Mayor Gavin Newsom is competitive about many things, garbage included. When the city found out a few weeks ago that it was keeping 70 percent of its disposable waste out of local landfills, he embraced the statistic the way other mayors embrace winning sports teams, improved test scores or declining crime rates. Workers sort plastics at the San Francisco Recycling Center. The city, with 7,800 tons of waste a day, keeps 70 percent of it out of landfills. Mayor Gavin Newsom is shooting for 75 percent. But the city wants more. So Mr. Newsom will soon be sending the city's Board of Supervisors a proposal that would make the recycling of cans, bottles, paper, yard waste and food scraps mandatory instead of voluntary, on the pain of having garbage pickups suspended. "Without that, we don't think we can get to 75 percent,' the mayor said of the proposal. His aides said it stood a good chance of passing. How does he describe his fixation with recycling dominance? "It's purposefulness that could otherwise be construed as ego,' Mr. Newsom said. "You want to be the greatest city. You want to be the leading city. You want to be on the cutting edge. I'm very intense about it.' In a more businesslike tone, Jared Blumenfeld, the director of the city's environmental programs, addressed one of the main reasons the city keeps up the pressure to recycle. "The No. 1 export for the West Coast of the United States is scrap paper,' Mr. Blumenfeld said, explaining that the paper is sent to China and returns as packaging that holds the sneakers, electronics and toys sold in big-box stores. Not that Mr. Blumenfeld does not have a competitive streak of his own. San Francisco can charge more for its scrap paper, he said, because of its low levels of glass contamination. That is because about 15 percent of the city's 1,200 garbage trucks have two compartments, one for recyclables. That side has a compactor that can compress mixed loads of paper, cans and bottles without breaking the bottles. (These specially designed trucks, which run on biodiesel, cost about $300,000 apiece, at least $25,000 more than a standard truck, said Benny Anselmo, who manages the fleet for Norcal.) Another major innovation in the past decade was the development of infrastructure for turning food wastes