January 2006 ISSUE
backgrounder
engineering meets agriculture sustainability challenge
Technology has come up with a better way to deal with carcasses of BSE-infected cattle. It’s just one of the cooperative roles engineers can — and should — create for themselves in the sustainability of agriculture.
Editor’s Note: The APEGGA Environment Committee is presenting a series of articles regarding the role of professional members in sustainability, climate change impact, and adaptation. These articles address industry specific initiatives, international initiatives and regulatory considerations. They are meant to raise the level of awareness and generate discussion, and do not necessarily reflect the opinions of APEGGA, its Council or its Executive Committee.
BY DR. RODERICK M. FACEY, P.ENG.
General Manager, Gensolutions Ltd.
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THE MACHINE AND THE BYPRODUCTS |
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How should sustainability be pursued in agriculture? This continues to be a topic of much debate.
That’s because, at least in part, the topic is all encompassing. It includes broad-based issues such as economic globalization, cultural indifference, corporate consolidation of food systems, soil and plant nutrition, biotechnology, food safety, health and nutritional issues, confinement-of-animal feeding operations, and the productivity and management of natural resources.
Sustainable systems must be economically viable, either by nature or through human intervention. Agron-omists, scientists, engineers and business people alike must play a key role in designing technology and economic activities that will sustain rather than degrade the natural environment, and guide us to live within the limits of the natural systems.
These groups must work together to provide the leadership for undertaking a new industrial revolution, designed to build upon the information and technological revolutions of the past.
In the case of engineers, it can be in the development of new technologies to address and protect society and the environment from today’s emerging problems in the agricultural industry. Most notable of these problems, of course, has been bovine spongiform encephalopathy, or BSE, in Alberta.
Ranching’s Dark Days
In 2003 Alberta reported its first case of BSE in a decade. This proved devastating
to the country’s beef industry. International reaction by many countries
was a ban on beef imports from Canada.
For Alberta, where cattle ranching is ingrained in the livelihood, the impact was significant. According to Alberta Agriculture department statistics, more than half a million live cattle were shipped to the U.S. in the previous year.
The Alberta cattle industry accounts for nearly 60 per cent of Canada’s beef production. Damage to consumer confidence and the issuance of international trade bans have been costly and devastating.
BSE is a disease of cattle that causes the degeneration of the function of the central nervous system. BSE belongs to a class of transmissible spongiform encephalopathies that are also known as prion diseases. These diseases have incubation periods of months to years between infection and onset of clinical symptoms.
The prevailing hypothesis is that these diseases are caused by novel agents called prions, short for proteinaceous infectious particles. There is the worrisome possibility that meat products contaminated with BSE infectivity can cause a human form of this illness, known as the variant Creutzfeldt-Jakob disease.
The Role of Thermal Hydrolysis
An example of how engineers can contribute to agricultural sustainability, as
it relates to food safety and public health, is in the development of new technologies.
Here in Alberta a small group of scientists and engineers have developed a patented
technology for dealing with contaminated carcasses.
It’s called thermal hydrolysis, or TDH.
TDH is a process that causes the hydrolytic breakdown and denaturing of protein compounds through the influence of pressure and temperature. Temperature-activated hydrolysis is fast acting, requiring a treatment time of less than 60 minutes. In addition, the technology is designed to achieve the highest possible log reduction for disease-causing prion agents.
The potential impact on the industry of this emerging technology is the alternative it offers to today’s traditional practices in the processing and disposal of animal byproducts and carcasses.
In North America and Europe, the accepted disposal practices have included rendering, incineration, alkaline hydrolysis, composting and landfill/deep burial. Although approved, these practices do not address fully the issues of disease transmission, nor do they represent the best benign disposal method in regards to the environment.
TDH offers a viable and economical alternative to traditional practices by creating a resource — for energy production — out of a waste byproduct. TDH is a viable pre-treatment method for the anaerobic digestion of organic matter for enhanced biogas production.
Anaerobic Biological Decomposition Explained
To appreciate this technology, one must understand the conventional process of
anaerobic digestion.
Anaerobic biological decomposition involves four steps: hydrolysis, fermentation, acetogenesis and methanogenesis. In a conventional process, the solids are rendered water-soluble through the influence of microbiological-produced enzymes. By reacting with water, the enzymes break down long-chain biomolecules, allowing the molecules to penetrate the cells of microorganisms.
For many substrates, particularly solids, hydrolysis is often the rate-limiting step of anaerobic digestion.
Enter TDH. It combines temperature and pressure to catalyze the hydrolytic breakdown of biowaste and increases the material fraction that is normally hydrolytically converted and dissolved in a conventional process.
The result is more material is available for biological degradation, resulting in increased biogas production over conventional anaerobic digestion. In addition, the required hydraulic retention of the process is shorter and there is less waste material generated at the end for disposal.
TDH technology has been successfully piloted and is now in its early stage
of
implementation.
This technology is just one of many examples of how scientists and engineers
can play a key role in agricultural sustainability through the development of
more environmentally friendly technologies. Engineers should also expect to join
forces with other disciplinary groups in unprecedented ways to lead society on
a more sustainable path.
Dr. Facey is a professional engineer with over 20 years of experience in the municipal, private sector, industrial, pulp and paper, agricultural, and oil and gas industries. He received his education at the University of Alberta and is a member of APEGGA, APEGBC, APEGS and PEO. Dr. Facey has been a guest lecturer, published numerous journal articles and conference proceedings, and been awarded patents for his innovative designs in waste management technologies.