NEW YORK (Bloomberg) - Aecom Technology Corp., the engineering services company working on New York City's Second Avenue subway project, agreed to acquire a Tyco International Ltd. unit for $510 million to boost revenue from global water-treatment projects.

The cash purchase of Earth Tech Inc. will be "slightly" dilutive to per-share earnings in fiscal 2008, and add to profit in 2009, Los Angeles-based Aecom said yesterday in a statement.

The transaction is expected to close in the quarter ending June 30.

Earth Tech, Bermuda-based Tyco's infrastructure division, provides engineering and construction services for the water and wastewater markets.

Aecom plans to sell as much as $200 million worth of assets from the unit, in operations outside the consulting and engineering business. Earth Tech had sales of $1.3 billion in 2007 and employs 7,000 people.

Tyco split into three publicly traded companies in June, spinning off the electronics and health-care segments.

CEO Ed Breen is selling some smaller units while running the remaining security, fire and industrial valve divisions.

In September, Tyco agreed to sell a Brazilian unit of the infrastructure division for about $295 million.

Tyco rose 40 cents to $40.36 in New York Stock Exchange composite trading. Aecom rose 92 cents to $26.82.