Two more City of Ottawa employees have been dismissed and two others have been disciplined in relation to a 1.2-billion litre spill of raw sewage into the Ottawa River in 2006.

Mayor Larry O'Brien announced the sanctions against the additional employees on Wednesday, the day before the city was to appear in court to face two charges under the Ontario Water Resources Act.

One of the employees who was disciplined faces a 20-day suspension, while the other was reprimanded.

O'Brien confirmed all four were managers.

The city intends to plead guilty to the charges on Thursday in the hopes of receiving a more lenient penalty.

One employee had been fired back in May, when the spill was first made public, for failing to report the spill immediately.

Up until the spring, city councillors and managers had been unaware of the spill, which has since been blamed for bacterial contamination that closed Petrie Island beach to swimmers for 45 days in the summer of 2006.

The city was charged by Ontario's Environment Ministry on July 31 with:

• Causing or permitting the discharge of sewage into the river that could "impair the quality of the water," contrary to Section 30 (1) of the Ontario Water Resources Act.
• Failing to notify the ministry of the spill when it was discovered, on Aug. 15, as required by Section 30 (2).

The charges are for contamination that took place between Aug. 4 and 15. The city could face fines of $25,000 to $6 million for each day or partial day of the spill, for each of the offence. However, the ministry said the city may not be convicted for all 12 days.