The first demonstration of a renewable method for hydrogen production from wastewater using a microbial electrolysis system is underway at the Napa Wine Company in Oakville, California. (Earlier post.)
This is a demonstration to prove we can continuously generate renewable hydrogen and to study the engineering factors affecting the system performance. The hydrogen produced will be vented except for a small amount that will be used in a hydrogen fuel cell.
—Dr. Bruce Logan, Penn State
Eventually, Napa Wine Company would like to use the hydrogen to run vehicles and power systems.
The wastewater comes from cleaning equipment, grape disposal, wine making and other processes. The company already has on-site wastewater treatment and recycling and the partially treated water from the microbial electrolysis system will join other water for further treatment and use in irrigation.
The demonstration microbial electrolysis plant is a continuous flow system that will process about 1,000 liters of wastewater a day. Microbial electrolysis cells consist of two electrodes—one carbon anode and one stainless steel cathode—immersed in liquid. The wastewater enters the cell where naturally occurring bacteria convert the organic material into electrical current. If the voltage produced by the bacteria is slightly increased, hydrogen gas is produced electrochemically on the stainless steel cathode.
The demonstration plant is made up of 24 modules. Each module has six pairs of electrodes.
The project is supported by Air Products & Chemicals, Inc., The Water Environmental Research Foundation Paul L. Busch Award and other donors. Brown & Caldwell, an environmental engineering consulting firm, was contracted to build the demonstration plant. The Napa Wine Company is donating its facilities and wastewater for the demonstration.