Suspended Senator Patrick Brazeau will spend at least two months at a drug and alcohol rehabilitation centre in Quebec's Eastern Townships while awaiting trial on charges he was impaired while in control of a motor vehicle.

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Under release conditions agreed upon in court Tuesday, Brazeau will be released Wednesday and must go to the treatment centre at least until Dec. 8, when he will be re-evaluated.

His stay at the closed centre could last as long as two years, Crown lawyers said outside the courtroom.

An officer on a routine patrol arrested the 39-year-old, who allegedly appeared to be intoxicated in the driver's seat of a parked car, on Riviera Street at about 1:40 p.m. ET on Monday.

A search of the vehicle uncovered a knife, Gatineau police said, and a breathalyzer test at the police station showed the man was two times over the legal blood-alcohol limit.

The vehicle he was sitting in was impounded for 30 days and Brazeau's driver's licence has been suspended for 90 days, police said.

Brazeau spent the night at the detention centre in Hull, and appeared in court Tuesday, where he was formally charged with:

Impaired care or control of a motor vehicle.

Having care and control of a motor vehicle with over 80 mg of alcohol per 100 ml of blood.

Breaching bail conditions.

Brazeau's lawyer said he intends to plead not guilty to the charges.

Last week, Brazeau learned he will stand trial in 2015 on sexual assault and assault charges after a February 2013 incident that led to the former Conservative's ouster from the party caucus.

That case is separate from an April 2014 incident, after which Brazeau was charged with assault, possession of cocaine, uttering threats and breaching bail conditions following an altercation involving a man and a woman at a home in Gatineau.

Brazeau also faces charges of fraud and breach of trust in connection with his Senate expense claims. The preliminary hearing in that case will start in June 2015.