Библиографическая ссылка на статью:
Весман А.В. Cleaning and restoration of water objects // Современные научные исследования и инновации. 2012. № 3 [Электронный ресурс]. URL: http://web.snauka.ru/issues/2012/03/10636 (дата обращения: 20.11.2016).
Water object – concentration of water on a land surface and in forms of its relief or in the bowels. Water object have borders, volume and lines of a hydrological mode. Reservoirs and waterways concern water objects.
The seas, oceans, the rivers, lakes, bogs, water basins, underground waters, and also waters of channels, ponds and other places of a constant concentration of water on a land surface (for example, in the form of a snow cover) are water objects. Water objects make a basis of water resources.
Settlements water supply is carried out from surface sources, quality of water in which becomes worse every year because of increasing anthropogenic load on components of natural environment. Because of this the value of fresh water as natural recourse is permanently grows.
The main part of all pollutants is a product of the human economical activity.
Water pollution is a big problem for a lot of countries. Here are several the most polluted rivers of the world:
1.Citarum — the river in Indonesia, proceeds near the capital of the country – Djakarta. Also collects a waste from the city with the population of 9 million persons. The local population has already forgotten that fish was found in the river. To collect dust in the river and to hand it over for processing — now much more favorably, than to fish.
This river is similar on disposal tip, but it is actually main source of water for agriculture and water supply for people.
The river in the big degree is polluted by human activity and has no water life. In December 2008, the Asian bank of development has given out the loan for $500 million to clean dust from the river. But, obviously, years be required to restore the dead river back to life.
2.Yamuna – the river in India in the general extent of 1376 km. Is the largest inflow of Ganges. It is one of the most polluted rivers in the world where 58 % of dust from the Indian capital New Delhi are fallen down in the river.Government of India has invested a lot of money to clean up the Ganges and Yamuna, but so far it’s useless.
3.Buriganga — the river proceeding about Dacca, the capital of Bangladesh, one of sleeves connecting Ganges with Brahmaputra. It is one of the most polluted rivers of a planet: it is impossible not only to drink water from the river, but even to use for washing and the technical purposes. Though in the country there is a legislative interdiction of dump of a waste in the rivers, in Buriganga daily merges 1,5 million cubic meter of industrial wastes. The river is recognized biologically dead.
4.Marilao river, Philippines.
You can find plastic bottles, labels, rubber bedroom-slippers and other dust in river Marilao. Waters contain poisonous chemicals, such as chrome, cadmium, copper and arsenic. This structure does water very dangerous. Despite slogans not to pollute water and impressive penalties, people still throw dust, and factories merge the waste in the river that leads to its further pollution.
5.The river Ganges is stretched from the Himalayas to Indian ocean on territories of India and Bangladesh, throughout 2510 kilometres. At present the river Ganges is very polluted. It is connected with fast growth of the population of India, industry influence, absence of the modern water drain. As a result of water pollution are extended set of illnesses, including a cholera, a hepatitis, a typhus and a dysentery. About 80 % of all problems and thirds of lethal outcomes in India occur to health because of dirty water.
In spite of the fact that the majority of the dirtiest water objects are in Asia, for other countries clearing and preservation of quality of fresh water is the important problem too.
Water deterioration not a unique problem: Building of water basins, roads and other human economic activities influences a hydrological mode too. Sometimes it leads to disappearance of water object.
The main sources of distribution of pollution and its influence on environment
The water object which is located in conditions of a natural-technogenic landscape in a greater degree is subject to pollution in comparison with the water object which is in conditions of not broken landscape.
The reason of it is that all pollutants come from refuse. And at unsatisfactory system of its removal pollutants migrate with products of wind and water erosion in environment.
The sources of distribution of pollutants could be classified:
1.The sources of dissipated distribution. These are objects from which pollutants arrive in an environment by diffusion way (for example, emission in atmospheric air).
2.The sources of local, concentrated distribution (for example, places of accumulation of production wastes and consumption, concentrated releases of sewage and etc.).
All sources could be conditionally divided in “initial” and “repeated”:
“Initial” sources – sources which promote pollutants receipt into surface water.Pollutants come from refuse or are the product of a technological process.
“Repeated” souses – sources which are formed as a result of physical, biochemical and others processes in environment after receipt in them of components from initial sources (for example, bottom deposits – anthropogenic silts).
Accumulation of pollutants in components of environment can be estimate by this dependence:
Zs=C1/Cb1+…+Cn/Cbn , where
Zs – summary indicator of accumulation of pollutants, C1-Cn – concentrations of each pollutant, Cb1-Cbn – background concentrations of each pollutant.
Water objects in most cases are a final link in flowing accumulations of the biggest parts of mobile technogenic substances. In landscape-geochemical systems substances from higher levels to lower hypsometric levels come with surface and underground flows, but in opposite direction only with atmospheric flows and rarely with streams of live substance.
Landscape elements representing initial, the highest links are geochemically autonomous. Also receipt of pollutants in these elements is limited.The elements of a landscape forming lower steps of geochemical system represent dependent or heteronomous elements which along with receipt of polluting substances from atmosphere receive a part of the pollutants arriving with a underground and surface flows from higher links of landscape-geochemical system.
Picture № 1 is elementary diagram of migration of pollutants in landscape-geochemical systems.
Self-recovery of water objects
Self-recovery is very important trait of natural systems. There is maximum permissible load that natural system can suffer from without irreversible changes. Also there are some processes which influence on the process of self-recovery. These processes can be divide into processes promoting clarification and processes promoting increase maintenance of harmful components.
Processes promoting clarification:
1.1. Mechanical sedimentation of suspensions
2.2. Biological or chemical oxidation of organic and other polluting substances with their mineralization and sedimentation.
3. Chemical processes passing with participation of oxygen, neutralization of heavy metals and similar pollutants
4.Absorption by bottom deposits and vegetation various pollutants and etc.
In water objects proceed processes of self-cleaning from heavy metals. For various components of polluting substances intensity of clearing processes depends on concrete conditions and fluctuates in considerable limits. Self-cleaning proceeding under the influence of chemical processes, depends as on a self-cleared component and its initial concentration, and from temperature, rigidity of water, a geological structure of a channel, presence of the centers of secondary pollution, and also from other factors.
Processes promoting increase maintenance of harmful components:
1.Escalating of organic weight by water plants by eutrophication
2.Secondary pollution of water by bottom deposits
3.Channel pollution by the died off trees and other dust
Weight of polluting substances left bottom deposits for a certain time interval, taking into account its molecular and convection diffusions in bottom deposits can be calculate according this formula:
M = F*(Cd – Cw)*(Dz*(t/n))^(1/2),
where F- square of polluted area, Cd and Cw- concentration of pollutants in bottom deposits and in water, Dz- index of molecular diffusion in bottom deposits, t-time interval, n-index of convection diffusion in bottom deposits.
Example of self-recovery
The great example of self-recovery is Spirit lake near the volcano Sent-Helens in northern part of USA. In 1980 there was an eruption of a volcano which has destroyed traces of residing of people in a multikilometer zone, and the lake has transformed into a fetid swill. In 1982 there was created a zone closed for visiting. Sent-Helens is the best natural laboratory for study ecosystem, reviving after eruption, in the world. Scientists enclosed this territory and wanted to know how would be restored the ecosystem, completely destroyed by a volcano, by itself, without the aid of people and influence from outside.
This picture shows the types of destructions: violet zone- zone of landslips and falling of fragments; pink- zone of dirt landslips; dark brown- zone of trees destroyed by lava; brown- zone of uprooted or bunt down trees. And there is the lake Spirit in red circle.
So how self-recovery proceeded?
When the top part of a volcano has slid off in water with a speed 240km/ch lake have filled the rests of the organic chemistry which has burnt down during eruption. Water was filled with solutions of coal, manganese, iron and lead, has got warm to a body temperature, and there in “industrial” scales bacteria began to breed. Aerobes were replaced by anaerobes, then there were bacteria eating nitrogen, then eating methane and heavy metals. In 1,5 years of a bacterium have started to die out, and inflow of clean water with streams and thawing snow has made water transparent. Further there were colonies of seaweed, behind them insects and amphibians have come. To the beginning 90s on shoal began to grow macrophytes and there appeared a trout which has quickly reached record weight.
Human activities of water treatment
In Russia, all human activities related to water resources regulates “The Water Code of the Russian Federation”.
The basic principle of economic regulation of the use, restoration and protection of water bodies is a payment for water use.
Economic regulation of the use, restoration and protection of water bodies provides for the establishment of systems: payments associated with the use of water bodies; finance the rehabilitation and protection of water bodies; economic incentives for sustainable use, restoration and protection of water bodies.
All types of cleaning water bodies can be divided into mechanical, chemical and biological.
Mechanical cleaning can be with or without earth-moving equipment. It use dredges, diving operations and etc.
Often at such type of clearing it is applied dredges with a various kind by the equipment: a rake, a ladle-pump, clamshell, a ladle for selection of the sunk wood, the device for installation metal tongue or wooden piles and etc.
Also various filters are applied.
This type of cleaning has big shortcoming: it is a problem of utilization of bottom deposits and other litter which were pulled from the water object. Also use of dredges and other devices can cause damage to benthic organisms and other inhabitants of the pond.
Chemical water treating is directed exclusively on formation an environment in a water object, where certain groups of substances or microorganisms are deactivated and water becomes clear. Thus formed deposit with certain periodicity also is required to be deleted mechanically.
Also application of biological products is possible. One of them contains (6-12) kinds natural aerobic and facultative mesophilic natural microorganisms for which the basic energy source of ability to live are organic substances and nutritious elements of nitrogen, phosphorus in water and bottom deposits of a pond.It is necessary for natural microbiological self-cleaning of a reservoir a complex of the natural microorganisms allocated from ecosystems of healthy balanced reservoirs. Thanks to preparation action consequences of pollution of a pond will be neutralized, the general loading on a reservoir decreases, in a reservoir self-cleaning is restored natural biological: water and ground adjournment are cleared of the organic chemistry, the weighed substances, nitrogen, phosphorus, the oxygen mode is restored, level of bottom deposits goes down, microbiological self-cleaning of water from harmful microorganisms (effect of self-disinfecting of a reservoir) is repeatedly intensified.
These pictures show some examples of using this type of cleaning:
Cleaning water bodies from oil
Liquidation of floods on a surface of water object assumes oil gathering by boom barrier, devices of various updating (petro collectors), sorbents, and also superficial application of biological products of microorganisms-destructors of oil.In time not taken operative measures on localisation and gathering pollutant lead to that oil or mineral oil absorbed by suspended in water organic and mineral particles, water vegetation and finally get on a reservoir bottom, negatively influencing on communities of benthic organisms up to their full degradation.At the moment, the Russian practice of cleaning water from oil and petroleum products to a greater extent is reduced to its collection from the water surface by materials and means of localizing and sorption with subsequent use of skimmer and extractors systems.Methods of cleaning sediment from oil using a pumping unit for the removal of contaminated sediments are not applied in practice due to formation of large amounts of contaminated soil, which should continue to be disabling (for removal of contaminated sediment layer at 10 cm from 1 ha of the bottom surface leads to the formation of 1,000 m3 of contaminated soil).
One Russian company has developed an improved method of water purification from oil and petroleum products.The first stage provides for technical cleaning for the pond – the collection of oil from the surface water and sediments, and shoreline cleanup. The second stage allows for the biological treatment – enhancing the ability of aquatic ecosystems to cleanse itself.
An example of such work: lake Schuche, Komi Republic
An example of human activity on cleaning the reservoir
The good example of human activity is cleaning of the Great Lakes.
Great Lakes (U.S., Canada) comprises a group of 5 lakes in eastern North America, in the St. Lawrence River Basin:
·Top (area – 82,400 km2, maximum depth – 393 m)
·Huron (59,600 km2, 208 m)
·Michigan (58 000 km2, 281 m)
·Erie (25 700 km2, 64 m)
·Ontario (19 500 km2, 236 m)
Before the beginning of 1970 lakes were contaminated with harmful substances due to lack of industrial wastewater treatment, the income from the runoff of fertilizers and waste. Thus, in this period, Lake Erie suffered from excess phosphorus, algal blooms, declines in fish populations. Particularly affected were indigenous (local) communities living aquatic organisms.
Since 1972, private and public sector spent over 500 billion USD for the control and treatment of wastewater, mainly – municipal and industrial point sources of pollution. In 1972, Canada and the U.S. began a systematic work to clean up the Great Lakes, resulting in dramatically reduced the discharge of pollutants from land-based point sources. Later in the Agreement in 1972 was supplemented in accordance with the current situation. So, in 1978, the Agreement included provisions on the need for an ecosystem approach in environmental activities and the need to combat persistent chemical pollutants. In 1987, the main areas of environmental policy for phosphorus load reductions, pollution coming from the air and land, and the problems associated with contaminated sediment (to reduce secondary pollution) and groundwater. In the same year plans were made for action to clean up previously identified 43 areas and begun extensive work on the implementation of action plans. Accordingly, the relief was cut in the number of persistent toxic chemical contaminants. Since 1972 there was a decrease of 71% of the volume of production, use and disposal of sewage 7 major toxic compounds. Since the end of 1980 managed to achieve reductions of toxic substances by 82%. As a result, drastic reduction of phosphorus and other pollutants significantly reduced algal growth in Lake Erie, and decreased oxygen deficiency in bottom waters. Announced earlier “dead” lake has become the world’s largest mining areas perch.However, in 1990 rapid urban and industrial development continued to cause environmental damage to the watershed. In the Great Lakes, found up to one thousand kinds of toxic pollutants that come there with sewage and acid rain. The problem of acid rain remains one of the most acute, approximately 50% of acid rain in Canada come from the United States. It was also found that 96% of chlorine-containing compounds in the waters of the Great Lakes come from the atmosphere. Perhaps that is why Canada has signed the first signatories of the Kyoto Protocol to regulate greenhouse gas emissions and put in its territory a mandatory reporting system on the quantity released into the atmosphere of greenhouse gases for industrial enterprises. At the same time, the U.S. has not signed the Kyoto Protocol.
To solve the problem in the first half of 1990 U.S.A. and Canada have developed a strategy to protect the Great Lakes from pollution by toxic substances, which started since 1997. The strategy includes activities related to the replacement of highly toxic chemicals in industrial cycles on low toxicity to the phasing out of substances that present a risk to human health and the environment. According to experts, the Strategy makes a significant contribution to the reduction and elimination of toxic chemicals in the Great Lakes Basin Ecosystem.
Also there are some eco-courses for school students and students about Great Lakes, where students receive environmental education and contribute to the conservation and cleaning of lakes.
Impact of changes in hydrological regime
Human economic activities often affect the hydrological regime of water bodies, either directly (construction of reservoirs, dams, dikes and other waterworks) or indirectly (road construction, soil compaction, a fence of small rivers into sewers, drainage of wetlands, etc.)
One of the best examples of such effects is the Aral Sea.
The Aral sea — was mouthless salty lake in Central Asia, on border of Kazakhstan and Uzbekistan. Since 1960th years of the XX-th century a sea level (and the water volume in it) began to decrease quickly owing to a fence of water from the basic feeding rivers Amu Daryas and Syr-Darya for the purpose of an irrigation, in 1989 the sea has broken up to two isolated reservoirs — Northern (Small) and Southern (Big) Aral sea. Prior to the beginning of a shallowing Aral sea was the fourth lake on size in the world.
The sewers-drainage waters arriving from fields in a channel of Syr-Darya and Amu Darya, became the reason of adjournment from pesticides and various others agricultural poisons, appearing in places on 54 thousand in km ² the former sea-bottom covered with salt. Dusty storms carry salt, a dust and poisons on distance to 500 km. Sodium bicarbonate, chloride of sodium and sodium sulphate are transferred by air and destroy or slow down development of natural vegetation and agricultural crops.
According to calculations of scientists to rescue Aral Sea is already impossible. Even if completely to refuse a fence of water from Amu Darya and Syr-Darya the former water level in it will be restored not earlier than in 200 years.
Since 1950th years and on the present were repeatedly offered projects on building of the channel for a transfer of waters from pool of Ob in pool of Aral sea that would allow to develop considerably economy of Priaralja (in particular, agriculture) and partially to revive Aral sea. Such building will demand very big material inputs (from outside the several countries — Russia, Kazakhstan, Uzbekistan), so practical realization of these projects is impossible.
The majority of experts do not see ways on restoration of level of all sea, except the Soviet project on turn of the Siberian rivers. In 1990th years it has been decided to rescue at least northern part of the sea (the Small sea or Small Aral).
Within the limits of the project «Regulation of a channel of the river of Syr-Darya and Northern Aral sea» in 2003-2005 Kazakhstan has constructed from peninsula Kokaral to a mouth of Syr-Darya the Kokaralsky dam with a hydraulic engineering shutter (which allows to pass superfluous water for regulation of level of a reservoir), fenced off Small Aral from other part (Big Aral). Thanks to it the drain of Syr-Darya accumulates in Small Aral, the water level here has grown to 42 m, salinity has decreased that allows to plant here some trade grades of fishes.
Another example is the restoration of nature after the extraction of gold.
In the Amur region gold-bearing scatterings are developed more than 100 years, thus annually anthropogenous loading is tested more by than 1500 hectares of the earths. In this time the area of territories of the natural Environment injured with gold mining, has reached 36 thousand hectares.
Usually, placer gold mining is conducted in channels of the rivers which are the basic sources of gold-bearing sand. There are various technologies of a gold mining, but all of them are similar in one – at carrying out of mountain works is carried out so-called “removal of peat” that means removal of the top layer of the earth at utter annihilation of soil horizons. At dredges way of extraction the range is prepared by carrying out removal works and all time moves ahead of the river of a drag moving on a channel. For its moving the foundation ditch (deep enough reservoir) is created. A drag usually name «floating factory» though it floats figuratively words. It turns out that the drag as though “irons” a river channel.
By this time in the Amur region as a result of gold mining in such a way are destroyed about 150 small rivers, total length about 200 kilometers, with a reservoir more than 12 thousand square kilometers.
These pictures show the part of the river Maliy Karaurak in the Amur region before and after gold mining.
As researches have shown, the nature can be restored approximately in 70 years, but the river don’t restored, backwaters and bogs are appeared, back on track no longer exists.
Human activity strongly influences on nature as a whole, makes changes to the normal functioning of water bodies. Some of these changes are irreversible and lead to the death of a reservoir, which leads the adverse environmental and economic consequences.In other cases it is required extreme financial cost and time-consuming to restore the normal functioning of the water body. Thus, the main human activities should be aimed at protecting and maintaining the normal state of water bodies and ecological systems can’t be allowed to an extreme degree of irreversible degradation.
Smetanin V.I. “Cleaning and restoration of water objects”