Land treatment: A viable and successful method of treating petroleum industry wastes

Land treatment is an environmentally attractive alternative for the disposal of petroleum refinery wastes. Diverse populations of soil microorganisms degrade waste oil and other organic compounds through a series of complex reactions to yield carbon dioxide, water, and innocuous byproducts. Approximately one-half of the disposable volume of oily sludges are currently land treated at more than 100 sites across the United States under a variety of soil and climatic conditions. Maximization of biodegration rates requires an optimization of management practices which stimulate aerobic microbial populations in the soil. These management practices include addition of fertilizer, judicious waste application, and frequent cultivation. Off-site migration of oily waste constituents that would endanger groundwater quality has not been observed in several field and laboratory studies. The leached residuals are apparently adsorbed, assimilated, or inactivated in the upper soil horizons. A prudent management system, however, requires an individually tailored monitoring system with dual objectives for an early detection of off-site waste constituent transport and for evaluating the performance of waste biodegradation processes. A cost comparison for the disposal of oily wastes by currently available technologies indicates that land treatment is the most economical option.