BioCycle Magazine

California agencies partner to increase compost use on roadsides

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Courtesy of Courtesy of BioCycle Magazine

THE California Department of Transportation (Caltrans) has enormous potential to increase compost use on highway roadsides throughout California. Caltrans manages more than 230,000 acres of roadside and maintains approximately 25,000 acres of landscaping annually. In the last three years, Caltrans has increased its purchase of compost and mulch products fivefold — from 13,700 cubic yards in 2004 to more than 70,000 cubic yards in 2006.
To help ensure that this positive trend not only continues, but accelerates, the California Integrated Waste Management Board (CIWMB) entered into an interagency agreement with the University of California Riverside (UCR) Extension in 2005 to identify and address the barriers preventing Caltrans from increasing its procurement of compost. The project involved a partnership between State agencies, academia, compost trade organizations, laboratories and erosion control companies. These included CIWMB, UCR Extension, Caltrans, the Association of Compost Producers, U.S. Composting Council, UC Cooperative Extension, Filtrexx International and Soil Control Laboratories. These diverse groups worked together to develop a new set of compost specifications, began development of a compost use index, held informative workshops and are creating a compost use manual.

According to the CIWMB’s 2004 Statewide Waste Characterization Study, 12 million tons of compostable materials were landfilled in California during 2003. This represents a significant loss of resources that could be used in a much more beneficial manner, instead of taking up landfill space.
Since the 1940s, Caltrans has revegetated soil areas disturbed by highway construction activities. This work typically involved a surface application of seed and/or straw materials to help prevent storm water pollution and control erosion. Recent research by Caltrans has indicated that successful establishment of permanent vegetation in disturbed soils is greatly enhanced through the use of moderate amounts of compost in the revegetation work. The research clearly demonstrated the contribution of compost to vegetation establishment, erosion control and storm water pollution prevention.
Cost, however, has been a major roadblock to Caltrans increasing its use of compost. The average cost to Caltrans for the last three years for applied compost has exceeded $300/cubic yard. A number of factors contribute to this high cost, but the most significant is application technique. Caltrans contractors typically apply compost, together with seed, water and fiber, through a 3/8-inch-diameter nozzle pressurized by a hydroseeding truck. While hydroseeding can efficiently apply compost up to a 1/64-inch-thick layer, applying larger volumes cost effectively requires revised application techniques and consequently new erosion control specifications. One method tested compost application using a snow blower attachment. The demonstration was a success, applying compost evenly on the slope and at a much more rapid rate than a hydroseed blower truck.

Considering that other state Departments of Transportation and researchers typically recommend compost applications ranging from 1- to 3- inches deep, Caltrans had to develop specifications (Erosion Control Compost Blanket) that facilitated new application techniques. The agency also revised existing specifications (Erosion Control Type C, Type D, and Drill Seed) to allow the use of bulk as well as bagged compost products. New specifications still under development include Incorporate Compost, Biostrip, Bioswale and Compost Filter Sock. Contractors have advised Caltrans that allowing bulk compost products should bring the average unit price for compost down from $300/cubic yard to $30–$40/cubic yard. This will allow Caltrans to apply up to ten times more compost for the same total price.
Specifying bulk compost materials helped bring down unit costs but raised another issue — quality control. Bagged compost materials used by Caltrans historically have maintained a consistent level of quality. Moving to allow bulk materials required the agency to identify and incorporate a consistent method of ensuring materials that would promote plant establishment, and protect water quality and public health.
Previous Caltrans specifications tested only for compost maturity. Compost was tested in the field — a difficult location to get consistently accurate test results. Based upon input from the project team, the new Caltrans specifications require that compost producers be certified under the USCC Seal of Testing Assurance (STA) program. The STA program requires that its members’ products be tested by STA certified labs on a regular basis according to industry standard test methodologies.
When a contractor provides Caltrans with compost for a project, the resident engineer is given the test results together with a certificate of compliance that document the quality of the product provided. Whereas the old specifications only tested for compost maturity, this new method, based upon the STA program, tests for pH, soluble salts, moisture content, organic matter content, maturity, stability, phytotoxicity, particle size, pathogens and physical contaminants. Opening the specifications up to allow for bulk material will lead to increased utilization of compost, lower compost prices and greater assurance of public health and safety. Other benefits include healthy roadside vegetation and improved storm water pollution prevention.

Education was identified as one of the barriers to increasing Caltrans’ use of compost. The education component of the project primarily targeted Caltrans staff and its contractors. Other parties included storm water regulators, local public works departments, compost facility operators and erosion control specialists. Workshops were held from August–October 2006 in five Caltrans district offices located in Los Angeles, San Diego, Oakland, Fresno and Sacramento. The workshops introduced the new specifications to district engineers, landscape architects, biologists, and storm water coordinators.
The workshops provided participants with the opportunity to listen to, and interact with, a diverse team of experts. Speakers included Ron Alexander (R. Alexander Associates) and Matt Cotton, USCC; Greg Balzer, Caltrans Headquarters; Dan Noble, Association of Compost Producers; Janet Hartin, UC Cooperative Extension; Larry Beran, Agricultural Coalition on the Environment, representing the Texas Department of Transportation; David Crohn, UCR Cooperative Extension; Britt Faucette, Filtrexx International; Monica Finn, Caltrans District 3 Landscape; Hilary Gans, Allied/BFI; Brent Hallock, Cal Poly San Luis Obispo; Mark Maurer and Sandy Salisbury, Washington State Department of Transportation; and Steve Nawrath, Caltrans.
A manual titled “Compost Use for Landscape and Environmental Enhancement” will soon be available for Caltrans, its contractors and other parties. The manual will contain information on soils, composts and composting, compost uses and specifications, and landscape plant establishment. Contributors to the manual include UC Cooperative Extension, Caltrans, CIWMB, and ACP. CIWMB plans to publish the manual by June 2007.

The new Caltrans compost specifications are the result of work that began with development of the ACP Compost Use Index (CUI). The CUI consists of the Compost Product Index (CPI), Best Use Manifest and Use Index. The CUI helps users quickly identify products that will meet their particular needs and eliminate inappropriate use. The CPI consists of the most important physical, chemical and biological properties of the compost needed to determine the appropriate use. These properties are represented by 12 test parameters of compost broken into six categories from low to high values and indexed.
Caltrans tracks its compost procurement as a result of CIWMB requirements (the State Agency Buy Recycled Campaign), as well as for internal reasons. According to the Caltrans Construction Database, Caltrans used about 18,000 cubic yards of compost in 2005 and 20,000 cubic yards in 2006.
Remaining challenges include improving the accuracy of compost procurement measurement, approval of specifications for filter socks and filter berms, ensuring continued support for outreach activities, and achieving increased compost use despite fluctuations in the Caltrans budget. Next steps include publication of the Compost Use for Landscape and Environmental Enhancement manual, case study development, approval of additional compost specifications, and additional workshops. Four workshops are planned for Summer/Fall 2007, to be held in San Bernardino, San Luis Obispo, Lake Tahoe and Redding. In addition, outreach efforts will be developed that focus on local government agencies that use compost for roadside applications, such as public works departments.

Brian Larimore is with the California Integrated Waste Management Board’s Organics Materials Management Section that is involved in developing California’s compost markets. For more information on Organics Materials Management, go to Greg Balzer is a Senior Landscape Architect with the California Department of Transportation (Caltrans) and is involved in developing landscape standards, manuals, and policy and procedures. For more information on Landscape Standard Specifications and Plans, go to Both Brian Larimore and Greg Balzer are speaking at the BioCycle West Coast Conference, April 16-18, 2007 in San Diego.


THE California Integrated Waste Management Board is proud to sponsor the 2007 BioCycle West Coast Conference: Composting, Organics Recycling and Renewable Energy — Sustainability In Action. We are pleased to provide presentations on a number of CIWMB initiatives, including an overview of California’s new greenhouse gas reduction legislation, research on how to mitigate emissions from green waste composting operations, a partnership between CIWMB and Caltrans to develop compost specifications, sustainable landscapes initiatives, and the development of a conversion technologies infrastructure in California. Thank you for helping us create a sustainable environment for all.

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