About Quality and Quantity: Seven Questions about Water Supply of Moscow

January 5
Municipal services

The Moscow water supply system is the oldest engineering structure in the city. It was officially opened in 1804. The aqueduct in Rostokino, that supplied water to Moscow from Mytishchi, reminds one of that time.

The capital water supply history began in the 19th century with construction of the first water pipeline, a little more than 20 kilometers long. Today, the length of Moscow's water supply networks exceeds 13 thousand kilometers, the city consumes about three million cubic meters of water daily, and Mosvodokanal, the largest water company in the country, is engaged in its preparation. The quality of drinking water is monitored around the clock according to 184 physico-chemical, microbiological and hydrobiological indicators at all stages of its way to the consumer. This year, more than 1.5 million analyses were performed," said Pyotr Biryukov, Deputy Moscow Mayor for Housing and Communal Services and Landscaping.

What the Moscow water supply system is today and what tap water is like — experts of Mosvodokanal JSC told mos.ru.

1. Where does Water Come to Moscow Water Supply System from?

Mosvodokanal is responsible for water supply to apartments. The largest company in its industry in the country renders services to almost 15 million consumers. Water is taken from rivers and reservoirs located in three regions — Moscow, Smolensk and Tver. From there it goes to the water treatment plants. Moscow has four of them: Rublevskaya, Zapadnaya, Severnaya and Vostochnaya. They can jointly produce over six million cubic meters of clean water per day. Water from rivers and reservoirs remains here from eight to 24 hours.

During this period, it undergoes several degrees of purification: it is settled, clarified, passed through sand filters and disinfected using special reagents. The stations are gradually modernized — in new reservoirs water is ozonized and passed through activated carbon. Membrane filtration is also used here: water is "forced" through a semi-permeable membrane with pore size of 0.01 micrometers. For comparison, the diameter of a human hair is about 50 micrometers. The technology both preserves the natural salt composition of water and safely removes bacteria and viruses.

Once water is completely purified, it enters the longest water pipeline in Russia — it runs for 13 thousand kilometers. Water can run to consumers through pipes for up to 12 hours, depending on the distance between the water treatment plant and the apartment.

2. Why is Water Chlorinated?

Water is purified using sodium hypochlorite with ammonia water added. As a result, substances with bactericidal properties ensuring safety are present there for a long time, and this is necessary where the water supply network is very long. This technology is used not only in Moscow, but in Paris, London and Tokyo too.

Mosvodokanal completely abandoned highly toxic liquid chlorine nearly10 years ago and switched to more technologically advanced sodium hypochlorite. It protects water from bacteria and microorganisms penetrating into it.

3. How Hard is Moscow Water?

The water from the Moscow water pipeline is classified as moderately hard. In all districts of the city, the minimum and maximum hardness values range from 1.9 to 5-5.7 hardness degree.

Surface waters (reservoirs and rivers), which are sources for the Moscow water pipeline, are softer than underground (artesian) waters. Their water hardness varies throughout the year: the highest values are usually in winter, but even then nothing needs to be further softened — the hardness is within the acceptable limits. In spring, when a lot of soft meltwater and rainwater gets into rivers, the indicator drops to minimum values.

At water treatment plants, hardness is not regulated in any way — it remains natural. Most often, it makes no sense to look for softer water. Absolutely soft drinking water is not suitable for a human. It is important for him to get magnesium and calcium with water, the salts of which just determine the hardness. According to the World Health Organization, to get a sufficient amount of these substances, the water hardness should be at the level of five degrees. If you switch to very soft water, the body may need pharmaceuticals.

4. How is the Operation of Such a Huge Water Supply System Monitored?

Thousands of Mosvodokanal employees monitor the large-scale network. They monitor the water supply system operation, conduct hydraulic tests, repair and reconstruct water pipe sections. Over the past 10 years, they have managed to avoid accidents that would require serious interventions and long shutdowns.

The company renews about 100 kilometers of water supply networks annually. Trenchless technologies are used during the scheduled works: new pipes are laid inside existing ones, horizontal directional drilling and polymeric hoses are used. This allows to minimize excavation works, which is critical in large megalopolis areas. By the way, the Moscow water supply is a looped system, and most often there is need to cut water supply to premises during repair works.

5. Who Controls the Water Quality and how Is It Controlled?

The water is checked all the way from the reservoir to the apartment. 450 lab employees conduct more than six thousand tests for physical and chemical, bacteriological and hydrobiological parameters every day. Water is first checked in the river heads in the Tver and Smolensk regions, then it is monitored at more than 140 points all the way to water treatment stations. The water treatment plants control water at 170 points of all stages of purification. The water supply network has over 250 control points.

Beside people, water is checked by automatic analyzers. More than 500 devices are installed at sources, water treatment plants and in the city network. They monitor water quality in a non-stop mode. One can see the values at a specific address on the website of Mosvodokanal JSC.

6. How is Water Quality Changing in Moscow Over the Years?

Statistics argue with those who believe that grass used to be greener and tap water cleaner. Data analysis shows that water quality has improved significantly over the past 20-25 years. Changes occurred in all indicators: turbidity decreased fivefold, aluminum concentration — threefold, the content of natural organic matter — by 1.5-2 times. The main reason is regulatory tightening that modernized the system.

The first water quality standards appeared in Russia in 1937. They gradually changed, but not fundamentally. The requirements for drinking water were rather getting less strict. The situation changed as late as in the 1990s, when monitoring of the content of organic matter and chloroform was introduced, and requirements for the content of viruses and parasites were tightened.

7. Will Moscow Have Enough Water in the Future?

Moscow does not lag behind the world's megalopolises in this matter. Despite the growing city, its water consumption does not increase. Moreover, it decreased by 30 percent over the past 10 years. The main reasons are that industrial enterprises are moved outside the capital, water meters are widely used in living premises, and infrastructure reliability is improved.

Today, a Muscovite consumes an average of 127 liters of water per day. This figure is reduced by two to three percent every year.

Water treatment plants have a large capacity reserve, so Moscow will have enough water even with a spike in consumption. The capital region consumes about three million cubic meters of water daily, and this is half of the planned stations’ capacity. Such a reserve ensures supply of water both to Moscow and the Moscow region. Water from the capital's water supply system comes to living premises of Dzerzhinsk, Mytishchi, Lyubertsy and other towns of the region.

Source: mos.ru

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