Description of Proposed Pollution Mitigation Measures

7. Description of Proposed Pollution Mitigation Measures

No formal study (feasibility or otherwise) has been conducted for the Smolensk Gorvodokanal.  The projects shown below are mitigation measures to improve the efficiency and effectiveness of the wastewater treatment facilities at four of Gorvodokanal’s operations.  They were developed and proposed by Gorvodokanal personnel and are at various stages of design, from detailed to conceptual.

Table 7.1 : Summary of Prioritized Mitigation Measures

Note:    prioritized by site as part of a 5 year plan

Each of these potential mitigations measures is described in the following sections.

Main Wastewater Treatment Plant:  Replacement of Screens

The existing screens were designed and the time of plant construction (1987) and have not been upgraded.  The screens for both lines are in poor condition.  The screens are a coarse with 16 mm lattice allowing relatively large amount of solid materials to pass through the screens.  These solid materials that pass through the screens adversely effects the performance of the downstream treatment processes (primary clarifiers, aeration tanks and sludge digesters).   The presence of solid materials also increases the wear on down-stream equipment, thus increasing maintenance and replacement needs.  Those materials that successfully screened (screenings) are removed manually.  Such removal is unpleasant for workers and potentially hazardous due to potential exposure of the workers to pathogens. 

GVK has commissioned and completed a feasibility study for this project, however, no funding is available for its implementation.  The proposed plan will be to reduce the screen spacing to between 6 and 8 mm.  Options, such as the inclusion of an automatic trash removal system, are considered but will be implemented based on the funding available.  The cost for the project quoted in the table above, 16,500,000 roubles, is the minimum effort project.  The maximum effort project has a value of approximately twice as much and the other.  If funding is secured, an ecological assessment must be completed then the project can commence.  Such an assessment would cost approximately 500,000 roubles.

Main Wastewater Treatment Plant:  Aeration Tanks

The combined aeration tanks been in operation since plant commissioning and are in poor condition.  No design plan has been developed and no feasibility prepared.  The estimated cost of 3,800,000 roubles is a rough estimate.  The project proposes to modernize the existing aeration tanks.  The rehabilitation would provide the aeration tanks with the ability to remove nitrogen and phosphorus compounds from the wastewater.  The aeration tanks would be partitioned with certain sections devoted to nitrification. 

Main Wastewater Treatment Plant:  Sludge Dewatering

To reduce the amount of sludge to be disposed of at the sludge lagoons it is necessary to install mechanical dewatering equipment.  The dewatering centrifuges are in poor conditions with many out-of-operations at a given time.  The screw of the centrifuges wear rapidly and require time-consuming and expensive re-fabrication.  

A project was previously prepared by an Institute in St. Petersburg to rehabilitate the dewatering system by replacing the centrifuges with a filter press, however, this was a number of years ago and if this approach is pursued the project planning would require an update.  Replacing the existing solid bowl centrifuges with modern versions of the same technology would also improve the current situation (reduce maintenance requirements and energy consumption, etc.). 

Main Wastewater Treatment Plant:  After-purification of Wastewater with Filters

Because the effluents have higher concentrations of BOD than is desirable, additional treatment of the effluents is considered desirable.   The project which has been proposed to address this issue involves the construction of two sand filters. 

Only a conceptual plan and a rough estimate has been prepared for this project to date.  Although the type and size of the sand filters has not been defined, the estimate is based on similar projects implemented elsewhere. 

Main Wastewater Treatment Plant:  Ultraviolet Light Disinfection

The facility was constructed with a chlorination chamber for disinfection, however, chlorine has an adverse impact on the quality of the river, therefore the practice was discontinued.  Additional treatment is required for the elimination of pathogens.  The proposed project comprises the installation of an Ultraviolet (UV) light disinfection system, although alternative approaches are still open for consideration. 

Only a conceptual plan and a rough estimate has been prepared for this project to date.  Although the type and size of the equipment has not been defined, the estimate is based on similar projects implemented elsewhere. 

Main Wastewater Treatment Plant:  Sludge Disposal

A project proposed in 2001 and designed (conceptually) by an Institute in St. Petersburg verified the need to expand the capacity of the sludge ponds to double the existing capacity (15 new ponds).  Although new calculations are required given the current circumstances, Facility Personnel believe this project is required. 

The remaining capacity in the existing sludge ponds is sufficient for 2 weeks of plant operations if the dewatering centrifuges fail. 

Main Wastewater Treatment Plant:  Outfall Reconstruction

The current configuration of the outfall is not optimal for the mixing zone of effluents discharge to the river.  Previously, an underwater diffusing system was in place but was destroyed in a flood event.  This project comprises the reconstruction of the diffusing system. 

Main Wastewater Treatment Plant:  Replacement of Air Blowers

The existing air blowers are operated by energy-inefficient motors and are in poor condition.  The capacity is too high (4 blowers at 400 KW each) for the low demand.  This project proposes to replace the existing air blowers with lower capacity blowers (175 kW) which would allow more efficient  regulation. 

Sheinovka Wastewater Treatment Plant:  Construction of New Aeration Tanks and Clarifiers

The project proposes to construct and additional set of aeration tanks to supplement the  existing aeration tanks.  Existing process equipment and structures are in poor condition and operate with low efficiencies.  The project would also replace the air blowing systems for the existing facilities.  

Sheinovka Wastewater Treatment Plant:  Biopond

The post-aeration bioponds require refurbishment.   These are cleaned regularly (August 2003: 250,000 roubles) and the bioponds are bypassed during the cleaning.   A surcharge is paid for the high-BOD discharge during the cleaning. 

Sheinovka Wastewater Treatment Plant:  Replacement of Air Blowers

The existing air blowers are operated by energy-inefficient motors and are in poor condition.  This project proposes to replace the existing air blowers.  This is considered a low priority project. 

Krasny Bor Wastewater Treatment Plant:  Precipitation Tanks

The pollutant loadings from these treatment processes exceed European Union limits.  Facility personnel have proposed the construction of a two stage precipitation tanks for removal of organic compounds.  To date, only a conceptual design has been completed with a rough cost estimate for construction. 

Krasny Bor Wastewater Treatment Plant:  After-purification of Wastewater with Filters

Because the effluents have higher concentrations of BOD than is desirable, additional treatment of the effluents is considered desirable.   The project which has been proposed to address this issue involves the construction of two sand filters. 

Only a conceptual plan and a rough estimate has been prepared for this project to date.  Although the type and size of the sand filters has not been defined, the estimate is based on similar projects implemented elsewhere. 

Krasny Bor Wastewater Treatment Plant:  :  Ultraviolet Light Disinfection

Additional treatment is required for the elimination of pathogens.  The proposed project comprises the installation of an Ultraviolet (UV) light disinfection system, although alternative approaches are still open for consideration. 

Gnezdovo Wastewater Treatment Plant:  Reconstruction of all Facilities

All the facilities at the treatment plant require reconstruction or replacement.  If the ceramic plant does not begin operations, it would be preferable according to GVK personnel to shut down the plant and set-up a small package plant to serve the community.    Three years ago, GVK was prepared to refurbish one block of aeration tanks (remove rust, repair equipment), however, funds were not available (700,000 roubles)so the project was cancelled. 

Gnezdovo Wastewater Treatment Plant:  Replacement of Air Blowers

The existing air blowers are operated by energy-inefficient motors and are in poor condition.  This project proposes to replace the existing air blowers.  This project is considered a low priority.

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