An underground diesel fuel spill at a county bus maintenance facility in San Jose, California was successfully remediated by constructing a pair of 50 feet deep, gravel-filled extraction trenches. Well casings with ejector pumps were set into the trenches for withdrawing the diesel fuel contaminated groundwater to a small, onsite treatment plant. Severe access restraints, the proximity of major structures, and heavy traffic demanded a quick, yet safe construction technique for installing the deep trenches.
The drainage trenches were installed by the innovative use of a modified version of the slurry trench technique using a biodegradable slurry, i.e. the bio-polymer slurry drainage trench (B-P Drain) technique. A bio-polymer slurry was used instead of bentonite slurry to temporarily to support the trench walls without structural bracing. Upon completion of backfilling, the slurry in the trench was chemically reduced to water and simple sugars [to activate the drain. The entire trenching and backfilling operation, including well placement, was completed in about two weeks.
Installation of a deep drainage trench by the bio-polymer slurry drain technique