FRANKFURT/STOCKHOLM, July 26 (Reuters) - Swedish buyout group Nordic Capital has started preparations for the sale of Swedish air treatment company Munters in a potential 1 billion euro ($1.10 billion) deal, people familiar with the matter said.

The private equity firm has mandated Goldman Sachs to handle the divestment, which will likely start in autumn, the people said.

Nordic Capital and Goldman Sachs declined to comment.

Munters is one of the world's largest makers of climate control systems and last year posted revenues of 580 million euros.

Nordic Capital took Munters private, paying 5.7 billion Swedish crowns ($659 million) for its shares in 2010 after a contentious bidding war with Swedish engineering group Alfa Laval.

Since then, Munters has sold a non-core asset to private equity firm Triton and acquired several companies including Rotem and Reventa, two makers of control systems for farmers.

Munters, founded by Swedish entrepreneur Carl Munters in 1955 and listed on the Stockholm stock exchange in 1997, today employs 2700 staff at 15 plants worldwide.

In a different auction of a European air treatment group, Triton bought Fläkt Woods in June.

Nordic did some pre-marketing presentations to potential Chinese buyers earlier this year, allowing them some extra time to compensate for still relatively slow decision making processes in China, one of the people said.

($1 = 8.6419 Swedish crowns)

($1 = 0.9092 euros) (Reporting by Arno Schuetze, Sven Nordenstam and Freya Berry; Editing by Maria Sheahan)