HDD Tech: Getting Fluids To Pass The Paint Test

By George M. Dugan, Regional Manager, CETCO Drilling Products | September 2008 Vol. 63 No. 9

Centrifuge dewatering systems are capable of discharging crystal clear water (below 10 ppm total suspended solids) and dry solids while processing over 65 gallons per minute. The down side to centrifuge dewatering systems is that the equipment is very expensive to lease or purchase and must be operated by knowledgeable and experienced dewatering personnel, making the cost difficult to justify for smaller projects.

Solidification is another effective method for dealing with material containing free liquids such as drill spoils. Various materials such as cement kiln dust, fly ash, dirt and lime, have been used in the past to absorb free liquids. While effective, these products add bulk to the material being solidified, which increases disposal tipping fees and can be labor intensive in their application.

A new solidification process has recently emerged which uses a self contained pumping/mixing system to meter in a re agent at a maximum required dosage of 2 percent by weight, and is capable of processing at 65 to 70 gallons per minute. This system discharges slurry that will solidify within approximately 10 minutes and can be mixed with native soil and backfilled or pumped into pits, dump trucks, and or roll off boxes without adding significant bulk to the material being solidified.

Regardless of whether drill spoils are deemed hazardous (such as spoils from environmental remediation projects) or non hazardous, it is easier and more cost effective to dispose of material that can pass a Paint Filter Test. Contractors must be aware of local regulations for the disposal of drill spoils and explore available options and factor disposal cost into projects.

CETCO, ( 847) 818 7935, www.cetco.com

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