What and how our streets are sprinkled

What and how our streets are sprinkled

On February 11, in Andorra la Vella, an international conference dedicated to the issues of winter treatment of roads ended. During the discussions, the participants came to the conclusion: the most advanced anti-icing technologies are used ... in Moscow. Formates, which are part of the reagents used in the capital, reduce the corrosive activity to the metal. Is it really true? But what about shoes eaten by "chemistry" and unfortunate animals suffering from burning asphalt? In order to find out what the streets of the capital are sprinkled with, Novaya conducted its own investigation, submitting an anti-icing preparation scattered on the street for examination.

In fact, they stopped “salting” the capital long ago. PhD in Chemistry, head of the ECHO chemical and environmental center Mikhail Reinov said that now sodium chloride (table salt) is used only by poor regions of the country. In Moscow, multicomponent reagents based on chlorides, formates and acetates are used.

- There is such a thing - "synergistic effect". This is when the components of the mixture enhance each other's action. So manufacturers are experimenting, selecting mixtures of calcium, sodium, potassium and sodium formates, adding biophilic components (urea, potassium chloride) to find the composition that is optimal in terms of price, efficiency and environmental impact, explains Reinov. (see table).

— In general, a quite predictable picture, — Mikhail Reinov comments on the results of our examination. - It seems that the content of formate is greatly underestimated - it is only 3.34%. The presence of a small amount of sulfate may be an impurity in the reagent used. Sulfate is harmless, does not bring harm to humans and animals, and in such small quantities it does not pose a threat to the soil either. Bischofite, also known as magnesium chloride, is actively sold wholesale and retail as an anti-icing agent. And if the analyzed sample was collected near some public building - a store, an office center, etc., then it is possible that the area near this building is periodically processed by workers from this building with purchased bischofite, and therefore a small amount, along with dirt and snow, got into a sample. Marble chips must be on the sidewalks, everything is correct here, it is marble, not granite.

But not everything depends on the reagents. It is much more important whether the technology of winter street cleaning is observed. The treatment of territories with anti-icing reagents is regulated by the document of the Department of Housing and Public Utilities of Moscow "Technology of winter cleaning", adopted in 2010.

The regulations clearly spell out how and with what to treat the icy surfaces of the capital's roads and sidewalks. Different reagents are used depending on the temperature. If the street is up to -8, then the roads must be treated with a liquid reagent. In frost down to -12, combined mixtures are used. And in the cold, a strong reagent is used from a mixture of formates (by the way, it is formates, according to the participants of the conference in Andorra la Vella, that are the best and safest to save from sleet).

In heavy snowfalls, it is necessary to cultivate the area after every 5 centimeters of snow that has fallen. Moreover, for processing, special machines are needed, equipped with an automatic system for distributing the substance.

If the fight against ice goes according to the regulations, the bulk of the reagents should end up at the snow melting point, and the remaining small part of them will not harm the environment.

But with the observance of technology - big problems. For example, on the streets of the capital, you can see trucks from which employees manually scatter reagents. This violates the dosage and uniform distribution of the substance. Wipers can scatter dry mixture even during a thaw and in completely arbitrary quantities (in fairness: the “Winter Cleaning Technology” does not indicate the standards for how much reagent should be per square meter of road surface). In addition, the snow porridge soaked with reagents is not always removed on time - as a result, the reagents enter the soil in excess.

PS*Pet owners are sure that reagents are detrimental to the health of their pets. This is not entirely true: dogs do not suffer from chemical burns caused by harmful mixtures. In winter, animals are more likely to be threatened by thermal burns due to rapid temperature changes. Reagents have high thermal conductivity, and therefore the liquid saturated with them, into which snow turns, quickly absorbs heat from the paws of domestic animals. In the case of severe frosts, such rapid heat exchange can cause burns on the sensitive skin of dog paws. *

Foreign experience

With ice in different countries are struggling in different ways.

Sand-salt mixtures . European roads are often sprinkled with sand-salt mixtures. The disadvantage of sand is that it clogs sewer drains. In addition, in the spring, during the post-ice period, it is very difficult to clear the streets of sand, and its disposal is not cheap.

Technical salt . In some countries, the streets are "salted" - only not with table salt, but with industrial salt. Technical salt is used, for example, in the United States. But this is one of the most environmentally harmful ways to deal with icing - shoes and clothes deteriorate from tekhsol, iron structures rot and soils become saline. Salt manufacturers in Russia are trying to balance the harmfulness of salt with other components that partially mitigate the impact of sodium chloride on the environment.

Baby . In some European countries, where the use of salts is limited, roads are treated not with reagents, but with stone chips. Very practical, for example, they do it in Finland. In the spring, gravel that has not been rubbed into powder is collected here (this is done using special equipment that looks like large vacuum cleaners). The gravel is washed and stored until the next winter to be used again on the roads.

Road heating . In some regions of Norway, for example, roads are heated instead of reagents. Under the sidewalks and highways, heat communications are laid - so the snow does not accumulate on the roads and immediately melts. Roads without “heating” are treated with boiling water and sand: hot water melts the ice, at the same time, grains of sand penetrate the ice cover to the asphalt, and when the road freezes again, a porous ice crust forms, so the roads are not slippery. In Japan, most of the bridges are "heated up". A few years ago in Russia, it was also planned to build several heated test roads as part of the Innovative Road program. The results of the experiment are not yet known.

"Carrot and stick" . In the United States, not only special equipment is fighting icy conditions, but also local residents with volunteers. They get all the necessary equipment from the municipalities, collect the snow-salt mixture and take it out. The collected "porridge" is then disposed of by special snow-melting machines. At the same time, in America and Canada there is a system of fines for evading snow and ice removal. If a private company or owners of private houses do not clean nearby sidewalks on their own, then they face a fine of $ 25-100. They are also obliged to pay for treatment and compensate for moral damage to a person if he accidentally slips in the territory for which private individuals are responsible.

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