Streamline - Spring 2012 - (Page 19)
The Sludge Bag
IN KEEPING WITH the objective of highlighting methods and equipment used for dewatering sludge,
BY DONNA J. LAWSON, WASTEWATER TECHNICIAN II
The sludge tube offers the operator another option for dewatering and can be adapted to many applications.
a method that is not widely used in Virginia is the sludge bag or dewatering tube. The bag is similar to the sludge box, but without the box. Recently, a small wastewater plant near Christiansburg did a pilot test for a sludge bag, specifically the Titan Tube TM by Flint Industries. The treatment plant, which is a part of the Montgomery County Public Service Authority, was contacted by the manufacturer to see if they would be interested in trying the new technology. Arrangements were made and the pilot test was scheduled. The following is an excerpt of the report from Robert Stull, Class I Operator, OIC: “The sludge bag dewatered just like the manufacturer said but was no drier than a good belt press…. To use the bag you need a firm level pad with a drain. We used the smallest bag available which costs between $300 and $400. Once the bag starts being filled it cannot be moved… We got better results by injecting the polymer directly into the sludge line going from the digester through a portable pump into the sludge bag. The sludge bag would be good for plants that did not have the initial money available for a belt press, or for a special project where they needed to dewater.” The bag offers many advantages over plain drying beds. The sludge dewaters quickly and the water released from the fabric is clear. Bags can be stacked on top of each other, up to four in one stack. Solids can be stored in the bags until removal and the bags can be filled over time to allow for smaller batches to be pulled as needed. Once a bag is full and dewatered, the bag must be slit in order to remove sludge with heavy equipment such as a front-end loader or backhoe. Low initial costs offer an advantage over traditional dewatering equipment such as a belt press purchase. Other than a polymer delivery system, the tubes have no maintenance costs. They are UV resistant and have reinforced ports and stress relief bands. The bag is made of a woven material similar to canvas. The tubes are available in various sizes from 30 to 60 feet in circumference and in lengths from 50 to 200 feet. They are also available to fit roll off boxes. The tubes do require a non-porous, nearly flat area to dewater that can collect the released water to a central point. The tube dewaters over the entire surface of the material; therefore, the drainage area must be carefully selected. A sludge-filled tube can move (slide) if the incline is too steep. Once the bag is full and the sludge has dewatered, the material is cut along the sides and pulled back in order to remove the sludge. The sludge tube offers the operator another option for dewatering and can be adapted to many applications. When a wastewater plant considers replacing traditional equipment or just augmenting dewatering needs on a temporary basis, the sludge tube system may be the answer.
Table of Contents for the Digital Edition of Streamline - Spring 2012
From the President
From the Executive Director
Where is Virginia’s Groundwater?
Basic Management Skills
Planning or Piecemeal?
CPEs and YOU
The Sludge Bag
Fracking Rapidly Becoming Unpopular
Amazing We All Learned English!
Springtime Safety – Outdoor Hazards
Spotlight on Western Virginia Water Authority’s Blue Ridge Brawler
VRWA’S 24th Annual Exposition Agenda
Throwing My Loop
Do You Know What Your VRWA Benefi ts Are?
Rural Water Review
Welcoming New Members
Board Of Directors
Index To Advertisers/Ad.Com
Streamline - Spring 2012