In situ biotreatment

Morgan, P. Watkinson, R. J. (1990). Assessment of the potential for in situ biotreatment of hydrocarbon-contaminated soils. Water Science and Technology, 22, 63-8. 

Successfiil inq>lemeiitation of such an approach would considerably reduce both the time and cost of in situ biotreatment. Pretceating groundwaters with sonication techniques would form VOCs that could be removed effectively by either bioremediation technologies or a dual vapor extraction technique (developed by Stanford University under the VOC-Arid Program, now part of Plumes Focus Area). Sonication could also be coupled widi technologies aimed at mobilizing dense nonaqueous phase liquids (DNAPLs) in the subsur ce, such as surfactant floodii. ... 

Inqiroved in situ biotreatment of contaminated soils and groundwater and Cost-effective and inqiroved efficiency thereby shortening the time required to clean-up a contaminated site. 

The Aerobic Biotreatment System (ABS) is an in situ technology that treats soils, sludge, and sediments contaminated with petroleum hydrocarbons, polyaromatic hydrocarbons (PAHs),... 

Two of the recognized limitations of in situ technologies are (1) physicochemical restraints (e.g., bioavailability, desorption kinetics), and (2) a need for extended treatment time as compared to ex situ biotreatment approaches. Inherent geological parameters such as permeability, vertical and horizontal conductivity, and water depth can also represent constraints that are critically important to recognize and appreciate (Norris et al., 1993 Norris Falotico, 1994). Another widely recognized limitation inherent to in situ processes is that the systems are difficult to monitor and thus effective and complete treatment is difficult toascertain and validate. 

In situ bench-scale microcosms as well as field pilot studies have been conducted to optimize in situ PCB soil biotreatment processes. This work has focused on dilute PCB contamination (less that 100 mg/kg) because of the current rate limitations of... 

Three field demonstrations of PCB biodegradation approaches are currently being tested at a natural gas pipeline site in Pennsylvania (Envirogen, Inc.) in situ aerobic biotreatment (solid phase land treatment landfarming ) aerobic soil slurry biotreatment and in situ anaerobic biotreatment. These studies are being conducted over a two-year time frame and will be completed by early 1996. Preliminary results are presented below. 

Bevrox Biotreatment, or liquid-solids contact (ESC) digestion, is a patented, ex situ process for the treatment of biodegradable contaminants in soil, groundwater, or process water. 

The BioTreat system is an in or ex situ treatment that uses specifically selected enzymes and nutrients to encourage biodegradation of hydrocarbons with the indigenous microorganisms. According to the vendor, the system has been used at a number of sites, however, no further information was available. The current availability of this technology is uncertain, however, the vendor has indicated that they plan to offer an improved version of BioTreat in the future. 

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