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General Description of Facility
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5.1. General Description of Facility
Municipal wastewater in Kyiv is provided by the Bortnichy Wastewater Treatment Plant (hereafter the BWTP), which is the subject of the assessment. This large complex is located on the east bank (left bank) of the Dnieper River, southeast and downstream of the city centre. The facility is part of Joint Stock Company (JSC) KyivVodokanal which includes the treatment and distribution of water as well as the collection and treatment of wastewater in Kyiv.
Service Population: The city, with an area of 836 km2, has a population of approximately 2,640,000 of whom 2,367,000 are connected to the sewage collection system. The BWTP receives effluent from both residential and industrial sources. Based on residential water consumption, the total amount of wastewater discharged to the BWTP from the residential population was estimated to be 473.6 million m3 in 2001.
Industrial Users: Approximately 300 industrial enterprises of Kyiv are connected to the BWTP. These include food processors, engineering works and electronic industries. Approximately 65 enterprises have pre-treatment operations before wastewater is discharged to the municipal system. Generally, the pre-treatment operations include physical and chemical treatment technologies.
Collection System: Most of the sewage network was constructed or reconstructed during the last 50 years. The pipes are made of ceramic, steel, pig iron and asbestos cement. Primary sewage pipelines are concrete-construction. Over 1,150 km of pipelines are ceramic, which are resistant to corrosion and mechanical wear, but sensitive to uneven soil settlement. The pumping stations serving the collection network equipped with basic physical treatment (mechanical rakes or screens (16-mm mesh)).
Treatment Systems, Wastewater: BWTP is a traditional activated sludge plant comprising three, parallel lines with design capacities of 600,000 m3/d. The treatment lines were commissioned in 1965, 1976 and 1988 and consist of the following components:
- Inlet chambers;
- Screen facilities (reciprocating rake type);
- Grit chambers (horizontal, rectangular, aerated- type);
- Primary clarifiers (circular, primary sedimentation tank);
- Aerated activated sludge tanks (contact stabilization process configuration) and associated air blower buildings;
- Secondary clarifiers (circular, secondary sedimentation tank).
Technical details of each of the above (size, capacity, etc.) are included in Appendix B.
Wastewater is discharged from two locations into a 7 km long channel that leads to the Dnieper River. The effluent from Lines 2 and 3 passes through a series of baffles before discharge to the channel, which is lower than the Dnieper water levels at the outlet. At the end of the channel, water is pumped to the Dnieper River by way of five pipes that are spaced across the river’s width to extend the size of the mixing zone.
The COWI Feasibility included an assessment of the facilities at the BWTP. With few exceptions, the assessment of all of the facilities of Line 1, constructed in 1986, were rated as very poor with severe deterioration and requiring immediate replacement or repair. The facilities of Line 2, constructed in 1975, were rated to be in poor condition, with function and appearance significantly affected by deterioration. Remedial action was stated to be required as follows:
- mechanical and electrical equipment within 2 years;
- structures, buildings and pipes within 5 years; and,
- other pipes within 10 years.
The facilities of Line 3, constructed in 1994, were rated as adequate, with deterioration being mainly visual, only having minor affects on function. Remedial action was stated to be required as follows:
- mechanical and electrical equipment within 2 to 5 years;
- structures, buildings and pipes within 5 to 10 years; and,
- other pipes within 10 to 20 years.
Details regarding the above can be found in Reference 4, Appendix 7.
The field work for the current program was carried out three years after the COWI field assessment and the conditions of the facilities were observed to be even more problematic. The conditions of facilities of Line 1 are particularly worrisome with the Line 1 Pumphouse requiring immediate attention.
Treatment Systems, Sludge: Primary sludge from each treatment line is pumped to thermophilic anaerobic sludge digesters (commonly called “methane tanks”) to eliminate pathogens and generate natural gas used as fuel for the facility heating station. The digesters comprise two sets of four tanks commissioned in 1965 and 1975. The set commissioned in 1975 is not in operation (poorly constructed).
The sludge from the digesters is pumped to sludge lagoons located off-site at two separate properties, one 9 km to the southeast and the other 15 km in the same direction. Some of the sludge is taken to new sludge centrifuges for mechanical dewatering prior to being trucked to the sludge lagoons. The capacity of the centrifuges is sufficient to dewater all primary sludge (Reference 3, Appendix 5.8, page 9), however funding for the polymers required is problematic.
Surplus activated sludge from the secondary clarifiers of each line is pumped to a centralized secondary sludge treatment area for thickening, aerobic stabilization and final thickening. The resulting sludge is pumped to the sludge lagoons. The system was supplemented with polymer addition to improve performance (reduce sludge volume/water content and reduce dissolved solids in the effluent) but, again, funding for the polymers required is problematic.
The remote sludge lagoons are reported to be near capacity with over 3 million cubic metres of sludge present. The reject water from the lagoons, which is pumped back to the BWTP for treatment, has a high suspended solids content because the lagoons do not working optimally when close to capacity. Sludge was previously applied to agricultural lands as fertilizer but farms in the vicinity cannot provide transport for sludge delivery and KVK does not have such transport available. Much of the sludge contains heavy metals in concentrations too high for agricultural application. One lagoon has been isolated as the sludge contents contain radionucleotides from the Chernobyl accident.
Technical details of the facilities described above (size, capacity, etc.) are included in Appendix B.
The COWI feasibility study rated the condition of the sludge treatment facilities to be in poor conditions as described above, with only one exception (sludge dewatering systems). This included the thickeners, digesters, gas storage tanks and sludge drying beds. The dewatering systems being newly supplied, were rates to be in good condition (Reference 4, Appendix 7).
The site reconnaissance of the current program verified the conditions observed by COWI. No large-scale restoration or new construction has been undertaken since the COWI study although some pilot projects are underway with respect to sludge drying (German Project).
Other Facilities: The large complex has numerous ancillary facilities including offices, workshops, garages and other structures. An on-site laboratory provides process and quality control by analyzing key effluent characteristics.
With respect to the internal pipelines, facility buildings, workshops, garages and laboratory, these facilities were rated between adequate to poor by the COWI feasibility study. The ratings tended to reflect their year of original construction (Reference 4, Appendix 7). No significant restoration has been undertaken regarding these facilities and their priority is considered low relative to more pressing maters respecting those facilities directly related to wastewater treatment and sludge management. There current condition of these facilities noted during the current project’s reconnaissance was observed to be similar to reported by COWI.
Plans for Rehabilitation: KVK has engaged the Kyiv Design Institute, who prepared the original design for the construction of the facility, to prepare a plan to rehabilitate Treatment Line 1. The plan, which is now being reviewed by authorities, is estimated to cost approximately $500,000 (2004 USD). Some of the projects proposed herein are included in this rehabilitation plan. It is uncertain whether funds will be available to implement this plan.
