POWRE: Methanogenesis from Biosolids Under Extreme Conditions of Pressure, Temperature and Salinity

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

0075054 Ahring The objective of this research project is to study the natural process of anaerobic degradation of treated sewage sludges (biosolids) under conditions of high pressure, high temperature and high salinity found in deep geological formations. This research is motivated by the desire to establish the feasibility of injecting biosolids into deep underground high permeability saline or depleted oil and gas formations. This could replace the current practice of disposing of biosolids on land or in landfills, thereby reducing the surface land impairment, truck traffic and associated emissions, impact on surface waters and groundwaters and release of greenhouse gases to the atmosphere. If the rate of biogas formation is adequate, methane could be recovered at the surface for beneficial reuse as a clean fuel. It is not known how conditions equivalent to the ones found in deep geological formations would affect the broad variety of microorganisms carried along with the biosolids. It is unknown to what extent the microbial populations colonizing the injected biosolids will actually come from the native populations existing at the deep geological formation or from the microbial populations introduced by the biosolids. Through the use of bench-scale deep-well simulators, the anaerobic degradation of biosolids under conditions similar to those found at deep geological formations will be tested for periods of six and twelve months. The rate of biogas formation, biogas constituents, and changes in the microbial populations present in biosolids, as well as in core materials, will be studied. Biosolids obtained from the Hyperion Treatment Plant in Los Angeles and core material and native fluids (brine) from the Aliso Canyon gas field will be used for these tests. ***