HALIFAX -- Another five million litres of treated hydraulic fracturing wastewater will be disposed of at a Nova Scotia cement plant.

Environment Minister Randy Delorey says he's approved a request from Atlantic Industrial Services to use the wastewater at the Lafarge plant in Brookfield.

The wastewater is left over from drilling that happened seven years ago.

It will be used as a coolant in a kiln at the Lafarge plant and evaporated at 700 Celsius after naturally occurring radioactive materials are put through a process called reverse osmosis.

Delorey says a previous pilot project of two million litres showed evaporation is a viable disposal solution for the province's existing hydraulic fracturing wastewater.

About 167 truckloads of water will be needed to transport the wastewater from holding ponds in Debert to the cement plant.

The department says there is about 10 million litres of wastewater remaining in the two ponds in Debert, while 20 million litres of wastewater remains in two holding ponds in Kennetcook following drilling projects conducted by Triangle Petroleum in 2007 and 2008.

Like the pilot project approved last April, the wastewater will be treated for naturally occurring radioactive materials and put through reverse-osmosis.

The treated wastewater meets Canadian Council of Environment Ministers and Health Canada guidelines for release into fresh water.

Environment Minister Randy Delorey is pleased the pilot showed evaporation is a viable disposal solution for the province's existing hydraulic fracturing wastewater.

The wastewater in both areas is from high-pressure hydraulic fracturing that took place in 2007 and 2008.