BioCycle August 2004, Vol. 45, No. 8, p. 22
Survey results provided by the California Integrated Waste Management Board cover latest developments in the state’s organics infrastructure.

HOW MANY TONS of green material, woody residuals, manure, agricultural by-products, food residuals, biosolids and other organics are utilized annually in California? What percentage is marketed as compost, mulch, boiler fuel or alternative daily cover? What’s the average bulk density – how many cubic yards are in a ton – of those products? California has a rich history of organic materials being used in landscaping, at nurseries and increasingly in agriculture; there has always been a question of how much compost and mulch are used in those market categories.
With the publication of its survey results on the state’s compost and mulch producers, the California Integrated Waste Management Board (CIWMB) provides much data on feedstock sources, products and markets. Information for the organics infrastructure was produced under contract for the Board by Matt Cotton. The following excerpts are from the CIWMB study.
OVERVIEW OF OPERATIONS
Organics materials comprise about 40 percent of California’s waste stream. Diverting a high percentage of these residuals is key to the state achieving and maintaining the diversion goals of AB939 of the state’s Integrated Waste Management Act. In general, California has developed a robust infrastructure to divert and process organics materials into useable products. However, unlike landfills and transfer stations, compost and mulch facilities are not required to report process and production data to the CIWMB.
One hundred seventy facilities were identified as operational (32 facilities declined to participate in the survey itself and thus are not counted in the data summaries). Of the 170 participating facilities, 101 are composters, while 69 are processors. Composters are defined as entities that actively compost organic material (composting implies a defined time and temperature period with the end of controlled decomposition). Processors are entities that process material but do not intentionally or actively compost the materials they produce. In California there is a significant regulatory distinction between composters, who are generally required to have a solid waste facility permit, and processors (often called “chippers” and “grinders”), who, until recently, generally were not required to have one.
To round out the data on use of green waste as alternative daily cover (ADC), information from 58 landfills on ADC use was added to the survey data. Out of the 58, all landfills reporting use of over 20,000 tons of green waste ADC were counted; some landfills use only green waste generated through curbside programs or from the self-haul sector, while other landfills rely heavily on independent contractors to provide all of their ADC.
Composters and processors in California recycle over 8.1 million tons of organics per year. From, this amount, they generate about 18 million cubic yards of products. In 2002, landfills reported over 2.1 million tons of green waste used as ADC – roughly one-quarter of all green waste tonnage processed in California. Composters and processors have seen modest increases in tons of material recycled. The 2003 survey showed that composters produced 5,664,956 cu yds; processors handled 12,755,282 cu yds; the total was 18,420,238 cu yds. (For the nonparticipating facilities, it was estimated that the 16 composters and 16 processors handled 1.7 million tons – bringing total figures to just under 10 million tons [9.8 million total.] Product quantities in the 2003 survey in cubic yards listed these amounts: Compost – 3,011,182; mulch – 2,325,708; boiler fuel 3,872,983; ADC – 8,482,372; beneficial reuse at landfills 258,150; other (i.e, fines, wood chips, bark products) – 469,843. Total amount in cubic yards came to 18,420,238.
Observations on product utilization included these points: California composters and mulch producers continue to access an enviable diversity of markets, with evidently no reliance statewide on a single sector. The majority of facilities still manufacture five or fewer products. Agriculture continues to be the largest single market for compost. Meanwhile, the California Department of Transportation continues to be an untapped market for recovered organics. Few facilities identified CalTrans as a significant user – with one percent or less listed. (In contrast, Texas specified over 400,000 cu yds of compost in 2003 for its Department of Transportation.)
Because of the large volume of food wastes and/or liquid wastes being disposed of, opportunities exists for new and existing facilities to process these types of “nontraditional” feedstocks.
THREE THREATS TO ORGANICS MANAGEMENT
The CIWMB study addressed these three threats to the organic materials management industry in the state:
Sudden Oak Death Syndrome. Initially the 12-county quarantine area might have been devastating to composters, but over time and through a joint effort by involving the CIWMB, the compost industry, university researchers, California Department of Food and Agriculture (CDFA), and the U.S. Department of Agriculture (USDA), composting was recognized as a viable treatment for SODS-contaminated materials. As a result, SODS has not had a significant impact on the green waste composting industry (or the landfill or biomass industries, which were recognized as treatment methods in the early stages of the spread of SODS). The survey documented that significant materials do flow across county boundaries, although the entire pattern is not well understood. In general, urban feedstocks are flowing to less urban areas for processing. While this raises some issues regarding transport of potential problems like Sudden Oak Death Syndrome, it is clear that composting is a suitable treatment method.
South Coast Air Quality Management District Proposed Rule 1133. Although the survey uncovered some interesting attitudes regarding PR 1133, it is too soon to understand the full impact this emerging regulation will have on the green waste composting and processing industry. It would appear that green waste ADC producers will largely be unaffected by this regulation. Biosolids and manure composters will be required to enclose at least a portion of their facilities. Composters of green waste will have to monitor PR 1133 to see what the ultimate outcome will be. One unusual outcome of the PR 1133 questions was the larger-than-expected reliance on odor-neutralizing agents by some composters. More investigation should be made of the methods which both composters and processors use to control odor. A surprising number of both composters (30 percent) and processors (15 percent) reported using odor neutralizers for odor control.
Persistent herbicides. While the data uncovered by the survey was relevant at the time it was collected, more recent analytical testing conducted voluntarily through an industry partnership with the CIWMB has revealed (at least for green waste facilities) that the samples of compost tested for Clopyralid appear to be decreasing. The most recent sample results showed 11 of 15 facilities testing positive for very low levels of Clopyralid, with the highest number being 6.4 parts per billion (ppb). This is most likely the result of a combination of industry outreach and education and statute requirements, which imposed a number of restrictions on the use and distribution of Clopyralid-containing products (PRC sections 13190 13192). This trend appears to be consistent up and down the West Coast (California, Oregon, and Washington). Each of these states has similar restrictions in place.
Under a section titled, “Areas for further study,” it was noted that CIWMB needs to study the effect that green waste ADC is having on the compost industry. There is the issue that the use of waste derived ADC constitutes diversion through recycling. Specifics include beneficial impact offered by the composting industry in terms of economic development, economic viability and employment opportunities.
As noted, the survey documented that agriculture is the largest single market for compost, so more work needs to be conducted to understand which segments of the agriculture industry are buying compost and why. Some questions to be addressed are: “Are there certain crops that use compost more than others?” “Is organic agriculture using more compost than conventional agriculture?” “What effects do various commodity prices have on compost sales?”
FEEDSTOCKS MANAGED
Composters and processors receive a wide array of feedstocks in California. Seventy-nine percent of facilities surveyed process green material; fifty-four percent process wood waste; 23 percent manure; 22 percent agricultural by-products; 10 percent food scraps; 9 percent biosolids; and 7 percent other materials such as stable bedding, sawdust, shavings and fish sludge.
Both composters and processors handle green material and wood waste (the bulk of materials processed). For obvious reasons, processors do not typically handle putrescible materials, such as food scraps, liquid wastes or biosolids. Processors are also more likely to process construction and demolition materials (typically for the clean wood available in the construction waste stream). Aside from these exceptions, there are no other appreciable differences in materials handled by processors or composters statewide.
Most facilities process more than one feedstock, with 80 percent reporting at least three feedstock categories. Composters tend to handle a slightly wider variety of feedstocks than processors. Only 32 percent of processors handle more than two feedstocks, while 47 percent of composters handle three or more diverse feedstocks.
Although the primary focus of this project was municipally generated feedstocks (materials diverted from landfills), the organics processing industry straddles many sources of potential feedstocks. These include municipal (franchise) contracts, commercial contracts, self-haul, materials recovery facility (MRF)-generated, in-house city sources, agricultural sources, wastewater treatment plants, and self-generated feedstocks. The survey showed that self-haul feedstock constitutes 21 percent of the total, municipal 13 percent, and commercial 49 percent.
The largest concentration of both processors (24 percent) and composters (27 percent), reported 50 tons per day or less for processing capacity. A much smaller percentage (12 percent of composters and 27 percent of processors) reported processing capacity in excess of 500 tons per day. Facilities were equally distributed in between these two extremes: 19 percent of composters and 14 percent of processors reported 50 to 100 tons per day; 15 percent of composters and 10 percent of processors reported 100 to 200 tons per day; 11 percent of composters and 10 percent of processors reported 200 to 300 tons per day; 4 percent of composters and 6 percent of processors reported 300 to 400 tons per day; and 11 percent of composters and 8 percent of processors reported 400 to 500 tons per day.
The processing capacity distribution reflects the breadth of facilities covered by this study and the diversity of facilities operating in California, from very small municipal projects, primarily focused on diversion, to large-scale commercial facilities receiving a wide range of feedstocks and producing a wide range of products. Processors are twice as likely to be very large (over 500 tons per day processed than composters).
Additional research is needed to understand how processing capacity relates to feedstock generation and transportation needs. Survey results may give an impression of substantial organics processing capacity, but without relating this information to the amount of organics waste generated and other geographical factors, it is impossible to gauge the overall need for processing capacity in California. The overall trend in 2003 is for fewer facilities to be processing more tonnage
MATERIAL BULK DENSITY
The 2003 survey included a question on product volume by asking respondents to report material bulk density. This information was requested as a way to convert responses given in cubic yards to tons and vice versa. Answers for the same commodities varied widely. The average bulk densities for the four major products are shown in Table 2.
The range of bulk densities in each material type reflects not only regional processing and handling methods, but also the diversity of feedstocks within a given commodity. For example, a compost made from yard waste exclusively will have a lower bulk density than a compost made with biosolids. The very high end of the range (8 yards per ton) in the biomass fuel category probably reflects those facilities which screen processed material to remove the “fines” (the undersized pieces of organic material which falls through the trommel screen). Fines from these types of operations are often used for purposes such as soil amendments. The ADC category may also be experiencing this phenomenon, as some facilities screen the processed material, sending the overs to ADC. There were fewer responses to the ADC category, perhaps because in many cases there is no incentive to track the material too carefully. Also, in some cases, ADC is not processed through a grinder prior to placement and is compacted after placement, so the bulk density varies depending on the stage of the process. Moisture content also varies widely and can have a significant effect on bulk density.
GEOGRAPHICAL DISTRIBUTION
Organic materials processing and composting is a regional rather than statewide business. Although many processing and composting facilities typically accept feedstock primarily from within the county in which they are located, increasingly feedstock goes out of the county to be processed. This is especially true for more urbanized counties, which often set up transfer points to move material to less densely populated areas where the siting and operation of facilities are easier. Siting composting and processing facilities in less urban areas is easier due to lower population density, proximity to markets, and lower costs for land and water.
The number of facilities per region varies significantly by region (with the Southern Region having the most and the Northern Region the least), but the relationship of processors to composters is fairly similar in each region, with the exception of the Central Valley Region, which has significantly more composters than processors. The only region which has more processors then composters is the Southern Region. This is undoubtedly due to the fact that it is significantly harder (due to population density and urbanization) to site a compost facility in the Southern Region. New South Coast Air Quality Management District (SCAQMD) regulations in the Southern Region are making it even more difficult. The trend of feedstocks from the Southern Region making their way to the Central Valley continues to increase.
Changes in participating facilities include slightly more processors in the Southern, Central Coast, Bay Area and Northern regions and fewer in the Central Valley Region. The overall trend is for slightly fewer composters participating in 2003 (particularly in the Southern, Bay Area, and Northern regions) and slightly more in the Central Valley and Central Coast regions.
In general, there is a gross relationship between population and/or MSW tons disposed of and the number of facilities in a given region. However, some counties ship material out of county, which can skew these figures significantly. Also, the number of facilities is meaningless without some idea of the size of those facilities. Two of the largest composting facilities are located in the Central Valley Region, but most of their feedstock comes from the Southern Region.
NUMBER OF PRODUCTS
The vast majority of processors (79 percent) and composters (77 percent) make one to five products, with few facilities reporting they produce more than five products. This trend is consistent for both processors and composters, with composters having slightly more respondents reporting five or more products, though some reported in excess of 15 separate products. No processors reported 15 or more products; in fact only 2 reported producing 10 to 15.
California processors and composters are well diversified within the existing organics markets. In addition to compost, most composters produce some mulch and some boiler fuel and some access the ADC market (typically overs from screening operations or contaminated material). Many processors access both the boiler fuel and mulch markets, but also produce ADC and other products, such as compost feedstock, directly land-applied material, or feedstock for manufactured wood. Composters rely much less on boiler fuel and ADC markets than do processors.
PRODUCT DISTRIBUTION
Compost is clearly the most dominant product for composters, though in a given region like the Bay Area, the boiler fuel market may be equally important. Composters in the Northern Region produce 75 percent boiler fuel, 18 percent compost, and 7 percent mulch. No Northern Region composters reported making ADC.
Composters in the Bay Area Region produce almost as much boiler fuel as compost. This may be due as much to the easy access to operating boiler fuel plants and availability of wood waste feedstocks as to the relative difficulty of siting large compost facilities (smaller facilities can process larger volumes of boiler fuel, which does not need the space that composting requires) in the Bay Area. A number of transfer stations in the Bay Area reported producing “compost feedstock” which is sent out of the region to the Central Valley.
Composters in the Bay Area also produce 27 percent ADC, 11 percent mulch, with 4 percent other products (primarily compost feedstock and land applied materials) and 1 percent beneficial reuse at landfills.
In the Central Valley Region, a significant 66 percent of material processed by composters is sold as compost in this region. This is followed by mulch at 28 percent. Clearly boiler fuel, at 6 percent, is not as significant a market in the Central Valley Region as it is in other regions. This may not be true for specific facilities or in specific counties. No composters in the Central Valley Region reported producing ADC.
The Central Coast Region is somewhat similar to the Central Valley Region as far as products made by composters. Surprisingly, 89 percent of materials processed by composters end up as compost in this region, with 4 percent other, 3 percent each mulch and biomass fuel, and 1 percent ADC.
Among composters in the Southern Region, compost makes up 41 percent of the products produced; ADC, 31 percent; mulch and biomass fuel, 12 percent each; and other products, 4 percent. As with the Bay Area Region, the data indicate relatively easy access to a variety of markets. Also, as in the Bay Area Region, a significant quantity of feedstock in the Southern Region travels to other regions, primarily the Central Valley Region but also the Central Coast Region, to be processed.
SERVICES PROVIDED
Many facilities provide multiple specialized services, such as blending, spreading, or bagging, while a surprising number (24 percent of composters and 49 percent of processors) provide no additional services. Survey responses regarding specialized services reveal California’s organics processing industry contains a mix of sophisticated, established companies offering multiple products and services and also very new players providing products on a more basic level. Composters are almost twice as likely as processors to report product knowledge as an additional service.
Composters provide more services than processors, though a large percentage (34 percent) still provide no or only one additional service beyond compost production. The most popular service is delivery (reported by 63 percent), followed in descending order by testing/product analysis (53 percent) which is interesting, since all composters are required to conduct, at a minimum, pathogen reduction and metals testing, and most do some more traditional composition analysis. Blending of compost (with other organic materials like topsoil, sand, or fertilizer was reported by 48 percent followed by 46 percent reporting product knowledge as an additional service. Spreading and bagging trailed other services with 20 percent and 19 percent respectively. A few facilities reported loading as an additional service.
Processors reported even fewer additional services provided, with the largest percentage (49 percent) reporting no additional services. Forty-four percent reported delivery as an additional service, followed by product knowledge (29 percent); blending and testing/analysis (16 percent each), bagging (13 percent), and spreading (9 percent).
ODOR CONTROL METHODS
The survey question on odor control methods was designed to understand how composters and processors within the South Coast Air Quality Management District (includes Los Angeles, Orange and Riverside counties) manage odors at their facilities. The survey allowed participants to select one or more of six odor control methods. Among the composters, the most popular was feedstock management (80 percent), followed by turning and moisture control (70 percent each). Odor-masking neutralizing agents (30 percent), biofilters, and aeration using methods other than turning was 20 percent or less. An interesting aspect of the data is use by both composters (30 percent) and processors (15 percent) of odor-neutralizing agents. Another interesting statistic was the relatively high use by processors of moisture control for odor reduction often in the form of using water for dust control.
FUTURE PRIORITIES
“Reduce Regulatory Burden” was ranked number one overall by composters and processors when CIWMB asked survey participants to rank priorities related to organics materials handling. (This may have had much to do with the timing of the survey which coincided with a major change in CIWMB regulatory policy.) Although this new change will affect both composters and processors, it will have the greatest impact on processors, some of whom were previously essentially unregulated. In addition, new C&D regulations may also affect some processors.
Coming in a close second in priority was “Expand Markets.” This concept was ranked number one among composters. There may be many reasons for this. All markets for organics materials fluctuate, but the past two years have provided a number of additional challenges for organics processors and composters alike. A number of specific challenges like Sudden Oak Death Syndrome and Clopyralid and other feedstock specific challenges have primarily affected composters. Heavy rains in early 2003 may have also dampened sales in some parts of California. Although not well documented, the value of some agricultural commodities also affects users ability to purchase and apply compost. Many commodities (especially grapes) had bad years in 2003. Similarly, the general economy affects the ability of the green industry (for example, nurseries, landscapers, and horticulturists) to use compost. California’s economic crisis in 2002 and 2003 may have hurt compost sales.
“Expand Markets” was the number two priority among processors. As with composters, there are numerous reasons for this. The biomass plants upon which many processors rely were unreliable and fluctuated significantly in 2002, particularly for those processors without contracts (who sell wood fuel on the “spot” market). California’s energy crisis also contributed to uncertainty in the biomass markets.
“Develop Standard Specifications” was ranked third by composters, somewhat lower by processors. There were no specific comments on “Develop Standard Specifications.”
Among composters, a changed ADC policy ranked fourth, and fifth among processors. The lower ranking among processors is probably due to the fact that more processors produce ADC then composters (though some composters also produce ADC). It also reflects a lack of consensus on ADC policy. Although some composters are opposed to the practice, many composters rely on ADC markets for their overs. Most (if not all) landfill operators are in support of the current ADC policy.
Interestingly, “Financial Assistance” ranked lowest overall of all the priorities. However, processors ranked this option third, while composters ranked it fifth. – J.G.
Additional details on the study, “Second Assessment of California’s Compost- and Mulch-Producing Infrastructure,” published by the California Integrated Waste Management Board (CIWMB), may be obtained from the Organic Materials Management Section of the CIWMB. Visit the website www.ciwmb.ca.gov/organics or e-mail ktaylor@ciwmb.ca.gov.