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Water factory in Majdevo

The Water Factory Majdevo

Based on the assessment that the water supply of the city of Kruševac is unsatisfactory, and based on the expected increase in water consumption, Communal WO Rasina Water and Sewerage from Kruševac, in 1976, financed from Energoprojekt Hidroinženjering, the production of the Krusevac Supply of Water Supply which was completed in 1977. the Study has exhaustively dealt with three variants of the future source: the water from the underground of the route Koševi-Globoder, the accumulation of Ćelje on the Rasina River, which dam was under construction at that moment, and the potential small accumulations on Srndaljska, Lomnička and Petinska river on the northern slopes of Jastrebac. For the source, the Ćelije Lake was selected as the richest with water and with the basic argument that the construction of its dam is coming to the end.

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According to the Preliminary Design of the Institute Jaroslav Černi from 1979. in Majdevo, the first part, that is, the first phase of the Water Factory, which started to work in mid of 1984, was constructed with a processing capacity of 700 l / s of raw in 630 l / s of drinking water. The planned final capacity of the Factory after the construction of the second phase, when required, was 1.400l / s raw in 1.260l / s of processed water.


Organizationally, Water Factory Majdevo, as a sector of the Kruševac Water Supply, has been operating from the beginning on the basis of the work of four services, which separately deal with processing, control of chemical and microbiological quality of water and maintenance; the maintenance of Ćelije Dam was added to the sector in 1990 as the fifth service when Serbia Vode gave the dam and its facilities to the PUC for maintenance.

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Lake, or raw water, which can be taken from one of five points in depth - with 3, 6, 9, 12 and 22m in relation to the elevation of normal slowdown of 277m elevation ., pipeline Ø 1.032 / 1.016mm, length2 , 716km to Ø 916 / 900mm, length 0.198km, arrives to the Water Factory.


Water purification in the Water Factory in Majdevo consists of a process of physicochemical assisted clarification, rapid filtration and multiple disinfection. This basic plan, with additions and improvements after the factory is put into operation after the recent reconstruction, remained essentially the same.


Pre-chlorination can be carried out with elemental chlorine, Cl2, and chlorine dioxide, ClO2. According to the project, the dosing of chlorine immediately prior to the introduction of raw water in the process of processing since 1991 it serves as a reserve, and pre-oxidation and pre-disinfection are carried out at the very beginning of the pipeline of raw water.


Water clarification is carried out in two sedimention tanks designed as pulsators by Degremont technology. However, after a series of experiments, the pulsators were completely shut down in 1994, because due to the stiffness of the regime of their operation, the pulsation can not be optimally modified. As the main coagulant, crystalline aluminum sulfate was used, Al2 (SO4) 3 • 18H2O, which from 1999 to 2002 was replaced by Koaflokom®, product of HI Župa from Kruševac, which according to the composition Aln (OH) mCl3n-m-2k (SO4) k. At the first time after the start of operation of the factory as an auxiliary coagulant, or as a flocculant, metasilic acid, H2SiO3, was applied on the spot from water glass, Na2SiO3, and sulfuric acid, H2SO4; it is relatively quickly replaced by polyacrylamide which has proven to be easier to handle and more reliable in the processing process. The cleansing process, in addition to its purely physical side, plays an important role in the removal of organic substances from the water, and thanks to Al3 + ion, it is an essential process for removing viruses from the water.

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After the clarification, the ozonization of water is carried out; ozonation takes place in two chambers in which the discharged ozone is produced in generators by high voltage; The original two Degremont ozonators generated ozone from the air.
Ozonized water passes through eight rapid filters, originally consisting of quartz sand of defined granulation ..


Filtered water is collected in a tank where final disinfection is performed with elemental chlorine. In the case of a standstill in the final chlorination, the correction is made which is carried out by stinginging in the final water pipe before leaving the factory circuit.


Fluorination was the last step in the finalization of water. The water was fluorinated with fluorosilicic acid, H2SiF6, stinging to the final water line before leaving the factory circuit. Fluorination was carried out until 2001, when the last quantity of fluorosilicic acid was consumed, which imports from Macedonia ceased after the disintegration of the SFRY, ie the closure of the Zletovo mine in 1992.

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CHANGES IN TECHNOLOGY


History of the Water Factory Majdevo can be divided into three parts. The first part represents the start of work, from July 1984 to March 1985, and includes a very short trial run filled with errors in the management of the water treatment process, which escalated the increased concentration of manganese in the final water and the pink colour of drinking water throughout the network for a week in March 1985.


The beginning of the second stage (Figure 2), under the new management, was an audit of construction facilities and equipment, which enabled the factory to work reliably to obtain high quality drinking water. After the audit, as far as possible, the design and construction defects were eliminated, which appeared immediately after the factory started.


Due to the close positions of the places where the introduction of chemicals into raw water pipelines, chlorine in the process of prefilation and activated carbon have been triggered, this has led to great difficulties in removing ammonia and water-sulphides that were produced in the last quarter of 1988 in the entire volume of the lake by the decomposition of the blue-green bacteria Aphanizomenon flos -aquae that caused the lake's abundant blooming that summer; Therefore, and in order to ensure the disinfection of the pipeline of raw water, ie preventing corrosion due to iron and manganese bacteria, the pre-chlorination was displaced in 1991 to a new building site just behind the lake dam.


In the beginning of 1989, metasilic acid as an auxiliary flocculation was not used any more and replaced with polyacrylamide.


Along with the advancement of technology and the introduction of innovations, water quality control has also progressed, which since 1987 included ecological testing of Lake Ćelje.

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The constructed capacity of the Water Factory could meet the needs of the population of the Kruševac municipality and Aleksandrovac, but due to the need to give water to all the municipalities of the Rasina district, except for Brus, especially Varvarin and Ćićevac, and the strengthening of the water treatment process due to the decline in water quality of the Ćelije lake, and reconstruction of technology. Based on the Project for reconstruction of the Water Factory and improvement of the processing process, the Institute Jaroslav Černi 2011 has expanded the capacity of the plant, the existing ones have been modified and new elements of water treatment technology have been added. With the upgrade, which took place in 2012 and 2013, the capacity of the Water Factory increased to 1.000l / s of raw in 920l / drinking water. The aforementioned essential concept of the processing process remained the same, but most of the existing phases were compounded and three New Phase (Figure 3) Although it is part of the classic water purification process, the current process of processing in the Water Factory is relatively complex because it consists of a large number of operations.

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  1. During the designing organogenic substance which oxidability is greater than 8 mg / l potassium permanganate, KMnO4, due to the formation of organohloric compounds. Two possibilities were offered: the construction of a chlorine dioxide plant at the site of the current prechlorination on Ćelije Dam or the use of a finished product. As the plant for chlor-dioxide is a small plant, which requires constant presence of workers due to potential explosiveness, it was decided to use TwinOxide®, a commercial product for the preparation of chlorine dioxide solution. However, elemental chlorine is also used, which is applied when there is no danger of elevation content of organochlorine compounds, which is during the largest part of the year.
  2. At the insistence of the designer, the dosing of carbon dioxide, also on the dam, was introduced to lower the pH values ​​of raw water, explaining that the optimal pH range for precipitation of the aluminum hydroxide flocculation between 6 and 7, in which its solubility is the smallest.
  3. In the reconstruction of the factory, coagulation and flocculation are separated. Flocculation is performed in two 2 + 2 basins with different mixing rates; the first two, smaller basins with faster and the other two, larger, with slower mixing.
  4. Former gravity sedimentation tanks are transformed into lamellar ones that are more efficient, which, in addition to replacing inlet pipelines with larger diameter pipes, enables the factory to increase capacity.
  5. The ozone change is represented by the replacement of old ozonators on the air, ozonators on the elemental oxygen Wedeco Effizon® HP SMO / SMA; additional interventions were made by modifying the chamber with diffusers in the diffusion chamber and the retention chamber; Also, diffusers for ozone spraying have been completely replaced. After installing the first Degremont ozonators, the ozone extraction furnace was quickly broken and no longer working; With the new ozonators, a furnace for the catalytic destruction of ozone depletion was installed.
  6. Filters have been converted into three layers, with fillings upward from gravel, quartz sand and anthracite. In the reconstruction, the maximum permeability of the double filter bottom is used as the limit value of the largest possible flow; This is supported by an increase in the permeability of filter fillings, or by reducing the thickness of quartz sand, which has the finest granulation.
  7. UV radiation was inserted into the main project after insight that the Preliminary Project did not solve the problem of possible penetration of planktonic organisms, especially zooplanktons into final water. As for the design of procedures for removing multicellular organisms from water, such as micro screens, for example, it was late, the problem is solved by the insertion of ultraviolet radiation into the treatment of final water. In relation to the projected maximum flow rate of 3.600m3 / h and considering the specificity of the organisms that can go through the process of processing and their resistance to UV radiation, three Trojan UVSwift ™ SC UV generators with capacity of 2.120m3 / h are installed.

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QUALITY OF DRINKING WATER


The efficiency of the water treatment process is monitored in the Water Factory laboratories by sampling, starting from the raw raw water beneath the Ćelije Dam, taken after each stage of processing in real time that is appropriate to flow. In addition, in the chemical laboratory, the operating parameters used to control the treatment process - blur, concentration of chlorine and ozone and the content of organic compounds are monitored more often, at intervals between one and three hours.


Since its foundation up to now, the City of Kruševac belongs to those cities in Serbia that have never had any infectious epidemic. A complex process of treatment in the Water Factory has provided even greater health reliability of drinking water. According to World Health Organization's Drinking Water Quality Recommendations, the systems from which more than 100,000 people are supplied are not at risk if the share of defective samples is less than 1% per year. During one year, the Public Health Institute Kruševac carried out chemical and microbiological analyzes of 156 samples of final water and between 1,800 and 1,900 samples of water from the reservoir and water supply network; At the same time, 730 samples of final water and about 650 samples from the distribution system were examined in the Waterworks laboratories. According to the results of both houses, the number of chemical and microbiological defective samples is regularly significantly lower than 1%. This shows high health safety of water.

 

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Contact us

Phone: 037 415-301
Fax: 037 415-314

Address: Dušanova 46,
37000 Kruševac

E-mail: vodovodks@ptt.rs