General Description of Facility

5.1. General Description of Facility

Municipal wastewater treatment for Smolensk and some surrounding communities is provided by the Gorvodokanal which operates a number of treatment plants in the vicinity.  The main wastewater treatment plant (hereafter the MWTP), Krasnoflotskaya Wastewater Treatment Plant, is the subject of the assessment.  This medium-sized facility is located on the north bank of the Dnieper River, west and downstream of the city centre.  It was commissioned in 1987 and provides conventional mechanical and biological treatment of wastewater.  There are four other wastewater collection areaswhich are also part of Gorvodokanal provide collection and treatment of wastewater in Smolensk.   

Service Population:  The city covers both the north and south side of the river and has a population of  approximately 353,000 of whom 257,690 are connected to the sewage collection system.  An additional 9,2000 residents have their wastewater collected from septic tanks and brought to the MWTP for treatment.  The MWTP receives effluent from both residential and industrial sources.  Based on residential water consumption, the total amount of wastewater discharged to the MWTP from the residential  population was estimated to be 28 million m³ in 2001.

Industrial Users:  Approximately 50 industrial enterprises of Smolensk are connected to the one of the three treatment plants with treatment processes.  Twenty of these enterprises conduct pre-treatment prior to discharge (generally physical and chemical treatment technologies).  The industries present in Smolensk predominantly comprise the following:

1. Power engineering;

2. Machine building;

3. Metal fabrication;

4. Chemical production;

5. Food processing; and

6. Electronic fabrication. 

There has been a 20 to 30% reduction in industrial activities in the area in the last few decades. 

Collection System:  As the city is constructed on seven hills, the sewage network is services by 21 pumping stations 7 of which have mechanical rakes the rest having grates (screens on 16 mm grids) to remove oversized materials (trash).  The pumping stations were built between 1972 and 1993 with one having operated since 1947 (extremely poor condition).  The main pumping station constructed in 1982 has issues associated with vibration which is undermining the structural integrity of the pump house. 

Most of the sewage collection system was built or reconstructed during the last thirty years. Sewer collection pipes are  made of ceramics, steel, cast iron and Transite^TM.  Trunk sewage lines are made of concrete.  Approximately 200 km of the system comprise  ceramic pipes which are resistant to wear but susceptible to breakage from soil settlement (frequent breaks). Approximately 11 km of soil pipes are made of steel, located above-ground and have a short service life.  Some parts of the system is combined and stormwater arrives at the treatment plant during rain events.  The stormwater contains significant quantities of sand overwhelming mechanical removal processes and degrading the performance and condition of downstream treatment processes. 

None of these facilities are the subject of the assessment and they were not inspected during the site reconnaissance. 

Treatment Systems, Wastewater:  The total wastewater treatment capacity of Gorvodokanal’s four treatment facilities is 48.9 millionm³/year (134,000 m³/d) of which 13.8 million m³/year (37,750 m³/d) is received from industrial sources.  A breakdown of quantities of wastewater treated is shown below: 

Table 5.1 : Wastewater Volumes Received at the Smolensk Wastewater Treatment Plants (WWTP) in 2002

The MWTP is the subject of this assessment and the only facility visited during the site reconnaissance stage of the work.  MWTP is a traditional activated sludge plant comprising two, parallel lines with at total capacity of 130,000 m³/d.  The lines are of unequal capacity with the new line (Line 2) taking 80% of the wastewater for treatment.  The treatment lines were commissioned in 1962 (old line: Line 1) and 1987 (new line: Line 2).  Line 1 comprises only a partial treatment line combining with Line 2 at the shared aeration tanks and downstream processes.  It has the following components:

- Inlet chamber;

- Screen facilities (grates on a 16 mm lattice and rakes);

- Grit chambers (2 horizontal, rectangular-type);

- Primary clarifiers (2 circular, primary sedimentation tanks).

Line 2 comprises the following components:

- Inlet chamber and flow measurement weir (composite sampling station located at this point);

- Screen facilities with comminutors (grates on a 16 mm lattice);

- Grit chambers (rotating, rectangular-type);

- Primary clarifiers (2 circular, primary sedimentation tanks);

- Aerated activated sludge tanks (contact stabilization process configuration, 2 four channel units) and associated air blower buildings;

- Secondary clarifiers (3 circular, secondary sedimentation tanks).

- Contact chamber (formerly for chlorination but the chlorination system has been decommissioned).

Technical details of each of the above (size, capacity, etc.) were not available.    

Wastewater is discharged from a single underground pipe that leads to an above-surface concrete outfall on the bank of the river.  Previously, an in-stream outfall in the centre of the river was the location of the effluent discharge, however, this was damaged and has not be replaced.

Treatment Systems, Sludge:  Primary sludge from each treatment line is pumped to a two-chamber sludge tank for some settling/decanting then sludge is pumped to centrifuges (6 units) for further dewatering.  The cake from the centrifuges is deposited directly into trucks for disposal at a local municipal landfill.  The high metals concentration of the cake prevents its application on agricultural land although it is used for landscaping at the facility. 

Although the facility has thermophilic anaerobic sludge digesters (commonly called “methane tanks”) to eliminate pathogens and generate biogas for use as fuel for the facility heating station, this system is not in operation (only one tank is operational).  Methane tanks are used occasionally for sludge storage.  In addition, sludge mineralizers and presses are present at the facility but are not operational. 

The filtrate from the centrifuges is to a series of 15 sludge ponds (capacity: 3000 m³ each) at the southeast corner of the facility.   They are currently at 50% of capacity.

Technical details of the facilities described above (size, capacity, etc.) were not available. 

Other Ancillary Facilities:  The complex has numerous ancillary facilities including offices, workshops, a boiler house and other structures.  The boiler has only provides hot water.  An on-site laboratory provides process and quality control by analyzing key effluent characteristics.

Other Issues:  The area sold of Line 2 is vacant and had been planned to be used for a third treatment line.  Finances and anticipated demand have postponed the construction of the third line. 

Sheinovka Treatment Plant:  This small plant (600 m³/day) receives water from a residential area.  One of the boilers in this district operating over the winter generates large volumes of wastewater.  A private bottling company also discharges significant quantities of wastewater to the plant.  The plant has an inlet chamber, 2 aeration tanks, 2 secondary settling tanks, and 2 final settling ponds (“bioponds”). 

Krasny Bor Treatment Plant:  Other than receiving wastewater from the surrounding residential area, the facility also receives water from a cheese-making operation.  The wastewater form the operation is high in suspended solids and organic compounds.  The operations has an inlet chamber, a grit chamber, a primary settling tank, two biofilters that work like aeration tanks, 3 secondary clarifiers and a contact chamber for chlorination (which is in operation).  Krasny Bor receives more industrial waste then Sheinovka.

Gnezdovo Treatment Plant:  This facility is outside of the city limits in a rural area and was constructed and operated by a ceramics plant which has stopped production. GVK took over operation of the wastewater treatment facilities of the operation which comprise a series of six lines of vertical aerations tanks constructed from steel. Four of these tanks were recently repaired but the condition of all the facilities is reported to be poor mainly due to their age.  The existing facilities are enough to serve the residential community.

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