Storm (rain) sewerage is a type of water disposal systems that timely remove drains from the served territory. Depending on the conditions of use, such systems may have a different set of functional components, differ in dimensional parameters and protective additions. As for the areas of application, the storm sewer system is used in the arrangement of city streets, in the infrastructure of production facilities and in the engineering and communications support of private households.
Sewage structure
Like any other plumbing infrastructure, rain sewers operate on the basis of pipeline networks. With the help of pipes, water passes from one functional point of the system to another. The working cycle begins from sections with storm water inlets that carry out local water collection. In this capacity, gutters are often used. They are mounted in the drainage ditches so that the drains can gravity flow to the distribution manifold. A variety of storm water inlets is also a door pallet. Such devices are installed either at the gate or near the entrance to the house.
Mandatory installation of storm sewer systems provides for the presence of capacitive water storage. These are devices that accumulate water collected in primary water inlets. They can be implemented in different ways, but the main task remains the same - to ensure sufficient intake of surface water to eliminate the risk of floods.
The cleaning function of the storm sewer system
Unlike a septic tank that accepts household waste and sewage, rainwater drainage does not require deep biological treatment. Of course, there are systems in which the septic tank also acts as a receiver of storm water. And in this case, the cleaning will completely depend on the capabilities of this tank. A septic tank can also act as a simple drive without cleaning functions, and as a means of multi-stage filtering. Separation of the tasks of a septic tank and storm sewage is just advisable due to different cleaning requirements. Rain water can very well be removed to the ground without the danger of disturbing the ecological condition of the soil. However, to protect the drainage complex itself, basic filtration is still required. Therefore, the storm sewer cleaning system often includes sand traps that trap large particles of soil, debris and stones. That is, mechanical cleaning filters are used that do not allow physical contamination of the pipeline, reservoir and collector assemblies.
Classification by drainage method
Currently, there are three types of sewer systems designed for rainwater. First of all, this is the aryky configuration with open drain channels. Such systems are usually used in cities and can perform several tasks, including drainage and irrigation of landscape gardens. Structurally, such networks are formed by systems of aryky concrete trays located along roads and streets. Aryk trays are distinguished by a perforated surface, which allows passively distributing water over the soil cover. Also, the system of external storm sewage can be used in the arrangement of private households with plots, but this solution will be ineffective. In urban conditions, an open system is beneficial just because of its high productivity, since it works with large volumes of water. But in a small area, the closed system option is more efficient. In this configuration, water drains are collected in trays that enter the structure of the landscape. In other words, the pipeline network is located in a soil niche and is covered with protective devices. The third option is a combined design in which open and closed sections replace each other depending on the conditions of passage of the drainage circuit.
Classification by configuration of catchment areas
Both open and closed sewer systems differ in the manner in which they are organized. In point schemes, receiving funnels with gratings are installed separately from each other. That is, small underground or ground tanks can be scattered throughout the site in accordance with the most intense flow of water. In this case, all points of the water collectors are combined into a single network directed to the drive. An alternative way is a linear layout of collections. Thus, a continuous system of drainage and storm sewage is formed on the site, which already collects several sources of water supply during the collection process. In the rest, the equipment for rainwater collection and removal channels is carried out according to general principles with the integration of filters, collector assemblies and gratings.
Rain sewer design
Even stormwater for small areas should be arranged on the basis of a design solution, which calculates the pumping lines, collection points, distribution and accumulation of water. Moreover, the basis for the project can be developed independently, by identifying the most likely sources of water spill and the optimal place for its reception. The plan will have to include the contours of drains, the location of communications, equipment and storage. More serious projects of the drainage system and storm sewage include the implementation of geodetic surveys of the area. One of the main objects of analysis will be the level of groundwater occurrence, which will determine the optimal location of the drainage system and the reservoir, which ensures the discharge of drains directly into the ground.
Installation of piping and related equipment
It is advisable to use plastic pipes, since they do not corrode, are easily mounted and practically do not require maintenance. Laying is done in a trench, the bottom of which is previously covered with sand, gravel and covered with geotextiles. Further, the formed network should be wrapped in geotextiles so that the drainage filler completely covers the surface of the pipes. Connections are made using complete couplings of the appropriate size. Then the functional units of the collectors, the collector and the receiver, with which the storm sewer system will interact, are arranged. Installation should be carried out in compliance with a bias towards the place of accumulation of water. So, at 1 m should provide about 1-2 cm of inclination. The same applies to networks in which the main collection point will be the main sewer network. You should not fill up the channels until the pipeline is tested under operating conditions.
Sewer installation
The simplest way to cover a trench with a storm sewer channel is to fill it with the same excavated soil. But for this you need to make sure that the line is tightly sealed, and in its structure are layers of sand and gravel. If the channel passes through the critical functional areas of the site, additional amplification may be required. Under paths, parking areas and the entrance to the transport, it is necessary to establish additional gain. For this, overlapping can be used, which in the future will also be covered with a dense layer of soil. But even at the stage of installation of the storm sewer system, it is recommended to calculate the load on the network using appropriate pipes. In particular, it is recommended to lay a non-perforated metal pipe under the road for the car. The use of plastic is allowed, but in an armored shell. Layers of drainage and geotextiles are performed in the same way as on the other contours.
Organization of a security zone near the sewer
Hydrological resources providing water supply, in accordance with the norms of SNiP, are introduced into special protection zones. The same rules apply to sewers. If we are talking about urban and public areas, then the radius of such sites should be about five meters. Of course, in the conditions of private home ownership, strict observance of this norm is not required, but it will still be useful to support some of the principles by which a storm sewage system with an adjacent area is protected. In particular, it is forbidden to build temporary structures near canals, arrange garbage dumps, plant flower beds and plant trees.
Storm sewer cleaning
Regardless of the type or location, rainwater drainage should be regularly flushed. For this, pumps are installed at the water collection points. In the household, you can do with one unit, rearranging it in turn to each circuit leading to the place of accumulation of water. The pump is connected to the local water supply system and the pressure jet is directed along the channel towards the slope. The flow eliminates pollution in confined areas where it is impossible to get physically. Also, the rules for using the storm sewer system require separate cleaning of the storage tank. Moreover, the internal surfaces must be regularly subjected to chemical disinfection in order to maintain the proper sanitary and ecological condition of the territory.
Features of the care of the drainage system
The drainage system associated with the sewer outlet of drains requires a special approach to maintenance. First of all, the upper layer of the drain should always be kept loose - this way it absorbs and passes water into the soil more efficiently. For the same reason, it is not recommended to walk on mounds of sand and gravel, and even more so, use heavy equipment on them. If the drainage and storm sewage system in the area is connected with intermediate wells and collector units, then they should be cleaned from dirt and sand in a separate order. It is advisable that this work be carried out automatically using pump washers with floats.
Conclusion
A variety of plumbing equipment for the garden allows you to organize a variety of configurations of rain sewers. The most reliable option will be a system in which a closed network (trench) is implemented, supplemented with trays, wells, a collector and filtering membranes. As for the cleaning function, the drainage and storm sewage system can be connected to the septic tank, which, in turn, will perform multi-stage biological treatment of wastewater. But, again, direct storm drains do not require fine filtration. It is enough to provide the system with high-quality sand traps and grids that hold up large debris. Another thing is that these components of the sewage system will require regular manual cleaning, otherwise there will be a risk of clogging of the channels and subsequent flooding of the site.