Ash transport & ash disposal area preparation / management

THE EUROPEAN UNION IPA 2013 PROGRAMME FOR KOSOVO*

Feasibility study for environment and other measures on Kosovo B Thermal Power Plant An EU-funded project managed by the European Union Office to Kosovo

Task 4: TRAINING WORKSHOP ON RETROFITTING

Ash transport & ash disposal area preparation / management Ing. Lorik HAXHIU, PhD.

THIS PROJECT IS FUNDED BY THE EUROPEAN UNION

Introduction Coal combustion residuals (CCRs), commonly known as coal ash, are byproducts of the combustion of coal at power plants by electric utilities and independent power producers. There are several different types of materials produced including: •

Fly Ash, a very fine, powdery material composed mostly of silica made from the burning of finely ground coal in a boiler.

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Bottom Ash, a coarse, angular ash particle that is too large to be carried up into the smoke stacks so it forms in the bottom of the coal furnace.

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Boiler Slag, molten bottom ash from slag tap and cyclone type furnaces that turns into pellets that have a smooth glassy appearance after it is cooled with water.

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Flue Gas Desulfurization Material (FGD), a material leftover from the process of reducing sulfur dioxide emissions from a coal-fired boiler that can be a wet sludge consisting of calcium sulfite or calcium sulfate or a dry powered material that is a mixture of sulfites and sulfates.

Coal ash contains contaminants like mercury, cadmium and arsenic associated with cancer and various other serious health effects. Coal ash is disposed of in wet form in large surface impoundments and in dry form in landfills.

The estimated potential risk and evaluation of damage cases demonstrate that, without proper protections, these contaminants can leach into groundwater and can potentially migrate to drinking water sources, posing significant public health concerns.

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Fly Ash Fly ash is a byproduct from the lignite combustion and is conveyed in the flue gases.

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At TPP Kosovo B the fly ash is collected initially by gravitation (the larger particulates) into: 1. ash hoppers located underneath the economizer, and 2. ash hoppers located underneath LUVO, and finally 3. electrostatically in the ESPs into their ash hoppers.

Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Ash hoppers located underneath the Economizer

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Ash hoppers located underneath LUVO

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Collector Air Slide located underneath the ESP hoppers

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Bottom Ash Bottom ash removal begins with drag chains conveying the ash from the boiler hoppers to cleated belt conveyors elevating the bottom ash to the main receiving bunker. From there, the ash goes to one of two crushers in the crusher/conditioner area.

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Internal Ash Handling Fly ash is conveyed from the precipitator hoppers by means of membrane-type (air slide) fluidizing conveyors, which utilize air blowers to provide the motive force for conveying.

The ash flows through an expander to a pneumatic elevating conveyor discharging to receiving hoppers, and then to the fly ash bunkers via additional air slide conveyors.

From each crusher, the ash enters a hydro conveyor that convey the ash to a pre-mixer and conditioner with a motor-driven agitator. At the pre-mixer, fly ash is also introduced, and all ash conveying from this point is by wet slurry.

Water for the ash handling system is drawn from an in-ground structure, which is fed by a canal adjacent to the plant. An underground pump pit containing three pumps delivers this water to a tank in the plant yard through a float-type level control valve. From this basin, two pumps are provided to supply water to the ejectors beneath the bottom ash crushers, and two pumps deliver water to the pre-mixers and conditioners.

Ash from the economizer and air heater hoppers is conveyed pneumatically via air ejectors to ash silos and then via the aforementioned pneumatic elevating conveyors to the fly ash bunkers.

Pneumatically-operated discharge valves convey the fly ash to the pre-mixer and conditioner, where it mixes with the bottom ash.

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Internal Ash Handling – Preparation of Ash slurry for transport

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Internal Ash Handling The fly ash quantity per Unit collected in the ash hoppers bellow LUVO ranges between 1.5 t/h to 4.5 t/h while the fly ash collected in the ESP hoppers varies from 45 t/h to 100 t/h. An average fly ash quantity of 63 t/h has been considered in the fly ash handling systems sizing.

The average quantity per Unit of bottom (wet) ash collected in the slag remover basin underneath the boiler furnace is considered as equal to 11 t/h.

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Current ash transport and disposal area At the outlet of each conditioner are two pumps in series, driven by the same motor, to pump the ash slurry through two separate pipe lines to the ash pond disposal area at the Mirash open pit mine. The piping conveying this slurry from the yard to the mine is of high-density polyethylene (HDPE) piping.

Ash handling is accomplished in a combination of wet and dry systems for removing bottom ash from the boiler and fly ash from the economizer, air heater and ESPs hoppers.

Ultimately, all ash is disposed in a slurry form (1:1 ratio) at ash disposal site in exploited part of the lignite mining area

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Current ash slurry disposal area

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Accumulation of leachate at the Ash disposal area

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Gypsum as a byproduct of Flue Gas Desulfurization

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Gypsum as a byproduct of Flue Gas Desulfurization 35,000 t

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Gypsum as a byproduct of Flue Gas Desulfurization The product of wet FGD process is gypsum (CaSO4x2H2O).

Gypsum formed in the wet FGD process, has the same properties as natural gypsum and it is environmentally safe.

For its deposit no additional measures are necessary in respect of the leachate, it could be mixed with the ashes to stabilize and consolidate. Self-storage of gypsum without stabilization is not desirable, in the event of a significant rainfall or accumulation of water on the landfill floor may occur liquefaction of material and the instability of the landfill.

The quantity of gypsum is a function of consumed quantities of coal, the annual quantity may move in the range of 15,000 t – 20,000 t

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Gypsum dewatering – Vacuum belt filters

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Current and Future Disposal Area The ash slurry from Kosovo B is being disposed in the eastern sector of the former Mirash open pit.

Reportedly the area will serve for ash slurry disposal for at least next two years.

In March 2016, with decision of KEK board, TPP Kosovo B received control over additional former mining area between existing disposal site and the Sitnica river, the so called Sitnica sector with area S = 44.48 hectares and with volume V = 8.55 million m3.

In May 2016, based on framework agreement Kosovo B has engaged INKOS Institute to draft a Plan for preparation of Sitnica sector for ash disposal, to prepare Ash Disposal Plan, and to support the change of area destination from a lignite mining site to a ash disposal dump with relevant permits based on applicable legislation in Kosovo.

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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View of future site for new ash disposal area

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Potential Hazards and contamination path ways Due to the fact that residual ash from coal combustion is generally known to contain a wide variety of potentially toxic trace elements it must be assumed that ash disposal of that magnitude constitutes a serious environmental problem.

The main hazards relate to: • soil contamination; • water/groundwater contamination due to leaching toxins (effluents and process waters); • dust dispersion; and • toxins entering the food chain.

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Risk assessment of waste waters Wastewaters from wet-disposed coal ash land fills can be classified into: • The water used in the ash transport • Landfill leachate Quantitatively water used to transport the ash is by far more important than landfill leachate since a constant waste water stream is generated to convey the ash to sedimentation ponds.

After sedimentation the overflow is usually released to the next tributary or river. This water contains dissolved ions and large amounts of suspended and floating ash particles. The total load of waste waters needs to be analyzed in acid digests following standard procedures as described in national water regulations.

Quality of wastewater (ash transport water and landfill leachate) need to be evaluated knowing current treatment practices such as sedimentation and pH control. For planning any water treatment a water balance of the individual sites is required. This includes inflow rates of natural streams (if present), precipitation, evapotranspiration, surface run-off, outflow rates from landfill leachates, and ash transport water flow rates. Missing quantities in the balance give an estimate of the amount of wastewater that infiltrates the groundwater. This will largely depend on the geological situation and the presence or absence of liners established before wet deposition of ash.

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Potential risk of coal ash surface impoundments Improperly constructed or managed coal ash disposal units have been linked in cases to harm to groundwater - leaking of contaminants into groundwater.

New requirements for coal ash surface impoundments and landfills include: • Groundwater monitoring around surface impoundments and landfills; • Liner requirements for new surface impoundments and landfills to protect groundwater; • Groundwater cleanup from coal ash contamination; • The closure of unlined surface impoundments that are polluting groundwater; • The closure of surface impoundments that fail to meet engineering and structural standards or are located too close to a drinking water source; • Restrictions on the location of new surface impoundments and landfills so that they cannot be built in sensitive areas such as wetlands and earthquake zones; and • Proper closure of all surface impoundments and landfills that will no longer receive CCRs.

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Feasibility study for environment and other measures on Kosovo B Thermal Power Plant

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Relevant Legislation Kosovo has pursued approximation to EU environmental standards, with important advances in legislation concerning air, water qualities, IPPC, EIA and waste. The new Law on Waste was enacted in 2012.

Harmonization of EU Directives with Kosovo's legislation is estimated to be near complete for the Directive on Waste (2006/12/EC), and advanced for the Directive on Hazardous Waste (91/689/EC), for the Directive on Packaging Waste (94/62/EC), for the Directive on Landfills (99/31/EC), and for the Directive on the Incineration of Waste (2000/76/EC).

In addition the adoption of new environmental laws, in particular the approval on 2009 of the Environmental Protection (Law n.3/L-025) and IPPC (Law n.3/L-043) laws, the approval on 2010 of the EIA (Law n.3/L-214) and SEA (Law n.3/L-230) laws, the approval on 2013 of the Water Law (Law n.4/L-147) and the further recruitment of staff at both central and local level (in particular the environmental and inspection officials) are positive steps forward.

The relevant legislation for Kosovo B ash disposal area include:  Law on Waste no. 04 / L-060, OGRK no. 17/29 June 2012  Law on Water no. 04/L-147 OGKR 29 April 2013  Law on Environmental Protection OGRK, no. 03 / L-025 26.02.2009  Law on Prevention and Integrated Control of Pollution OGRK, no. 03 / L-043 26.03.2009  Law on Air Pollution, OGRK, no. 03 / L-160 12.03.2010  Law on Environmental Impact Assessment, OGRK, no. 03 / L-214 23.09.2010  Law on Strategic Environmental Assessment, OGRK, no. 03 / L-230 30.09.2010  Law on Chemicals No. 02 / L-116 OGRK No.18 / 26 March 2014  Law on Nature Protection No. 03 / L-233 OGRK no. 85/09. 11. 2010.

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Case of CCR specific disposal regulation: The 2016 IPA CCR Rule In 2016 the US Environmental Protection Agency finalized national regulations to provide a comprehensive set of requirements for the safe disposal of CCRs, commonly known as coal ash, from coal-fired power plants. The final rule is the culmination of extensive study on the effects of coal ash on the environment and public health. The rule establishes technical requirements for CCR landfills and surface impoundments, including: • Location Restriction • Design Criteria • Structural Integrity • Air Criteria • Hydrologic and Hydraulic Capacity • Inspections • Groundwater Monitoring and Corrective Action • Closure and Post-Closure Care • Recordkeeping, Notification, and Internet Requirements

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The IPA CCR Rule Measures and Actions Location Restriction

Inspections

 Complete demonstration for placement above the uppermost aquifer

• Initiate weekly inspections of the CCR unit

 Complete demonstrations for wetlands, fault areas, seismic impact zones, and unstable areas

• Complete the initial annual inspection of the CCR unit

• Initiate monthly monitoring of CCR unit instrumentation

Design Criteria

Groundwater Monitoring and Corrective Action

• Document whether CCR unit is either a lined or unlined CCR surface impoundment

• Install the groundwater monitoring system;

Structural Integrity

• initiate the detection monitoring program; and

• Install permanent marker

• begin evaluating the groundwater monitoring data for statistically significant increases over background levels

• Compile a history of construction

• develop the groundwater sampling and analysis program;

• Complete initial hazard potential classification assessment, initial structural stability assessment, and initial safety factor Closure and Post-Closure Care assessment • Prepare written closure and post-closure care plans • Prepare emergency action plan Air Criteria

Recordkeeping, Notification, and Internet Requirements

• Prepare fugitive dust control plan Hydrologic and Hydraulic Capacity • Prepare initial inflow design flood control system plan

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• Conduct required recordkeeping • Provide required notifications • Establish CCR website

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Questions and Discussion

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