Biological treatment of coke making wastewater.
| dc.contributor.advisor | Soares, Ana | |
| dc.contributor.advisor | Stephenson, Tom | |
| dc.contributor.author | Raper, Eleanor | |
| dc.date.accessioned | 2022-06-01T14:30:02Z | |
| dc.date.available | 2022-06-01T14:30:02Z | |
| dc.date.issued | 2017-04 | |
| dc.description.abstract | Production of coke for steel manufacturing produces a wastewater containing total nitrogen (TN) (up to 600 mg/L) alongside toxic compounds phenol (60 - 400 mg/L), thiocyanate (SCN-) (100 - 400 mg/L), polycyclic aromatic hydrocarbons (PAHs) (Ʃ6PAHs:179±35 µg/L) and trace metals. Emission limits introduced by the Industrial Emissions Directive (IED) in 2016 require treated coke effluent to contain <50 mg/L TN, <4 mg/L SCN-, <0.5 mg/L phenol and <50 µg/L Ʃ6PAHs which cannot be consistently met by the conventional activated sludge process (ASP). Treatment process modifications were investigated to ensure compliance. Activated carbon addition to the ASP (400 mg/L) increased Ʃ6PAHs removal by 20% enabling emission compliance whilst increasing nickel, chromium and cadmium removal. The addition of 0.5 g/L of a commercial bioaugmentation product increased dissolved Ʃ6PAHs removal by 51%. Biostimulation (addition of micronutrients/alkalinity) enabled SCN-and phenol emission compliance. Survival of supplemented exogenous bacteria in a simulated river water discharge was investigated for the first time showing limited survivability. Thiocyanate degradation mechanisms were poorly understood but were important to ascertain, especially as SCN-degradation produces ammonia increasing TN loading. Control of influent ammonia and phenol concentration was important enabling SCN-degradation under anoxic and aerobic conditions. Deoxyribonucleic acid sequencing of the mixed culture identified a new species of Thiobacillus which had metabolic similarities to T. thioparus and T. denitrificans. Nitrification was limited (41%) confirming the importance of intrinsic alkalinity availability in the wastewater, however, sodium carbonate addition (300 mg/L as CaCO₃) increased efficiencies to 96%. An anoxic-aerobic ASP was investigated for TN removal enabling an effluent TN <50 mg/L when the soluble chemical oxygen demand (sCOD):TN ratio was maintained above 5.7. Acetic acid was identified as a suitable source of carbon addition to maintain this ratio. An anoxic-aerobic ASP combined with AC and bioaugmentation can ensure compliance with the IED. | en_UK |
| dc.description.coursename | PhD in Water | en_UK |
| dc.identifier.uri | http://dspace.lib.cranfield.ac.uk/handle/1826/17988 | |
| dc.language.iso | en | en_UK |
| dc.rights | © Cranfield University, 2015. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder. | |
| dc.subject | Coke wastewater | en_UK |
| dc.subject | total nitrogen | en_UK |
| dc.subject | thiocyanate | en_UK |
| dc.subject | polycyclic aromatic hydrocarbons | en_UK |
| dc.subject | phenol | en_UK |
| dc.subject | trace metals | en_UK |
| dc.subject | activated sludge process | en_UK |
| dc.subject | activated carbon bioaugmentation | en_UK |
| dc.subject | biostimulation | en_UK |
| dc.title | Biological treatment of coke making wastewater. | en_UK |
| dc.type | Thesis | en_UK |