distinguished:

• perpendicular pattern  - the perpendicular is formed here due to the laying of sewer pipes or collectors perpendicular to the movement of water in the reservoir. Such a scheme effectively removes dirty water from clean waters;

• crossed circuit  - collectors that are located on the territory of the sewage basin are installed perpendicular to the reservoir and intercepted by the main or main collector, which is installed parallel to the coastline of the river. This scheme is used where there is too much slope towards a river or some other reservoir, and where more thorough wastewater treatment is required;

• fan or parallel circuit  - in the case of sharp slopes towards the river, the external sewage pipe is laid parallel to each other, but at an obligatory angle with respect to the reservoir. Such systems are also intercepted by the main collectors, which successfully divert waste water away from settlements to treatment facilities;
• zone or zone diagram  - this scheme allows dividing the city sewer into sections or zones, but it is not possible to let wastewater into the sewage treatment system by gravity, so pumping pumping stations are installed on the lowest intercepting collector;
• radial or decentralized scheme  - here the wastewater is directed in a non-centralized way and gets to different treatment facilities. This scheme works very well only on flat terrain and large volumes of sewage entering the external sewage pipe.

  Photo: schemes of external sewer networks: a - perpendicular; b - crossed; in - parallel; g - zone; d - radial

All types and classifications of external sewage systems differ among themselves in the structure of construction, purpose, relief terrain conditions, wastewater volumes and other parameters and factors that affect the planning and routing of certain types of sewers in its outer part.

Network Composition

External sewage systems have certain sections of pipelines, complex and simple designs of all kinds of wells, slopes, transitions and turns in laying the pipes themselves, tanks, where temporary accumulation or transportation of sewage occurs, treatment, and then the withdrawal of purified water into water bodies.

  By and large, the external sewage system consists of such structures, components and structures:

• pipeline - along the length of which pipes of various lengths and diameters are used;

  Photo: sewage pipeline

• wells - as a rule, inspection (revision), drainage, overflow and rotary wells are involved;

  Photo: sewage wells

• releases to the receivers - they provide the unhindered exit of wastewater from the pipeline to the tank;
• collectors are whole tunnels, which are huge pipes that provide sufficient space for the accumulation and collection of sewage water, as well as their subsequent distribution and transportation to treatment facilities or pumping stations;
• local treatment facilities are various septic tanks, aerators, biodisk equipment, and other structures whose purpose is to treat waste water and discharge it to water bodies, rivers, or use it for technical or, for example, agricultural needs;

  Photo: local sewage treatment plants

• paging stations - are not used in all external sewage systems, namely, where a portioned supply of wastewater to treatment plants is required;
• other elements are all kinds of components, additional mechanisms and other elements of the external sewer network.

Basic design requirements

As already noted, the need for strict adherence to all state standards and rules of the sanitary-hygienic and construction order.

This is necessary in order to avoid violations and accidents that may occur in the further operation of a particular section of the external sewage system.

Important! Only when all Construction Norms and Regulations are observed and all work is done in proper quality, then only the object of sewer networks can be put into operation.

All these points relate not only to the exact implementation of the rules and norms by state or commercial structures, but also to individuals who independently lay pipes for autonomous sewage, or sewage, which is supplied from the cottage, private house to a centralized sewage system.

  Photo: SNiP

Before proceeding with the design of any external sewage system, you must first determine the nature of the terrain on whose territory the sewage system will be located, as well as its type: separate, semi-divided or alloyed.

The rules and norms provided by the Guest require strict compliance with the phased implementation of works on laying and installing the sewage system.

To begin with, preparatory excavation is carried out according to the project plan:

• digging trenches with a larger diameter than the pipes themselves, in accordance with the norms of SNiP;
• ramming trenches or supplying them with “pillows” or any other covering elements;
• in order to avoid freezing, various heaters and deeper trenches are used.

  Photo: sealing seams of sewer pipe joints

After warming, laying the pipeline with all the wells and other fittings, the system must pass all the relevant SNiP hydraulic tests and only then it will be filled up with soil and rammed.

  Photo: laying sewer pipes

Septic tanks

Structures such as septic tanks must be placed at a distance from the foundation of the house or well with drinking water from 10 to 12 m.

These requirements must be strictly observed, otherwise sewage or fumes can enter the drinking water through the soil, which subsequently leads to the appearance of various infectious and bacterial diseases.

For installation and installation, a cottage or a country house, you must first dig a large pit.

Given that almost all modern septic tanks are made of light materials: plastic or fiberglass plastic, you need to prepare for it a concrete platform and fixing belts, or reinforced concrete rings.

All this is done so that the septic tank does not “pop up”, but remains fixed underground. All connecting pipes with wells must consist of anti-corrosion materials that are not exposed to the aggressive environment of sewage.

Thus, these pipes and wells can last as long as possible.

  Photo: septic tank

The mechanism of operation of the septic tank also contains aerobic and anaerobic bacteria, with the help of which the wastewater entering the first chamber decomposes, forming water and sludge.

Then, the water, filling the first chamber to a certain level, is poured into the second chamber, and from there (if the septic tank is 2-chamber) into the perforated pipe, through the openings of which the purified water enters the ground, thereby not infecting the soil.

Biological deep wastewater treatment

Modern solutions for effective wastewater treatment have come to the best solution - it is a biological deep wastewater treatment, which is carried out using whole plants and structures using bio-disks, where bacteria are present that work to decompose sewage into water and sludge.

The operating mechanism of a deep-cleaning station is based on the principle of the septic tank, but only in an improved and modified version to the extent that it purifies dirty waste water by 98%.

  Photo: biological deep wastewater treatment

It is good to install such a structure in private houses, dachas, cottages, where the centralized external sewage system is located far enough and the installation of an autonomous sewer system is required.

Such a deep-cleaning station is installed almost in the same way as a septic tank, only with the obligatory consideration of all the norms and rules for external autonomous sewer systems.

Consequences and liability of non-compliance with Construction Norms and Regulations on design, installation and installation

The legislation of the Russian Federation provides for appropriate penalties and liability for violations of SNiP on installation and laying of external sewers.

Compliance with SNiP is checked by specially created commissions in the presence of suitable documentation.

Responsible for compliance with all rules and regulations are the following persons:

• developers (customers) - are responsible for preparing for the operation of the finished sewer network, taking into account all personnel issues, ensuring the proper operation of equipment, setting up technological processes, developing project capacities within the time frames specified in SNiP “Sewerage. External networks and structures ”;
• design organizations - are responsible for the accuracy of all calculations, drawings and design plans for outdoor sewage networks;
• research organizations - are responsible for all issued documents and digital data on climate, ecology in the region or area where the outdoor sewage was laid;
• construction and installation organizations - are fully responsible for observing all the rules and regulations during the work and testing of the finished structure, prescribed in SNiP 2.04.03-85 “Sewerage. External networks and facilities. ”

In case of violations of SNiP by any of the above persons, they are brought to administrative, disciplinary, criminal and other liability in accordance with the legislation of the Russian Federation.

All penalties are imposed on the perpetrators because their negligence in case of non-compliance with all relevant rules and norms can lead to or lead to disasters, epidemics, or any accidents associated with a violation of the sewer pipeline, blockage or any other breakdown.

All the issues discussed regarding the preparatory and installation work on the design and installation of outdoor sewer systems can shed light on the correct conduct of all installation and construction works in this type of activity.

This applies not only to the construction of the state central system of external sewage, but also to autonomous sewer structures.

Important! Any deviation from SNiP by any citizen who decided to do the independent laying of the sewage system, or by any organization or company that installs the external sewage pipeline, can lead to catastrophic consequences, various diseases of the population or emergency breakdowns that will cause irreparable damage to the environment.

Video: how to properly arrange sewers in a private house

DEVELOPED by Soyuzvodokanalproekt (G.M. Mironchik - topic manager; D.A. Berdichevsky, A.E. Vysota, L.V. Yaroslavsky) with the participation of VNIIVODGEO, Donetsk PromstroyNIIproekt and NIIOSP them. N.M. Gersevanova Gosstroy of the USSR, Research Institute of municipal water supply and water purification of the Academy of Public Utilities named after KD Panfilov and Giprokommunvodokanal of the Ministry of Housing and Communal Services of the RSFSR, TsNIIEP of engineering equipment of the Gosgrazhdanstroy, MosvodokanalNIIproekt and Mosinzhproekt of the Moscow City Executive Committee, the Research and Design Institute of Urban Economics and the UkrkommunzhIIShimkost and the Institute of Mechanical Engineering and the Institute of Mechanics and Industrial Engineering of the USSR and the Institute of Mechanics and Industrial Engineering M.T. Urazbaev of the Academy of Sciences of the Uzbek SSR, Moscow Institute of Civil Engineering V.V. Kuybysheva of the Ministry of Higher Education of the USSR, Leningrad Civil Engineering Institute of the Ministry of Higher Education of the RSFSR.

AGREED by the Ministry of Health of the USSR (letter of 10.24.83 N 121-12 / 1502-14), the Ministry of Water Economy of the USSR (letter of 04.15.85 N 13-3-05 / 366), the Ministry of Fishery of the USSR (letter of 26.04.85 N 30-11- 9).

With the introduction of SNiP 2.04.03-85 "Sewerage. External networks and structures," SNiP II-32-74 "Sewerage. External networks and structures" expires.

SNiP 2.04.03-85 "Sewerage. External networks and structures" introduced Amendment No. 1, approved by Gosstroy of the USSR dated May 28, 1986 No. 70 and entered into force on July 1, 1986. Items, tables, as amended are marked in these Building codes with the sign (K).

These rules and regulations must be observed when designing newly built and reconstructed permanent outdoor sewage systems for settlements and national economy objects.

When developing sewage projects, one should be guided by the “Fundamentals of Water Legislation of the USSR and Union Republics”, comply with the “Rules for the Protection of Surface Water from Pollution from Wastewater” and the “Rules for Sanitary Protection of Coastal Waters of the Sea” of the USSR Ministry of Water Economy, USSR Ministry of Fisheries and the USSR Ministry of Health, requirements of water protection and coastal stripes of the country's small rivers "and" Instructions on the procedure for approval and issuance of permits for special water use "of the USSR Ministry of Water and Water, as well as instructions on other regulatory documents, ut erzhdennyh or concerted USSR State.

1.1. Sewerage facilities should be designed on the basis of approved schemes for the development and deployment of sectors of the national economy and industry, schemes for the development and distribution of productive forces in economic regions and union republics, general, basin and territorial schemes for the integrated use and protection of water, schemes and projects for district planning and urban development and other settlements, master plans of industrial nodes.

When designing, it is necessary to consider the feasibility of cooperating with sewage systems of facilities regardless of their departmental affiliation, and also take into account the technical, economic and sanitary assessments of existing facilities, provide for the possibility of their use and intensification of their work.

Sewerage projects of facilities should be developed, as a rule, simultaneously with water supply projects with a mandatory analysis of the balance of water consumption and wastewater disposal. In this case, it is necessary to consider the possibility of using treated wastewater and rainwater for industrial water supply and irrigation.

1.2. In the rainwater drainage system, the most contaminated part of the surface runoff generated during the period of rainfall, snowmelt and washing of pavements, that is, at least 70% of the annual runoff for residential areas and sites of enterprises close to them in terms of pollution, must be treated, and the total volume of runoff for the sites of enterprises, the territory of which may be contaminated with specific substances with toxic properties or a significant amount of organic substances.

1.3. The main technical decisions made in the projects and the sequence of their implementation should be justified by comparing possible options. Technical and economic calculations should be performed according to those options whose advantages and disadvantages cannot be established without calculations.

The best option should be determined by the smallest amount of reduced costs, taking into account the reduction in labor costs, the consumption of material resources, electricity and fuel, as well as on the basis of sanitary and hygienic and fishery requirements.

1.4. When designing sewage networks and structures, advanced technical solutions, mechanization of labor-intensive work, automation of technological processes and maximum industrialization of construction and installation works through the use of prefabricated structures, standard and standard products and parts manufactured at factories and procurement workshops should be provided.

1.6. When connecting the sewer networks of industrial enterprises to the street or intra-quarter network of a settlement, outlets with control wells located outside the enterprises should be provided.

1.7. The conditions and places for the release of treated wastewater and surface runoff into water bodies should be agreed with the bodies for regulating the use and protection of water, the executive committees of local Councils of People's Deputies, bodies implementing state sanitary supervision, protection of fish stocks, and other bodies in accordance with Union law Soviet Socialist Republic and Union Republics, and places of release into navigable water bodies, watercourses and seas - also with the management bodies of the river fleet of the Union Republics and the Ministry of the Marine ota.

1.8. When determining the reliability of the sewage system and its individual elements, it is necessary to take into account technological, sanitary and hygienic and water protection requirements.

In case of inadmissibility of interruptions in the operation of the sewage system or its individual elements, measures must be provided to ensure the uninterrupted operation of their work.

1.9. In the event of an accident or repair of one structure, the overload of the remaining structures of this purpose should not exceed 8-17% of their estimated capacity without reducing the efficiency of wastewater treatment.

1.10. Sanitary protection zones from sewage structures to the borders of residential buildings, sections of public buildings and food industry enterprises, taking into account their prospective expansion, should be taken:

from wastewater treatment plants and pumping stations of industrial sewage systems not located on the territory of industrial enterprises, both during self-cleaning and pumping of industrial wastewater, and when they are combined with domestic wastewater treatment - in accordance with SN 245-71, the same as for production, from which receives wastewater, but not less than those indicated in table 1.