Vacuum drum dewatering filter replaces filter press in oilfield operation
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. 708/479-6100; www.alarcorp.com.
Centrifuge allows quartz mine to increase production
Problem: In 2008, a quartz and sables lot in France had a capacity expansion problem. The demand for quartz was continuously increasing, forcing them to double production. The bottleneck of the system was the sludge processing. They were at capacity running four filter presses 24 hours a day.
Solution: Rather than install additional filter presses, it was recommended that the facility install a single centrifuge from DRYCAKE. According to the engineer, beyond the cost of the filter presses themselves, the extra filter presses required additional full-time staff. The pilot went well, as a mobile device mounted on a container processed 3.5 tons per hour of cake sludge. The centrifuge offered a lower capital than a filter press with the same capacity, continuous operation rather than cyclical, good clarification and clay handling, compact equipment and no staff.
Result: In the end, a DR650H 26-inch-bowl-diameter decanter was installed with the same treatment capacity as four filter presses combined. They are now only using two filter presses in tandem with the one centrifuge. The facility has maintained its recycling rate of nearly 98 percent of water from washing. The machine works regardless of the chemistry of the material being fed to the machine operator. 877/379-2253; www.drycake.com.
Refinery water treatment system improves efficiency
Problem: Operators of the Delek Refinery in Tyler, Texas, needed to update their aging ion exchange system, which had become inefficient and costly to maintain. Waste from the system was generated every two days, and chemical and treatment costs were high. In addition, the plant desired higher quality water to feed the high-pressure boilers. Refinery operators needed a system upgrade that would comply with strict suspended and dissolved solids quality requirements for boiler feed water.
Solution: With on-site space constraints, engineers from OriginClear’s Progressive Water Treatment were brought in to design and install a safe and user-friendly water treatment system. In order to use a small area located in the heart of the facility, they designed the system so that three complete 250 gpm RO units were mounted on one 37- by 39-inch skid. The system would reuse 100 percent of the water on site, with the option of using the RO reject as feed for the cooling towers and the RO product as boiler feed water. The improved system used existing equipment where appropriate, and included completely automated controls, further reducing supply and maintenance costs at the facility.
Result: The water treatment system has reduced supply costs, improved operating efficiency, decreased maintenance costs and provided a consistent high-quality boiler feed water supply. 877/999-6645; www.originclear.com.
Dewatering technology used to replace centrifuge
Problem: One of the centrifuges thickening waste activated sludge at Wildcat Hill Wastewater Treatment Plant in Flagstaff, Arizona, was old and needed a costly repair.
Solution: “I was aware of a unique Trident KDS Thickener/Dewaterer technology that had the potential to replace the centrifuge,” says Troy Dagenhart, operations supervisor at the plant. “The KDS potentially required 94 percent less power and 50 percent less maintenance, so we scheduled a demonstration.” The KDS Thickener uses a low-speed grid and rotor technology, which because of the slow mechanicals has low energy and maintenance specs. The correct-sized KDS could use the existing concrete pad and require minor plumbing changes.
Result: The material tested was 0.7 percent solids fed to the unit at a volume of 20 gpm, which is about 25 percent of the total plant volume. The unit performed quickly. Using polymer dosing, the material thickened to 6.5 percent solids. The centrate was reduced to 13.3 mg/L TSS. “That’s probably the lowest centrate number I’ve ever seen,” says Dagenhart. “It was really clear.” The system ran quietly with no vibration. The KDS’s power cost, for double the present volume, is estimated to be 6 percent of the centrifuge. 800/799-3740; www.tridentprocesses.com.