Environmental Assessment of Proposed Pollution Mitigation Measures

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9. Environmental Assessment of Proposed Pollution Mitigation Measures

 

In this section, the proposed mitigations are assessed from the perspective of their positive impact on the environment in general and the ecological health and biodiversity of the Dnieper River Basin in particular. 

 

The goals of facility personnel do not always coincide with the goals of the Dnieper River Basin Strategic Action Plan.  KVK’s goals, similar to those expressed in the COWI Feasibility Study, are to develop a sustainable system for the provision of services to the service population.  Those services being the provision of potable water as required by the population and industry and the collection, treatment and disposal of wastewater and associated wastes in a manner that is safe for the population, including downstream communities and the environment.  The sustainable element to this goal has many dimensions including a financial viable system that is affordable to the population, a self-maintaining system that can rehabilitate or replace aging infrastructure and effective management that is efficient and can respond to changes demanded by the service population and industries.  The goal of the Dnieper River Basin Strategic Action Plan is to improve the water quality in the basin, encourage biodiversity and mitigate adverse impacts on transboundary water systems. 

 

The assessment of environmental benefits of each of the mitigation measures described in this report is summarized on the table below. 

 

Table 9.1 : Summary of Environmental Benefits of Mitigation Measures

 

 

Direct benefits to the Dnieper River Basin indicate that the project will result in a measurable decrease in pollution loadings to the Dnieper River and/or pollutant concentrations in the effluent.  A project having indirect benefits to the Dnieper River Basin include improved treatment efficiencies which may or may not result in an overall reduction in pollution loadings and pollutant concentrations to the river.  General environmental benefits include improved operations that may result in reduction of emissions to the atmosphere from the treatment process or a reduction in energy consumption and/or other consumables such as treatment chemicals (e.g. flocculants). 

 

One of the issues that is difficult to assess is the risk of a major failure in the treatment process resulting in a release of untreated or partially treated effluents to the river, causing a major upset and damage to the environment.  As equipment and structures become aged and worn, the chance of such a failure increases.  The condition of the facilities for Line 1 are particularly dire.  The hard work and ingenuity of KVK staff can only limit the possibility of such an occurrence.  Without funds for implementing rehabilitation programs, such an event becomes inevitable. 

 

The assessment of environmental benefits of each of the mitigation measures described in detail in the following sections. 

 

 

WWT-14  Monitoring Equipment

Installing process monitoring equipment and upgrading equipment in the on-site laboratory will have an other all direct impact on improving the water quality or biodiversity in the Dnieper River Basin by optimizing treatment processes and improving the quality of effluent discharged.  In addition, indirect benefits, will likely result.

 

Improved laboratory and monitoring equipment will allow improved process control of facilities resulting in high process efficiencies.  The environmental benefits of improved process efficiencies include the following:

- better treatment rates of pollutants resulting in decreased loading of pollutants at each stage of the wastewater treatment process;

- more efficient use of electricity and fuel (operation of air blowers);  

- decreased wear on equipment and facilities extending the life-expectancies and minimizing the need for replacement (aeration tanks, diffusers, air blowers);

- decrease sludge generation by more efficient biological treatment;

- reduced generation and emission of volatile compounds to the air, particularly greenhouse gasses. 

 

Negative impacts to the environment for implementing this project would be minor to none.

 

 

WWT-19  Grit Chambers (Line 2 & 3)

As mentioned previously, the poor operational efficiencies of the grit chambers have a negative impact on downstream processes from the perspective of downstream operation efficiencies, increase maintenance requirements and equipment wear.  Their replacement would have a direct benefit to the environmental condition of the river basin due to better treatment rates of pollutants in downstream processes.  The sludge digesters would be the major beneficiary .  Indirect benefits would also result as follows:

- more efficient generation of biogas and less reliance on purchased natural gas (less sand in digesters);

- decreased wear on equipment and facilities extending the life-expectancies and minimizing the need for replacement (sludge digesters, aeration tanks);

- new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment. 

 

Negative impacts to the environment for implementing this project would be limited to the impacts of construction. 

 

 

WWT-1A  Replacement of Screens (Line 1)

As above, the poor operational efficiencies of the screens have a negative impact on downstream processes from the perspective of downstream operation efficiencies, increase maintenance requirements and equipment wear.  Their replacement would have a direct benefit to the environmental condition of the river basin due to better treatment rates of pollutants in downstream processes. The primary clarifiers, aerations tanks and sludge digesters would all benefit (all are adversely affected by accumulated trash by-passing the screens).  Specifically, those benefits would be as follows:

- decreased wear on equipment and facilities extending the life-expectancies and minimizing the need for replacement (grit chambers, primary clarifiers, sludge digesters, aeration tanks);

- new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment.

 

An important benefit to workers is reduced exposure to pathogens due to the automated trash handling systems in the proposed screens. 

 

Negative impacts to the environment for implementing this project would be limited to the impacts of construction. 

 

 

WWT-13  Sludge Digesters No 1-4

The sludge digesters are old and have poor operational efficiencies largely due to up-stream process failures.  Although replacing or rehabilitating the digesters has no direct benefits to the environmental condition of the river basin, indirect benefits will be realized as follows: 

- improved quality of digested sludge (stabilized);

- maximization of biogas production and less reliance on purchased natural gas;

- minimization of fugitive emissions of biogas;

- new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment.

 

Negative impacts to the environment for implementing this project would be limited to the impacts of construction. 

 

 

WWT-18  Sludge Dewatering

Implementing effective and efficient sludge dewatering system (both primary sludge and surplus activated sludge) will have no direct benefits to the river basin but will have indirect benefits by reducing the load on the sludge lagoons and eliminating or decreasing the need for treating reject/decanted water from the lagoons.  As the volume of sludge that must be pumped to the sludge lagoons decreases and the quantity of reject/decant water requiring pumping back to the facility for treatment is minimized, the risk posed by pumping these materials over long distances is decreased.  The benefit of reduced energy consumption for pumping these materials is likely balanced by the increased energy consumption for operating the dewatering systems.  Finally, new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment.

 

Negative impacts to the environment for implementing this project would be limited to the impacts of construction.

 

 

WWT-26B  Sludge Disposal, Phase 1

Implementing an effective sludge disposal program for the sludge will have no direct benefits to the river basin but will have indirect benefits as follows:

- reduced risk of catastrophic release for over-capacity lagoons;

- the quantity of reject/decant water requiring pumping back to the facility for treatment is minimized therefore the risk posed by pumping these materials over long distances is decreased;

- reduced energy consumption for pumping reject/decant water;

- better treatment rates of pollutants in the treatment processes because the quality of reject/decant water is improved due to improved settling in the sludge lagoons;

- decreased wear on equipment and facilities extending the life-expectancies and minimizing the need for replacement (sludge digesters, aeration tanks);

- new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment. 

- Negative impacts to the environment for implementing this project would include the following impacts of construction/rehabilitation;

- transport of sludge; 

- disposal of sludge (agricultural land or landfilling).

 

 

WWT-21  Return Sludge Pumps (Line 1)

Implementing this project would neither directly nor indirectly improve the environmental condition of the Dnieper River Basin.  General environmental conditions may benefit from a decreased risk of spills or catastrophic failures of the pumps. 

 

 

WWT-4A  Primary Clarifiers (Line 1)

Poor operational efficiencies of the primary clarifiers have a negative impact on downstream processes from the perspective of downstream operation efficiencies, increase maintenance requirements and equipment wear.  Their replacement, however, would only have indirect benefits to the environmental condition of the river basin.  Specifically, those benefits would be as follows:

 

- better treatment rates of pollutants in downstream processes with the sludge digesters being a major beneficiary;

- decreased wear on equipment and facilities extending the life-expectancies and minimizing the need for replacement (sludge digesters, aeration tanks);

- new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment. 

 

Negative impacts to the environment for implementing this project would be limited to the impacts of construction. 

 

 

WWT-11A  Secondary Clarifiers (Line 1)

The poor operational efficiencies of the secondary clarifiers have a negative impact on wastewater effluents from the facility as these are the last stage of treatment prior to discharge to the river.  Their replacement would have direct benefits to the environmental condition of the river basin by improving the quality of water discharged.  Indirect benefits would also be realized including the following: 

 

- decreased wear on equipment and facilities extending the life-expectancies and minimizing the need for replacement (surplus activated sludge aerobic treatment system);

- new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment. 

 

Negative impacts to the environment for implementing this project would be limited to the impacts of construction. 

 

 

WWT-20  Sludge Thickeners

Installing modern sludge thickening processes will have no direct benefits to the river basin but will have indirect benefits by reducing the load on the sludge lagoons and eliminating or decreasing the need for treating reject/decanted water from the lagoons.  As the volume of sludge that must be pumped to the sludge lagoons decreases and the quantity of reject/decant water requiring pumping back to the facility for treatment is minimized, the risk posed by pumping these materials over long distances is decreased.  The benefit of reduced energy consumption for pumping these materials is likely balanced by the increased energy consumption for operating the dewatering systems.  Finally, new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment. 

 

 

WWT-7A  Aeration Tanks (Line 1)

The Aeration tanks are the most important element of the treatment processes at the plant.  The removal and elimination of most of the contaminants that have a negative impact on the river basin take place at this stage of treatment.  In particular, the aeration tanks in place now can only manage partial denitrification of wastewater.  After this project is implemented, full denitrification will be realized with the additional benefit of increased phosphorus removal.  Compounds of nitrogen and phosphorus in the river basin are the cause of eutrophication in reservoirs both upstream and downstream of Kyiv.  Eutrophication has adverse effects on water quality (decreased ability of river to recover from pollution loadings through natural processes) and biodiversity (decreased oxygen kills aquatic organisms).   The COWI report states that discharges from the facility are contributing to the eutrophication of the Kanesvskoe Reservoir (downstream reservoir) in a significant but not decisive way (Reference 1, page 6-3). 

 

Indirect benefits to the environmental condition of the river basin would also be realized as follows:

 

- decreased wear on equipment and facilities extending the life-expectancies and minimizing the need for replacement (sludge digesters, secondary clarifiers);

- new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment. 

 

Negative impacts to the environment for implementing this project would be limited to the impacts of construction. 

 

 

WWT-3A  Grit Chambers (Line 1)

As mentioned previously, the poor operational efficiencies of the grit chambers have a negative impact on downstream processes from the perspective of downstream operation efficiencies, increase maintenance requirements and equipment wear.  Their replacement, however, would only have indirect benefits to the environmental condition of the river basin.  Specifically, those benefits would be as follows:

- better treatment rates of pollutants in downstream processes with the sludge digesters being a major beneficiary;

- more efficient generation of biogas and less reliance on purchased natural gas (less sand in digesters);  

- decreased wear on equipment and facilities extending the life-expectancies and minimizing the need for replacement (sludge digesters, aeration tanks);

- new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment. 

 

Negative impacts to the environment for implementing this project would be limited to the impacts of construction.  

 

 

WWT-25  Gas Storage

Rehabilitating the biogas storage tank would only have indirect benefits to the environmental condition of the river basin.  Specifically, those benefits would be as follows:

 

- more efficient storage of biogas and less reliance on purchased natural gas (less losses to the atmosphere);  

- new facilities have decreased chance of failure or breakdown which can result in spills, upsets and releases to the environment. 

 

Negative impacts to the environment for implementing this project would be limited to the impacts of construction.