Paper

Balefill and wrapped baling technology versus conventional land fillinganalysis.

31/03/2005

Conference Name: Landfill 2005

Title:Environmental performance review and cost benefit analysis of landfill operations utilizing Bale fill and wrapped baling technology versus conventional land filling Analysis.

Presenter: Grant Lacey

Author: Grant Lacey and Danny Glennon

Company: New Waste Solutions Pty Ltd

Postal Address: PO Box 2064NerangDC QLD 4211

Telephone: 07 3209 9180

Mobile: 0418 784 341

Fax: 07 3208 8044

E-mail:

Bale Fill and Wrapped Baling Technology versus Conventional land filling analysis.


Introduction

This study reviews the difference between “conventional landfill” and “wrapped balefill” through environmental economical and operational analytical results. The core focus of this paper is the economical analytical review. The landfill industry consists of many varying classes, sizes, methods and types of waste burial treatment facilities. For the purpose of this study we have reviewed and compared a large quantity of20,000 ton landfill sites, compared their current cost of running the existing “conventional landfill”vs. operating the site as a “wrapped balefill” process.

The “conventional landfill” is where waste that is delivered by general waste trucks is compacted using man powered machinery with steel wheels and sequentially the waste is covered in 2m lifts with 300mm of soil floorsand batters that are covered nightly by 150mm of soil to reduce environmental impact and to meet compliance. This has been seen to date as the most economical means of handling waste treatment and burial. For this reason the predominant form of waste treatment and burial in Australia and throughout the world has been “conventional landfill” even though there have been obvious problems both operationally and environmentally and now increasing pressures on air space availability. All other merging solid waste technologies have been expensive compared to the current waste charges per ton achieved at most 20,000 ton landfills.

The “wrapped balefill process” includes the automatic square baling of waste in a controlled environment using an oxo-degradable landfill bale wrap (Enviro Wrap™). Wrapped and temporarily treated bales are then transported to the landfill working face by flat deck trucks and fork lifted into place. There is no exposed work face therefore proposed that the lift heights for the waste can be up to 10 meters high before the requirement of the 300 mm soil floor layer. Due to the temporarily treated bales there would be no working face or batter 150mm soil cover requirements.

Bale fills have been operated in Europeand around the world for many years without the availability of a landfill degradable stretch wrap to cover the bales as all plastic technologies at the time did not degrade in this controlled landfill environment.

A balefill without a degradable wrap was seen to be a similar operation to a conventional landfill with some advantages in the sheltered receivable area and initial treatment of waste before delivery to the landfill site. Unwrapped baled waste was not fully treated leaving exposed areas that required further treatment or covering at the landfill site generally with soil. The lift height would remain the same as conventional landfill regulations (varies 2m – 2.4m) before a 300mm to 350mm soil floor would be required.

New OXO-BIO-DEGRADABLE plastic stretch wrap technology ( has been tested and developed to encapsulate the bale temporarily and sequentially degrades in the heat of a landfill environment. This creates a normal landfill environment which haspotentially highlighted significant advantages economically, socially and environmentally. Bale technology has also been through many years of reform and improvements thanks to material recovery facilities.

Operational Comparisons: Conventional Landfill vs. Wrapped Balefill

The conventional landfill process consists of: -

1. Consolidation of refuse volumes at a transfer station

2.Recycling, resource recovery operations

3. Transfer of remaining refuse to the disposal facility

4. Direct tipping of the refuse on to the ground at a prepared site.

5. Placement, compaction and covering of the refuse at the site

The landfill system through previously compacted waste or “wrapped balefill”: -

  1. Consolidation of refuse volumes at transfer station
  2. Recycling resource recovery operations
  3. Balers compress the refuse into dense, self contained degradable wrapped bales.
  4. Placement and floor covering of the bales at the landfill site.

The following assessment is the perceived differences between “conventional landfill” and “wrapped balefill”from direct customer feedback during the evaluation of many potential balefill sites, through group forums, balefill studies and results from balefill operations internationally. Certain elements of this study are in the early stages and require further investigation. Further studies by QUT in Brisbane are currently looking at deeper bio-reactive and design advantages or disadvantages with this process.

Advantages and drawbacks of bales
Aspects / Conventional Landfill / Bale fill / Plastic wrapped Bale fill
Visual Impact / *** / ** / *
Leachate / *** / ** / *
Odour/gas emmisions / *** / ** / *
Windblown litter / *** / ** / *
Birds / *** / ** / *
Spontaneous ignition / ** / * / *
Density / *** / * / *
Operating Labour / *** / ** / *
Reception structure / ** / ** / *
Moving machinery / *** / * / *
Services Infrastructure / ** / ** / **
Closure / *** / ** / *

Assessment *Good **Medium *** Poor

The results indicate many advantages in the wrapped balefill process over the conventional landfill process. It was determined during the study that the landfill market is broken up into many segments all containing site specific requirements and infrastructure which vary greatly. In each case however these common elements in the above table appeared to be favouring the balefill process. Waste stream analysis information had little variance over borders and councils.

The conventional landfill process could be improved

  • Increased air space and life span of each cell and the landfill site.
  • increased incentive/opportunities to recycle, pre process waste
  • reduced fire risks
  • reduced litter and vermin problems
  • reduced noise
  • reduced dust
  • reduced vehicle numbers using the site
  • no requirement for specialized refuse transfer vehicles from transfer stations to the landfill
  • reduced leachate generation in the early stages of operation
  • reduced gas generation in the early stages of operation

Most studies available on the balefill operations relate only to the unwrapped balefill operations. The oxo-degradable technology was only recently developed as a wrap for balefill.

Wrapped Balefill Process

Methods for baling-wrapping refuse consist of a mechanical press which allows compression of the refuse. Traditionally they have been developed from those already existing for compression of materials such as textiles, paper, straw, etc. The newer machines have been specifically designed and built for refuse applications. There are two types of bales: rectangular and cylindrical.

Cylindrical bales are produced by a single mechanical press which both compresses and plastic-wraps the refuse. However, the rectangular bale technique involves two separate machines working in sequence: first the press compacts the waste into bales, then a second machine linked in series wraps the bales in plastic.

A major difference between the two systems is the degree of compression, which is lower for the cylindrical technique. In the case of highly compressed rectangular bales, the process results in the pressing-out of a liquid when compressing materials with a high moisture content diminishing the potential generation of leachates. However, the compression liquid has to be treated. The quantities of liquid produced with the cylindrical technique are negligible compared to the rectangular method.

In general, the baling-wrapping facility consists of a reception are that constitutes the feed for a conveyor belt, which in turn feeds measured doses into a continuous automatic press. The produced bales can be transported and stacked by a forklift truck or a front loader fitted with a special loading device. In both cases, the same material can be used as plastic-wrapping film: Enviro Wrap degradable plastic with a thickness of 25µm. This material has a high, although not total, degree of resistance to perforation and tearing. Its stretching produces adhesive effects which facilitate a stable union between the different layers of Enviro Wrap™.

With regard to the stability of the plastic wrap against UV-light, the maximum storage time of the bales, without covering the bale stock, should be 28 days. Pointed or sharp edged objects within the waste can perforate LDPE plastics. Enviro Wrap is a stretch degradable film similar to shrink wrap that does not suffer from perforations to the same extent. Any perforations can easily be repaired using off the shelf tapes.

The main reasons for wrapping bales with a degradable plastic film are:

  • It protects the refuse from moisture, rainwater or any other liquids.
  • The internal surface of the plastic film is adhesive, so that the different layers of the wrapping adhere to each other.
  • The wrapped material inside the bale preserves its properties.
  • Protection from atmospheric conditions enables the outdoor storage of the bales.
  • Fewer fire risks. Self ignition is avoided.
  • Odours are considerably reduced or eliminated.
  • Litter is considerably reduced or totally eliminated

The rectangular wrapped bale technique

These systems consist of a metal conveyor belt, which acts as the waste receiver and feeds doses of waste into the rectangular continuous automatic press, where only the compression process is performed. The previous shredding of the refuse is not technically required by the rectangular method. The quantity of liquid pressed out depends on the moisture content of the waste.

Essentially, they use two different materials to band the bale before the wrapping process in order to ensure that the bales do not break open: an automatic binding system using tough polyester bands, with a variable number of bindings depending on the type of waste and an automatic binding system using steel wire.

Performance of the wrapped bales

The behaviour of the wrapped bales differs from the processes that occur in a conventional landfill. The most obvious are the increased time before leachate is generated as the initial baling process presses out leachate from any high moisture content refuse which is easily contained and disposed of at the bailing facility. Secondly the bales are wrapped and protected from rainfall infiltration during storage, transport and placement at the disposal site. Intermediate cover is placed prior to degradation of the wrap occurring further delaying and reducing leachate production.As a result of the baling process landfill gas production isdelayed and landfill odours greatly reduced or eliminated.

Analytical review of “Conventional Landfill” vs. “Wrapped Balefill Process”

This example produced similar results as other similar sized landfill results during the studies.

Key Landfill information

The table below is the key information about the landfill site and cell construction that help form the analysis.

Conventional Landfill vs. Wrapped Balefill data: / Normal / Baled
Gate price per tonne / (gp) / $ 70.00
Length / Width / Height
M3 capicty per Lift / 60 / 40 / see below / cl / 4,800 / 21,600
M3 capacity of Cell / 60 / 40 / 32 / cmc / 76,800 / 76,800
Floor Area M2 / = L x W / fa / 2,400 / 2,400
EPA Soil Depth Required for workface 150mm * in reality 250mm / (dsd) / 0.15 / 0
EPA Soil Depth Required for Floor 300mm * in reality 350mm / (fsd) / 0.35 / 0.2
Lose soil to Compacted soil ratio / (sr) / 1.3 / 1.3
Waste Compaction ratio / (cr) / 0.7 / 0.65
Work face size m sq / = nbw x bd x nbd / (wf) / 700 / 7.90
Height per lift / = bh x bd / lh / 2 / 9
Engineered void cost per m3 / (ev) / $ 8.00 / $ 8.00
Through put per year / Tonnes / tpy / 24,000 / 20,400
C & D Waste per year / Tonnes / 15% / 3,600
Through put per day / Tonnes / = tpy/op / tpd / 80 / 68
Cubic meters used per day / = tpd/cr / cmd / 114 / 104
Cubic meters used per year / = op x cmd / cmy / 34,286 / 31,385
Cubic meters used per day in Daily cover / = wf x dsd / dcm3 / 105
Cubic meters used per cell in Daily cover / = (fc - 1) x wl x dcm3 / ydcm3 / 34,535 / -
Density m3 per tonne incl daily cover / =(dcm3 + cmd)/tpd / d / 2.75
No of days per Lift = / No of daily covers per lift / = cl / (cmd + dcm3) / wl / 22 / 207
No of floors per Cell / = H / lh / fc / 16.0 / 4.0
M3 of airspace consumed by floor cover per lift / = L x W x fsd / acf / 840 / 480
M3 of airspace consumed by floor cover per cell / = acf x fc / acfc / 13,440 / 1,920
M3 of airspace consumed by refuse & daily cover per cell / = cmc - acfc / acbc / 63,360 / 74,880
Total Refuse tonnes that can be placed in cell / = acbc/d / tr / 23,078 / 44,532

Key Landfill Information cont.

Bale Stacking Configuration Analysis

The study included identifying different techniques to place the bales and the Commercial and demolition waste. The system and technique can vary however the results remain fairly similar as long as the stacking height is achieved.

BALE STACKING CONFIGERATION / Height / Length & Width
Bale Dimensions / Bd / 0.75 / 1.10
Airspace between Bales / Ab / 0.05
M3 of air space consumed by a bale plus gap / 0.99
M3 of air space consumed by a bale / 0.91
Weight of each Bale / 0.59
Density of Bale including airspace void / m3 per tonne / 1.68
Number of bales high / 16
Number of bales wide / 5
Number of bales deep / 1
Suface area of floor each day / m2 / 11
Suface area of floor each week / m2 / 66
No of days between floor covering / * assume 1 days cover min 250m3 & max exposure of EC is 14 days / 14
No of Bales per year / 34,584
No of Bales per day / 115
No of Bales per cell / 75,493
No of days per Cell / 657
Length of Workface / - / 5.8
Length of Side Batter / - / 1.7

Daily Operating Costs Conventional Landfill vs. Wrapped Balefill Process

The table below identifies the daily operational cost for the conventional landfill vs. the wrapped balefill process consideringthat daily cost may vary from site to site.The key cost component in this case study is the cost to cart and cover with venom or soil. The use of soil cover uses up valuable air space and costs to cart are normally not known or are hidden in the operational cost pool in conventional landfill.

Daily operating costs for Normal and Wrapped Baled landfills / Normal / Baled
Equipment / Cost / Landfill / Bale fill
Weighbridge ops
Compactor / $120.00 / 6 / $ 720.00 / $ -
Refuse Bulldozer / $153.00 / 5 / $ 765.00 / $ -
Excavator/ Manitoe / $72.97 / 8 / $ - / $ 583.76
Excavator / $72.97 / 4 / 0.29 / $ 291.88 / $ 20.85
Trucks x2 / $75.00 / 4 / 0.29 / $ 300.00 / $ 21.43
Cover bulldozer / $91.73 / - / $ - / $ -
Forkhoist / $45.00 / $ - / $ -
Pointsman / $25.00 / 0 / $ - / $ -
Odour/Bird/Windblown Litter / $25,000.00 / $ 83.06 / $ -
General Roading, Staff Etc / $75,000.00 / 0 / $ 249.17 / $ -
Total Cost per day / ttcd / $ 2,409.11 / $626.04
Total Cost per tonne / $ 30.21 / $7.85
Net Movements per day / Per Cell / $ -
Net Movements per tonne / $ -
AIRSPACE COSTS
Daily value of airspac used by daily cover / =dcm3 X ev / vdev / $ 840.00 / $ -
Yearly value of airspace used by daily cover / = vdev X op / ydev / $ 252,840.00 / $ -
Value of airspace consumed by daily cover per tonne / = ydev / tpy / $ 10.54 / $0.00
Value of airspace used by Floor Cover per Cell / = acfc X ev / yfev / $ 107,520.00 / $ 15,360.00
Daily value of airspace used by Floor Cover / = yfev / ( tr / tpd ) / dfev / $ 371.48 / $ 23.38
Value of airspace consumed by floor cover per tonne / = yfev / tr / $ 4.66 / $0.34

20,000 tonne Wrapped balefill Construction and Equipment Costs

The table below reviews the cost of the facility and in this case a retrofit to the existing building was possible. Construction costs may vary however in the 20,000 ton market it is not anticipated that cost will be much greater. (Note that the result in each table drills down to the price per ton).

Cost
Facility / $350,000.00 / $350,000.00
Miscilanious / $100,000.00 / $ 100,000.00
Baler / $ 175,000.00 / $ 175,000.00
Second Baler / $ 175,000.00 / $ 175,000.00
Wrapper / $ 100,000.00 / $ 100,000.00
Forklift / $ 50,000.00 / $ 50,000.00
TOTAL / $ 950,000.00
Simple Interest / 8% / Int / $ 76,000.00
Life expectancy in years say / le / 10
Total cost over 10 years / = total + (Int X le) / tc10 / $ 1,710,000.00
Facility Cost per year / = tc10/le / $ 171,000.00
Staff / 3 / - / $ 171,570.00
Weighbridge & Excavator / 0 / $ -
R & M & Electricity per year / $ 50,000.00 / $ 50,000.00
Total Operating Cost per year / $ - / $ 392,570.00
per Day / $ - / $ 1,304.22
Total Cost per tonne / $ - / $ 16.36

Bale Transport Costs

Transport savings can be realised if the waste is being transferred to the landfill through improved density and flat deck transport as opposed to specialised transport. In this case the bale plant is at the landfill and these costs represent the delivery of the bales to the work face.

Transport Costs / Payload tonnes / 12 / 20
No of trucks per day / = tpd/12 / = bpd/20 / 6
Trucking costs / per lift / $70.00 / $ 420.00
Total Cost per tonne / $ 5.27

OXO-Degradable Enviro Wrap™ and Bale Strapping Costs

The Oxo-degradable Enviro Wrap™ degrades through heat in the landfill environment. The bales after stacking can be exposed for up to 28 days and longer in cooler months. The degradation times can be controlled and are being adjusted for the maximum advantage at the landfill.

The added cost of wrapping in facts saves money operationally and air space. It is important to look at the overall costs of both options.

ENVIRO WRAP
Cost of Enviro Wrap per Bale / = cost/bpr / cpb / $ 4.16
Total Enviro Wrap Cost per Day / ewcd / $ 477.97
Total Cost per tonne / $ 5.99
BALE STRAPPING
Cost of Strapping per Bale / = cost/bpc / cpb / $ 2.01
Total Strapping Cost per Day / scd / $ 231.47
Total Cost per tonne / $ 2.90
Days operation per week / dow / 6 / 6
Days operation per year / op / 301 / 301
Hours of operation per day / wh / 7.6