Engineering Commons^™

Two-Phase Anaerobic Digestion To Reduce The Nox Emission Potential Of Biogas, Nathaniel Manuel Olivas

Master's Theses

Anaerobic digestion can be used to decrease the mass of organic wastes to be disposed of while producing useful biogas (CH₄ and CO₂) for heat or power production, but in air basins with strict emissions limits, biogas combustion is difficult to implement due to the high costs of controlling NOx emissions. NOx production can be minimized by blending H₂ gas with CH₄ at a volume ratio of 15:85 H₂:CH₄, which allows burning at ultra-lean air-to-fuel ratios. For biogas systems, a potential low-cost NOx control strategy is to produce H₂-CH …

Methane Production By A Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water, Sean Richard Thomson

Master's Theses

Packed-bed digesters are an alternative to covered lagoon digesters for methane production and anaerobic treatment of dilute wastewaters such as dairy barn flush water. The physical media of packed-beds retain biofilms, often allowing increased treatment rates. Previous studies have evaluated several types of media for digestion of dilute wastewaters, but cost and media fouling have setback commercial development. A major operational cost has been effluent recirculation pumping.

In the present effort, a novel approach to anaerobic digestion of flush dairy water was developed at pilot-scale: broken walnut shells were used as a low-cost packed-bed medium and effluent recirculation was replaced …