In order to address the plastic ocean debris problem, toxic ingredients in traditional plastics, and the need for increased recycling and pollution safeguards, DTSC researched the development of sustainable bioplastics production in biorefineries with funding provided by CalRecycle. A biorefinery is a cradle-to-cradle facility that can use biomass and used bioplastics as feedstock to produce fuels, value-added chemicals and bioplastics from organic wastes.
Environmental and Economic Advantages of Biorefinery Derived Bioplastics
|Plastic resins that are made closer to their feedstocks might reduce transportation costs and the associated carbon footprint. |
|Producing bioplastic using waste as a feedstock might reduce production costs, does not compete with food crops, does not use petroleum, and might have a negative carbon footprint. |
|Combining the biorefinery infrastructure with biochemicals and biofuels (such as ethanol, biodiesel and hydrogen) could share and reduce capital and operating costs. |
|Sustainable bioplastics will not build up in the ocean because they biodegrade back into their organic constituents. |
|Locating biorefineries on public waste management facilities in public-private partnerships should further reduce production costs and generate revenue for local government agencies. |
Sustainable Bioplastics Research Projects
DTSC worked with Stanford University to develop a particular biotechnology that will sustainably produce bioplastics from waste-derived methane. This would be one of the technologies used in the biorefinery to recycle bioplastics into new bioplastics. DTSC also conducted market studies to determine the best products for the new bioplastics. If a new biorefinery infrastructure becomes a reality, new jobs would result from their construction and operation, and from the incubator industries needed to support the biorefineries. DTSC worked with several universities on studies to assess the the potential of sustainable bioplatics:
- Development of new bioplastics technology- PHA from waste-methane and bioplastics recycling development (Stanford University)
- LCA comparing PET with sustainable PLA and PHA water bottles (UC Berkeley, UC Davis, UCSB and Stanford)
- Leaching (migration) study of PET, PLA and PHA water bottles (UC Berkeley/LBNL)
- Marine degradation studies (CSU Chico)
- PHA bottle development study (CSU Chico)
- Sustainable bioplastic market studies (UC Davis and UC Berkeley)
Biodegradable materials can be broken down by natural processes into more basic components. Products are usually broken down by bacteria, fungi or other simple organisms. This definition however, does not take into account the amount of time it takes the material to break down. Even though a product may say it's biodegradable, it may not be environmentally friendly.
Compostable materials are capable of undergoing biological decomposition such that the material is not visually distinguishable and breaks down into carbon dioxide, water, inorganic compounds, and biomass, at a rate consistent with known compostable materials. Compostable materials often have to be composted under strict conditions that would be hard to replicate in your backyard (because they require a considerable amount of consistent heat).
Polyethylene terephthalate(PET) is a protroleum-based thermoplastic used in food and beverage containers, among other uses.
Polyhydroxyalkanoates (PHA) are produced by bacterial fermentation. They are produced by the bacteria to store carbon and energy and can be turned in to biodegradable plastics.
Polylactic acid PLA is a biodegradable plastic derived from renewable resources, such as corn starch or sugarcanes.
DTSC explored the feasibility of using regional organic waste sources (biomass, agricultural waste, municipal solid waste, algae, sewage sludge and used bioplastics) to produce fuels, chemicals and products, including bioplastics. The biopolymer segment of the biorefinery conceptually could use the same feed stream as for cellulosic ethanol production (glucose), or it could use waste streams from the biomass conversion (for example, volatile fatty acids or waste derived methane) or even waste streams of the cellulosic ethanol production.
The North Pacific Gyre is an area between California and Hawaii, where the ocean currents converge and cause floating plastic waste and other marine debris to accumulate. It covers an ocean area estimated to be twice the size of Texas, containing over 100 million tons of plastic. Other oceans of the world also have gyres and debris, but this one appears to be the largest. The sustainable bioplastics program was formed with support from CalRecycle to research and develop biodegradable ‘bioplastics’ to spur the creation of sustainable beverage containers. Funding for DTSC's work on this project has expired, however staff at CalRecycle are continuing the research.