The Current State of Composting and Alternative Technologies
Robert Rynk
Concerns about water and air quality, odors and neighbors as well as the need for alternatives to fossil fuels and improved farm economics are creating opportunities for improved and new technologies for managing manure and other farm residuals. Although compost basics have not changed in the past 30 years, management practices to optimize the process have been introduced as the market for compost continues to grow. Ongoing challenges in composting include maintaining good neighbor relations, reducing odors and addressing air quality issues. In addition, there is a need for research data on the environmental impact and economic feasibility of composting. However, compost has a positive image and new niches for its use are being developed, including remediation of lead contaminated soils and manufactured top soils. In addition, there is a growing interest in additional feedstocks such as animal mortalities, food residuals and compostable paper. In addition to composting, anaerobic digestion, gasification, and alcohol fuels are growing industries that offer opportunities to turn waste products into resources.
The PowerPoint presentation can be accessed online via the link at www.oardc.ohio-state.edu/ocamm.
Discussion:
Brian McSpadden Gardner (OSU) asked if the environmental apathy Rynk noted as a challenge to the composting industry is a reflection of the downturn in the economy. Rynk responded that his personal observations indicate the apathy appears to be a lack of interest and an increase in cynicism resulting in fewer concerns for the environment. However, there is still strong student interest in environmental issues.
Maurice Watson (OSU) noted his involvement with the US Composting Council’s (USCC) Standards and Practices Committee in developing guidelines and specifications for compost use. There are concerns that the guidelines could be used to restrict use and/or increase regulation of the industry. Rynk noted that the specs must be tailored to a particular use increasing the complexity of the task. For example, compost used along new highways require larger particle sizes which tend to be wood. However, wood is not good for agronomic uses because it ties up nitrogen.
Currently, the USCC has implemented the STA (Seal of Testing Assurance) which ensures testing procedures and ingredients. The next step will be to develop some general guidelines for broad classes of use based on maturity.
Fred Michel (OSU) noted that a survey of Ohio dairies indicate that about 7% use composting as part of their manure management and asked if there are any changes in this practice. Rynk responded that, based on personal observation, farms appear to be the only area that composting seems to be growing. The growth is primarily the result of environmental pressures.
Ted Short (OSU) asked if there has been a change in the number of subscribers to BioCycle (a journal for composting and recycling) over the past several years. Rynk said there’s been a slight decrease recently, but overall subscriptions have been relatively consistent over the past 8 years.
Short asked whether other technologies, such as anaerobic digestion, are increasing in popularity due to increased press coverage. Rynk noted that BioCycle is providing more information on bioenergy (approximately 1/3 of the coverage) because the composting industry is relatively stagnant. While the change has not affected the number of readers, the bioenergy conferences hosted by BioCycle attracts a very different, though similar size, audience than those that focus on composting. (For information on the upcoming conference, Renewable Energy from Organics Recycling, see http://www.jgpress.com/conferences1/conferences1.html
Peter Ling (OSU) asked if more data are needed to document odors during composting. Rynk responded that there is a need for basic and field research to document the cause and distribution of odors. However, accurately measuring odors is very difficult.
Ling asked if the lack of economic and other data reflects the stagnancy of the industry. Rynk suggested that it in part reflects a lack of effort to collect the data, but the complexity due to high variability of biological systems also hampers research.
Watson noted that application of manure or compost to soil is affected by variations in soil temperature, moisture and type. Rynk cited a study that indicated a significant reduction in irrigation needs after transitioning to organic agriculture and using compost. More data is needed to verify the impact of compost amended soil on water needs including the economic value of decreased energy, water and labor costs.
Brian McSpadden-Gardner (OSU) suggested that the impact of compost on water needs is greater in the west because of a greater drought risk. Rynk agreed and noted that there is a larger market for compost in the west.
A participant in Columbus suggested that vermicomposting should minimize odors as it proceeds at a faster rate and requires oxygen, reducing odors from anaerobic processes. Rynk responded that he lacked direct experience with vermicomposting but had visited several sites, including a biosolids one, and had not observed odors. However, vermicomposting must be done on a smaller scale as it requires organics be added in small, controlled amounts.
Notes by Mary Wicks
The OCAMM (Ohio Composting and Manure Management) Program is funded by OARDC/OSU.