Michael Knaub, Schaefer Systems International Inc. executive with more than 40 years in the waste and recycling industry, is retiring June 30.

Knaub, Schaefer senior vice president of waste technologies for the Charlotte-based Schaefer, spent 23 years with the storage and material handling company.

Beginning July 1, Maria Frizzell will lead the Schaefer Waste Technology Division. She currently is executive director of sales & operations. She joined the company 11 years ago.

Knaub joined the company as regional sales manager. During those years he served on several industry boards and committees, including the boards of the Waste Equipment Technology Association (WASTEC) and the Solid Waste Association of North America (SWANA) North Carolina. He also was WASTEC chairman for a year and SWANA international corporate director for two years.

In 2009, Knaub was inducted into the Hall of Fame of the Environmental Industry Association (the predecessor of the National Waste & Recycling Association).

Knaub’s father owned and operated a waste hauling and recycling company started by his grandfather in 1915, and Knaub worked for the company starting at a young age.

 “The board of directors of Schaefer Systems wishes to express their thanks and gratitude to Michael for his 23 years of service and compliment him for his high level of integrity and dedication to which he conducted our business,” said Arnold Heuzen, Schaefer Systems president Arnold J. Heuzen.

In retirement, Knaub plans to continue his work with the Toys for Tots Foundation and homeless shelters in the Charlotte region. He also plans to travel with his wife, Karen, and his grandchildren.