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Groundwater Control Since 1934

Coal Ash Dewatering Solutions

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Groundwater Control Since 1934

WE ARE GRIFFINDewateringGriffin has provided service and equipment to the construction dewatering and groundwater pumping market since 1934 gaining the respect of Griffin’s clients by solving their groundwater problems.

Pumps & EquipmentGriffin Pump has over 80 years experience in manufacturing innovative equipment that is a direct result of field experience.

Filtration and TreatmentGriffin offers treatment systems for any application using the appropriate technologies to best treat the water on our client’s jobsite.

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Griffin Dewatering has the engineering capabilities, the experienced personnel and the wide range of equipment and services needed to handle complex dewatering challenges.

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Coal Combustible Residuals: Challenges and Solutions to Dewatering and Disposal• Fly ash has low/no compressibility• Stabilization of fly ash for dry excavation results from

reduction of pore water pressure, thus increasing cohesion• Key success factors for excavation dewatering:

• Field permeability testing of fly ash in situ• Proper engineering analysis of permeability, flow conditions and

expected drawdown• High intensity of dewatering by using closely spaced wickpoints that

operate without disruption• Preventing recharge from aquifers or runoff• Effective filtration/treatment of discharged water

Ash Pond Dewatering

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Lowering the water content of ash pond materials by pre-drainage increases coal ash cohesion and stability.

This allows for vertical cuts to be made for large scale excavation with conventional excavation equipment.

The primary methods of ash pond dewatering are:

• Wickpoints• Deep Wells• Well Points• Eductors• Sumping

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Three Distinct Sources of Water

Ash Pond Dewatering

• Impounded/free water which lies on top of the ash and comes from precipitation and/or sluicing.

• Groundwater which may intrude into the bottom of the ash.

• Interstitial water which lies in the pore spaces of the ash.

Staging between the 3 pumping systems is a key factor in preventing the potential for leachate entering the groundwater.

Ash Pond Dewatering

Three Part Solution

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Groundwater Control Since 1934

Kingston Fossil Plant Ash Pond, Kingston NC

Coal Combustible Residuals: Griffin’s Approach toEngineered Dewatering Solutions for Ash Pond Excavations

• Groundwater Modeling

• Engineering and Design

• Dewatering Systems

• Pumps and Equipment

• Filtration and Treatment

• Maintenance and Operation

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SEEP 2DGriffin utilizes two dimensional seepage analysis in order to calculate the flow lines, constant head lines and water table for specific projects like dam seepage and cutoff wall dewatering.

Using MODFLOW helps analyze the 3D models for the dewatering system. The cone of depression resulting from dewatering can be simulated and shown in 3D view. The flowrate required for drawdown at each jobsite can be estimated for each well location.

MODFLOW

• Dewatering Systems Design (Permanent and Temporary)

• Aquifer Testing (Pumping Tests and Slug Tests)

• Uplift Pressure Calculation / Relief Well Design

• Recharge Well Design

• Dewatering Submittals

• Developing Dewatering Specifications Soil stratigraphy, using GMS Borehole Module, based on the available borehole data. Case study: Treatment Facility in Norfolk, VA

Engineering and Design

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SilterMops for free water pumping

Dewatering Systems

• Geotextile filter assembly

• Tailored to site conditions

• Suspended solids control

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Full Line of Dewatering and Treatment Systems

Dewatering Systems

• Deep Well Systems

• Wellpoint/Wickpoint Systems

• Eductor Systems

• Open Pumping/ Sumping

• Filtration and Treatment

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Wellpoints Deep Wells

Eductors Wickpoints

Dewatering Systems

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• Griffin wick drains are constructed using formed polystyrene core with a nonwoven spun bonded filter fabric.

• The core provides an uninterrupted path for water to flow.

Wickpoint System

Dewatering Systems

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Pumps and Equipment

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Filtration and Treatment

Griffin has extensive experience treating groundwater and offers field tested solutions and equipment for our client’s water treatment requirements.

Griffin offers systems to address standard groundwater issues such as:

• Total suspended solids• Nuisance mineral removal (Iron, manganese, etc.)

• Hardness

• pH

• Hydrogen sulfide

• Heavy metal removal

• Radium

• Radon

• VOC contamination

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Maintenance and Operation

Griffin has available specialists trained to operate, maintain, and repair a wide range of dewatering and treatment systems and equipment.

Griffin’s core dewatering business, includes construction, dewatering, systemsintegration, operation and maintenance.

Kingston Fossil PlantAsh Recovery Project

Tennessee Valley Authority2012

Case Study

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Griffin was contracted to lower water in ash more than 10’, creating a stable working platform and allowing a barrier wall to be constructed.

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Please visit our website for more details at:www.griffindewatering.com

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