Nova Scotia Environment Minister Randy Delorey

Nova Scotia Environment Minister Randy Delorey said he's approved a request from Atlantic Industrial Services to use the waste water at the Lafarge plant in Brookfield. (CBC)

An additional five million litres of treated hydraulic fracturing waste water will be disposed of at a Nova Scotia cement plant following a successful pilot project earlier this spring, the province's environment minister said Tuesday.

Randy Delorey said he has approved a request from Atlantic Industrial Services to use the waste water at the Lafarge plant in Brookfield.

The waste water is left over from drilling that occurred seven years ago. It will be used as a coolant in a kiln at the Lafarge plant and evaporated at 700 C after naturally occurring radioactive materials are put through a process called reverse osmosis.

A previous pilot project of two million litres showed evaporation is a viable disposal solution for the province's existing hydraulic fracturing waste water, Delorey said.

He said there are no more plans at this point to dispose of more waste, but the government will assess any proposals.

"As of right now we only have the request for the five million (litres) through Lafarge and the rest of it we will wait for the proponents to come forward with their applications."

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

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

Testing was carried out at the Lafarge plant's main stack in May and June by Air Testing Services in order to determine emission rates while using production water and fracking water for stack gas cooling.

The testing report said an analysis of water batch testing, air emission and sediment testing showed no statistically significant difference between the operational water drawn from Shortts Lake and the waste water "before, during and after evaporation."

For both tests, particulate emissions were below levels permitted for the plant and below federal target levels, the report said.