The production of renewable methane from organic waste streams has recently gained a momentum in the US because of new EPA’s RFS2 regulation, stringent disposal criteria and increased tipping fees. Biogas primarily consists of methane (55-65%), but it also contains considerable amounts of carbon dioxide (35-45%) and trace levels of hydrogen sulfide and other impurities. We recently developed an integrated waste-to-energy-nutrient recycle system (IWENRS) for anaerobic digestion (AD) of municipal sewage sludge, manure and food waste with biochar, byproduct from pyrolysis of lignocellulosic biomass to produce pipeline quality biogas (&gt;90% methane). In this novel process, we fully integrated the <i>in situ</i> sequestration and adsorption of carbon dioxide into the production of renewable methane and digestate as high value-added eco-fertilizer. Our process was successfully scaled up from bench-scale digesters to pilot-scale digesters. The process optimization was achieved by using simulation modelling for field-scale applications. This process offers an excellent strategy of efficient biogas production and carbon dioxide removal for development of practical and scalable in-situ biogas upgrading technology at field-scale. The greenhouse trial results showed that the growth of the switchgrass as energy crop was superior to the control pots because of the high nutrient contents (N,P, K,Ca,Mg and Fe) in the biochar supplemented digestate. The paper will also highlight the associated data from scaling up the process to the farm digest,ers. We will compare the closed loop economic performance of the IWENRS with the conventional biogas production and clean up technologies, such as pressure swing adsorption and iron sponge. The IWENRS offers an alternative approach to produce biogas with high methane content and reduce or minimize the need for biogas cleanup as well produce high fertilizer value digestate from waste streams.

Scaling up an <i>in situ</i> biogas production and upgrading process for renewable methane and organic fertilizer production

254th National Meeting (2017)

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Scaling up an in situ biogas production and upgrading process for renewable methane and organic fertilizer production