Several abandoned wood-preserving sites have been identified in Alberta, Canada, which pose a potential threat to human health and the environment. The physiochemical, environmental, and toxicological properties of wood preservatives are discussed together with the predominant human exposure pathways for these chemicals in the environment. A Level II soil fugacity model is used to illustrate the comparative environmental fate of individual organic wood treatment chemicals following release to the soil environment. An evaluation of risk management options at five priority sites is used to illustrate problems associated with the treatment and disposal of mixed organic and inorganic contaminated soils, soil property limitations, and the predominance of organic contaminants within the residual oil phase. The latter reality dominates options for exposure reduction and risk management. Key words: contaminated soils, wood-preserving sites, remediation options, screening, fugacity model.
ChevronTexaco began investigating bioremediation as an option for treating Exploration and Production (E&P) wastes and remediation of site spills in 1992. In 1993, ChevronTexaco began full-scale landfarming operations of E&P wastes in Colorado. Since then ChevronTexaco has initiated numerous site-specific cleanups using bioremediation technologies such as composting and in-situ remediation, and we continue to operate bioremediation facilities for the treatment of ongoing E&P wastes that are generated as part of our normal operations. ChevronTexaco has successfully implemented bioremediation in diverse climates and in remote international locations. In this paper our top ten "lessons learned" in successfully applying bioremediation will be reviewed. These include predicting bioremediation end-points, the use of commercial microbial products, how to monitor treatment effectiveness, field equipment needed, interfacing with regulators, reusing treated wastes, costs by waste type and technology, and training of personnel. We will also discuss how to determine when bioremediation is a good option, when it is not a good option, and how to select the best biotechnology for a specific site. Introduction Biological treatment technologies are among the most practical and cost-effective methods for managing exploration and production (E&P) wastes such as tank bottoms, pit sludges, drilling muds, and oily soils from spill cleanups. Biological treatment methods depend on the ability of microorganisms to degrade oily waste into harmless products (carbon dioxide, water, and biomass) through biochemical reactions. The most common biological treatment technologies applied in the upstream petroleum industry include:composting (windrowing, forced aeration piles, and static/ passive aeration piles), andland treatment (landfarming, landspreading, and in-situ biotreatment). In biological treatment processes, microorganisms decompose hydrocarbons into water, carbon dioxide, and biomass. The bacteria and fungi responsible for biodegradation require oxygen, water, nutrients, and a source of carbon (such as the carbon in crude oils) to thrive. Biological treatment technologies commonly used in the upstream petroleum industry include composting and land-based treatment methods such as landfarming, landspreading, and in-situ biotreatment. In-vessel composting, bio-slurry systems, soil venting, and saturated zone bioremediation technologies are not commonly used due to high costs (typically >$100/ton) and/or their limited applicability to E&P wastes and site conditions. ChevronTexaco began investigating bioremediation as an option for treating E&P wastes and remediation of site spills in 1992, and has successfully implemented bioremediation technologies around the world. In this paper our top ten "lessons learned" in successfully applying bioremediation will be reviewed. Lesson #1 - Special "Bug" Products Are Not Needed There are many commercial microbial products (commonly referred to as "bugs") on the market for enhancing soil bioremediation. Published results by independent researchers indicate that these products do not enhance biodegradation rates or end-points for hydrocarbons or other organic compounds.1,2,3 The reason that "bug" products are not needed for soil bioremediation is that most soils contain a sufficient population of microorganisms to biodegrade amenable contaminants. For example, soils contain up to 10 million bacteria per gram, and a significant portion of this indigenous population is capable of degrading hydrocarbons.4 This indigenous population of hydrocarbon-degrading organisms will "bloom," or increase within 24–48 hours of exposure to hydrocarbons. Tilling, watering, pH maintenance, and adding nutrients to the soil will ensure that optimal conditions are maintained for the microbes. Figure 1 illustrates typical results in that the population of microorganisms increased from 10 million to 1 billion per gram per gram of soil 5 days after crude oil addition and establishment of optimal soil environmental conditions.
As a production-sharing contractor to BP-Migas, PT Caltex Pacific Indonesia (CPI) is Indonesia's largest oil producer. CPI employs approximately 6,500 people and contracts an additional 25,000 people in its operating area throughout Riau Province on the island of Sumatra. The distances between CPI's producing fields, limited waste management infrastructure, and the evolving nature of Indonesia's waste management regulations complicate waste management efforts. CPI's activities generate both domestic waste as well as conventional E&P waste. E&P waste management initiatives often focus exclusively on treatment and disposal. The 5R strategies of source reduction, re-use, recycle, recover and replace offer greater potential environmental and financial benefits for many common E&P wastes. As part of CPI's integrated waste management initiative, practical 5R strategies have been identified for several waste streams: seismic shot, excess cement, empty drums and containers, construction and demolition material, oil-based drilling mud, batteries, consumable IT products, used tires, paper, cardboard, and used oil. Development of these strategies is underway. Eventual implementation will minimize waste management costs and benefit the environment. Introduction PT. Caltex Pacific Indonesia, commonly known as CPI or Caltex, is a production-sharing contractor to BP-Migas, Indonesia's national energy company. Caltex is Indonesia's largest oil producer, producing over 500,000 barrels of crude oil per day from 82 fields within 3 contract blocks. The distances between CPI's producing fields and operational bases range up to 150 km. Figure 1 depicts the general location and geographic range of CPI's operations. CPI has produced oil from within Riau Province, Sumatra since 1952. Riau province is an equatorial lowland area comprised primarily of palm oil plantations, swampy areas and secondary rainforest. Commercial enterprises and municipal infrastructure have been historically limited in the area, necessitating self-sufficiency in CPI in terms of housing, schools, hospitals, electricity, roads, pipelines, telecommunication, heavy equipment and vehicles. CPI employs approximately 6,500 people and contracts an additional 25,000 to produce oil and provide these services. Collectively these industrial, residential, institutional, construction, and municipal activities generate several types of waste. Waste Management Program CPI's goal is to be recognized by industry and the community in which we operate as a leader in health, environment, safety, reliability and efficiency. In accordance with this intent, CPI covened a team to critically review current waste management methods to ensure regulatory compliance and technical adequacy. Upgraded waste management techniques were identified as an important strategy to minimize operating costs by preventing the creation of remediation liabilities. A structured five-phase project management process was employed to ensure stakeholder alignment, decision quality, and efficient execution:Identify the gaps between the current and desired state;Define the optimal solution that closes the gaps;Refine the selected alternative and develop an implementation plan;Implement the selected alternative socialize the new procedures. Phase 1 - Define the problem Phase 1 was initiated by collecting the data necessary to assess the adequacy of the prevailing waste management practices and facilities. Inventories of generated wastes and waste management facilities were prepared, and the methods currently used by individual groups to manage each waste type were documented. The current waste management practices were critically assessed to identify procedural or technology gaps. Easily rectified gaps were closed as a priority.
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