Waste Connections Inc.’s operating income increased 18 percent for its third quarter compared with the previous year, aided by strong pricing and recycling markets.

The company reported that revenue rose 16.8 percent from the previous year to $404 million, compared with $345.8 million in 2010. Operating income reached $89.3 million compared with $75.7 million a year ago.

Net income climbed to $46.3 million, or $0.41 per share on a diluted basis. A year ago net income totaled $41 million, or $0.35 per share on a diluted basis.

“We once again exceeded the upper end of our revenue and margin expectations due primarily to continuing strength in pricing, special waste activity and recycling commodity values,” said Ron Mittelstaedt, chairman and chief executive officer, in a news release. He said the improvement came despite a 35 percent increase in fuel expenses, among other factors.

Waste Connections’ recent agreements to purchase Alaska Waste and the completion of the Town of Colonie landfill privatization during the third quarter brought annualized revenue from transactions for the year to date to about $200 million. The company increased its dividend 20 percent.

For the nine-month period ended September 30, operating income rose 19 percent to $242.7 million, compared with $204.6 million for the same period in 2010. Revenue reached $1.13 billion, a 14.4 percent increase over revenue of $983.8 million a year ago.