BioCycle Magazine

Food Residuals Composting in the U.S.


Courtesy of Courtesy of BioCycle Magazine

For many years, the public sector has been at the forefront of the developing composting industry. For example, when biosolids composting first got started, it was the sanitation departments of municipalities and local sanitary authorities pushing projects. With yard trimmings composting, municipalities and counties were the primary entities developing programs. Even the fledgling steps of solid waste composting were the result of hand holding by public agencies. Food residuals composting, however, breaks the mold. As this sector of the composting field evolves, it’s the private sector pushing its development.

The fact that food residuals composting is in the domain of the private sector shouldn’t really come as a surprise. After all, the private sector is the primary source of those feedstocks, just as the public sector is the primary source of biosolids and yard trimmings. It makes sense that the people with the need for alternative disposal options are the ones who find the appropriate solution. Furthermore, most waste streams from industry don’t fall under the public sector’s purview. When a public agency gets involved, often it does so to help a local industry.

While food residuals composting has experienced growth over the five years that BioCycle has been conducting this survey, it hasn’t been dramatic. That is due in part to the cautious nature of regulators, who often are required to approve the addition of a new feedstock to a permitted composting project. But it is also due to the economic conditions surrounding the solid waste field in general. With tipping fees at competing sites (landfills and incinerators) largely flat over the past five years, the incentive for generators to seek out alternatives is minimized. A number of project managers responding to the survey talked about the difficulty of signing up customers for composting service.
Because of these reasons, and perhaps because of their own cautiousness, many composters surveyed in 1999 have been slow to incorporate food residuals into their existing operations. As a result, food residuals composting is tracking more sideways than shooting upward.

Still, the frontier continues to be pushed forward. In the last year, several significant projects have opened. Rivanna (Virginia) Solid Waste Authority recently opened a 50 tons/day (tpd) capacity facility that utilizes the Ag-Bag technology. In New York, Capital Compost started up a 10,000 tons/year (tpy) project that uses two 25 tpd units from Wright Environmental Systems. The largest project (an estimated 67,000 tpy) to begin operating this year is Land Recovery Inc.’s new “Compost Factory” facility in Puyallup, Washington.

The 1999 Survey
The 1999 Food Residuals Composting survey took a slight twist from the previous ones that BioCycle has conducted. This year’s survey excludes institutional projects — which in last year’s survey numbered 116 — that only handle residuals generated on-site. Instead, we focused on projects that handle food residuals from a combination of institutional/commercial/industrial (ICI) sources — or commercial only — and those handling food processing residuals (FPR) from only industrial generators. A significant difference between the projects tracked in this report and on-site institutional ones is scale. Typically, the on-site projects have throughputs of five to 100 tpy. Those tallied in this report can easily reach (not that they all do) upwards of 100,000 tpy. In addition, there are differences relating to collection, materials handling and end product use, which led to our rationale for separating on-site institutional only from ICI and FPR projects. BioCycle will continue tracking the institutional composting sector, which is probably exhibiting the fastest growth in the food residuals arena.

BioCycle tallied a total of 118 food residual projects throughout the United States. Of those, 95 are full-scale facilities, and nine are pilot projects, primarily at existing composting sites. Another 14 projects are in various stages of development.

Geographically, there is a very sharp division in the distribution of food residuals composting projects, with the Northeast and West Coast containing the majority of the facilities. In total, 55 of the 95 full-scale projects are in the New England and Mid-Atlantic states. Another 13 full-scale projects are on the West Coast. That leaves only 27 facilities in the entire rest of the country.

in analyzing the data from the survey, we looked at both operational and financial aspects of the projects. Operationally, the type of compost process and equipment used was reviewed, as well as facility throughput. On the financial side, revenue from tipping fees was explored. Additionally, we looked at what type of markets the projects relied on and what prices they have been able to obtain.

In all, completed questionnaires were received from 35 full-scale ICI projects and 18 FPR projects. Additionally, four pilot ICI projects and four ICI projects that are being developed completed surveys. One other FPR project in development responded. This information was supplemented with data from state and local agencies and other sources.

The Ici Profile

As discussed in the introduction, the private sector clearly dominates the public sector when it comes to developing ICI composting projects. Of the 43 operators completing the survey questionnaire, 35 are private initiatives. In many cases, however, the public sector has had a hand in project development. Massachusetts and Minnesota, among other states, have taken an active role in encouraging food residuals composting. At the local level, government agencies are often the catalyst needed to stimulate projects, marrying generators with private concerns interested in composting. For example, several Natural Resource Conservation Districts in Vermont, including Caledonia and Lamoille counties, coordinate projects that bring commercial and industrial food residuals to local farms for composting.

Although most of the ICI projects are of recent origin (at least 15 started within the past five years), there are several veterans in the group. The Woodhue site in Wrightstown, New Jersey dates back to 1984, while American Soils in Freehold, New Jersey initiated its project in 1988. Table 1 provides a complete list of facilities taking ICI residuals. It indicates what combinations of the ICI stream are being processed.

Project Operations

Composting Method: While any number of processes will transform food residuals into compost, there is a distinct preference for the traditional windrow method among the operations surveyed. Of the full-scale operations, more than half (24 of 43) utilize the windrow method. (Six of the 24 use aerated windrows, which combines forced aeration with windrow turning.) Half of the pilot projects and those in development are using or plan to use windrows.

Composting processes used by the remaining projects are: static piles (4); aerated static piles (3); and in-vessel (3 — two NaturTech and one Wright Environmental). The only vermicomposting operation taking ICI feedstocks that filled out a questionnaire is the JWH Industries facility in Trio, South Carolina, which handles approximately 800 tpy of food residuals. Three of the projects in development will employ in-vessel technologies.

Throughput and Feedstocks: For the most part, ICI residuals are not the dominant feedstock at the projects cited in this report. In all, 14 of 23 projects had food residual throughputs of less than 1,000 tpy. On a percentage basis, a little more than half (17) of the 31 sites providing this data had food residual throughputs of ten percent or less; 12 were five percent or less.

Community Recycling in Sun Valley, California had the greatest throughput, estimating it accepted almost 90,000 tons of food residuals in 1998. Total throughput at that plant — which services more than 1,000 grocery stores, produce terminals and other ICI generators — is 350,000 tpy. By comparison, another large-scale facility in the Seattle area received 165,000 tpy of material, of which only two percent is ICI feedstock. In both cases, yard trimmings make up the bulk of the remaining material composted.

On the whole, the private projects have greater throughputs than the public facilities. Of the six publicly owned operations reporting, none have total throughputs in excess of 10,000 tpy. Of the private sector facilities reporting throughputs, eight of 22 receive more than 20,000 tpy and another six have throughputs above 10,000 tpy.
What constitutes the remainder of the incoming material varies from facility to facility. The most common, however, is yard trimmings, reported by 31 facility operators. Other popular feedstocks include manure (reported by 22 facilities), wood (16) and sawdust (14).

Equipment: A variety of equipment is used at the composting sites surveyed. Twenty-four of the 43 full-scale ICI facilities have grinding systems. As expected, given the predominance of windrow systems, 19 facilities have turners. In terms of postprocessing, 29 of the 43 full-scale facilities utilize screens to finish off the compost prior to marketing.

Pads: Although the construction of all-weather pads enables composters to operate year-round, only 14 of the 43 sites reporting have one. It’s interesting to note that two-thirds of the operations owned by public agencies compost on pads, while only about a third of the private facilities do. That number may be low because many of the ICI projects are relatively low throughput operations at farms. Of those facilities specifying pad type (12), half were built with asphalt and a quarter were made from concrete. Clay was used at two other sites and gravel at another. Only three projects compost under roof.

Postprocessing: Besides screening to enhance the finished product, facilities are using other methods to improve compost marketability. A total of 17 sites make soil blends with the compost. And five facilities have bagging capabilities, so that they are better able to sell through retail outlets such as garden centers and department stores.

Of Markets and Money

Of the 43 full-scale projects reporting tipping fees, only one (a public facility) did not charge to drop off food residuals. The fees at the sites ranged from $10 to $62/ton, with most in the range of $25 to $35/ton. At the 20 private facilities providing tipping fees, nine charged $20/ton or less, five were between $20 and $30/ton, and six exceeded $30/ton. Of the five public sites with a tipping fee, four charged between $20 and $30/ton. One site’s fee was $10/ton.

According to our survey data, the highest value markets for compost vary among operators. About half (15 of 32), however, noted that they get the best price from the landscape industry. The retail market was mentioned by seven operators, followed by agriculture (5), nurseries (3) and soil blenders (1).

In terms of the markets which represent the bulk of sales, a slightly different picture emerges. The landscaping industry is still the leader, but it is not nearly as dominant. Eight operators note landscapers are their principal market, followed closely by retail sales (7), and soil blenders and agriculture (4 each).

The wholesale prices of compost start at $4/cubic yard (cy). Retail prices range from $10 to $54/cy. Overall, of the 19 facilities reporting wholesale prices, five were $10/cy or less, another five were from $10 to $15/cy, four went from $15 to $20/cy, and four exceeded $20/cy. On the retail side, only one facility reported selling compost for $10/cy; six operators charged between $10 and $15/cy, and two between $15 and $20/cy. Eight charge more than $20/cy, with two exceeding $40/cy.

Food Processing Residual Composting

The second category of composting facilities surveyed were those taking residuals from industrial-scale food processors. Table 2 provides a list of the FPR operations. There are several important distinctions between these facilities and the operators that handle ICI materials. First, as a category, these projects have a much longer operating history than do the ICI facilities, with some going well back to the early 1980s. One project — Vital Earth of Gladewater, Texas — has been functioning since 1972.

Second, in some cases, the sites handling industrial food processing residuals are “captive facilities,” such as Anheuser-Busch’s Baldwinsville, New York plant, which exclusively processes material from that brewery. In other instances, a third-party composter only deals with a single generator. There are a number of such projects in Maine, where a composter is taking seafood residuals from one processor. With ICI facilities, the material almost always comes from a variety of sources.

As with the ICI projects, the FPR composting field is dominated by the private sector. Of the 19 full-scale sites, 15 are privately owned and operated; only four are publicly managed.

Operating Parameters

Composting Method: Composting at FPR facilities is almost exclusively done in windrows. Of the 15 privately run operations, 13 use some form of windrowing (eight straight windrows and five aerated windrows). Of the remaining two, one composts in aerated static piles and has in-vessel equipment. Three of four publicly managed sites use windrowing (one is an aerated windrow system). The fourth uses an in-vessel system.

Throughput and Feedstocks: Overall, total throughput at the FPR facilities is significantly lower than the sites taking ICI material. Half (seven of 14) of the private operations reporting receive 10,000 tpy or less. Only six exceed 20,000 tons, and none composted more than 50,000 tpy. Comparatively, 14 of 22 private ICI facilities composted 10,000 tpy or more, and six had throughputs of better than 50,000 tpy. Three of the four public facilities that compost FPR handle 5,000 tpy or less. The other public facility, Bluestem Solid Waste Agency in Iowa, has a total throughput of 110,000 tpy.

The amount of FPR composted at most of these sites is modest. Of the 16 facilities providing this data, ten estimated FPR throughputs of 1,000 tpy or less. Four others took between 1,000 and 5,000 tpy. One facility, Mass Natural Fertilizer Co., received between 5,000 and 10,000 tpy. The site taking the greatest amount of FPR is New Milford Farms in Connecticut, which receives in excess of 20,000 tpy.

In general, the proportion of food residuals comprising total throughput at FPR composting sites is greater than at ICI facilities. Better than half of the reporting ICI sites composted 10 percent or less food residuals. The throughput at more than two-thirds of the FPR facilities (12 of 17) was in excess of 10 percent food residuals. And half of those topped 25 percent food residuals.

The other types of materials composted at the FPR facilities aren’t nearly as heavily weighted toward yard trimmings. Ten private operations report that manure is the most common amendment used, followed closely by sawdust (eight facilities). Yard trimmings are composted at seven sites, wood at four, and papermill sludge at three. All four of the public sector sites also compost yard trimmings and three include wood in the mix.

Equipment: Nine of the 15 private sites utilize size reduction equipment prior to composting; three of four public sites have grinding systems. Every private site but one that composts in windrows uses a turner. Of the three public windrow sites, one uses a turner.

Pads: The use of compost pads is prevalent at FPR facilities. Of the 19 full-scale sites reporting, 12 compost on an improved pad. All four public facilities use pads, while only eight of 15 private sites do. Of the 11 sites identifying the type of pad used, four were gravel, three were asphalt, three were concrete and one was clay.

Postprocessing: Improving the quality of the compost produced appears to be a high priority at the FPR facilities. All but five have screening plants to finish the compost. Ten, all private, make soil blends on site. Seven have bagging capability.

Tip Fees and Markets

Tipping fees are very much a part of the revenue stream at the FPR composting sites. Eleven of 12 private operations reporting this data charge tipping fees, which ranged from $6 to $25/cy. Three of four public sites have tipping fees, ranging from $15 to $35/ton. All but two facilities reported tipping fees of $10 to $30/ton.

The markets for FPR-based compost are fairly well distributed. Six facility operators report that landscapers generate the highest per unit price. Nurseries and the general agricultural market were reported by three operators, as was the wholesale market. Soil blenders and retail sales were the highest value markets for two facilities.

Five facilities stated that landscapers are the largest volume purchasers of the compost. Three sites ranked agriculture and wholesale markets as the largest purchasers, while the nursery and retail market were each mentioned by one operator.

Wholesale prices paid for compost ranged from $6 to $40/cy, while retail prices went from a low of $12/cy to a high of $40. Two operators reported wholesale prices of less than $10/cy, seven were between $10 and $20/cy and four had prices above $20. On the retail side, three sell compost for between $10 and $20/cy, one is between $20 and $30/cy and four have retail prices that exceed $30/ton.

Into the Future

The ability to process and market compost containing food residuals has clearly been demonstrated by both public and private entities over the past five years. It now remains to be seen whether food residuals composting will continue to develop slowly as it has over that same period, or if it will take off just as yard trimmings composting did in the late 1980s.
For now, given the lack of any outside stimulus such as dramatic increases in disposal fees or bans on disposal, it’s likely to be more like a jogger’s gait than a sprinter’s. By Jim Glenn and Nora Goldstein


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