Crews have begun cleaning up the untreated pulp mill waste that leaked Tuesday from the Northern Pulp effluent pipe at Pictou Landing.

Environment Canada has ordered the company to contain and clean up the mess, CBC News has learned.

“A direction was issued on June 10 to Northern Pulp under the Fisheries Act in relation to the spill,” said Kelly Cowper, an Environment Canada spokesperson in an email to the CBC.

“The company has been directed to take all reasonable measures to remove untreated effluent pooled by the pipeline break and to develop and implement an action plan to remediate the site.”

Wednesday night, large pumper trucks started moving into the area where the effluent remains pooled in a wetland and is slowly leaking into the nearby East River Estuary.

Nova Scotia's Minister of Environment Randy Delorey has estimated the pooled effluent at 4-million to 5-million litres, but the department said Thursday it is still trying to determine the exact amount.

The vacuum trucks were allowed to pass a blockade erected by members of the Pictou Landing First Nation, which is protesting the treatment and discharge of the mill’s effluent at Boat Harbour near their reserve.

"We are going to allow the sucker trucks to come in to pump that effluent out of there," Chief Andrea Paul told assembled protesters Wednesday, after a meeting of the band council.

"Unfortunately, the only place they have to put it is in Boat Harbour, in the settling ponds. They

have to put it somewhere we don't want it running into the harbour," she said.

The band is demanding the closure of the treatment facility at Boat Harbour. It is still not allowing equipment onto the site that could repair the effluent pipe.

David MacKenzie, a spokesperson for Northern Pulp, and another company official met with Paul on Wednesday.

The mill has been shut down since the leak was detected at 7 a.m. Tuesday. It cannot resume production until the effluent pipe — which Northern Pulp said carries 70-million litres a day — is back in operation.

Mackenzie said so far none of its 250-person workforce have been laid off and woodland harvesting is continuing.

Broken pipe nearly 50 years old

Nova Scotia's Department of Environment says the effluent pipe that leaked was part of the original effluent treatment system built 47 years ago.

It was not part a pipeline replaced in 2009 after a leak in another part of the line shut down the mill for three weeks.

The department has also hired its own consultants — Strum Engineering — to carry out water tests at the site of the leak. The department usually relies on information supplied by the company.

Lori Errington, spokesperson for the Nova Scotia government,  says the province wants to "own the data" so it can release it publicly.