9 Composting Trends

Feedstock Diversity

Yard trimmings, leaves, grass, brush, etc. have been composting mainstays since the late 1970s, but a recent trend involves increasing compost's feedstock diversity. Several composting facilities now are handling significant amounts of commercial food waste that can be easily segregated at grocery stores, food processing centers and restaurants.

Community Recycling and Resource Recovery, Sun Valley, Calif., for example, operates one of the country's largest commercial food residuals recovery programs, collecting and composting food waste from more than 1,500 grocery stores.

Not to be excluded, major cities such as San Francisco have developed programs to capture food waste, too. San Francisco began collecting residential food waste in 1999 as part of a comprehensive effort to achieve a high recycling goal. The city currently has a 75 percent recycling goal. Los Angeles and San Jose, Calif., also are developing food waste collection pilots.

A growing number of composters also are accepting liquid wastes for processing. In arid regions such as Texas, liquid wastes, which can be expensive to dispose of or prohibited from landfilling, provide a double benefit. The liquid adds needed moisture and a source of nutrients for compost, while the added revenue from the tipping fee contributes to the bottom line.

Integrated Facilities

Increasingly, composting facilities are being located adjacent to landfills and transfer stations — as opposed to stand-alone facilities. In states with landfill bans or high diversion goals, it is increasingly difficult to find a landfill or transfer station that isn't involved in some organics recycling.

An existing solid waste facility, such as a landfill, can be a good site for a composting facility because it often has under-utilized space and some of the necessary equipment necessary for composting. The Highway 59 landfill in California's Merced County is a perfect example.

“Our landfill is an ideal composting site” says Jerry Lawrie, county solid waste manager. “We've already gotten the value out of the land, and all of our landfill infrastructure is there to support the composting operation — the scales, the recordkeeping, the maintenance and employee facilities, wells for water, etc.”

Transfer stations and material recovery facilities also may participate in part or all of the organic recycling system. In addition to accepting source-separated yard trimmings, a few California transfer stations have realized that the same trucks delivering organic materials are willing customers for the finished products. Facility owners have set up mini-materials yards, sometimes incorporating traditional landscaping materials like sand and decorative bark into the compost and mulch products.

This also has become a useful marketing tool for several composters and mulch producers.

Fewer, Larger Facilities

The commercial viability of composting is affected by economies of scale. Composting is relatively capital-intensive. And although regulations vary by state, commercial composting increasingly is a regulated activity. Larger facilities are better able to absorb costs without affecting the bottom line.

In California, due to the high cost of developing commercial composting operations, fewer but larger facilities are being built. Several are more than 100 acres in size, which also makes the facilities better equipped to handle a wide variety of feedstocks and create a diverse number of products.

On-Farm Composting

Farmers have been recycling organics since the beginning of agriculture. Also, farms often have been seen as the likely market for recovered organics as a way to “close the loop.” A recent survey by the California Integrated Waste Management Board (CIWMB), Sacramento, documented that in the Golden State, more compost goes to agriculture than any other market segment.

But in addition to using compost, some major growers are seeing the value of starting their own compost operations. This provides an outlet for the farm's own organic materials; generates revenue from off-farm inputs (such as a nearby community's yard waste, which can make an excellent bulking agent for manure); and allows farmers to control the quality of the end-product. And because farmers can sell the finished product, they have another revenue source.

More Regulation, Not Less

Roughly half of the nation's states currently have regulations regarding the organics disposal. But regulations governing landfilling organics vary tremendously. Some states barely regulate composting of yard waste. Other states, using solid waste regulations as a guide, have developed complicated rules.

As the industry learns more about the effects of composting and continues to diversify feedstocks, more regulations likely are coming. In response to the non-attainment of Federal Air Quality standards for particulate matter and ammonia, the South Coast Air Quality Management District (SCAQMD), Diamond Bar, Calif., recently passed regulations for composting operations within its air basin. The SCAQMD oversees California's Los Angeles, Orange, San Bernardino, and Riverside counties.

These regulations will affect the viability of composting within and outside of the SCAQMD basin. Other air authorities in similar non-attainment and dense urban areas could follow suit.

The U.S. Department of Agriculture's (USDA) National Organic Program (NOP) also should affect compost production — at least for producers that wish to sell compost for organic agriculture.

Under the new organics rules, most compost is acceptable. However, many growers look to independent verification agencies such as the Organic Materials Review Institute, Eugene, Ore., for assurance that a given compost is appropriate for food that will be certified “organic.” Information can be found at www.omri.org, which also has a link to the NOP Web site.

Appreciating the Benefits

Compost increasingly is being used in nontraditional applications. For example, results on compost as erosion control are just beginning to be appreciated and documented. Many states now have compost specifications for their transportation departments.

Farmers are expanding compost for use on specific crops or in specific applications, too. For instance, compost is beginning to make in-roads into conventional agriculture versus being restricted to organic agriculture. And compost appears to have promise as part of the solution to agriculture practices that are no longer viable — like using methyl bromide on strawberries to control soil pathogens.

Ohio State University and other research institutions are documenting the disease-resistant properties of some composts.

Home Composting

When it comes to the cost-effective diversion of residential organics, nothing is more cost-effective then home composting. Not everyone is willing to compost his own yard trimmings in the backyard, but many people do.

Because gardening is America's No. 1 pastime, it makes sense that a large segment of the population would be willing — even enthusiastic — about home composting. But home composting often is an under-utilized part of an integrated organics recycling system that would include collection of residential organics.

Nonetheless, some communities have built effective home composting programs and have found that they can increase the quality of participation in curbside yard waste collection programs. Home composting also can help to generate a market for finished compost.

“In these tight budgetary times, we find that our backyard composting program provides a high cost benefit ratio by facilitating quality contact with residents; encouraging greater participation in the curbside programs, increasing the market for finished compost; and promoting collaboration with other funded programs such as water quality education and urban gardening” says Michele Young, residential services manager for the city of San Jose, Calif.

There are numerous home composting bin manufacturers, ample technical information and years of workshop experience for cities looking to implement a home composting program.

Tested Technology

In the past, many of the technological innovations in composting were variations on existing themes. But there are several relatively new composting systems that can take an existing windrow facility to the next level of process control without breaking the bank.

The majority of the existing composting facilities in the country use a relatively straightforward turned windrow production method. This system works well and is appropriate for most feedstocks, provided adequate care is used in siting a facility.

But niches exist for more sophisticated methods of composting with increased process control and biofiltration.

For example, some of the composting systems in today's market are variations on the aerated static pile method and have stripped the process of unnecessary bells and whistles and reduced it to its component parts. Windrow-hybrid techniques to treat the early stages of composting — which often are the most odorous — in a more-controlled system also are being developed.

Every operation needs to evaluate its system needs according to its site-specific constraints and feedstocks. But in an increasingly odor-sensitive world, today's composters may find the right technology can add process control and minimize their facilities' effects on the environment, whereas in the past composters might have been forced to relocate their operations.

Focus on the End-Product

More attention is being paid to the quality of the material that is diverted and produced. Like any recycling project, the effort that goes into collecting and processing the material is wasted if the material can not be marketed.

Early municipal composting programs were content to give the finished compost away for free. But increasingly, compost is marketed as a value-added product with real-world applications.

Recognizing this trend, the US Composting Council, Happauge, N.Y., has developed a Seal of Testing Assurance (STA) program to increase consumer confidence in recycled organic products and to develop national compost standards. The program still is in its infancy, but some state departments of transportation already are requiring “STA Compost.” (See details at www.compostingcouncil.org/STA.)

More than 15 million cubic yards of organic materials are being diverted from California landfills annually, according to the CIWMB. So clearly, the future for compost and diverted organic materials is bright — especially as solid waste managers, recycling coordinators and municipal planners better understand the role that compost can play in a comprehensive waste management program.

Matt Cotton is principal of Integrated Waste Management Consulting, Nevada City, Calif.