"We compost manure from all of the nonprimates, including zebras, giraffes, elks, hippos, and four elephants. That's just to name a few," Dr. Doo explains. "And I am on the outskirts of the city and have a four-lane highway on one side and then a park. So it's a nice buffer. We've never had odor complaints."

Shephard stores the animal waste from a particular keeper's area in a separate manure bin specific to his or her unit. From there it goes into a larger bin and is trucked to the Zoo Doo facility and gets composted immediately.

"So I don't get odors started, I get the oxygen mixed into the material right away," Shephard says. "I'm lucky enough to have a good supply of manure and bedding materials so I can just mix it as is."

Compost distribution system

Having a good carbon-to-nitrogen ratio is important for a good-quality composting operation, and Dr. Doo gets his "ready-made." The animals do most of the work for him. For instance, he explains, giraffes put out a very small amount of "doo" that he describes as similar to rabbit pellets, although giraffes require a large amount of bedding material. Conversely, elephants need very little bedding but donate huge amounts of material to the Zoo Doo facility. Shephard adds that he rarely has to use bulking agents.

"The people in the Seattle area like the poo," says the veteran composter of the 17-year Zoo Doo program. "There is twice as much demand as supply. In fact, we have a lottery each year to decide who can come and scoop poop at the Fecal Festival every fall and spring. They use it directly on their gardens and landscape. And we are fully licensed, so everything is tested prior to going out to the public. In essence, we have clean poo."

All joking aside, Seattle's tipping fees are currently $99.75/ton, so it's very expensive in Washington to simply dump waste when it can be composted and used. The zoo is a five-star member of the King County EnviroStars Program and since 1985 has been saving around $60,000/yr. in disposal costs. The equivalent of 600 tons of waste would be landfilled if it weren't for Dr. Doo and the Zoo Doo staff members' enthusiasm for turning poo into loveable, highly useable zoo doo.

Odor: An MSW Catch-22

Bob Wieden, chief marketing officer with Quattro Brands in Bloomington, MN, says one of the primary challenges is exposure time. "Anytime waste is just sitting around, it gives the odor something to latch onto."

Calvin Pride, the president of Ambio Biofiltration Ltd. in Rockland, ON, agrees. "Odor management involves two things. For one thing, [MSW facilities in general] must develop good housekeeping practices, and secondly [they must] realize that odor is in the nature of the business and they need to have an end solution. And they absolutely need to budget money for odor control."

However your company chooses to attack the odor problem, it must be considered and budgeted for in a plant's business plans. Confronting the problem head-on gives managers the tools they need when odor complaints are received. So from the simple to the extravagant, this article examines what some cities and companies have done to solve their odor problems and how their solutions have worked to help resolve issues with their neighbors.

Let's Get Moving . . . Away

For discarding yardwaste and excess organic waste, composting is a prudent option as compared to disposal. Similar to the Woodland Park Zoo program, many communities select composting as a way to divert organic waste from local landfills. By doing so, they provide landscapers and agriculture with an inexpensive source of a valuable soil enhancer.

The City of Spokane, WA, however, found that there can be a downside to processing large amounts of greenwaste in urban surroundings. The Spokane Regional Solid Waste System (SRSWS) made its first attempt to create a successful composting operation in 1994 and eventually worked with two different companies on the project.

Dennis Hein, director of SRSWS, says both of the companies did their best to work with the problems at hand. "Both contractors worked very hard," he emphasizes. But ultimately they were unable to overcome some inherent problems.

One problem, Hein says, is the cycle of yardwaste. The materials available for compost change with seasons. In early spring - the months of April and May - the community's yardwaste consists of yard cleanup debris, including pine needles and a lot of old leaves. These wastes contribute lots of carbon. Next, in late May through the end of the summer, there's a huge influx of grass - very green and a heavy nitrogen contributor. Then as fall progresses, the yardwaste returns to pine needles, leaves, and very little grass.

"There is such an inconsistency of product delivered," Hein stresses. This inconsistent mix in part led to odor problems. The first company hired by SRSWS used windrows to make compost. "Any movement of the wet, decaying organic matter would cause odors. And although the area surrounding our compost operation looks rural, there were a number of houses in the area."

Compost odor control

Directors prior to Hein worked closely with the elected officials and homeowners to solve the problem, but in the end they simply could not promise that they could find a way to make the odor go away completely. The City of Spokane ended up purchasing 15 homes in the final outcome.

Hoping to eliminate the odor issues, the city turned to a company that used in-vessel bag units to make compost. The technology, while better than exposed windrows, still was causing odor complaints, and in the meantime SRSWS found out that its compost was high in clopyralid, a broadleaf killer applied in yards across Spokane that wouldn't break down in the composting process.

"When we discovered that the compost was high in clopyralid, it was the straw that broke the camel's back, so to speak," says Hein. "We couldn't eliminate the chemical from the wastestream coming from our residents, and we couldn't use the compost in gardens or flower beds."

In September 2002, Spokane issued a request for proposal and subsequently selected Waste Management of Eastern Washington for the processing, transport, and recycling of the area's organic waste.

Ken Gimpel, municipal relations manager with Waste Management, explains what they do with the waste and how it has solved the problem for Spokane: "Basically we move it. It gets loaded into long-haul trailers and trucked to Boardman, Oregon, where it's composted and used as animal bedding for the cows at the dairies, composted over and over again, and ultimately sold to commercial nurseries and landscapers."

Waste Management enlisted partners Puget Sound Truck Lines (PST) and Threemile Canyon Farms (TCF) to provide a contemporary solution to Spokane's organic-waste problem. After the waste is brought in to Spokane's three transfer stations, Gimpel describes, PST takes over and hauls it to Boardman, where TCF has 93,000 ac. of farms, including three dairies, 36,000 ac. of mint and onions, and a 120-ac. composting operation.

The dairies' bedding pens are "gravity feed with flushing troughs," explains Gimpel. In other words, cows kick the compost bedding, and along with some added manure it goes into its own wastewater treatment system equipped with its own pumps and "slope screen separators."

Essentially the wastewater and sludge are separated so the sludge can be rerouted into the compost operation and the liquid can be pumped out of the retention ponds and used for irrigation. After the fines are screened and processed three times or more, they are sold to nurseries and commercial landscapers.

Basically Spokane solved two issues. It eliminated its odor problem by removing the source of the odor for the region, and it found a creative way to recycle tons and tons of yardwaste. By managing the compost on the farms, Spokane diverted 41,000 tons of organic matter from its solid waste system and provided fertilizer and bedding for an eminent agriculture operation.

No Perfume Here, Please

Charlie Hong liked high-pressure misting systems so much that when his company constructed the 75,000-ft.² building to enclose Pomona Valley Recycling Center (PVRC), it had one installed throughout the entire building. Hong is general manager of Sunrise Industries, which owns PVRC in southern California. In addition to being a single-stream residential recycling center, PVRC accepts and processes large amounts of cardboard and paper products. "We are fiber specialists," Hong says.

To help neutralize the fiber odors, Hong decided to use the odor neutralizer Ecosorb. Although people aren't supposed to put organic waste in the blue household bins, Hong says they often do. Then PVRC ends up with unexpected and sometimes unidentifiable odors in the building. One reason for choosing Ecosorb's injectable neutralizer is that it attracts a variety of odors and neutralizes them on contact. "And there's no perfume smell at our facility," Hong adds. "It just smells clean."

Although PVRC is located in a heavy-industry­zoned area, the company has residential neighbors within a block or so from its facility. To set up a good neighbor program, Hong hired an outside consulting firm. The firm spoke directly with the people of the area to find out what issues they wanted to discuss with Sunrise Industries.

The company also monitors the outside perimeters for air quality, and to accept and direct odor calls, a hotline was set up so citizens immediately would know whom to call if they smelled anything bad coming from the plant. Hong describes the program as "very interactive." After the firm interviewed neighbors, it analyzed the data and sent a report to Sunrise Industries and the City of Pomona.

Hong believes that all of PVRC's activities add to a positive image in the community. Even the front, public area of the building is manicured nicely. Whether the street debris is a result of a recycling truck or not, employees pick it up and get rid of it.

"Image does make a difference. The face says your company is just as clean as another business," Hong points out. "Be proactive! Let the public know it's a forethought on your part - not just an afterthought."

Not in My Backyard

Craig Littleton, operations manager for MicroCool, a division of Nortec Industries in Palm Springs, CA, says there is what's called an odor syndrome with some communities and citizens who purchase homes in rural areas. "Landfills are built outside of the town, and then the town grows up around them. And communities actually generate the odors themselves by the waste they put out."

But all the same, when a company works with materials that generate odors, Littleton agrees that it must take responsible steps not to offend its neighbors.

Although odor is a byproduct of organic matter decay and to some degree is in the nature of the business, Littleton says image is still an important factor to consider when developing an odor management plan. Small things, such as washing trucks and sweeping continuously, have a positive impact. And depending on the needs and practices of the company, there's an immense variety of odor management products and equipment available on the market.

For instance, in Minnesota a large, privately owned transfer station was receiving so many odor complaints, fines, and warnings that the Ministry of Environment and Energy was calling for immediate attention to what it termed a "critical situation." As a temporary measure Ecolo Worldwide installed a fogger to disperse its airSolution #23 in the wet garbage area. Within a few days, neighbors were calling with compliments and inquiries instead of complaints.

For a more permanent solution, the station installed a nozzle system equipped with pulleys to raise and lower it for servicing. Ecolo representatives explain that each line has a winch at either end of the building so a cable can be used to maneuver the nozzles, thereby leaving each line in a stable state of suspension while in operation.

Living Down a Bad Reputation

Prior to 1985 the Twin Falls Wastewater Treatment Facility heat treated sludge before it was trucked to crop fields nearby and used as fertilizer. The Idaho plant is located at the bottom of Snake River Canyon and has two local golf courses for neighbors. Land at the top of the canyon is highly valued for the breathtaking views it lends to homeowners.

But the City of Twin Falls was overwhelmed by odor complaints not only at the canyon facility but also all the way up the canyon to the homes and along the route the flow traveled - some 10 mi. meandering through town.

After Operations Management International (OMI) Inc. took over management of the plant in 1985, things slowly started to turn around. OMI is a subsidiary of CH2M Hill and works directly with that company's expert environmental engineers. The municipally owned wastewater treatment plant now receives flow from the City of Twin Falls, the nearby rural town of Kimberly, and seven major industries along the canyon rim. Some 75% of the organic loading comes from these industries, says John Keady, project manager with OMI.

After dropping 400 ft. to the plant below, the average 7-mgd waste flow goes into the preliminary treatment area where concentration is measured and flow rates are determined. This is also where large objects are filtered out. Much the same as other plants, after flow measurement it splits off to two primary (75-ft.-diameter) clarifiers where the solids settle and the flow starts the biological process.

Aeration basin

Using biofilters, bacteria break down the activated sludge and add oxygen. From there they go into aeration basins and get mixed with microbes returned from the secondary clarifier. In the secondary clarifier, solids settle, and a ratio of bacteria is returned to the aeration basins or wasted from the system. The effluent from the secondary clarifier is clear at this point and meets most permit requirements, except for disinfection requirements.

After many years of dealing with the dangerous and controversial addition of chlorine to the end water, Keady says they now disinfect using ultraviolet lights (UVL). "Using the UVL, it takes about half a second to sterilize the water."

Since OMI took over management of the Twin Falls Wastewater Treatment Facility, the odor problems have been pretty much under control at the facility itself. But since OMI is in charge of the pump stations in the collection system, the company still gets complaints about areas upstream. "One stage of odor is at the junction of a potato processor and a cheese manufacturer," Keady explains. "Waste from these industries creates just the right ratios of what's needed to produce odors."

At the peak of the odor complaints, pungent odors were seeping into an area hospital's air vents and saturating a local private school. During certain hours of the day, the park was unusable. A committee was formed to decide how to attack the odor problem. City officials and environmental engineers met with local citizens and began a stringent monitoring program. Outposts were formed, with people carrying weekly logs to record information about the odors. Canvassers collected information from citizens on when the odor was noticed and what kind of smell was detected (e.g., sewer, rotten eggs, or dirty socks). From the log data, the engineers traced the smells to the sources.

After a bid process, Keady says the city hired contractors to construct a device that adds oxygen to the system at the problem junctions. The 80-ft.-long x 24-ft.-high storage tank utilizes large blowers to bubble the oxygen into the system. After two years of use, Keady says the number of odor complaints has reduced "significantly." Of course, there still are those calls that are traced and found to be from other sources along the river.

"We previously were using about $250,000 a year in chemicals, and we weren't always being successful at that."

Having to overcome the reputation of being an odor-generating facility was a challenge. But Keady and his staff took a proactive approach to the extreme, and it has worked.

"We're very open and honest about the problem if and when it's there," he emphasizes. "And we let people know whom they can call or what we're doing all the time."

OMI sponsors an educational booth at the local summer festival and developed a water awareness program aimed at children in elementary schools. In addition, employees formed a group that volunteers to clean up the parkway areas of the canyon where Rock Creek Park is located. They call themselves the Rock Creek Brigade. Being involved in such community activities as baseball, volleyball, and skateboarding has created camaraderie among the employees of OMI and local citizens.

In 2001 the City of Twin Falls signed another 10-year contract with OMI, and in 2003 OMI was awarded the second-place prize in the Environmental Protection Agency's Biosolids Management Excellence Award program, a hard-earned Clean Water Recognition award.

Pierce County Recycling, Composting, and Disposal

When Pierce County Recycling, Composting, and Disposal LLC - doing business as Land Recovery Inc. (LRI) - opened its composting doors outside of Seattle in 1999, it had a huge hurdle to overcome with odor perception. The community already had its fill of composting and had worked to shut down the one previously located in Puyallup.

"LRI did a lot of community involvement up front," Carrie Gregory, compost quality manager with LRI, explains. "They went to the community and talked to them about the new composting facility and found they would not be easily convinced; they would have to see it to believe it."

Gregory says LRI offered to take citizens out to its other partner facility in Purdy, WA, so they could see how the company operated.

"The Purdy facility isn't enclosed, so LRI told [citizens] that the new facility will go even further to protect the neighborhood from odor nuisances," Gregory says. "It will be enclosed and use biofilters and other up-to-date equipment."

The receiving area of the new Puyallup facility - LRI Compost Factory - is three-sided and gets swept down to the floors every single night. All of the air inside of the enclosed area gets run through the biofilters. The curing area is in the rear of the building and also is treated by biofilters when the aeration is in the negative mode, says Gregory. The entire facility (more than 3 ac.) is aerated through the bottom of the floors.

"We sweep all of the time," she adds. "The packer trucks that come in and out are a source of odors because they pick up yardwaste, and it gets juicy and nasty. There were times it was sloshing off the trucks, so they worked with the drivers to clean the trucks at the facility and get rid of the liquids before they leave the site."

The trucking companies have been very helpful in agreeing to haul smaller loads, creating less liquids and therefore creating less odor potential.

When the new facility first developed its plan of operations, it included an odor management plan. There are stages in the standard operating procedures for odor management problems.

LRI Compost Factory's plan of operations was created with flexibility to ensure odor management. The following steps are used in the investigation of odors:

• Initial contact by complainant
• Thorough investigation with or without the help of the complainant
• Pinpointing the problem or problems
• Management meeting to discuss solutions
• Implementing the agreed solution
• Following up with the neighbor

These steps are accomplished working hand in hand with local regulators to keep them informed during all steps of an investigation, which ensures accountability.

"We allocated the flexibility to not be shut down but instead to be accountable to follow the procedures," Gregory stresses. "If a problem continues, we need to communicate back to the committee, and then we have to address the problem. It has to be all the way back to the bottom line, which includes building renovation if necessary."

The community involvement effort by LRI has paid off. Not only is the community happy with the facility, one member actually delivers the uniform overalls to the company. And she's happy with the operations.

"They're happy to have composting here now," Gregory says proudly. "They see the benefits and what we do. They help us monitor and keep track, and we encourage people to be in touch with us and let us know if there is a malodor and where and when they noticed it. Our neighbors have learned that odors happen occasionally but that when they do, LRI will immediately explore corrective action and take necessary steps to correct the situation."