30. Patient D, 37 years old, after examination, the doctor diagnosed: chronic generalized periodontitis of severe severity with a depth of periodontal bone pockets of more than 4 mm, destruction of the interalveolar septa up to 2/3 of their height, mobility of teeth of II-III degree.
Which surgical method most appropriate in this situation?
1) simple gingivectomy
2) radical gingivectomy
3) gingivotomy
4) osteogingivoplasty
5) curettage
Methods for cleaning soils from oil pollution.
Oil is an oily liquid that is a complex natural solution of organic compounds, mainly hydrocarbons. High-molecular resinous-asphaltene substances, as well as low-molecular oxygen-, nitrogen- and sulfur-containing substances are dissolved in hydrocarbons organic compounds. In addition, some inorganic substances are also dissolved in oil: water, salts, hydrogen sulfide, compounds of metals and other elements.
The following classes of hydrocarbons are distinguished in the composition of oil:
aliphatic (methane);
cyclic saturated (naphthenic);
cyclic unsaturated (aromatic).
There are also mixed (hybrid) hydrocarbons: methane-naphthenic, naphthenic-aromatic.
Among the methane hydrocarbons in oil there are gaseous, liquid and solid. Gaseous (methane, ethane, butane, etc.) are dissolved in liquid hydrocarbons and are released when the pressure changes. Solid high-molecular hydrocarbons (paraffins) are also in a dissolved state. Their entry into the soil is especially dangerous, since, having a low pour point, paraffins firmly clog all the channels through which the exchange of substances occurs between the soil and the plant, the soil and the atmosphere.
Oil with a predominance of methane hydrocarbons is of the methane type. Among its varieties, there are high-wax oil (paraffin content more than 6%), paraffinic (1.5-6.0%) and low-wax (less than 1.5%).
Naphthenic hydrocarbons are present in all types of oil, but oils with a predominance of this class of hydrocarbons are rare. Among aromatic hydrocarbons, low-molecular structures predominate (benzene, toluene, xylene, naphthalenes). In minor quantities there are homologues of 3-6-ringed hydrocarbons (polycyclic aromatic hydrocarbons - PAHs). In some types of petroleum, PAHs contain significant amounts of 3,4-benzo(a)pyrene and other carcinogenic hydrocarbons.
High-molecular aromatic structures, also containing oxygen, sulfur, and nitrogen, are resins and asphaltenes. Resins are viscous substances, asphaltenes are solid. Both are dissolved in liquid hydrocarbons. The high content of resins and asphaltenes in oil determines an increase in its specific gravity and viscosity. Such oils are inactive, but can create a stable source of pollution in the soil.
During the economic activities of the structural divisions of the branches of JSC Russian Railways, the roadbed of the railway and adjacent territories, as well as the soil of production areas, is polluted with petroleum products. The reasons for this are their leakage from tanks at loading stations and during transportation due to malfunction of boilers and drainage devices, ingress of lubricants during refueling of wheel pair axle boxes at receiving and dispatching and outfitting points, ingress of oil during equipment and movement of locomotives and special rolling stock. composition, ingress of petroleum products into the territory of bases and storage facilities for fuels and lubricants. Contamination of soil and soil is possible in emergency situations during the transportation of dangerous goods.
To ensure environmental safety railway transport New technologies are being developed to eliminate the possibility of contamination environment, as well as equipment for cleaning contaminated soils and subgrades
Inspection of sites of impact soil contamination with oil and petroleum products
Flows of oil and petroleum products in soils can be visible and hidden (intrasoil). Visible flows are outlined visually. In these cases, the source of pollution is determined without difficulty.
Hidden flows most often arise as a result of failures of pipelines passing at some depth from the surface of the earth. The appearance of hidden oil flows is detected by a sharp increase in the content of petroleum products in groundwater located close to the source of pollution, surface water (rivers, streams, canals, lakes, ponds). Intrasoil flows manifest themselves by seepage of oil on slopes, walls of ditches, and ditches. Hidden pollution can be detected by changes in vegetation cover: yellowing of herbaceous vegetation, drying of trees and shrubs.
To delineate the oil flow area and vertically and to determine the location of the spill, it is necessary to determine the landscape-geochemical position of the study area:
1) type of elementary landscape (autonomous - on a flat hill, transeluvial - on a slope; eluvial-accumulative - in small local depressions of the relief; transsuperaqual - the foot of a slope, floodplains of rivers; transaqual - rivers and other watercourses);
2) types of geochemical connections in local landscapes that determine the nature of the movement of matter: the ratio of lateral and vertical flows; forms of migration, the nature of geochemical and physical barriers that retain oil along the path of flow.
When determining the types of mating, the following are important:
a) depth of atmospheric water infiltration; b) depth of groundwater.
Based on the data listed in points I, II, a series of soil cuts (or hand wells) is laid. The number of sections depends on the complexity of the landscape geochemical situation and the oil flow.
Soil sections (wells) are combined into a system of profiles extending in the direction of movement of surface runoff from the site of the spill to the place of intermediate or final accumulation. The minimum number of profiles is 3, the minimum number of sections is 12 (3 on each profile and 3 background ones, one for each elementary landscape). If the problem cannot be reliably solved with a minimum number of cuts, the required number of additional cuts is provided.
Soil sections are divided into support sections and “pins” (test soil samples). Reference sections are laid near the spill site and on the main elements of the landscape-geochemical
profile. The purpose of studying such sections is to determine the depth of oil seepage, the presence of intrasoil flow, and the nature of the transformation of the soil profile.
The incision is approximately the following dimensions:
The width of the short wall is 0.8 m, the long wall is 1.5 m, the depth is 2.0 m (if groundwater is not opened at a shallower depth). The incision is positioned so that the short front wall is illuminated by the sun. The soil is thrown onto the long side walls: the upper horizons - in one direction, the lower ones - in the other. Sampling is carried out on the front wall and the soil is described using it. The wall is cleaned, a centimeter is descended along it, along which the sampling depths and boundaries of soil horizons are marked. Sampling begins from the lower horizons. A sample is taken with a size of 10 x 10 cm, and if the thickness of the horizon is less, then the entire thickness.
Samples are taken using a soil knife. After taking each sample, the knife is cleaned of oil products with a swab dipped in an organic solvent.
Before taking samples, a description of the landscape and soil horizons is carried out (color, moisture, structure, density, mechanical composition, new formations, inclusions, root system, carbonate content).
If identifying soil genetic horizons is difficult, samples must be taken every 20 cm, accompanied by a detailed description.
“Digs” for taking soil samples are removed to the depth of the lower front of the oil flow in the soil, which can usually be determined from the reference section.
Oil and petroleum products can move and remain for a long time at depths of 0.5-1.0 m or more under the relatively dense and slightly polluted upper horizons of the section. Therefore, the study of reference sections when monitoring soil contamination with oil and petroleum products is mandatory.
Due to the strong variation in the composition and properties of the soil, even within the profile, 5-8 samples are taken horizontally from the front side of the section to compile a mixed soil sample. Total weight of the mixed sample is 0.6-0.8 kg
Methods for cleaning soils from pollution can be divided into physical, chemical, physicochemical and biochemical.[...]
Physical methods involve removing the top layer of soil from contaminated areas to a landfill or specially designated areas. These should also include all options for washing the soil with the dissolution of pollutants in the washing liquid (water).[...]
Chemical methods include thermal methods, leaching processes, binding pollutants into complex compounds, etc.[...]
Thermal methods are used to remove organic matter and some non-ferrous metals, chemical stabilization of soils. They are implemented in various options: heating in air, in vacuum, pyrolysis, etc.[...]
Heating in air is used for lands contaminated with oil, oils, gasoline, halogen-containing and other organic compounds. Heat treatment usually involves holding the material at 700-800°C with the combustion of hydrocarbons. The physicochemical properties of the soil change slightly. The biological activity of thermally treated soils is restored by adding compost and other minerals if necessary.[...]
Currently, stationary and mobile installations for heat treatment of soils in air clean up millions of tons of contaminated soil. In particular, the total annual productivity of installations from Nord (Germany) alone is 300 thousand tons with their unit capacity of 50-80 thousand tons. The storage capacity is equal to the total annual productivity of installations (Massive...).[...]
The vacuum mho-thermal method of soil remediation has been implemented in the USA in the form of a mobile unit. Soil contaminated with organic compounds is loaded into a concrete mixer-type vacuum drum mounted on a car chassis. Drum length 4.5 m, diameter 2.4 m, rotation speed 10-18 min. When heated, volatile organic compounds evaporate and are further liquefied in a condenser located on the car trailer. After cleaning the condensate into a filter, it is suitable for use for its intended purpose. The duration of the processing cycle for one load of soil is 45 minutes (Crosby). [...]
Thermal methods are implemented not only in special installations to which the soil to be cleaned is delivered, but can also be carried out directly on site. One such method involves vitrification of the soil. Electrodes are inserted into the latter and, passing a current, it is heated to high temperatures (2160°C). In this case, the soil melts, the organic matter is pyrolyzed, and the resulting gases are sent for purification. Subsequent cooling of the soil leads to its vitrification and binding of pollutants such as radionuclides and heavy metals(In situ...).[...]
Leaching as a chemical method of cleaning soils involves treating the soil with a 2% solution of hydrochloric acid at a pH of 2 for 10 minutes. The content of pollutants such as arsenic, cadmium, copper, nickel, zinc and lead is reduced by 86-98% (Acid...).
Clean water, one of the foundations of human life, is on a par with such important components as food and air. The results of industrial emissions and man-made disasters have raised the question of restoring a valuable resource to humanity. Today, the problem of cleaning contaminated lands and waters from various harmful impurities, primarily oil and petroleum products, is one of the most acute, especially for residents of large cities. Thus, in our country and in other developed countries of the world, there is a noticeable trend of falling housing sales in environmentally unfavorable areas of cities and an increase in demand for houses and apartments in the nearest suburbs and environmentally friendly areas. It should also be taken into account that Eurasia, and Russia in particular, are in first place in the world in terms of oil reserves, which are processed by a huge number of factories, and thousands of kilometers of oil pipelines have been laid. This makes the problem of cleaning soil from oil pollution very urgent.
The properties of oil as a substance hazardous to nature are also a very important factor. When it gets into the ground, soil or water bodies, this type of pollution actively inhibits significant life processes, almost completely suppressing them or forcing them to take place in a different direction. The main cause of leaks is the production activities of oil refineries, and the methods of pollution are spills of petroleum products during transportation to their destination, as well as accidental spills from tanks of railway and road transport. The most effective method is to clean soil from contaminants using the microbiological degradation method. The Poliinform company offers the following methods for purifying surface and groundwater (please follow this link).
Pollution problem
The main source of water is usually surface and underground groundwater sources, which until recently were considered relatively clean and suitable for domestic use. Unfortunately, they are the ones that are most exposed to various petroleum products and chemical impurities. Currently, more than 30% of all environmentally hazardous substances found in the natural environment are benzene derivatives and other hydrocarbons.
Shallow groundwater can be quite clean due to the action of various soil microorganisms, which destroy many bacteria and act as a filter for various impurities. However, the process of self-cleaning soil from pollution occurs only when it is contaminated with organic waste that is subject to biochemical oxidation by microorganisms. A more serious problem is represented by inorganic heavy metals and their salts that penetrate, gradually accumulate in the soil and sink into deeper layers. When carrying out deep plowing of contaminated lands, these substances can re-enter the trophic chain.
Recently, in Russia, as in other developed countries of the world, various methods for sanitary cleaning of soil and water from contamination with petroleum products and heavy metals have been created and implemented. One of the results of the research was the appearance of a flotation unit. To clean soil from contaminants using this installation, several stages are used:
- the installation removes a layer of contaminated soil;
- soil cleaning in a special mobile unit;
- supply of special cleaning agents to the installation;
- returning cleaned soil to nature.
However, we should not forget that the best way to protect and clean the soil from pollution is to be careful.
Cleaning up land and water pollution
Penetration of oil and hazardous substances into the natural environment chemicals is a common problem for all responsible structures and organizations - environmentalists, authorities, departments of the Ministry of Emergency Situations. The most dangerous in this regard are the traditional regions of production, refining and transportation of oil and its derivatives, including places where oil pipelines lie, ports, railway etc. Enterprises that consume petroleum products and chemicals also pose a danger. Recent accidents have demonstrated the need for widespread introduction of inexpensive natural sorbents for sanitary soil purification, such as natural zeolites - sokyrnites. The unique property of these substances is the ability to reliably contain a wide range of pollutants in their structure, as well as high sorption and ion exchange capacity, which ensures their high efficiency in eliminating accidents. Poliinform has developed an innovative drug Soylex for the bioremediation of soils and waters contaminated with petroleum products. You can get acquainted with it on this page: biological product for cleaning soils and waters from oil.
Types of water pollution and treatment methods
First of all, it is worth saying that timely measures can avoid large costs for eliminating the consequences of accidents. In particular, we invite you to promptly pay attention to the condition of your equipment. Our company offers a convenient method for non-contact assessment of the technical condition of pipelines.
There are three main ways to purify water and localize oil spills using sorbents:
- Localization of spills using containment booms equipped with mesh with zeolites. The size of sorbent fractions is from 1 to 4 mm. The role of booms is not only to localize the spill, but also to remove oil and petroleum products from the water.
- The use of sokirnite (natural zeolite) with a fraction size of 1 to 4 mm as a filtering agent at water treatment plants.
- Spraying a finely dispersed sorbent (fraction up to 0.14 mm) of zeolite over the surface of contaminated water. The substance absorbs pollution and gradually settles to the bottom of the reservoir, preventing the spread of oil.
Technologies for water purification from oil products
The following techniques are used for water purification and are selected according to the degree of contamination and the type of pollutant. All existing methods can be divided into the following three groups:
- Mechanical purification – water filtration in several stages followed by settling. This category includes oil product separators, widely used at gas stations, service stations, parking lots, etc. For filtration, filters with porous fillers are used that allow water molecules to pass through, but retain larger molecules of oil, kerosene, fuel oil and other petroleum products. However, the effectiveness of mechanical cleaning is limited to approximately 60-65%, which is why it is used primarily as a preparatory step.
- Chemical cleaning. It involves the use of special reagents added to the liquid being purified. These substances react and precipitate as insoluble sediments. Surfactants and water-oil emulsions, as well as special adsorbents, such as aluminum oxide, are most often used as chemical reagents. Chemical cleaning can remove up to 98% of contaminants.
- Biological purification of water from oil and petroleum products. The most advanced cleaning method, based on the activity of special microorganisms for which oil is the main source of nutrition. There are more than a hundred species of such microorganisms and they belong to various categories - fungi, bacteria, yeast, etc. They have useful property process complex hydrocarbon compounds, i.e. petroleum products, causing their oxidation. As a result, easily decomposed substances and non-toxic products are formed, which ensures the highest degree of purification.
There are also three main methods for cleaning soils and other hard surfaces:
- Sanitary cleaning of soil by adding sorbent (zeolite) to the surface of the soil being cleaned, followed by collection and disposal. This ensures the collection of oil and other hazardous substances spilled on the surface. If we are talking about oil, then after collection the substance can be burned and reused.
- Cleaning of land with a low level of contamination can be accomplished by applying zeolite to the surface using conventional agricultural spreaders of mineral fertilizers. Next, cultivation and sowing with any herbs that are not consumed by humans and animals is necessary. The sorbent will absorb petroleum products, bind them and stop further spread; it will “pull” pollution from the soil, reliably bind it, prevent further spread, including stopping penetration into groundwater. It will take 1-2 years to restore the soil this way.
- In case of large contaminations, zeolites are used, saturated with bacteria - oil destructors, which decompose oil and contribute to the complete cleansing of soil from contamination and restoration of its economic and natural significance.
Poliinform company offers an extensive range of services in the field of environmental safety, soil and water purification, and examination of the technical condition of equipment and pipelines. In addition, we will help you with the assessment - with our specialists
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