Assessing the co-production of ammonia and methane for resource recovery optimization

The wastewater treatment is crucial to safeguard people and ecosystems from health and environmental risks. The treatment requires a significant amount of energy for their processes, and it could represent 30-40% of the total energy spent by municipalities. Moreover, the energy used in wastewater treatment plants is the most significant contributor to carbon emissions in the sector. However, wastewater has immense potential for recovering valuable resources such as methane and ammonia. The recovery of these resources could assist these facilities in offsetting energy expenses and carbon emissions, moving them towards net zero. This research used microcosms to assess the co-production of methane and ammonia using different solids, including solids from a new technology for primary filtration called cloth media filters (CMF). Primary solids, secondary solids, and anaerobic digester sludge were sourced from 4 major water recovery facilities near Denver, and CMF solids from Mines Park Water Reclamation Facility. The results showed that the co-production assessment is achievable in a single batch assay using solids concentrations equivalent to the ones used in the operation of real digesters, with similar methane fractions and ammonia in the same order of magnitude. The low C/N ratio was beneficial for accumulating ammonia in the centrate making it an interesting subject for ammonia recovery. For biogas, the pH of the microcosms was the most determinant factor in optimizing the methane fraction in the biogas. The Pearson test proved the correlation between pH and methane fraction, and the combinations with a pH higher than 7 had more methane content, following the optimum pH range for methanogenic Archaea. The addition of phosphate buffer to maintain the pH values close to neutral was also studied. Results suggest that higher concentrations caused a more significant reduction on the biogas yield, and the phosphate buffer also reduced the VS reduction of a few of the solids, especially the CMF. On the other hand, the final ammonia concentration increased with the addition of phosphate.

Name thesis:degree_name

Master of Science (M.S.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Civil and Environmental Engineering

Grantor dc:publisher

Colorado School of Mines. Arthur Lakes Library

Year dc:date.issued

2024

Author dc:creator

• Ito, Katia M.

Advisors dc:contributor.advisor

• Cath, Tzahi Y.
• Figueroa, Linda A.

Committee members dc:contributor.committeemember

• Vuono, David Charles
• Sharp, Jonathan O.

• resource recovery
• wastewater

Statement dc:rights

• Copyright of the original work is retained by the author.

Language dc:language.iso

eng, English

Dc Identifier Other

T 9910

OAI identifier oai:identifier

oai:repository.mines.edu:11124/180350