Rita Lavelle, former head of the Environmental Protection Agency's toxic waste "Superfund," is expected to be released from federal prison this week, her lawyer said yesterday.

Lavelle has served five months of a six-month prison term after being convicted of lying to Congress about her dealings at EPA with her former employer, Aerojet General Corp.

Her attorney, James Bierbower of Washington, said in a telephone interview that he had been told by prison authorities that she would be released sometime this week, three weeks early, because of good behavior.

"She's been a model prisoner," he said. Lavelle has been an English teacher for inmates at the federal prison at Pleasanton, Calif., he said.

"She has no plans," he said. "Hopefully, she'll go back to work somewhere."

Lavelle was fired from her Superfund waste cleanup post. She was sentenced in December 1983.

Although her appeal is pending before the Supreme Court, she chose to serve her sentence to get the prison term over and to get on with her life, Bierbower said.

Lavelle's conviction stemmed from testimony about the timing of her discovery that her former employer was one of the companies dumping toxic waste at Stringfellow Acid Pits near Riverside.