Craig Dufficy U.S. EPA Office of Resource Conservation and Recovery

Craig Dufficy U.S. EPA Office of Resource Conservation and Recovery

Overview What is a Landfill? Basic waste properties. Area and Volume calculations. What is allowed in a landfill and what is not. How does a landfill work? Good landfill practices. Federal requirements for a landfill from conception to closure.

What is a landfill? Just what is a landfill? A landfill is a large, outdoor site designed for the disposal of waste. There are different kinds of landfills that accept different material including municipal solid waste (MSW) the trash and garbage that we throw away every day at home, work and school as well as construction and demolition (C&D) debris, industrial waste, hazardous waste and land-clearing debris.

What is a landfill? Many years ago, there were few or no regulations regarding landfills. It showed. Many people remember smelly, unlined dumps that contaminated groundwater and caused other environmental problems. It s different today. Modern landfills are well-engineered facilities that must meet strict U.S. Environmental Protection Agency (EPA) requirments. When you think of it this way and most of us don t garbage disposal is no less an essential public service than police or fire protection.

What is a landfill? Landfills that accept MSW must be built in suitable geological areas away from faults, wetlands, flood plains and other restricted areas. The design of landfills includes plastic liners and other materials like clay to prevent groundwater contamination. Monitoring is required to determine if there is any groundwater contamination. Daily operation of landfills includes compacting (crushing) and covering waste with several inches of soil or other cover material to reduce odor and litter as well as control rodents and pests. Closed landfills must have a final cover that includes a synthetic cap and a soil layer.

What is a landfill? Once the landfill is closed, the responsibility of the landfill operator doesn t end. Landfill operators must set aside funding to provide environmental protection during and after the closing of a landfill. In short, today s landfills are expensive to design, build and maintain.

What is a landfill? Beyond the expense, landfills also are difficult to build simply because the public frequently opposes new construction. People remember the poor practices of the past and are concerned about their health and environment as well as property values, noise, odor and traffic if a landfill is built near their community.

Basic waste properties The physical composition of solid waste is established by those items or materials actually discarded; moisture content and the density of the waste.

Basic waste properties The moisture content of MSW is usually expressed as the weight of moisture content of wet material. A moisture content of 20%-25% is considered typical. Food waste ranges from 50%-80%. Vegetative wastes average range from 30%-80% (% by weight).

Basic waste properties Typical densities (weight/volume, or pounds/cubic yard) for the average types of MSW are: residential curbside - 250 lbs/cubic yard commercial/industrial 500 lbs/cubic yard (uncompacted) MSW in a packer truck 750 lbs/cubic yard

Basic waste properties Why are these values important to know? Because the average landfill operating density is 1,000-1,200 lbs/cubic yard So if you know the type of MSW you are dealing with, you ll get a good idea of how much you need to run your compactor.

Area and Volume calculations Why do we need to know area/volume calculations? Day-to day operations- If you are working at a drop off area and you need to know what size truck do I need to collect white goods, or you are moving a pile of MSW what size container do I need?

What size roll-off do I need to move this?

Area and Volume calculations height = 10 ft Diameter = 30 ft radius = 15 ft

Area and Volume calculations Volume = ⅓ (3.14) ( 15)² (10) Volume = (0.33 X 3.14 x 225 x 10) Volume = 2,331 cubic ft (27 cubic ft = 1 cu. yard) Volume = ⅓ r ² h Volume = 2,331 cu. ft X 1 cu. Yd./27 cu. ft. Volume = 2,331/27= 86 cu. Yd ~ 90 cu. Yd Area of the cone = r s Area of the base = r²

Area and Volume calculations

Other common shapes

What is allowed in a Landfill and What is not? In-Garbage, refuse, sludge from a waste water treatment plant, water supply treatment plant, or air pollution control facility and other discarded material, including solid, liquid, semi-solid, or contained gaseous material resulting from industrial, commercial, mining, and agricultural operations. Out- Liquid wastes (bulk) that is not from a household. Radioactive wastes. Regulated hazardous waste. Rainwater (run-on and run-off controls).

How does a landfill work? The daily operation at a MSW landfill includes the disposing of waste into a specific area of the landfill called a cell, the compaction (crushing) of the waste and the daily covering of the waste with a soil layer.

How does a landfill work? Waste is disposed of into an open area of the landfill called a cell. Think of a cell as a small football stadium it has a flat floor (the football field) and slopes built all around it (seating). MSW landfills almost always just have one cell open to accept waste. This cell or area is called the working face. At the same time another cell is being built so it is ready when the other cell is full.

How does a landfill work?

Lift and Cell Structure

How does a landfill work? MSW is compacted to save space. Space is money at a landfill. Did you know that on average about 1,200 pounds of waste can be compacted into one cubic yard of space?

How does a landfill work? At the end of the day, the working part of the cell is covered with a layer of soil to minimize odors, pests and blowing litter. This is called the daily cover. This three-step process is repeated over and over again until the cell is filled. The waste can be piled to a certain height based on the permit.

How does a landfill work? When a MSW landfill is full, it is closed with a final cover that includes a cap and soil layer.

Simple diagram of a completed landfill

How does a landfill work? Once the MSW landfill is closed, the responsibility of the landfill operator does not end. Operators must continue to pump the leachate, test the groundwater wells, inspect the cap and repair any erosion, fill low areas due to settlement, maintain vegetation and prevent trees from growing. In addition, operators must set aside funding (financial assurance) to close the landfill and provide post-closure care in the event the operator abandons the site.

Parts of a Landfill The basic parts of a landfill are: Bottom liner system-separates trash and subsequent leachate from groundwater Cells (old and new) -where the trash is stored within the landfill Storm water drainage system -collects rain water that falls on the landfill Leachate collection system -collects water that has percolated through the landfill itself and contains contaminating substances (leachate) Methane collection system -collects methane gas that is formed during the breakdown of trash Covering or cap -seals off the top of the landfill

Good Landfill Practices Some areas that we can establish good practices are: 1) Siting 2) Landfill Cell Design 3) Construction QC 4) Waste Disposal 5) Waste Receipt 6) Monitoring 7) Reporting 8) Community Involvement 9) Financial Assurance

Regulations Cover Six Basic Areas ( 40 CFR 258) The Federal regulations for Landfills covers the six basic areas: Location Restrictions Operating Criteria Design Criteria Groundwater monitoring and corrective action Closure and post-closure care (30 years) Financial assurance

Operational requirements for landfills under 40 CFR 258 will include: 1. Ensure that hazardous waste is not accepted. 2. Provide daily cover for the waste disposed. 3. Control on-site disease vectors such as insects and rodents. 4. Provide monitoring for build-up of methane gas. 5. Eliminate noxious open burning of waste. 6. Control public access to the facility. 7. Construct run-on and run-off controls. 8. Control discharges to surface water. 9. Prohibit the disposal of most bulk or non-containerized liquids. 10. Keep operating records that will demonstrate regulatory compliance.

Design - New MSWLF facilities and lateral expansion of existing units must comply with either a design standard or a performance standard for landfill design. The design standard requires a composite liner composed of two feet of soil with a hydraulic conductivity of no more than 1 X 10-7 cm/sec, overlain by a flexible membrane liner and a leachate collection system. A performance-based design must demonstrate the capability of maintaining contaminant concentrations below maximum contaminant levels at the unit s relevant point of compliance.

Groundwater Protection Water resources should be protected by locating the landfill down-gradient from major aquifers and drinking supplies. Provide an impermeable bottom liner (or a low permeable soil layer) to reduce groundwater contamination. If no liner, a minimum separation should be maintained between bottom of landfill and the high groundwater table and bedrock surface wherever possible. No water supply wells should be located within 2 miles down gradient of the landfill and a greater distance of vertical separation is desirable.

Groundwater Monitoring Criteria Must install monitoring wells. Wells must be in the uppermost aquifer Must have representative wells upgrade & downgrade from the landfill - At least 1 upgrade and 2 downgrade. - Number depends on fluctuation in flow direction, etc. Wells must be designed to last the life of the LF and throughout closure (additional 30 years). Must be installed at the relevant point of compliance.

Relevant Point of Compliance MCLs can not be exceeded at relevant point of compliance. No farther than 150 meters from the landfill boundary and on land owned by the landfill owner Source: EPA 530-SW-91-089, 1993.

Groundwater Monitoring Sampling and analysis must be done at least twice a year. If contamination detected above MCL: Must begin assessment monitoring. May make determination that landfill is not source. If source, must take corrective action Evaluate alternatives Public comment Clean up to drinking water quality or background levels. Corrective action continues for 3 yrs after standard met.

Closure & Post Closure Care Closure must begin within 30 days of final receipt of waste. Closure must be completed in accordance with closure plan within 180 days, certified by engineer. Install final cover to minimize infiltration & erosion. Infiltration layer: equal to bottom and side liner protection; 18 in of material, e.g., compacted clay and/or synthetic flexible membrane liner (FML); permeability bottom liner or no > 1 10-5 cm/s, whichever is less. Erosion layer: minimum 6 inches of soil capable of sustaining native plant growth Notation must be placed in land deed (limits future use).

Post-Closure Care Prepare post-closure plan; enter into Landfill operating records by October 1993 or before first receiving waste, whichever is later. Post-closure care for 30 years. Maintain integrity of final cover Monitor groundwater and gas Continuing leachate management Time period may be varied by approved state.

Financial Assurance Must demonstrate financial responsibility for costs of closure, post-closure care, and corrective action for known releases. Mechanisms: Trust fund with a pay-in period Surety bond Letter of credit Insurance Guarantee State assumption of responsibility Multiple mechanisms (combination of above)

Questions? Craig Dufficy Dufficy.Craig@epa.gov Telephone: 703-308-9037