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Research
ASU Research
The Department of Energy estimates that the organic content of wastewater can potentially produce $2 billion of energy. Animal wastewater produces three times that amount. And food processing, with its high sugar content, low bacteria concentration, and clean effluent is a potential energy source worth $2 billion. The total energy potential from all these sources adds up to $10 billion. The trick to recapturing energy is breaking down the walls of the cell. That’s where OpenCEL’s technology comes in. Improving Methane Production from Wastewater SludgeOpenCEL’s system works with a treatment plant’s normal, anaerobic processes. Methane is a byproduct of the microbiological activity in anaerobic treatment.
But, methanogenesis has limitations. It does not completely destroy the organic solids in sludge, and because of this, the amount of methane produced is small compared to what it could be. In treatment plants, methane is usually “flared”--burned in an open flame. Water reclamation supervisors at the Mesa Northwest Water Reclamation Plant expect to increase the yield of methane from their digested sludge. Tests Show Boost in Methane ProductionFor methanogenesis to occur, bacteria must be able to “digest” organic matter, which is their “food.” Two measures of the amount of “food” available for bacteria to digest are Soluble Chemical Oxygen Demand (SCOD) and Dissolved Organic Carbon (DOC). The more food available, the more methane bacteria can produce. The research team at the Center for Environmental Biotechnology showed that OpenCEL’s technology increased SCOD and DOC. Methane production increased four-fold with PF treatment, compared to the untreated control. This graph shows the longer biosolids were treated with PF, the more “food” they released into solution.
The research is conducted by Dr. Michael Salerno, Hyung-sool Lee, and Dr. Bruce Rittmann, in conjunction with the City of Mesa and its Northwest Water Reclamation Plant.
Two anaerobic digestors containing waste activated sludge from the Mesa Northwest Water Reclamation Plant are producing methane via microbial transformations. The right reactor contains sludge pre-treated with a Pulsed Electric Field (PF) process that lyses cells and makes organic material more available for the methanogenic bacteria to digest. This increases the destruction of organic solids and the production of methane. |
The 
Microbiological generation of methane, or methanogenesis, has been used for over a century. In wastewater treatment plants, where methanogenesis takes place inside anaerobic digestors, a complex community of microorganisms degrades the organic solids in sludge and converts the biosolids’ energy to methane gas (CH4). 
How did this happen? Pre-treating the sludge with OpenCEL’s pulsed electric field (FP) technology broke apart the biosolids and increased the availability of energy sources (e.g., sugars). This increased methane production and decreased the residual solids.
