R. Al-Daher

Bioremediation of oil-contaminated soil : microbiological methods for feasibility assessment and field evaluation

Abstract Bioremediation is emerging as a promising technology for the treatment of soil and groundwater contamination. The technology is very effective particularly in dealing with petroleum hydrocarbon contamination. However, bioremediation is a site-specific process and feasibility studies are required before full-scale remediation can be successfully applied. The type and scale of the feasibility studies that will be needed are specific to the bioremediation approach to be employed during full-scale clean-up operation. In all cases however, these studies have the same goals: to accurately determine if specific hydrocarbon contaminants are amenable to biological treatment and to determine the time and cost required to treat the contaminants of concern according to the regulated clean-up criteria. This contribution provides background information on the chemistry and microbiology of hydrocarbon contamination, discusses the prospective of using biological methods for addressing this problem and describes several microbiological methods which can be used for the feasibility assessment of soil bioremediation. The focus of this chapter is to highlight the needs for the integration of laboratory data to full-scale bioremediation.

Bioremediation of oil-contaminated desert soil: The Kuwaiti experience

The remediation of the soil contaminated during the invasion of Kuwait is currently being considered. Three different bioremediation approaches were used: landfarming, windrow composting piles, and static bioventing piles. Up to 82.5 and 90.5% reduction in the total petroleum hydrocarbons and total alkanes, respectively, were removed within a 12-month period, depending on the bioremediation method used. Excellent results were produced by the bioventing soil pile method, despite the low operation and maintenance cost of this particular method, in comparison with the other two methods. In general, the results showed that bioremediation is effective in the remediation of oil contamination. This paper summarizes the results obtained from the field demonstration and discusses the prospective of using biological methods for large-scale remediation of the oil-contaminated soil in Kuwait.

Bioremediation of damaged desert environment using the windrow soil pile system in Kuwait

A number of diverse technological options are being considered for the remediation of contaminated soil in Kuwait. A bioremediation technique involving the use of composting soil piles was selected among the most appropriate methods and evaluated at pilot scale. The experiment was initiated in November 1992 at the Burgan oil field in which soil piles were constructed from the contaminated soil after amendment with necessary soil additives. The piles were subjected to regular irrigation and turning over and a monitoring program including monthly soil sample collection from each pile in which the petroleum hydrocarbon concentration, PAHs, microbial population, and dry substances were measured. The results obtained showed that the windrow soil pile system resulted in a significant reduction of oil contamination within 10 months. This paper describes the technology used and summarizes the results obtained.

Compost Soil Piles for Treatment of Oil-Contaminated Soil

A number of diverse technological options are being considered for the remediation of soil contaminated with weathered crude oil in Kuwait. The bioremediation technique involving the use of composting soil piles was selected from among the most appropriate methods and evaluated on a pilot scale. The field test was conducted from November 1992 to September 1993 at the Burgan oil field. Soil piles were constructed from the contaminated soil after amendment with necessary soil additives. The piles were subjected to regular irrigation and turning, and a monitoring program was carried out, including monthly soil sample collection from each pile for the measurement of petroleum hydrocarbon PAHs, soil microbial counts, mineral and metal concentrations. The results obtained showed that the composting soil pile treatment resulted in the reduction of up to 59% total extractable matter of oil contamination within 8 months. This article describes the technology used and summarizes the results obtained.

Algae removal by sand filtration and reuse of filter material

Abstract Integrated pond systems consisting of facultative and high-rate ponds operating in series can produce an effluent low in dissolved organic material, nutrients, and hazardous bacteria. However, the effluent is rich in algae, and cannot meet stringent water-quality criteria on suspended solids. The algae, therefore, must be removed before final discharge or reuse of the effluent. This study reports on the efficiency of slow sand filtration in removing algae from high-rate pond effluents. When agricultural sandy soil with an effective grain size of 0.08 mm was used as the filter medium, an average filtration rate of about 1.3 m 3 /m 2 .d was obtained. If filtration was preceded by sedimentation, the duration of a filtration run was about 100 h. At the end of each run, the filter was cleaned by scraping off the top few centimeters of the filter bed. The filtered effluent consistently had a biochemical oxygen demand (BOD) value less than 20 mg/L and undetectable fecal coliforms. The filter media, being rich in organic matter and having moisture-retaining properties, can be used as a soil conditioner.

Bod and cod removal in waste stabilization ponds

Two identical facultative ponds were operated in parallel under the same environmental conditions with the same sewage supply. While one pond was operated as control at fixed depth and constant sewage inflow, the hydraulic conditions for the other pond were varied. It was observed that the BOD and COD removals in the control pond varied almost linearly with areal loading at all times. On the other hand, BOD and COD removals exhibited distinctly different patterns in the variable pond.