Strategic Analysis: Contamination and Remediation of Brownfields Sites - Essay Example

STRATEGIC ANALYSIS: CONTAMINATION AND REMEDIATION OF BROWNFIELD SITES A Report Submitted by YOU YOUR ACADEMIC ORGANISATION HERE APPROPRIATE HERE OTHER RELEVANT COURSE INFO HERE STRATEGIC ANALYSIS: CONTAMINATION AND REMEDIATION OF BROWNFIELDS SITES Introduction In general, a Brownfield site (or Brownfield) is a piece of land where potential expansion, reuse or new development might not be possible due to the presence of harmful substances, pollutants, or contaminants. These sites vary in size, location and in their past history. Brownfields can be located in urban, suburban, and rural areas. In this rapid age of industrialization, land is not available in abundance. Hence the demand for assessing Brownfields is necessary. In United States, the term 'Brownfield' is always associated with land that was formerly used for industrial or commercial purposes. In United Kingdom, Brownfield is defined as "previously developed land" (or PDL) that has the potential to be redeveloped, but need not always refer to land that has been used for industrial and commercial purposes. Though a government survey in UK shows that the 2008 target of constructing 60% of new homes on Brownfields has been achieved, there are still 150,000 sites under the Brownfield sector. In comparison, there are about 80,000 and 100,000 Brownfields in Australia. The nature of contamination of Brownfields could be real or perceived. When a land is declared a Brownfield, it is possible that the contaminants could include deposits of heavy metals, harmful pesticides and toxic hydrocarbons. This contamination can result from improper environmental management and inefficient waste disposal practices, or unwarranted use of contaminated fill to level the site. It could also result due to unsealed underground storage tanks and random spills in industrial, agricultural or commercial activities. Specific industries and common land activities have been tied to site contamination. The extent of contamination may vary based on the rate and extent of the concerned activities. Brownfield sites pose legal and financial burdens on a community. However, these sites can be redeveloped into powerful engines for economic vitality and community pride. Brownfield sites are mostly in excellent locations. Their remediation or redevelopment provides developers and investors desirable sites with existing infrastructure systems for industrial, commercial, residential, agricultural, public and recreational uses. In most cases, connections to water, sewer and energy resources is readily available along with good access to transportation networks. Hence, communities benefit from the remediation of Brownfields by facilitating new businesses, jobs and increased productivity, which otherwise would have been underutilized and unproductive. For example, Commonwealth of Massachusetts in the United States reported that after 20,000 Brownfields sites had been addressed, about 8000 jobs were created thus increasing tax revenues by approximately $1 billion (NALG 2004). Geotechnics and Environmental Engineering are two branches which assist in developing a deeper understanding of contamination assessment procedures and various remediation solutions of Brownfields. In the consequent sections, we shall discuss these techniques and formulate a unified approach to deal with this issue. We will then critically review this approach with a case study. Geotechnical Procedures to Assess Properties of the Soil Geotechnics plays a very important role in Brownfield assessment. Founded in 1985, Geotechnical Engineering involves investigation of existing subsurface conditions and materials in order to determine its physical, mechanical chemical properties for assessing risks posed by site conditions. It also monitors site conditions, earthwork and foundation construction. It is important to establish the sub-soil characteristics of a Brownfield considering its potential to shrink or swell with change in natural water content. Table 1 lists all the geotechnical tests conducted to determine the various physical properties of soil. In UK, most of these tests are conducted as part of National House-Building Committee guidelines. These guide the house-building and construction industry to provide risk management services that work towards raising the standards of new homes and also provide consumer protection to new home buyers. Figure.1. Classification of Soil Layers. Source: Enchanted learning. Sno Test Name Function 1 Consolidation Test Determines strength & stress-strain relationships of a cylindrical specimen of saturated cohesive soil. 2 Cylindrical Test Examines liquefaction or cyclic strength. The sine loading unit generates sinusoidal, triangular, square and ramp. 3 Constant Volume Direct Shear Stress Deformation and strength characteristics of cohesive soil obtained by consolidated constant volume direct shear test. 4 Direct Shear Stress To determine the shearing strength of the soil. 5 Triaxial Test and Unconfined Compressive Test To determine the unconsolidated, un-drained strength of cohesive soil. 6 Sieves, Hydrometer & Atterberg To determine the statistical distribution of the particle sizes in the soil and calculate the Liquid and plastic limits. 7 Bender Element Test This test estimates the initial shear modulus or the shear modulus at very small strain level 8 Multifunctional Triaxial Evaluates soil behavior shear stiffness at small strain 9 Unsaturated Triaxial Apparatus Designed for unsaturated soil, apparatus analyzes soil shear behavior. Table.1. Soil Testing in a Geotechnical Engineering Laboratory: School of Civil Engineering at Asian Institute of Technology. Site Contamination Assessment and Remediation The growth of population, industry and commerce has created a great demand in the new areas of towns and cities. This forces construction companies to utilize Brownfield and formerly used industrial sites. Most of these former industrial sites have suffered for several years from environmental contamination. The other apparently clean locations have been badly affected by contamination acts such as illegal dumping. For construction companies, this demands an understanding of ground conditions and possible effects on future land use. The Contaminated Land Management imposes specific guidelines on local government and owners concerning the redevelopment of contaminated land. There are typically five stages involved in Contaminated Site Investigations and Remediation. Cyrus (2006, pp.5-10) discusses each of these stages. Figure.2. Statistics of Land Contaminants. Source: Sydney Geographic Information System, Shoalhaven Report on Land Contamination. The process starts with a Preliminary Site Assessment. This stage is often referred to as the 'desk study' stage, although a site walkover is usually the protocol. This involves interviewing the site management, owners and the local government. In this stage, there is a review of site history and past records. Initial Soil Sampling can also be a part of this process. This site assessment indicates data on the possibility of existence of the contaminants and also the individual components. This initial assessment determines if there is a need to proceed to the second stage. The second stage is Detailed Site Assessment. Detailed soil and groundwater sampling survey is done to establish the exact amount of contamination for the potential contaminants. This assessment judges if the individual contaminant level is within acceptable limits or if remediation is required. Table2 shows the various contaminants that can be found in a Brownfield. At this end of this stage, site-specific remediation objectives should be identified. The third stage is called Remedial Action Plan (RAP) stage. A list of feasible remediation options capable of achieving the acceptable remediation criteria for the site-specific constraints should be identified. This evaluation should take account of Best Practicable Environmental Option (BPEO), which will minimize the cost benefit and maximize the environmental outcomes. The Remediation Strategy sets out redevelopment options for each selected pollutant and determines if it must follow In-situ (on site) or Ex-situ (off-site) technologies. Table2 lists some remediation solutions. The fourth stage is Site Remediation, which basically implements the RAP. The Implementation Plan is mapped to the Remediation Strategy through a clear set of remediation activities. The robustness in design, practicality in implementation and follow up on verification aspects are considered for long-term monitoring of the remediation approach. The final stage is Validation. The validation stage indicates the completion of remediation. The results of the analyses are compared with the guidelines. If determinants exceed these guidelines, additional analyses may be required. We shall henceforth refer to this entire methodology as the Brownfields Development Model. The approach discussed here outlines the methodology that will be applied to a case study. The picture below shows the remediation of a former auto-dealership. Figure.3. Site Remediation of former auto-dealership. Source: EWD Corporation. Table.2. Contaminants and Primary Remediation Techniques. Sources: DFAIT (2004), Environment Canada, Ontario Region (n.d. a&b); Hayward and Anderson (2002). Case Study: Sydney Olympics Games site Any evaluation regarding the feasibility and practicality of the contamination assessment and remediation approach is only possible with its application to case studies (Smith 2008). In this context, we will discuss a case study in Sydney which will illustrate the value of Brownfields development. It is important to understand the driving factors behind such development. Our case study relates to the Olympics Games 2000 site at Homebush Bay, Sydney, Australia. This Olympics site was constructed on a large area of derelict land in Sydney. This site was formerly a storage facility, a major regional abattoir and an industrial waste landfill. On the profits derived out of hosting this major event, the state government contributed to the remediation of the site and development of a new medium density urban residential area. The important motivation factor behind this Australian Brownfields development was attention to public health protection which was accomplished by remediation of the sites. Figure.4. Former 2000 Olympic Games site built on a Brownland at Home Bush Bay, Sydney, Australia. Source: Waste Services NSW. Figure.5. The Residential Suburb of Newington Developed on the Brownfields Site of the 2000 Olympics Games at Homebush Bay in Sydney. Source: Waste Services NSW. An important question in this case study that needs to be answered regarding remediation is whether human health and environmental degradation has been controlled. This is supported by a strong scientific and engineering component in Brownfields planning, which was taken care by the first and second stage in the Brownfield development (which we discussed earlier). 'Risk communication' is a critical part of planning, which involves engaging the government and local communities in land remediation. It is necessary to understand that the essential components to the success of any Brownfield development include uninterrupted financing funding, accurate cleanup estimates, effective community involvement, and negotiation with regulators. Taking the reference of the above case study, it is easy to understand how each of these factors might have played a role in the overall success. The development could have been severely undermined with the failure of any one of these factors. Contaminant Treatment Technologies Contamination Treatment techniques can range from traditional methods to complicated process based approach. In deciding on the contaminant treatment technique for Brownfields, it is imperative that the traditional planning approaches must yield to complex scientific consensus and include scientific considerations. The Brownfield development is associated with contaminant treatment and thus requires careful planning giving due consideration to the range of chemical contaminants. Rhodes (2003) discusses the various treatments used to separate and discard the contaminants in Brownfields. The variables which determine the treatment approach are types of contaminants, site conditions and the nature of risks. The process methods can be undertaken on-site (In-situ) or off site (Ex-situ). Ex-situ treatment involves digging up and treating the material while in-situ treatment can be done without any external handling. The contaminant removal process can be done through several treatment methods. Some of these treatment approaches are physical, biological, chemical and thermal in nature. The common Physical Treatment approaches include Soil Vapor Extraction and Soil Flushing. Soil Vapor Extraction is an In-situ process which involves removal of volatile and semi-volatile compounds. Soil flushing is an ex-situ process which deals with using water through the contaminated soil to remove the contaminants. The ultimate goal of Biological Treatment is to accelerate the breakdown of complex hydrocarbons into carbon dioxide and water. It is effective mostly on intermediate chain length alkanes. Ex-situ treatment can be performed by treating ground level soil with biopiles, land farming, composting or slurry reactors. In-situ treatment can be done by direct application of nutrients into the soil. Chemical treatment can be done in-situ with the chemical destruction of the contaminants. This involves converting them into less toxic forms, using hydrolysis. It is a combination of de-chlorination and oxidation (or reduction) based on the contaminant. In the ex-situ chemical extraction process, certain chemical agents are added to the water to improve the recovery process. Another popular and effective methodology is Thermal Treatment. There are various approaches like Incineration, Steam Sparging, Vitrification and Desorption. The process of Incineration involves combustion of contaminants in a rotary kiln, which gets transformed into carbon dioxide, water and other components. However, this process generates a lot of ash, which again needs to be decomposed. The Steam sparging process raises the temperature of the soil, thus increasing the volatility of the contaminants. In the Vitrification process, soil is melted into an insoluble glass-type substance to a temperature higher than 2000C using high-energy electrical current. This method requires persistent supply of high energy and is used only when the other processes have failed. The thermal desorption method results in chemicals being released from contaminated soil through a controlled heating process. This is done by subsequent controlled high temperature heating step. There are several other Civil Engineering methods like Evacuation, Encapsulation, Soil Fractionation, Stabilization and Solidification techniques which can deal with a wide range of contaminants. The excavation option can only remove restricted volumes of contaminants. In Encapsulation, a layer is built across the surface of the site, to prevent its access with the contaminants. In-Soil fractionation, bulk material is passed through a series of sieves to isolate most of the contaminants within a small volume of fine soil. These are later handled separately and treated. Stabilization and solidification techniques restrict the exposure of the contaminants into the environment. They are mostly used to treat inorganic compounds such as heavy metals and asbestos. Stabilization involves converting the contaminants to their least soluble form, using chemical reagents or modifying the solubility of the compound. Solidification involves engulfing contaminants in a monolithic mass of high structural integrity, by mixing the soil with cement, thermoplastics or other polymer-based binders. Some of the contaminated Groundwater Treatment processes include Sludge Processing, Gravity Separation and Air Stripping. The Sludge Processing technique accelerates the microbiological decay of organic compounds and inorganic compounds into less toxic forms. This technique is useful to separate pesticides and heavy metal from the ground water. The gravity separation method separate solids from the water owing to gravitation. Air stripping involves the removal of volatile compounds, such as hydrocarbons. Conclusion Quoting the famous actor and environmentalist, Robert Redford, "I think the environment should be put in the category of our national security. Defense of our resources is just as important as defense abroad. Otherwise what is there to defend" By no means is this an exaggerated statement. In this age of rapid modernization where there have been rapid strides in science and technology, most governments spend billions of dollars building a robust external defense mechanism, but have lost perspective on what they are protecting. Among several other problems faced by natural resources, any environmentalist will agree that the contamination of the land is a problem that is widely neglected. Land is continued to be treated as a commodity that can be misused rather than as resource, which should be protected and nourished. On the basis of study of the Brownfield development model, which involved understanding the contamination assessment and remediation techniques, we can conclude that it is built on a strong engineering pillars with emphasis on risk management. It positively addresses human health and ecological issues. By making Brownfield sites accessible in urban areas, it reduces migration of urban populations to sub-urban communities thus preserving open space and decreasing urban expansion. This was well illustrated with the case study, where a Brownfield was turned into residential complex. Considering the positive impact that the Brownfield Development has on the social, economic and the well being of any society, it is in the best interests of any government to back it with financial funding, advanced research and necessary infrastructure. Reference list Brownfield Basics[online].(2006).[Accessed8 December 2008].Available from World Wide Web:. Bureau of Investigation and Remediation[online].(2005).[Accessed8 December 2008].Available from World Wide Web:. Cymru,L.(2006).Land Contamination: A Guide to Developers.July 2006.Available from:Name of the list.[Assessed8 December 2008]. Enchanted Learning(2008).Classification of Soil Layers[online].[Accessed8 December 2008].Available from World Wide Web:. Environmental Industries(2005).Primary Remedial Technologies by Contaminant and Application[online].[Accessed8 December 2008].Available from World Wide Web:. EWD Corporation(2008).Site Remediation of a former Auto Dealership[online].[Accessed8 December 2008].Available from World Wide Web:. Geographic Information Systems(2004).Land Contamination[online].[Accessed8 December 2008].Available from World Wide Web:. Geographic Information Systems(2004).Potential Land Contamination Database Council 2004[online].[Accessed8 December 2008].Available from World Wide Web:. Geotech Engineering and Testing[online].(2008).[Accessed8 December 2008].Available from World Wide Web:. Geotechnical and Material Testing Consultants[online].(2008).[Accessed8 December 2008].Available from World Wide Web:. 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