CONTAMINATED SOIL MANAGEMENT IN AUSTRALIA

Transcription

1 CONTAMINATED SOIL MANAGEMENT IN AUSTRALIA R. PARKER Golder Associates Pty Ltd, PO Box 6079, Hawthorn West, Victoria, 3122, Australia SUMMARY: This paper discusses the management and disposal of contaminated soil in Australia and more particularly in the State of Victoria. Systems have been developed in Victoria to classify hazardous waste, including contamianted soil in terms of the risk it presents to the environment. Based on this system, material is classified for final disposal. Measures have also been implemented to discourage landfill disposal of contaminated soil either through potentially banning certain contaminated soils from landfill and by progressively increasing the landfill levy, now up to A$250. As the cost of disposal for contamiated soil continues to increase, the interest in alternative treatment technologies is rapidly increasing. 1. INTRODUCTION There has been a contaminated land investigation and remediation industry in Australia since the late 1980s. The major forms of remediation have been on-site management, disposal to landfill and in the case of petroleum hydrocarbons, landfarming mainly involving volatilisation of lighter fractions. These practices generally continue today although gradually, remediation technologies are becoming more common as landfill costs increase and regulators enforce waste hierachy objectives. As a result of the legacy of historical poor waste management practices and the urban renewal programmes in major Australia cities involving soil remediation, contaminated soil has become a significant component of the hazardous waste stream going to landfill. Although most states in Australia are trying to minimise the generation of hazardous waste, the State of Victoria has over several years developed specific programmes to minimise and improve the management of manufacturing waste and contaminated soil. This paper outlines some of the measures introduced in Victoria to reduce the volume of contaminated soil going to landfill and more specifically to maximise the likelihood of contaminated soil being treated rather than disposed. Parker and Stokes (2007) discussed broader hazardous waste management issues and is a useful adjunct to this paper. In Victoria hazardous waste from industry and contaminated soil are referred to as Prescribed Industrial Waste (PIW) (wastes prescribed in regulation). In late 2000, the Victorian Government gazetted an Industrial Waste Management Policy (Prescribed Industrial Waste) (IWMP). This document detailed the development of both statutory and voluntary programs to

2 improve the management of PIW in Victoria. Since the implementation of the IWMP there have been a number of steps taken towards reducing the amount of hazardous waste generated in Victoria and there is significant progress in reducing the amount of hazardous waste that is disposed to landfill. While not all of the proposed measures in the IWMP have come to fruition, significant steps have been taken towards reduction in volumes of PIW requiring landfill disposal, particularly for the higher hazard waste. 2. HAZARDOUS WASTE POLICY IN VICTORIA The IWMP (EPA 2000) was introduced to encourage waste minimisation and the reuse, recycling and recovery of energy of waste that cannot be avoided. The policy is a key instrument in: avoiding/reducing the generation of prescribed industrial waste; reducing the amount of prescribed industrial waste sent to landfill by reusing, recycling and recovering energy; and ensuring the safe management of residual prescribed industrial waste generated in Victoria. These elements reflect the waste management hierarchy of avoidance, reuse, recycling, recovery of energy, repository storage, treatment and containment 1. Building on existing controls, the policy requires waste generators to apply the waste management hierarchy in all management decisions regarding prescribed industrial waste. The policy focuses on avoiding the generation of waste and the diversion of unavoidable waste to productive purposes. Important elements of the IWMP are that it provides: A framework for classification of waste that ensures that waste management options for any given waste or project are pushed as high up the waste hierarchy as practicably possible; A basis for EPA to develop a framework for the classification of waste according to the hazard, providing appropriate disposal of residual waste; A basis for EPA to effectively ban landfill disposal if practicable options are available for the reuse, recycling or energy recovery for a particular type of waste. EPA with the ability to require certain design elements for disposal, long term containment or short term storage of PIW. These elements have been progressively implemented through: A hazard classification system for better management of disposal of manufacturing prescribed industrial waste (PIW) with categorisation according to the type of receiving facility (EPA, 2005); Revised classification system for disposal of contaminated soil PIW according to the receiving facility (EPA, 2007); Various classifications for specific PIW, banning disposal to landfill where opportunities are available for reuse, recycling or energy recovery. An attempt was made to site a long term containment facility (LTCF) in Victoria although this project was abandoned by the Victorian Government in early 2007 (see EPA 2004) for performance requirements for a LTCF). This facility was to provide for a higher level of management than current best practice landfill for hazardous waste management (such as that proposed by Golder Associates 1999). In the absence of a LTCF, the Victorian Government announced higher landfill levies for the disposal of PIW. As of 1 July 2008, the highest levy for landfill disposal will be A$250 2 per tonne (levies are discussed later in this paper). It was also 1 Containment is a term used in the IWMP to to express a higher level of management than disposal to landfill 2 A$ 1.00 equals about A$ 0.95 although has been historically much lower

3 proposed by Government that landfill disposal of higher hazard waste would cease by It will therefore be important in Victoria over the next decade to cease generating hazardous waste, including contaminated soil, or develop management and treatments systems that avoid the need disposal of high hazard waste. 3. CLASSIFICATION BY HAZARD Most Australian States have a classification system for hazardous waste disposal which includes classification a classification system for soil (either as a general classification for all waste for specifically for soil). Generally the classification is based on the severity of the hazard posed by the waste with the most hazardous materials requiring the highest level of landfill management. In Victoria, the IWMP enables EPA to classify wastes based on the hazard they present to human health and the environment.. The policy specifies that prescribed industrial wastes should be categorised as follows: Category A - wastes which require a very high level of control to protect human health and the environment. These wastes require hazard reduction before they can be sent to landfill. Category B - wastes which require a high level of control and on-going management. Category C - wastes which pose a low hazard or only exhibit offensive aesthetic properties. EPA Publication 996 provides Guidelines for Classification of Solid Prescribed Industrial Waste (EPA, 2005). This guideline is for manufacturing waste only and provides a waste generator with a framework for the classification of waste. The Guideline sets out total and leachable concentrations of contaminants which enable classification into Categories A, B and C. The document also provides a basis for seeking a specific classification by EPA based on the immobilisation (either intrinsically or by process) of contaminant leachability. EPA Publication 448 Classification of Wastes (EPA, 2007) provides a framework for classification of contaminated soil into Categories A, B and C based on total and leachable concentrations. The document mirrors much of the classification system in Publication 996 but has differences tailored to contaminated soil management issues. Publication 448 also includes an additional category below Category C waste being Fill Material which is for soil that can be used at any location in Victoria provided it does not result in environmental harm (for example, an acid sulphate soil may meet all the concentrations for Fill Material but could still result in environmental harm). All contaminated soil destined for landfill must first be classified by hazard category. Victorian EPA Publication 1178 (EPA 2007) provides a methodology for sampling and testing of soil for waste classification. Based on the currently available landfill options in Victoria: Category A contaminated soil waste must be treated, immobilised or stored pending treatment since it is not permitted to be disposed at landfill unless first treated; Category B contaminated soil waste can be disposed at one landfill (Lyndhurst Landfill) located in the south-east of Melbourne. This landfill has dedicated and appropriately lined cells for receipt of Category B waste (discussed later in this paper). The Victorian Government advises that this landfill will be available for disposal of PIW until Category C contaminated soil waste can be disposed in best practice municipal waste landfills. There a number of landfills around the State that are licensed to receive Category C contaminated soil.

4 4. BAN ON LANDFILL DISPOSAL The IWMP allows for banning from landfill of defined waste types. To demonstrate intent, EPA (2002) foreshadowed the banning of high-level contaminated soil (now Category B contaminated soil) from landfill. The classification was based on soils contaminated with certain organics having opportunities for treatment available in the foreseeable future. The classification specifically refers to high-level contaminated soils (now Category B contaminated soil) that are contaminated with total petroleum hydrocarbons, monocyclic aromatic hydrocarbons, organochlorine compounds and polycyclic aromatic hydrocarbons. A soil organic recycling facility (SORF), located in the south east of Victoria is currently under construction. Once this facility is fully operational (anticipated to be mid 2008), then landfill disposal of Category B soils contaminated with petroleum hydrocarbons may not be a permitted option, depending on whether or not EPA enforces the ban. Robbie (2008) reports that the SORF will be able to treat organic wastes (garden and vegetable waste) as well as soil contaminated with petroleum hydrocarbons using an aerobic in-vessel processing. The facility is about 200 km from Melbourne which is the centre of most contaminated soil generation in Victoria. Victorian EPA is currently evaluating the approach to enforcement of the foreshadowed ban on landfill disposal of contaminated soil. 5. LANDFILL LEVIES AND DISPOSAL COSTS When the LTFC project was abandoned in early 2007, the Victorian Government announced that landfill levies for hazardous waste (both manufacturing waste and contaminated soil) would be substantially increased from 1 July 2007 and most likely further increased again in 1 July Levies increased on 1 July 2007 to A$50 per tonne for Category B waste and A$130 per tonne for Category B waste. It is now legislated that landfill levies from 1 July 2008 will be as follows: Asbestos waste A$30 per tonne Category C waste A$70 per tonne Category B waste A$250 per tonne. It is expected that the costs of disposal of contaminated soil after 1 July 2008 will be in the vicinity of: Category C contaminated soil A$ 100 per tonne Category B contaminated soil A$500 to 600 per tonne. These levies apply to both manufacturing and contaminated soil PIW. The increase in levies (along with other measures) are having a significant impact on volumes of manufacturing PIW being sent to landfill and on Category B contaminated soil being sent to landfill. As will be discussed later in this paper, the increased levies are not significantly impacting on the volumes of Category C contaminated soil being generated. It is of interest to note that in the months immediately prior to 1 July 2007 there was a significant spike in the volumes of PIW going to landfill with generators trying to avoid impending the price increase. 6. LANDFILL DESIGN The LTCF foreshadowed by the IWMP was intended to be a hazardous waste system that would safely store Category B PIW for hundreds of years (EPA 2004). Detailed discussion of this

5 facility is beyond the scope of this paper but was being designed to contain Category B waste in multiple lined cells under a roofed structure that could be moved from cell to cell. Capping of each cell also involved multiple lining systems. This proposal failed on planning grounds given that the location chosen to site the facility, while being technically excellent, was located 500 km from Melbourne where most of the waste was generated. Category B manufacturing waste and contaminated soil can only be disposed at one facility in Victoria located at Lyndhurst which is about 40 km south east of the centre of Melbourne. The facility has accepted PIW since the early 1990s initially as a co-disposal operation with municipal waste. In the early 2000 the licence for the site was changed so that all PIW was disposed in dedicated cells. Two PIW cells have been constructed and a third is in early stages of design and development. The lining system for the PIW cells is relatively conventional for hazardous waste although it does not have a secondary leachate system given that the base of the landfill is below the water table and a secondary would most likely be redundant. The lining system from top down comprises: Primary leachate collection system comprising coarse gravel and collector pipes under a geotextile filter layer; Primary liner comprising a geotextile cushion, 2 mm HDPE geomembrane and geosynthetic clay liner; and Secondary liner comprising 2 mm HDPE geomembrane over a 1 m of compacted clay liner. The IWMP (EPA 2000) states that Category C PIW can be disposed at a best practice municipal waste landfills. EPA publication 1208 (EPA 2008). For Category C contaminated soil, the landfill cell must be designed in accordance with a Type 2 3 landfill and consist of at least a composite barrier liner and leachate collection system. The cell design should include the following suggested measures: a leachate collection system comprising not less than 300 mm thick gravel, or other approved drainage material, placed over the composite liner with leachate collection pipes and a leachate extraction system; a composite liner consisting of HDPE membrane, or other approved geomembrane, and compacted clay not less than 1 m thick with hydraulic conductivity not more than 1 x 10-9 m/s, or other approved mineral layer; and geotextiles to protect the geomembrane and the leachate collection layer. Landfills previously licensed to receive low level contaminated soil which now corresponds to Category C contaminated soil are expected to upgrade to the above lining standard as new cells are developed. 3 A landfill receiving putrescible waste designed in accordance with Best Practice Environmental Guidelines for Siting, Design and Operation of Landfills (EPA 2001)

6 7. AVAILABLE TREATMENT TECHNOLOGIES FOR SOIL As noted above, there has been significant reliance in Victoria and elsewhere in Australia on disposal of contaminated soil to landfill and on management of contaminated soil on-site in secure facilities or where appropriate, under buildings, pavements and other structures. With the increasing price of landfill disposal, particularly in Victoria, there is greater interest in treatment of contaminated soil. Soil remediation technologies now available in Australia include: Bioremediation Land farming has been a common remedial technology for petrol and light hydrocarbon fractions. However, volatilisation as a primary means of remediation is increasingly discouraged by regulators throughout Australia and particularly, Victoria where it is not acceptable to transfer contaminants from one medium to another as a form of remediation. Conventional biopile and other forms of bio-treatment are used regularly throughout Australia although site constraints and project timing often mitigate against use of these methods. Stabilisation Various forms of encapsulation, complexation and stabilisation are used throughout Australia to make material suitable to remain on site or more commonly suitable for landfill disposal. Thermal Desorption While incineration is rarely used in Australia (essentially only for medical waste), thermal desorption is developing rapidly as a treatment method for soils contaminated with polycyclic aromatic hydrocarbons and chlorinated hydrocarbons. Both direct and indirect fired systems have been introduced into Australia and one form of static thermal treatment is available. Greater use of thermal treatment systems can be expected in the near future, particularly in Victoria. Solvent washing Veolia has recently trialled solvent washing in Victoria to remove PCBs from soil. It can be expected that this technology will also gain some favour in the Victorian contaminated soil market. While price of landfill disposal will drive soil remediation use of technologies, two critical issues would enhance the rate at which technology is implemented: Streamlined permitting of technologies so that particular technologies could be used on multiple sites thus avoiding the need to seek regulatory approval on a site by site basis; and The availability of a treatment facility located near capital cities (particularly Melbourne and Sydney) where multiple technologies could be implemented. 8. TRENDS IN CONTAMINATED SOIL DISPOSAL The amount of manufacturing PIW (both Category B and C) sent to landfill has been reducing steadily since 2000 and for the year 2007 is expected to be less than 60,000 tonnes. In contrast the mass of contaminated soil sent to landfill has been more variable, and as shown on Figure 1 (from Parker and Stokes, 1970) below has ranged below 350,000 and 450,000 tonne per year between 2000 and 2006 (noting at the time the equivalent terms for Category B and Category C contaminated soil were contaminated soil and low level contaminated soil, respectively). Although 2007 figures have not been released, it is expected that the total volume of contaminated soil sent to landfill in 2007 will increase while the mass of Category B waste will be around 50,000 tonne. If the mass of Category B waste is equal to or less than 50,000 tonne in 2007, this will at least be equivalent to the lowest year to date of There has been substantial reduction in volume of Category B contaminated soil going to landfill since At

7 that time, the cost of disposal for the higher classification waste was relatively cheap and a number of major gasworks remediation projects were the major drivers of the high tonnage to landfill. Contaminated soil sent to Victorian landfills Volume (tonnes) 500, , , , , , , , ,000 50,000 0 contaminated soil low-level contaminated soil Year Figure 1. Contaminated soil sent to Victorian landfills. Land remediation in Australia including in Victoria is development driven. Therefore generation of contaminated soil is dependant on the economy and in particular urban renewal projects. There is a critical need for governments to promote urban renewal in major Australian cities to reverse the long term trend of sprawling cities. As a consequence it will be necessary for governments to maintain an orderly and economically sensible system of contaminated soil disposal and management. The A$50 per tonne levy for disposal of Category C soil did not make a significant difference to the amount of contaminated soil disposed in 2007 and the increase to A$70 is similarly not expected to have a major impact on the market. A significant factor with Category C soil is that there are numerous landfills licensed to receive this material and there is significant competition so that even after 1 July 2008 the total cost of disposal is likely to still be under A$100 per tonne. At this price it will still be cheaper to dispose than treat, particularly when holding costs of land are included when land is being developed. However, there will be much greater interest in treatment of the high cost Category B contaminated soil and the Category A contaminated soil which cannot be disposed to landfill. 9. CONCLUSION The main form of land remediation is Australia is to excavate the contaminated soil and dispose of it to landfill. With increasing cost of disposal, there is rising interest in technologies for treatment of contaminated soil. In Victoria, substantial increases in landfill levy for hazardous waste is resulting in less high level hazardous waste being disposed to landfill. Already the high cost of landfill disposal for Category B waste is seeing much greater interest in the use of remedial technologies. While this interest is high, the following factors are tending to inhibit more rapid uptake of remedial technologies in Victoria:

8 A simple system of permitting technologies for use on multiple sites; and The availability of a treatment facility located near Melbourne where multiple technologies could be implemented. There is need for the cost of Category C waste disposal to be maintained at an affordable level to minimise the impact on landfill cost that could stifle urban renewal programmes that are commonly located on old industrial land which is generally contaminated. REFERENCES EPA (2001) Environment Protection Authority of Victoria, Best Practice Environmental Management Guideline, Siting, Design, Operation and Rehabilitation of Landfills, Publication 788. EPA (2002) Environment Protection Authority of Victoria, Publication 878 Classification for Contaminated Soil. EPA (2004) Environment Protection Authority, Performance Requirements For Long Term Containment Facilities, Publication 941. EPA (2005a) Environment Protection Authority of Victoria, Guidelines for Hazard Classification of Solid Prescribed Industrial Waste, Publication 996. EPA (2005b) Environment Protection Authority, Proposed Long-term Containment Facility The role of EPA Victoria, Publication EPA (2007a) Environment Protection Authority of Victoria, Publication 448 Classification of Wastes, Publication EPA (2007b) Environment Protection Authority, Soil Sampling Guidelines (Off-Site Management and Acceptance to Landfill), Publication EPA (2008) Environment Protection Authority of Victoria, Publication 1208, Best Practice Guidelines for Landfills Receiving Category C Prescribed Industrial Waste. Golder Associates (1999) Report to Department of Conservation and Natural Resources on World s Best Practice, Hazardous Waste Landfill, Siting, Design, Operation and Closure Government of Victoria (2000) Victoria Government Gazette, Special No. S 183 Tuesday 5 December 2000, Environment Protection Act 1970, Industrial Waste Management Policy (Prescribed Industrial Waste) Government of Victoria (2000) Environment Protection (Prescribed Waste) Regulations 1998, S.R. No. 95/1998, Version incorporating amendments as at 1 October 2000 HWCC (2000) Hazardous Waste Consultative Committee Final Report to Government of Victoria. Robbie (2008) Soil and Organic Waste Facility Creating Sustainable Environmental Solutions, Envio08, Melbourne, May 2008 Parker R. and Stokes J. (2007) A Framework to Reduce and Manage Hazardous Waste, Victoria, Australia, Sardinia 2007, Eleventh International Waste Management and Landfill Symposium.