Two graduates from Princeton University and Northwestern University have developed a process for converting greenhouse gases from sewage treatment plants, landfills, and power plants into a biodegradable plastic called AirflexTM. Under the auspices of their company, called Newlight Technologies, LLC, the technology counts as a way to capture methane and carbon dioxide, and in a sustainability twofer it could also help cash-strapped cities and towns capture some revenue from their wastewater treatment plants.
Making Biodegradable Plastic from Greenhouse Gas
As described by Newlight, the process for making AirflexTM breaks down into a few simple steps. First, a mix of gases, including methane and carbon dioxide, is funneled into a reactor. Next, carbon and oxygen are separated out, and then they are reassembled into a long-chain thermopolymer (aka: a form of plastic).
That’s the basic AirflexTM. With further tweaking, AirflexTM can be processed into different grades of plastic, including substitutes for polypropylene, polyethylene, and polystyrene that perform just as well as their petroleum-based counterparts.
The Sewage Gas Gold Rush
As far as sewage gas goes, it seems like the new operation could fit seamlessly into many modern wastewater treatment facilities that handle household sewage. Municipal sewage treatment is a natural process in which microbes digest organic material, venting copious amounts of methane-rich biogas as they chew along.
In the past, the gas was simply flared off. Nowadays, there is more interest in capturing methane biogas from wastewater plants and reclaiming it to power equipment at the site.
That can help to offset the cost of grid-supplied power. In addition, wastewater treatment plants are already beginning to harvest revenue from biogas, by piping it offsite to the conventional natural gas supply grid.
Waste Gas Comes Into Its Own
Newlight notes that its waste gas-to-plastic process can apply to other kinds of operations that produce waste gas, including landfills and power plants.
Other companies are also beginning to churn out liquid fuels and other substitutes for petroleum product from waste gas. For example, industrial operations are another potential source of raw materials for ethanol, as demonstrated by the New Zealand company LanzaTech.
Biogas from food processing and beverage operations, including biogas from breweries, is another potential feedstock that can sub in for fossil fuels.
Another emerging trend is capturing biogas from livestock operations for use on site or for sale to the grid, a technology that can be scaled down to serve undeveloped communities as well as large farms.
Image (cropped): Courtesy of Newlight.
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