ON THE PROSPECT OF HUMAN WASTE AS A FERTILIZER ALTERNATIVE
| dc.contributor.author | Krounbi, Leilah | |
| dc.contributor.chair | Lehmann, C. Johannes | |
| dc.contributor.committeeMember | Nelson, Rebecca J. | |
| dc.contributor.committeeMember | Van Es, Harold Mathijs | |
| dc.date.accessioned | 2019-04-02T13:59:50Z | |
| dc.date.available | 2020-01-02T07:01:31Z | |
| dc.date.issued | 2018-12-30 | |
| dc.description | Supplemental file(s) description: Data files 3 chapters | |
| dc.description.abstract | Effective, safe, and affordable waste management should both mitigate human exposure to pathogens while recovering valuable nutrients for agricultural production. Containing 4-5% nitrogen (N), 2-3% potassium (K), and 2-3% phosphorus (P), HSW is gaining relevance as an alternative fertilizer as mined P supplies dwindle, and environmental and economic costs of synthetic N increase. Furthermore, N forms in urine are plant-available and recoverable through novel adsorption processes. The HSW sanitization methods evaluated in this study, thermophilic composting, torrefaction, and pyrolysis, had varying effects on the fertilizer-equivalent value of HSW amendments in soils, according to the temperature and oxidation conditions of each method. Composted HSW contained between 16 and 858-fold more extractable N than pyrolyzed waste (300-700 °C). Conversely, HSW pyrolyzed at 600 °C had four-fold higher extractable P and five-fold higher plant-available K than composted HSW. Benchmarked against market fertilizer prices, P and K comprised 52-87% of the value of HSW while plant-available N contributed less than 2%, making thermochemically-treated HSW at 600 °C of greatest value, averaging 220.0 USD Mg-1, more than four-fold of composted HSW, 52.7 USD Mg-1. We observed a tradeoff between N and P availability across soils of varying pH and texture caused by amendment temperature treatment, which was ameliorated with urine additions. Low N and P availability was observed with composted HSW, 29.4-46.2 kg N ha-1 and 5.5-14.7 kg P ha-1, ample N and moderate P was available with torrefied HSW, 71.2-106.5 kg N ha-1 and 12.1-30.2 kg P ha-1 while excess mineral N and ample P were provided in soils amended with pyrolyzed HSW (500 °C) + urine, 404.3-486.2 kg N ha-1 and 32.9-81 kg P ha-1. A process of material accretion in pyrolyzed HSW through sequential chemisorption of carbon dioxide (CO2) followed by urine-derived ammonia (NH3) was also discovered. Organic N in pyrolyzed waste is not plant available but chemisorbs CO2 (50 kJ mol-1) into acidic functionalities, which have high affinity for NH3. Adsorption kinetics of pyrolyzed oxidized wood exposed sequentially to CO2 followed by NH3 revealed continued, albeit diminishing NH3 uptake following CO2 surface treatments: 5.9 mmol NH3 g-1 for the first NH3 exposure, and 3.5 and 2.9 mmol NH3 g-1 for the second and third. Penetration of 15NH3 and 13CO2 measured by NanoSIMS reached over 7 µm deep into pyrolyzed oxidized wood and pyrolyzed HSW, demonstrating large NH3 capture. Pyrolyzed HSW absorbed less NH3 compared to pyrolyzed oxidized wood due to potassium carbonate precipitation. Pre-rinsing of the mineral ash may improve NH3-loading, and better-facilitate the fertilizer-growth process within the pyrolyzed HSW matrix. However, removal of P and K, the two valuable, plant-essential elements in the ash fraction, will lower the value of HSW. Multiple N-stripping techniques, such as NH4+ from solution- as well as gas-phase NH3, may help optimize N uptake in py-HSW as well as P and K concentrations. | |
| dc.identifier.doi | https://doi.org/10.7298/ddxy-9731 | |
| dc.identifier.other | Krounbi_cornellgrad_0058F_11151 | |
| dc.identifier.other | http://dissertations.umi.com/cornellgrad:11151 | |
| dc.identifier.other | bibid: 10757974 | |
| dc.identifier.uri | https://hdl.handle.net/1813/64834 | |
| dc.language.iso | en_US | |
| dc.rights | Attribution-ShareAlike 4.0 International | |
| dc.rights.uri | https://creativecommons.org/licenses/by-sa/4.0/ | |
| dc.subject | pyrolysis | |
| dc.subject | ammonia | |
| dc.subject | human solid waste | |
| dc.subject | urine | |
| dc.subject | Adsorption | |
| dc.subject | biochar | |
| dc.subject | Soil sciences | |
| dc.title | ON THE PROSPECT OF HUMAN WASTE AS A FERTILIZER ALTERNATIVE | |
| dc.type | dissertation or thesis | |
| dcterms.license | https://hdl.handle.net/1813/59810 | |
| thesis.degree.discipline | Soil and Crop Sciences | |
| thesis.degree.grantor | Cornell University | |
| thesis.degree.level | Doctor of Philosophy | |
| thesis.degree.name | Ph. D., Soil and Crop Sciences |