Cover Soil

1
Cover Soil

• Its the single biggest (avoidable) cost of
  operating most landfills

2
Why Use Cover Soil?

• It keeps litter in
• It keeps vectors and moisture out
• It provides a driving surface
• It keeps the landfill looking sanitary
• ITS THE LAW

3
Completed Daily Cell is Covered

• The finished cell is covered with soil and/or
  other material

4
Daily Intermediate Cover

• Daily
• Its applied every day
• Its 6 thick
• It provides a temporary barrier
• Intermediate
• minimum of 12 inches
• more stable base for driving
• Semi-permanent barrier

5
Completed Landfill is Covered

• The finished landfill is capped with soil and/or
  other material. This is called Final Cover.

6
Final Cover

• Final
• Base Layer
• Low-Permeability Layer
• Top Layer
• Permeability equal to bottom liner

7
Final Cover It Mirrors the Liner

• Final Cover will typically mirror the liner.
• Heres a look at soil and GCL being placed as
  part of Final Cover,

8
Final Cover

• GCL is covered with a protective layer of soil

9
Final Cover

• The protective layer of soil is graded and
  compacted

10
Final Cover

• Final cover is completed by grading and
  re-seeding to prevent erosion

11
Liners Are Expensive
A large landfill might spend million per year on
liner construction
Yes its true. Liners are expensive. They
represent a major cost of operation for most
landfills. How can you reduce liner
costs? Change the design? ...OK Bid in
the off- season? ...Sure Do some of the work
yourself? ...Yeah, thats fine too. But, if you
really want to reduce liner costs, manage your
airspace.
12
Want to Reduce Liner Costs by 25?
Forget re-design and off-season bids. Let a
contractor do the work.
If you want to cut liner costs, get out in the
field and focus on compaction and cover soil.
Some landfills could reap up to 40 savings in
liner costs by working on those two things.
13
Whats the No. 1 Problem?Too Much Soil

• Using too much cover soil is the most common (and
  most costly) operational problem at most
  landfillsin my experience
• So what do we do about it?
• Measure it
• Track it
• Check it
• Stop using so much soil

14
Daily Intermediate Cover

• Its good
• It provides a barrier
• Its required
• Its bad
• It costs money to place
• It costs money to purchase
• It takes up lots of airspace

15
Stripping Soil

• Same analysis as alternate daily cover
• May have regulatory impact

16
Track-Walking Saves

• Track-walk prior to placing daily cover
• This can save 2 of cover.
• How much money is that worth?

17
Cover Soil Placement

• Strip Soil Prior to Placing Next Cell
• Optimum Cell Geometry
• Properly Finish Cell Surface Before Covering
• Determining the Optimum Cover Ratio
• Placement Methods
• Tracking Cover Soil Volumes

18
Covering with Scraper Wastes Soil

• The Scraper uses 1/3 to 2/3 more dirt than the
  dozer/
• The Scraper
• Not quicker
• Not cheaper

19
To Save Soil, Airspace and ,Use the Dozer to
Spread Cover
20
Do your own Test

• 1. Finish the cell properly
• 2. Cover with the D8 (1 week)
• a. Count loads
• b. Keep track of time
• 3. Cover with the D5 (1 week)
• a. Count loads
• b. Keep track of time
• See for yourself.If the D5 is not
  better let me know.

21
Different Techniques for Various Soils

• Criteria
• gradability and cohesion
• Silts, Loams and Weathered Shales
• typically most efficient

• Cohesive Soils and Clays
• grading is very difficult
• Dry Sand and Loess
• cohesiveness is poor

22
Soil Conversion Factors

• Units of Measurement
• Loose cubic yard
• Bank cubic yard
• Compacted cubic yard
• Soil Swell
• Soil Shrink

23
Measuring Cover Use

• Cubic yards
• Tons
• Most common is Cover Ratio

24
What is a cover ratio?

• Its like a recipe. In this example, 3 parts
  waste to 1 part soil indicates a 31 cover ratio.
  A 31 cover ratio is an industry
  standardwhatever that means.

Waste
Soil
25
Misunderstandinga 31 Ratio

• Here are some common mis-conceptions
• The typical Landfill
• operates with a 31 cover ratio
• covers with 6 of daily cover soil
• is somehow going to meet these standardsno
  matter what - Its Magic!!

26
Dont get Hooked on a 31

• Dont get hooked on a 31 cover ratio
• Large landfills could do a lot better especially
  if they use ADC
• For small landfills, 31 may be out of reach

27
Optimum Cover Ratio

• Maximize use of cover soil.
• Must first determine minimum cover ratio.
• Based on cell geometry.

28
ADC Criteria

• Why is it 6 inches of soil?
• Its a performance standard
• How could ADC help your landfill?
• Insects Aesthetics
• Fire Regulations
• Litter Cost
• Animals Vectors

29
With ADC, It Gets a Lot Better
30
What Does an Extra Truckload of Soil Cost?

• Lets figure it out.

31
Solving the Cover Mystery

• Set a Benchmark
• Measure Cell... find average surface area
• Calculate how much soil is required _at_ 11
• Select a realistic cover ratio as a budget
• Accurately track soil volume
• Record No. of truckloads
• Reconcile against paid to quarry
• Cross-Check
• Dig random holes and measure soil depth

32
Check your own cover ratio

• Calculate the volume of soil used for cover.
• Convert volume to cy.
• Measure the cells surface area.
• Divide the volume by the surface area.
• The result is the effective depth of cover.
• Dig some test holes as a cross-check.

33
Cover Soil Budget

• Determine the correct soil budget .
• Operators must know how much to use each day.
• Track amount used each day.
• Records should be compiled and checked.
• Adjust the operation or budget if need be.

34
Minimizing Cover Soil Use

• Optimum Cell Geometry
• Build Cells Properly
• Finish Cells Properly
• Place Cover Soil With Dozer
• Use an Alternative Daily Cover
• Strip Available Soil Prior to Placing the Next
  Cell
• Prepare a Cover Soil Budget