Time to save mankind from thirst?

Of the 10 years which form the un-declared Drinking Water Decade three have already passed. Mankind has accumulated a considerable experience. Several schemes which appear to be promising have failed to justify themselves. These include artificial cloud control with a view to obtaining additional precipitation. The thus provoked rains frequently fall where they are not needed.

The shortage of fresh water is also due to the fact that 80 per cent of it is diverted to the irrigation of fields (250 million hectares of agricultural land, almost 100 million of which fall to the share of the developing countries). Meanwhile stable crops can also be obtained in other equally effective ways – by employing agricultural practices designed specially for arid and by choosing the hardiest crops and their varieties. An interesting experience is that of some Baltic farms, which have introduced irrigation by low-salinity sea water.

It is absolutely inadmissible to dump uncleaned sewage into rivers and lakes. The most effective method of protecting the water environment is to shift to a closed production cycle. This offers a triple advantage: saving of water (cleaned, it can be reused), opening the way for extracting valuable substances from the wastes and ruling out harm to nature.

Today water recycling in industrial enterprises is a reality. In the former Soviet Union, for instance, recirculated water systems are already functioning in many plants and factories. The volume of recirculated water supply in our country has reached per cent of the total of fresh water used infilling production requirements.

Technological progress makes possible the constant improvement of urban water-supply systems as well. In Ukraine more than given are spent annually on construction of purifiers. Now the scale of cleansing structures inmost of our large cities makes it possible to process all industrial and domestic effluent. However, cities expand and with them water consumption also expands.

Date: 2015-09-02; view: 354; Нарушение авторских прав