Water use refers to the process of water consumption, its source is natural objects or water supply systems.
It is customary to normalize water consumption, that is, to determine its measure established by the plan. This is done taking into account the quality of the natural resource. As well as those standards that are approved for the release of a unit of industrial production.
What is rationing for?
Its main task is to guarantee in production and in everyday life such volumes of water resources use that are most effective.
Rationing in the field of public utilities is carried out on the basis of the relevant Construction Norms and Regulations, and industrial enterprises use specially developed guidelines for this. What exactly is subject to it?
It is customary to normalize the total amount of water consumed during production (per unit), fresh drinking water, as well as technical water. In addition, water is taken into account, which is reused and recycled. As well as wastewater, i.e., sewage water (both discharged from the consumer and production).
What data does SNiP "Norms of water consumption" use?
The basis of this standardization is the so-called specific value. What is this water consumption rate? This unit is equal to the maximum permissible water volume accepted under the plan (with the appropriate quality), which is required for the production of a unit of production of a standard sample under certain production conditions or for consumption for drinking or economic purposes.
The formation of specific norms is carried out by using their element-wise components. What is laid in them? Basically, we are talking about the specific consumption of water for production (per unit) or for the volume (area) of the enterprise. The same rate of water consumption for the enterprise exists for each individual process, which includes both its drinking and household needs.
Another calculated value governs those losses in the production cycle that are irrevocable. We are talking about leakage, evaporation, entrainment, filtration, etc. These are commonly referred to as factory, industry, and interbranch ones. Norms are measured in physical units (liters, cubic meters, etc.).
About rationing of water disposal
But experts are not only interested in the rate of water consumption. It turns out that the opposite procedure is also subject to accounting. Water disposal, that is, discharge of water, is the process of removing wastewater beyond the places where the primary use of the resource occurs (enterprise, locality). They are removed to natural sources or transferred for cleaning to specialized organizations.
Under the norms of water disposal is meant the planned largest number of effluents, also accepted per unit of output. At the same time, water can belong to one of two degrees of pollution - conditionally (normative) pure and requiring purification.
In connection with the continuous improvement of technologies, the norms of water consumption and water disposal are reviewed without fail after five years. They are calculated directly at the factory with the approval of management.
How water quality is taken into account
Requirements for the quality and composition of drinking water in centralized water supply systems are set out on the pages of SanPiN, published in 2001.
Industrial water is divided into 4 separate categories with their own requirements for each.
I - water-coolant at thermal power plants, nuclear power plants, etc. The presence of mechanical impurities, rigidity and aggressiveness are excluded. Effluents of such water do not need to be treated, but can be hot.
II - water for washing products, containers, raw materials. The drains are highly contaminated.
III - raw water (for food products, in the construction industry, etc.).
IV - water for complex use.
Given this separation, production technology is selected as rationally as possible with minimization of environmental damage.
What is the water consumption limit?
This is taken according to the calculation results, the basis of which is the norm of water consumption, the amount of drinking and industrial water for each enterprise according to production conditions, planned losses, and a program for saving resources.
The limit of wastewater is the amount of wastewater consumed that is sent to a natural object, taking into account its condition and standard standards.
Both of these limits, calculated and accepted directly at the enterprise, must be approved by the water use agency. They are generally accepted for a period of one year, but in difficult conditions with water resources - monthly or even daily.
Water in the household
Providing the population with drinking water is the most important matter on a national scale, one of the first duties of the authorities of any locality. In the absence of clean drinking water, diseases instantly arise - right down to epidemics. The world is still full of places where access to water of acceptable quality is an inadmissible luxury.
In our country, the Water Code proclaims the priority of public water supply. First of all, regardless of conditions, the population should be provided with clean water. Its supply should not be below the 97% mark (this means that only three days out of a hundred interruptions in water are permissible).
Of course, in this area there is its own norm of water consumption. The structure of municipal water supply in this case is as follows.
56% is allocated to drinking water supply, 17% to public buildings, 16% to industry. The rest goes to other needs (firefighters - 3%, city - fountains, watering, etc. - 1%, the same for all others).
Household drinking water is consumed in the following percentage: for drinking and food purposes (cooking) - 30%, for washing - 10%, use of bathtubs - 30%, flushing of toilet tanks - 30%.
Norms of water consumption - a day in a big city
Residents of large cities are allocated up to 600 l / day of water for all domestic and communal needs. This is the norm of water consumption per person. The structure of its consumption looks like this:
- for personal needs - 200 l;
- for utilities - 100 l;
- to maintain urban cleanliness - 100 l;
- to local enterprises - 200 l.
For municipal water supply the following is characteristic.
Water quality should be extremely high in terms of properties of both physical (color, transparency, taste, smell) and chemical (hardness, mineralization, acidity, composition of impurities) nature.
This also includes the content of organic substances, the normalized radiation of radioactive particles, the bacterial composition. Drinking water should not contain parasites, viruses, pathogenic microbes.
The best water
Quality standards (the first of them in our country dates back to 1937) tend to tighten from year to year.
What is the reason for this? Science does not stand still, every year new facts about the effect on humans of certain substances appear. Accordingly, the quality requirements for the composition of water are subject to revision.
The best content is in interstratal underground artesian waters, which are considered as protected from pollution. Somewhat worse - groundwater, not so deep, but less suitable for water supply surface water.
So that the water meets the quality standards, it is subjected to filtration, coagulation (sedimentation of impurities), chlorination, removal of unwanted and the introduction of the necessary impurities.
About uneven consumption
Another property of water consumption in the housing sector is the combination of relative uniformity of water consumption throughout the year with uneven daily. If the percentage of seasonal fluctuations is no more than 15-20, then the difference is much greater per day (about 70% of the water we spend in the daytime). Therefore, a special coefficient of unevenness (hourly and daily) has been developed. Thanks to it, the fluctuation of water consumption by hours and months is taken into account, which is required when designing supply systems. After all, their task is to provide guaranteed supply even in the maximum water consumption mode.