Dewatering/Separation Equipment, Water & Wastewater Management

Problem

A total disposal recovery operation on a Watford, North Dakota, oilfield took in and processed oilfield tank bottoms, cutting fluids, DAF sludge and drilling mud. A plate-and-frame filter press was used for oil recovery and mud dewatering. The cuttings and large slugs of solids were removed with a centrifuge, and the centrate was sent to the press system. Despite the centrifuge doing the heavy lifting, the mud blinded the filter plates and the solids coming off the press needed excessive amounts of fly ash to absorb the moisture.

Solution

ALAR Engineering introduced the Auto-Vac® rotary vacuum drum dewatering filter. Mud samples were shipped to ALAR for bench simulation testing. Satisfied with the results, the company shipped a tote of its wastewater to ALAR for a test bay demonstration. Grab samples of the dry solids and clear effluent were taken and sent out for lab analysis. The company rented a pilot test unit, and later purchased a trailer-mounted Auto-Vac Model AV660.

Result

Once installed, the Auto-Vac® produced water with less than 50 ppm TSS, and solids that were many times drier than from the filter press. The need for fly ash was eliminated. In fact, the Auto-Vac® solids were used to absorb the moisture from the centrifuge solids. On some occasions, it would extract valuable condensate from the process, which was recovered in the clean-water tanks. The low TSS enhanced post desalinization or other ultra-filtration methods.