Caspian Sea 2011
one of the potential sources of Caspian Sea pollu- tion. To date, about 50 to 70 million m 3 of highly contaminated liquid waste has accumulated in the filtration sections of the tank. The wastewater contains high concentrations of chlorides, am- monium salts, sulfates, and heavy metals (cop- per, zinc, chromium). Oil-content levels amount to 200 per cent of maximum permissible concen- tration (MPC) and phenol between 20 and 80 per cent MPC. As a result of the sea-level rise of the Caspian, the coastline is closely approaching (up to 10 km) the sedimentation tank. During sea- level surges, this distance can be reduced to 3 to 4 km. If these waters flow into the Caspian Sea, this could result in serious environmental conse- quences (Questionnaire KZ 2010). Russian Federation: Pollution of water bodies and land in the Astrakhan oblast is mainly caused by overloading the design capacities of wastewater treatment plants in towns and urban settlements. In some areas, there are no such plants. The total amount of all pollutants entering the pre-estuary part of the Volga River from Astrakhan oblast does not exceed 10% of the basic mass of pollutants car- ried by Volga waters through the oblast territory. A major problem in the city of Astrakhan is ex- pansion of network for collecting and transport- ing of storm and dranage water runoffs, as well as the lack of appropriate facilities and equipment for their treatment. The average annual volume of runoffs is about 540 thousand m 3 , and most of it is discharged into the Volga delta. The main sources of surface water pollution in the oblast are communal town services which not only generate their own wastes but also receive the waste of other enterprises located in these towns. It is clear that if industrial wastewaters of some en- terprises are polluted with organic and other toxic substances, these should be properly treated at lo- cal treatment facilities prior to their discharge into the town sewage system. (It should be noted that if any of the polluting substances in the discharge exceeds the maximum permissibnle level, then all sewage waters are considered to be polluted).
In 2007, a reconstruction of the aeration system at the Southern and Northern sewage treatment fa- cilities (STF in Astrakhan oblasts) was carried out: this included reconstruction of sludge beds, pri- mary and secondary dirt collectors on the northern STFs as well as reconstruction of biological ponds on the right bank STFs. These measures resulted in a significant improvement in BOD indicators, in ammonium nitrogen levels and weighted sub- stances and in reducing discharges of a number of other pollution sources. In connection with sewerage wastewaters, there are seven municipal sewage systems with more than 100 tonnes per year of BOD that dis- charge into the Volga delta. These are located in Astrakhan, Buinaks, Derbent, Izerbash, Hasavy- urt, and Makhachkala. The total volume of sewage water discharge in 2005 was some 410 million m 3 , including polluted waters that accounted for about 68 million m 3 or 16.6% of total volume of sewage water discharge. The main source of contaminated discharge in the Volga delta is run offs from the city of Astrakhan - in 2005, 63.6 million m 3 of polluted sewage was discharged into the delta. In 2005 – 07, pollution of waters from oil products and phenols was minimal. In the Republic of Dagestan, the total volume of polluted wastewater discharge in 2007 was more than 74 million m 3 . This was a reduction of 0.04 million m 3 compared to the 2006 figure. Some parts of the wastewasters are untreated, for exam- ple from such towns as Izerbash, Derbent, and Dag- estanskiye Ogny. The bulk of polluted wastewater discharged into the Caspian Sea is absorbed by a treatment plant (Municipal sewage treatment fa- cility “Mahachkala-Kaspiisk”), responsible for 52.5 million m 3 , constituting 70% of the total discharge of polluted run offs in the Republic. There are seven cities on the territory of Caspian regions of Russia (Astrakhan, Buynaksk, Derbent, Izberbash, Hasavyurt and Makhachkala), where the biochemical oxygen demand (BOD) of sewage exceeds 100 tons per year.
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