Clean isn’t always green

Pub date April 17, 2007
WriterG.W. Schulz


There’s no more symbolic and tangible an issue for elected officials than clean streets.

Not everyone can see firsthand how well local schools are operating, whether nonprofits receiving city grants are spending the money wisely, or if every board and commission is complying with open-government rules.

On the other hand, everyone knows when the streets are filthy, and if a grease-soaked, wind-tossed burger bag slaps you in the face on your way to the ballot box, you’ll angrily remember it.

But clean doesn’t inherently equal green. Street sweepers don’t magically cause dirt to disappear. Where do the used condoms, food wrappers, trails of frothy malt liquor, puddles of urine, auto exhaust particulates, oil and gas residue, toxic chemical spills, and arching piles of trash go after being sucked into a street sweeper’s collection bin?

Well, two places really. When haulers and street sweepers at the Department of Public Works pick up junk from the streets, as much as possible gets recycled at a site on Tunnel Avenue.

"DPW separates materials we pick up for recycling [furniture, appliances, construction debris, etc.], which as recently as 2003 went to the landfill," department spokesperson Christine Falvey told the Guardian.

Then, however, the street sweepers all congregate at a DPW maintenance yard on César Chávez Street, where workers hose charming layers of sludge off the inside reservoir panels of the trucks and out onto two grates — little more than storm drains, which ultimately empty into the bay.

Harvey Rose, chief budget analyst for the Board of Supervisors, released a comprehensive management audit of the DPW in January. Buried on page 149 is a description of what San Francisco does with all this waste scrubbed from the city’s asphalt surfaces and left clinging to the inside of street sweepers.

For the audit, Rose’s office hired health and safety experts from the San Francisco Public Utilities Commission and the San Francisco International Airport to conduct an inspection of the maintenance yard.

We recently requested a copy of the report, and it shows that the foul and possibly toxic liquids removed from the trucks — still swirling with smaller debris that slipped through the grates — wind up in the city’s sewers.

A capture basin below the drains, which the SFPUC cleans out once a week, gathers some of the smaller debris such as trash and gravel. But the basins lose their treatment capacity once they’re a third full, and auditors noted that the basins were almost overflowing when they visited. And despite the presumably high concentration of pollutants in the waste liquids (uninhibited runoff from the streets is a chief contributor to water pollution), no special attention was being given to their handling.

"There are no measures in place to prevent an acute discharge of a collected hazardous material," the analyst’s report concluded, "or to reduce the chronic influx of pollutants generated from this activity."

In other words, the city is cleaning crud off the streets, where people can see it — then dumping it into the bay, where it’s a lot less visible.

In the DPW’s official response to the audit, director Fred Abadi did not dispute how poorly the agency was treating discarded waste from street sweepers and vowed to link the catch basin to a multichambered oil-grit separator, as auditors proposed. Falvey admitted that sometimes night-shift sweepers dumped their entire loads at the César Chávez yard, but she said that habit stopped after the audit was released. The DPW is currently in the market for an oil-grit separator, she added, and the maintenance yard’s drains that receive material from the sweepers have been covered with metal nets.

Of course, all that flushing also requires a lot of water — and that’s in scarce supply right now. San Francisco is experiencing its fourth driest winter on record, and to fill the region’s water needs, there’s talk of diverting more precious flow from the Tuolumne River, threatening fish and wildlife (see "Draining the River").

The DPW’s "street flushers" can each hold 3,200 gallons of water and use about 15,000 gallons of freshwater every business day to cover an average of 25 routes.

In comparison, three average San Francisco households would have to cease using water for an entire month to equal the amount of water used to clean local streets each day. The DPW’s Bureau of Street Environmental Services used 5.6 million gallons of water last year, according to figures provided by water officials. The agency used 90.8 million for landscape maintenance, mostly irrigation for street medians, which during droughts in the late ’80s was temporarily outlawed to conserve water, according to SFPUC spokesperson Tony Winnicker. San Francisco is not there yet, but "for now we would just like everybody to cut back," Winnicker said, "and certainly the city has room to do that as well."

There are costs involved in not cleaning the streets. The Maryland-based Stormwater Center, funded in part by the Environmental Protection Agency, argues that it’s not clear how much street cleaners help remove surface pollution before it runs directly into the oceans. The center says, however, the runoff could be reduced by 5 to 30 percent with the right modern trucks and aggressive maintenance.

Street sweeping as a municipal function historically began as a matter of aesthetics. Unmanageable layers of trash and slime on the street are unsightly and generally not considered to be a part of good public policy, to say the least.

More recently, though, cities have looked at how street cleaning can also help green their locales. "They still want to pick up trash and litter, which was the original idea," said Jim Scanlon, a program director for the Alameda Countywide Clean Water Program. "But it’s moving a little bit more toward wanting to pick up the finer particles because of the pollutant-reduction capabilities."

To its credit, the DPW has planted several thousand trees in the city over the past three years at the direction of the mayor, helping to contain burgeoning stormwater during heavy rains that would otherwise overflow into the ocean. It’s a strategy lauded by groups such as San Francisco Planning and Urban Research. And elsewhere at the César Chávez maintenance yard, auditors noted the DPW’s good housekeeping, including its storage of toxic materials.

But scooping up noxious sludge in one place and pouring it out somewhere else isn’t exactly the sort of green behavior that Mayor Gavin Newsom likes to talk about. *