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precipitation (with snow only after thawing) takes depending upon the surface,on those the precipitation falls, different ways:
The water seeped with an infiltration rate, those dependent is from the already existing water content of the soil and the permeability of the soil. The not seepable quantity fills up the hollows, and after the hollow replenishment the residue flows abovegrounda waters off. Depending upon temperature, sun exposure and wind velocity a part of the water evaporates.
With natural fastened surfaces the portion of the infiltration is large, and only with heavy rain aboveground water flows off.
With fastened surfaces the portion of the infiltration is small, and most waterflows off aboveground.
With the drainage of roads outside of localities the rain water is often led over the shoulder directly laterally in a ditch or an infiltration hollow. If area conditions or the contamination of the rain water do not permit this, the water becomes over rainwater gutters and road intakes into a rain water channel led.
Within localities with the separation system the rain water is led over rainwater gutters and road intakes into a rain water channel, while the waste water is derived separately in a waste water channel.
With the mixing system the rain water is likewise collected over rainwater gutters and road intakes, but together with the waste water (mixed) in a combined sewage channel derived. Since the peak discharges cannot be treated with strong rains in the purification plant, at suitable locations combined sewage discharges are built, at those combined sewages in the order of magnitude 2 - or triple waste water discharge to the purification plant passed on and the remaining diluted water ina waters is relieved . Usually this discharge with a rainwater treatment is combined.
waste water fee
of sealed surfaces into public drains rain water running off must i.d.R. as waste water to be paid. If a split fee for dirt and rain water is raised, the fee computes itselfafter the sealed surface, otherwise as addition to the fee for the waste water.
by the increasing surface sealing comes it with violent rainfalls to overloading of the sewage systems and inundations , there the coming down water runs off immediately again and again and not in the soilto seep can. In drains or between drains and waters rain support plants are established, in order to obtain a discharge comparison moderation to the receiving stream and an absorption of the discharge points.
contamination of rain water
rain water takes in the atmosphere and with the discharge on fastened surfaces and in the rain water channelor combined sewage channel of pollutants of different origin up:
- atmospheric dirt and pollutants
- at the earth's surface taken up materials
- of waste water constituents of the Tockenwetterabflusses
- Resuspendierte of materials from channel deposits
- eroded Sielhaut
in mixing drains arise rather higher concentrations at individual suspended matters, organic contents material as well as nitrogen - and to phosphorus connections than in separation drains.There partially high concentrations at filter offable materials arise , which can clearly exceed the values of mixing drains.
The concentrations are very different as a function of the catchment area, rain duration, rain quantity and other factors. In the order of magnitude is however the contamination of rain water from rain water drainsand of relieved combined sewage equally large.
use of rain water
the use of rain water as custom or industrial water enjoys of increasing popularity.The rain water is usually caught in addition in underground cisterns. Even if rain water is used in the toilet flushing, further valuable drinking water can be saved.
Owners of rain water use plants do not need to pay the waste water fee only if they can prove that the water only for the garden one uses.
Also a far spreading of rain water cisterns can reduce the discharge of floodwater in waters only few, since on the one hand the cisterns are filled with weather conditions, which can lead to flood, usually, thus no rain support volume offers, on the other hand the theoretically possible volume in the comparison toDischarge of floodwater is much too small.
|Wiktionary: Rain water - word origin, synonyms and translations|