Complementing WTEA Proposal to Implement Recycling and Remediate the GT Landfill

Complementing WTEA Proposal to Implement Recycling and Remediate the GT Landfill

Complementing WTEA Proposal to Implement Recycling and Remediate the GT Landfill

Complementing WTEA Proposal to Implement Recycling and Remediate the GT Landfill

Complementing WTEA Proposal to Implement Recycling and Remediate the GT Landfill

Complementing WTEA Proposal to Implement Recycling and Remediate the GT Landfill

New Concepts in Waste DisposalBy: Walling Whittaker, MSc

Presentation Outline

• A brief look at the GTLF – Issues and challenges

• Innovation in Landfilling - Energy from Wastes– Solar Landfill– Sustainable Landfill

• Potential for energy recovery at the GTLF

Addressing the Problem

Closing and Capping GTLF

Engineered Containment

Groundwater

Lining System

Waste

Leachate

Rainfall

Leakage

Gas

Cover System

Demerits of Mining the Existing Landfill

According to GBB, it will take 19 years to mine the landfill and reduce it to grade

During this period there will be a continuous release of landfill gas and odors over George Town

Continuous risk of Explosions, Sparks causing fires

Workers will be continuously exposed to hazardous materials injury and loss of life

A Typical Landfill Cap

Is A Renewable Energy Cap the Remedy?

Need for topsoil andvegetation iseliminated. In areaswhere water is limitedthis saves money inO&M phase of project.

Need for additional fillmaterial (and associatedheavy equipment andmanpower) iseliminated while theremedy is equallyprotective.

A Solar Cap provides aprotective barrier whilegenerating energy torun equipment orproduce revenue

Solar Energy Landfill Caps

An Innovative Alternative to Traditional Landfill Capping

Advantages of Solar Energy Landfill Cap

• Transforms a liability into a revenue • Potential to reduce post-closure care costs• Sale of renewable power• Carbon cap and trade credits• Innovative end-use for closed landfill • Positive public image

Solar Energy Landfill Caps

• A great way to protect the environment and provide clean, renewable energy

• Landfill Design Benefits: – Promotes positive drainage – Minimizes infiltration – Reduced maintenance – Accommodates settlement – Produces high quality stormwater runoff

Two Types of Solar Caps

Flexible solar panels Rigid panels

Low power production efficiency ca. 6%

Higher power production efficiency > 13%

Light Heavier (steel frame, glass)

Flexible, unbreakable Stiff frame

Works well with diffuse light

Less efficient with diffuse light

Works well with temperatures above 40°C

Less efficient with temperatures above 40°C

Rigid Panels

Flexible Panels

Placement of Rigid Panels

Project Opportunities for Flexible Solar Caps:

• Closed or ‘inactive’ landfills• Sites located near transmission lines• Sites adjacent to large electricity load/demand

Existing Solar Landfill Projects• Malagrotta, Italy: 998 kW from

PV in landfill cap• Brockton, Massachusetts 460 kW

“Brightfield” with ground mounted panels

• Nellis Air Force Base, Nevada 15 MW from tracking panels on old landfill

• Republic Services, San Antonio, TX – solar demonstration project to incorporate PV membranes in landfill cap

• FPL’s 250 kW solar panel array on closed Bee Ridge Landfill in Sarasota, FL

• New Jersey Meadowlands Comm. Proposal for 5 MW solar project on Erie Landfill

• FLS Energy to build and operate 1 MW PV array on closed landfill in North Carolina

• Epuron PV array adjacent to G.R.O.W. Landfill owned by Waste Management in Bucks Co. PA

Solar Integrated Technologies, Malagrotta Italy

1 Megawatt Landfill Application.

Flexible Panel

Tessman Rd. Landfill, Houston Tx

Winner of the 2010 SWANA Gold Excellence Award for Landfill Secondary Use

Hickory Ridge Landfill Atlanta, Georgia

• 48 acres• 7,000+ solar panels to produce over 1 MW of

renewable energy over a 10-acre south slope • Construction completed in July 2011

If this can be done in other countries…why not in Cayman?

A Solar Farm at GTLF• Solar radiation in Cayman

reaches 6.6 Kwh/m2/day, from March to September

• Can be designed using either flexible panels or rigid panels, ground mounted at 15 degrees angle.

• With the price of energy averaging US$0.37/Kwh

• Has the potential to produce 2.2Mw electricity

A Solar Farm at GTLF

• A small section ( 10 acres ) of the GTLF could accommodate 9,300 rigid panels of 235 watts, each.

• Based on climate data (10 years average), it has a potential capacity of 2.18 Mwp, on just 40,950 square meters of the site.

• Enough electricity to power about 300 homes

A Solar Farm at GTLF

• Total Investment: US$ 6.1 MM• Installed Capacity :2.18Mwp• Average production/yr:3.9MMKwh• Project life:25 yrs• Pay Back Years - 8• Internal Rate of Return - 18%• NPV - US$8.9MM (6%)

Sustainable Landfills

What is a Sustainable Landfill?• An engineered landfill in which the cells are designed

to operate as ‘bioreactors’ so that they can be reused again and again

• Create conditions for waste degrading organisms to thrive

• Most typically performed by increasing moisture content– Leachate recirculation– Air Injection

• A large scale composting operation

0 10 20 30 40Time (Years)

Gas

Pro

duct

ion

Bioreactor Landfill

Conventional Landfill

The Sustainable Landfill

Landfill Cover

LeachateAir

Leachate Collection System

Economic Benefits of Sustainable Landfills

• Reduces the need to build new landfills• Enhanced gas production• Recovered space• Reduced env. impact• Reduced post-closure care

Existing Projects

• 10 field-scale demonstration projects in the US and Canada– Waste solids decomposition– Nitrogen cycling and management– Liquid distribution– Gas production modelling– Liquid waste bioassay development– Methane oxidation and emissions measurement

• 8 patents issued 6 applications pending• Existing projects in Florida

New River Regional Landfill

• Lined Landfill• Manages waste from

several North Florida Counties (approximately 800 tons per day)

Gas is converted to “green” energy

Landfill Engineering is Becoming Innovative

Clay and plastic liningto prevent leaks; pipescollect leachate frombottom of landfill

GroundwaterLeachatemonitoringwell

GroundwatermonitoringwellLeachate pumped

up to storage tankfor safe disposal

Leachatestoragetank

Leachatetreatment system

Pipes collect explosivemethane for use as fuelto generate electricity

Electricitygeneratorbuilding

When landfill is full,layers of soil and clayseal in trashMethane storageand compressorbuilding

Methane gasrecovery well

Compactedsolid waste

Leachatepipes

Probes todetectmethaneleaks

Topsoil

GarbageClaySand

Garbage

Subsoil

Synthetic linerSandClay

Sand

Better Engineered Landfills

Questions