February 19, 2008
Terrenew, LLC, is pleased to announce that it has just signed an agreement with the New York State Energy Research and Development Authority (NYSERDA) for a project entitled “Efficient hydrogen sulfide removal from landfill gas for bioenergy.” This agreement totals $192,000 from NYSERDA with in-kind and cash matches from Terrenew and Casella Waste Management.
Hydrogen sulfide (“rotten egg gas”) has an unpleasant smell, is toxic to humans and animals, and it is highly corrosive to machinery. In landfills with construction and demolition waste, hydrogen sulfide is produced from microbial degradation of wallboard and similar materials. If the landfill also contains high levels of organic wastes, substantial amounts of methane can be produced, and this can be combusted for bioenergy production. However, the presence of hydrogen sulfide at more than about 200 ppm will void the manufacturer’s warranties for gas turbine generators. Therefore, an efficient method to remove hydrogen sulfide from the biogas produced from landfills is required.
Further, biogas containing 40-60% methane (most of the rest is carbon dioxide) can also be produced on farms by anaerobic fermentation of manure. This biogas can be used on-farm but, if the process is efficiently done, there will be surplus electrical energy produced that can go back onto the grid. However, the biogas from manure also contains 4,000 to 7,000 ppm of hydrogen sulfide. This can be used directly in piston engines that drive electrical generators, but the oil has to be changed at least daily to avoid corrosive effects of the gas. Even if this biogas is burned, the hydrogen sulfide is converted to sulfur dioxide, which is a pollutant that is a principal contributor to acid rain.
Technologies to remove hydrogen sulfide from gas for energy production have been available for more than 100 years (it was first used to remove hydrogen sulfide from coal gas). However, efficient and convenient systems for use in smaller landfills and on-farm use are not available. Terrenew is developing such systems. The expectation is that they can be easily and conveniently used on smaller landfills and for on-farm uses. This is expected to increase the production of bioenergy from waste materials such as manures and landfill wastes. It is anticipated that the final material generated from removal of hydrogen sulfide can be easily disposed of, for example, by land spreading with the residue that is left from manure digestion.
This technology is part of Terrenew’s larger vision for complete commercial utilization of manures on farms. Terrenew has a line of products based on manure for oil spill pickup (OilMaster) and removal, and another for plant propagation. These products are composed primarily of dairy manure. The Company envisions on-farm systems where manure is harvested and directly converted into the OilMaster and plant propagation products using energy generated from biogas. The biogas, of course, would be purified using the processes developed in conjunction with this NYSERDA agreement.
Terrenew is a spin-off company from Cornell University. Terrenew’s Chief Scientific Officer, Gary Harman, is a Cornell Professor, and its Secretary-Treasurer is Terry Spittler, who is a retired analytical chemist from Cornell. Harman and Spittler have worked together on the development of the hydrogen sulfide, OilMaster and plant propagation products in Harman’s lab at Cornell with grants from Terrenew and from Cornell’s Center for Advanced Technology. The Company’s offices are in the Agricultural and Food Technology Park in Geneva.
