A Fresh Approach, Made to Odor, for Waste Facility’s Ills

Residents near a waste transfer station in Stanton say they suffer on hot summer days. The heat is one thing, but there’s also the smell.

“It gets pretty bad,” said Eric Schommer, 42, who lives in a condominium complex next door to the CR&R; Inc. facility on Knott Avenue, where nearly 1,500 tons of trash is processed daily. “It’s not consistent, [but] it’s overpowering. And you can’t smell anything else.”

Relief may be on the way.

In the next few weeks, transfer station operators will install a biofilter, a device used to reduce noxious odors at sewage treatment plants and pig and dairy farms. Designers say it will be the first time the device--to be installed at an estimated cost of $250,000 to $500,000--is tried at a transfer station.

The company and city officials have high hopes for the biofilter, which they said will work in a natural way to convert noxious odors into less offensive ones.

“We’re very excited about this,” said Mark Lloyd, Stanton community development director. “Our understanding is it’s been tremendously successful. We’re hopeful the same benefits will be derived at the facility in Stanton.”

First patented by an engineer at the Los Angeles water district in 1957, biofiltration is used throughout Europe to solve odor problems. Businesses in the U.S. use it less, but that could change as population densities increase, Lloyd said. “In Southern California, space is critical. It’s important to apply these technologies to land uses that typically might be considered to have negative impacts,” he said.

At the transfer station, trash is sorted, compacted and loaded in large trucks headed for landfills and recycling centers. That process takes less than a day, said Paul Relis, a vice president at CR&R.; But that’s long enough for bacteria to feed on decomposing food and landscaping waste and produce volatile odors.

Residents in the surrounding communities have complained about the occasional smell for a long time. Often on hot days, they stay indoors with the windows closed, and some say they don’t let their children outside.

Over the years, CR&R; has tried various remedies. In 1987, the company enclosed what had been an open facility. It started washing floors daily, opening vents and installing fans and a high block wall after a 1994 city report documented residents’ complaints.

None of this eliminated the problem. The company received nine violation notices in 1998 from the South Coast Air Quality Management District, which took 247 complaints from irate residents.

“That was a bad summer for odor,” Relis said.

The number of complaints dropped to 19 in 1999, and there were no violation notices that year.

Still, in search of solutions, Relis went to a solid waste conference in North Carolina. There, he met Jan Allen, a senior technologist from CH2M Hill in Seattle who told him about biofiltration.

As it turns out, scientists say, bacteria both cause the odor problems and have the potential to solve them. A lack of oxygen in decomposing waste causes some bacteria to use biochemical processes that produce many of the fumes. Temperature speeds up the process of degradation, increasing the odors on hot days. But given plenty of oxygen, other bacteria and fungi can feed on the chemicals and break them down.

Biofiltration takes advantage of microorganisms’ natural cycles to break down malodorous compounds in a remarkably simple process. Fans inside the facility blow the offending air out of the building through perforated pipes. Released air comes in contact with a layer of wood chips where bacteria and fungi grow. The microorganisms feed on the distasteful chemicals and convert them into the harmless byproducts carbon dioxide and water, Allen said.

The drawbacks to biofilters include their high cost, the need for empty land--the one at CR&R; will take up half an acre, which the facility has to spare--and limited effectiveness when unwanted chemicals are present in high concentrations.

However, those working with biofilters give them rave reviews.

“Any biological process can get screwed up, but when biofilters work, they work really, really well,” said Kevin Janni, a professor and extension engineer of biosystems and agricultural engineering at the University of Minnesota who has helped design biofilters for several swine facilities and dairy farms. At one swine facility, Janni measured about 85% of the odors gone.

Allen of CH2M Hill said his biofilters have also worked well. A compost facility in Washington would have gone out of business if not for a biofilter he helped design, he said. And Allen is optimistic the biofilter at CR&R; will perform equally well.

The owner of the Gill Management Co., which manages 407 condominiums west of CR&R;, certainly hopes that proves true.

Joyce Gill said her homeowners want to enjoy barbecues and swimming on summer days just like everyone else.

“Every time they do something new, it’s my absolute dream it will take care of the problem,” Gill said.