Biofuels company Qteros has entered into a joint development project with Applied CleanTech (ACT), a commodities recycling company based in Israel, to use ACT’s Recyllose-based feedstock, produced from municipal wastewater solids (sewage sludge), for more efficient and lower-cost ethanol production by Qteros’ Q Microbe technology. Qteros’ system converts a wide array of cellulosic biomass directly into ethanol in a single step, consolidating enzymatic hydrolysis and fermentation, largely eliminating enzymes and associated pretreatment, and simplifying the production process.
Qteros and ACT’s researchers have found that an ethanol production plant could produce 120-135 gallons of ethanol per ton of Recyllose with the Q Microbe technology.
Qteros CEO William Frey said that with previous technologies, a cellulosic ethanol plant would have to produce roughly 20-30 million gallons per year (MGY) in order to be profitable. With the proposed Qteros-ACT process, Frey said, production with these economics could be viable at a smaller scale. ACT President Dr. Refael Aharon said that a wastewater plant that handles 150 million gallons a day (serving a population of about 2 million people) can be sufficient to supply a smaller-scale ethanol plant with cellulose.
The companies said they are the first to demonstrate commercial success in creating ethanol from the cellulose in municipal and agricultural liquid waste, and to offer a process that all municipalities can use to help reduce expenses.
Our customer is every municipality that has a wastewater treatment plant. It will provide a value-added product for municipal waste water plants, thereby making treatment plants much less expensive to run and helping local governments throughout the world with their constrained budgets.—Jeff Hausthor, Qteros co-founder and senior project manager
In July, Qteros showed that its Q Microbe process yields ethanol outputs of 70 grams per liter (9% by volume) in a single-step process on an industrially pre-treated biomass feedstock. A yield of 50 grams per liter is considered to be the threshold for commercial production of cellulosic ethanol. (Earlier post.)
ACT’s Sewage Recycling System (SRS), a solution for recycling wastewater solids, produces alternative energy sources for the production of electricity or ethanol, while reducing sludge formation and lowering wastewater treatment plant costs and increasing plant capacity.
ACT has spent six years developing the integrated sewage recycling solution. The Recyllose-based feedstock offers high cellulose content and low moisture, facilitating more efficient ethanol production. The SRS is already in commercial use, with facilities in Israel and the United States currently making Recyllose-based products from sewage sludge and other cellulose-rich waste while reducing sludge output and wastewater treatment plant costs.
Since Recyllose is low in lignin (a major component of plant cell walls that is difficult to degrade), and lignin can be inhibitory to efficient conversion to ethanol, the material improves cellulosic plant operational efficiency 20% over higher lignin content feedstocks, according to Hausthor.
The research has been supported in part by a grant from the Binational Industrial Research and Development (BIRD) Foundation, which funds joint efforts between Israel and the United States.