California Energy Commission (CEC)







The Anaerobic Pump

Dr. Keith A. Schimel, Technology Matrix Corporation



The Anaerobic Pump (AP) is a two stage, hybrid anaerobic process for converting wet biomass to biogas (methane, carbon dioxide and ammonia gases). The unique reactor design drives hydrolysis due to including a combination of three technical advancements; (1) gas transfer via applied low pressure, (2) automatic in-reactor substrate and bacterial thickening, and (3) plasticization via applied high pressure.


Conventional Anaerobic digestion achieves limited volatile solids reduction (20-40%) because it is based on gas-liquid equilibrium. Instead, the Anaerobic Pump utilizes the gases produced by anaerobes to drive hydrolysis via innovative pressure swing design. Completely converting these materials to methane has not been achievable until now.


This project presents some risk, but large payoffs and is technically feasible. Historically, a large proportion of the volatile solids in biomass are not degraded to any appreciable extent by anaerobes. AP has achieved extraordinary volatile solids reduction (~90%) in converting waste activated sludge (WAS) that is composed mainly of bacteria with complex polysaccharide cell walls. The sludge mixture used in this study contains cellulose and may yield much different AP performance results.


The objective of this project is to test the Anaerobic Pump's ability to completely convert a waste sludge mixture through three steady states. Standard analytical methods are used and performance parameters derived.


There is a great need to derive energy from a wide variety of wet biomass materials while eliminating these materials from causing environmental damage.


This project will be a success if it can clearly show that the Anaerobic Pump concept is capable of fully converting the nondigestable fraction of the sludge mixture.


AP will result in a broad economic impact on the biomass to energy market and waste disposal industry. The potential payoffs for the taxpayer are; (a) alternative energy production which will help to reduce the national deficit primarily due to foreign oil purchases and (b) tax relief from waste disposal at WWTPs and IWTP (industrial waste treatment plant) facilities and (c) solution to nagging environmental problems.


There is a market where the prospective customer needs low cost power, income from power production (PURPA) and is under some regulatory pressure to solve an environmental problem(s) with their waste biomass. These customers are predominately water, industry and agriculture.


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