Where space and time are a concern, the WX-D belt filter press from Phoenix Process Equipment Co. of Louisville, Ky., can process sludge from two different sources, allowing for the simultaneous thickening of one sludge and the dewatering of another.
Essentially two presses in one, the WX-D is an independent gravity belt thickener and a belt filter press that can be operated independently or in conjunction.
A diverter in the operator-controlled mode directs sludge from the pre-thickener belt discharge to a digester or another point in the process, while a separate nozzle directly feeds the press gravity zone.
“You can use the thickener to pre-thicken the sludge and feed the belt press below or you can divert the thickened sludge to the hopper and pump it to a digester or an aerated sludge holding tank or storage vessel prior to be taken away for land application,” says Allen Justus, Phoenix’s municipal sales manager. “At the same time you’re doing that, you can be feeding the belt press from another source below.”
For a treatment plant with limited floor space and a tight budget, the unit’s independent operation feature enables both operations to be performed in a single shift, rather than thickening at one time and dewatering at another time.
The gravity belt thickener can process from 200 to 300 gallons per minute per meter of belt width, depending on the sludge, while the belt press below can handle between 70 and 100 gallons per minute per meter.
In the market since the early 1990s, the combination press was initially designed to thicken paper sludge and later adapted for other uses. “We simply stacked a gravity belt thickener on top of a belt press,” Justus says. “What we did with this concept is reduce the height of the machine. We have a compact, low-profile gravity belt thickener on top of a conventional belt press.” The unit stands slightly taller than a conventional belt press, approximately 11 feet, and measures 18 feet long.
“Most of the time the gravity belt thickener was simply used to pre-thicken very dilute sludges, which you can do with this one. In fact, the first of these units we put in Puerto Rico, where land is at a premium. They simply take the dilute sludge directly from the secondary clarifier to the gravity belt thickener, pre-thicken it and then send it to the belt press below.”
In addition to the third belt pre-thickener and extended gravity and wedge zones, the combination press has a fully welded and easily accessible mainframe for easy maintenance. Its mostly nonproprietary components can be obtained from local supply houses.
A compact MC (medium capacity) model press is also available in either a two-belt or three-belt, dual gravity zone configuration for lower feed rates. A 2-meter unit takes up less than 16 square feet. Standing 6 feet tall and 8 feet long, it’s designed for plants where space is truly at a premium. Output is in the 60- to 80-gallons per meter range. For more information: 502/499-6198; www.dewater.com.
