Estimation of Existing Sewer Clearing Constructions and Their Influence on Pollution Atmospheric Air——On an Example of City of Vladivostok

KRUS Y P

(Vladivostok State University of Economics and Service，Vladivostok 690990，Russia)

The twentieth century is characterized by intensive growth of the population of the Earth，development of a urbanization.Development of the industry，transport，power，industrialization of an agriculture have led to that anthropogenous influence on an environment has accepted global character.The increasing requirement of growing cities and a developing manufacture for tap of industrial drains has led to mass construction of the water drain and construction of clearing constructions.But not in all cities sewage are exposed to clearing to the full and on 100%.It is very difficult，labour-consuming and expensive process.In this connection sharp deficiency of clearing constructions is observed.In Vladivostok only 10% of sewer sewage pass biological clearing，and 90% are reset in water pools without clearing.

In the city of Vladivostok three sewer stations of clearing constructions ofbiological sewage treatment of the open type now function:sewer clearing constructions of biological sewage treatment of settlement of a fruits-berry experimental station，the plywood factory and De-Frieze.

During the clearing sewage on technology consistently takes place all stages.Sewage moves from sewer pump station on pressure head collectors in the chamber of clearing of a pressure.Then on trays it is distributed on horizontal mud traps with circular movement of water.Mud traps intend for allocation from sewage of heavy mineral impurity(mainly sand).The deposit from mud traps leaves suction elevator on sands platform.Suction elevator well washes sand from organic impurity.

After mud traps sewage on trays is distributed on primary two-story sediment bowls.In two-story sediment bowls there is a upholding sewage，sludge digestion and condensation of the dropped out deposit.Fermented the deposit leaves from the septic chamber through silt a pipe under hydrostatic pressure of a water column on sludge bed.After mechanical clearing water on trays acts on biological clearing by means of aerotanks.Work aerotanks is based on use of biochemical oxidation of organic substances of sewage by aerobic microorganisms which colonies form active silt.Aerotanks are in a building.

After clearing in aerotanks sewage should be separated from active silt.The stream silt waters on trays goes on secondary sediment tanks of vertical type where silt settles on a bottom，and the clarified water is poured through a spillway of sediment bowls in removed trays and on trays goes on disinfecting.Disinfecting of the cleared sewage occurs in the contact tank where there is a destruction of pathogenic organisms.After the contact tank the cleared water on release is dumped in a reservoir.

During clearing sewer sewage from surfaces of each concrete block in an atmosphere harmful substances act:hydrogen sulphide，ammonia，ethyl mercaptan，methyl mercaptan，carbon monoxide，nitrogen dioxide，metane.

Technological process of sewage treatment identical，but quantitative characteristics of emissions of harmful substances depend on the area and concentration saturated fume for each concrete construction.

Calculations of emissions of harmful substances from clearing constructions are lead by a technique，Temporary design procedure of quantity of the polluting substances allocated from unorganized sources of stations of aeration of household sewage，Mosvodokanalproekt，Scientificallyindustrial enterprise RADAR，Moscow，1994.

According to dismissed a technique of emission of polluting substance from clearing constructions it is made under the formula［1］:

Miu=5.47×10－8×(1.312+u)·

Calculation of total emission is made under the formula:

Where:

u—the speed of a wind blowing a surface of a construction，km/s;

F—the area of a surface of a construction，m2;

Ci—concentration saturated fume polluting substances，mg/Nm3;

K2—factor of overlapping of a surface(it is defined depending on values of a total area of construction F and the area of open surface F0);

Mi—molecular weight of polluting substances(is accepted under the table 1);

tg—temperature of cleared water，℃;

t—an operating time of constructions，h/a.

Ci—concentration saturated fume polluting substances is set for a concrete construction and thrown out polluting substance，according to the appendix of 1 given technique.

Mi—the molecular weight of polluting substance is accepted under the table 2 present techniques for each polluting substance separately.

Calculation of quantity of emissions of harmful substances is spent with the purpose of definition of a quantitative level of pollution of an atmosphere emissions from sewer clearing constructions.

Table 1 The list of polluting substances thrown out in atmospheric air from sewer clearing constructions

Criterion of quality of air is maximum permissible concentration，and for a ground layer of an atmosphere as such criterion ground concentration acts，the standard for which also is maximum concentration limit of polluting substances.

Table 2 Value of maximum concentration limit and a class of danger of polluting substances

Substances，except for carbon monoxide，concern to specific，for these substances the concrete quota on pollution of an atmosphere stands out，for carbon monoxide the quota on pollution of an atmosphere stands out in addition.

Calculation of the maximal value ground concentration(CM)from a cold source of emissions is carried out under the formula，according to All-Union normative document(OND-86)［2］:

Where:

h—the dimensionless factor considering influence of a lay of land;

A—the factor depending on temperature stratification of an atmosphere;

E，m，η—the dimensionless factors connected with features of receipt of emissions in an atmosphere;

M—quantity of the harmful substance which are thrown out in an atmosphere，gy/s;

Н—height of a source above a level of the ground，m;

D—diameter of a mouth of a source，m;

N—quantity of identical sources of emissions;

V—volume of gases acting in an atmosphere，m3/s，from sources;

Т—difference between temperature of thrown out gases(Tg)and air，℃.

After calculation of ground concentration of polluting substances，for a sanitary-and-hygienic estimation of a degree of pollution of a ground layer of an atmosphere harmful substances make calculation of dispersion of polluting substances in a ground layer of an atmosphere under the unified program of calculation of concentration in atmospheric air UPCPA the ECOLOGIST，version 3.00 Copyright© 1990—2003 FIRM(INTEGRAL)，developed according to OND—86.

In view of that the background of atmospheric air on some substances is close to maximum concentration limit for maintenance of ecological safety of a life of the population with federal service on ecological，technological and nuclear supervision the quota of normalized concentration of harmful substances stands out.The analysis of dispersion of harmful substances in a ground layer of an atmosphere has shown，that ground concentration on one of the listed harmful substances has not exceeded requirements of the installed quota:-on specific substances and for carbon monoxide 0.10 shares of maximum concentration limit of the occupied places(the basis:the letter of Federal service on ecological，technological and nuclear supervision about a quota of normalized concentration).

Conclutions

For all sewer clearing constructions the sizes of sanitary-protective zones were depending on their productivity.According to SanPiN 2.2.1./ 2.1.1.1200-03，Sanitary-protective zones and sanitary classification of the enterprises，constructions and other objects，the size of sanitary-protective zones for clearing constructions with mechanical and biological way of clearing with sludge beds fermented and deposited，and also sludge beds made:

—Productivity more than 5.0 up to 50.0 thousand m3/d diffuses 400 m(for sewer clearing constructions，De-Frieze);

—Productivity more than 0.2 up to 5.0 thousand m3/d diffuses 200 m(for sewer clearing constructions，The Plywood factory);

—Productivity up to 0.2 thousand m3/d diffuses 150 m (for sewer clearing constructions fruits-berry experimental station).

With a view of a safety the population and according to the federal law about preservation of the environment，the reduction influence of pollution on atmospheric air(chemical，biological，physical)up to the values installed by hygienic specifications is necessary to provide the Law of the Russian Federation［3］.

By the results of the executed calculations of dispersion the maximal ground concentration on border of a sanitary-protective zone and in a zone of the nearest housing estate on one of thrown out substances and groups summation have not exceeded the shares of normalized concentration，and will not render negative influence on an environment and an organism of the person［4］.

［1］ Mosvodokanal Proekt Scientifically-Industrial Enterprise RADAR.Temporary Design Procedure of Quantity of the Polluting Substances Allocated from Unorganized Sources of Stations of Aeration of Household Sewage［S］.Moskow:Publishing House of Standards，1994:1－11.

［2］ Industrial Enterprise RADAR.OND—86 the Design Procedure of Concentration in Atmospheric Air of the Harmful Substances Containing in Emissions of the Enterprises［S］.Leningrad:Gidrometeoizdat，1987:80－94.

［3］ Federal Law of the Russian Federation.About preservation ofthe environment:Union ofRight Forces.The Adviser Plus［R/OL］.The Federal Law of the Russian Federation Vol3.No.7.2002－10－01［2011－02－11］/http:www.ebrd.com/ pages/project/eia/stprd.pdf

［4］ Wildlife Management.GOST 17.23.02—78，An Atmosphere Rules of an Establishment of Admissible Emissions of Harmful Substances in the Industrial Enterprises［S］.Moskow:Publishing House of Standards，1978:1－8.