Hydraulic and biotic impacts on neutralisation of high-pH waters
The management of alkaline (pH 11–12.5) leachate is an important issue associated with the conditioning, afteruse or disposal of steel slags. Passive in-gassing of atmospheric CO2 is a low cost option for reducing Ca(OH)2 alkalinity, as Ca(OH)2 is neutralised by carbonic acid to produce CaCO3. The r...
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ftunivnorthumb:oai:nrl.northumbria.ac.uk:43370 2023-05-15T15:52:45+02:00 Hydraulic and biotic impacts on neutralisation of high-pH waters Gomes, Helena I. Rogerson, Michael Burke, Ian T. Stewart, Douglas I. Mayes, William M. 2017-12-01 text https://nrl.northumbria.ac.uk/id/eprint/43370/ https://doi.org/10.1016/j.scitotenv.2017.05.248 https://nrl.northumbria.ac.uk/id/eprint/43370/1/45_Gomes_flumes_STOTEN.pdf en eng Elsevier https://nrl.northumbria.ac.uk/id/eprint/43370/1/45_Gomes_flumes_STOTEN.pdf Gomes, Helena I., Rogerson, Michael, Burke, Ian T., Stewart, Douglas I. and Mayes, William M. (2017) Hydraulic and biotic impacts on neutralisation of high-pH waters. Science of the Total Environment, 601-2. pp. 1271-1279. ISSN 0048-9697 cc_by_4_0 CC-BY F800 Physical and Terrestrial Geographical and Environmental Sciences Article PeerReviewed 2017 ftunivnorthumb https://doi.org/10.1016/j.scitotenv.2017.05.248 2022-09-25T06:12:10Z The management of alkaline (pH 11–12.5) leachate is an important issue associated with the conditioning, afteruse or disposal of steel slags. Passive in-gassing of atmospheric CO2 is a low cost option for reducing Ca(OH)2 alkalinity, as Ca(OH)2 is neutralised by carbonic acid to produce CaCO3. The relative effectiveness of such treatment can be affected by both the system geometry (i.e. stepped cascades versus settlement ponds) and biological colonization. Sterilized mesocosm experiments run over periods of 20 days showed that, due to more water mixing and enhanced CO2 dissolution at the weirs, the cascade systems (pH 11.2 → 9.6) are more effective than settlement ponds (pH 11.2 → 11.0) for lowering leachate alkalinity in all the tested conditions. The presence of an active microbial biofilm resulted in significantly more pH reduction in ponds (pH 11.2 → 9.5), but had a small impact on the cascade systems (pH 11.2 → 9.4). The pH variation in biofilm colonized systems shows a diurnal cycle of 1 to 1.5 pH units due to CO2 uptake and release associated with respiration and photosynthesis. The results demonstrate that, where gradient permits, aeration via stepped cascades are the best option for neutralisation of steel slag leachates, and where feasible, the development of biofilm communities can also help reduce alkalinity. Article in Journal/Newspaper Carbonic acid Northumbria University, Newcastle: Northumbria Research Link (NRL) Science of The Total Environment 601-602 1271 1279 |
institution |
Open Polar |
collection |
Northumbria University, Newcastle: Northumbria Research Link (NRL) |
op_collection_id |
ftunivnorthumb |
language |
English |
topic |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
spellingShingle |
F800 Physical and Terrestrial Geographical and Environmental Sciences Gomes, Helena I. Rogerson, Michael Burke, Ian T. Stewart, Douglas I. Mayes, William M. Hydraulic and biotic impacts on neutralisation of high-pH waters |
topic_facet |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
description |
The management of alkaline (pH 11–12.5) leachate is an important issue associated with the conditioning, afteruse or disposal of steel slags. Passive in-gassing of atmospheric CO2 is a low cost option for reducing Ca(OH)2 alkalinity, as Ca(OH)2 is neutralised by carbonic acid to produce CaCO3. The relative effectiveness of such treatment can be affected by both the system geometry (i.e. stepped cascades versus settlement ponds) and biological colonization. Sterilized mesocosm experiments run over periods of 20 days showed that, due to more water mixing and enhanced CO2 dissolution at the weirs, the cascade systems (pH 11.2 → 9.6) are more effective than settlement ponds (pH 11.2 → 11.0) for lowering leachate alkalinity in all the tested conditions. The presence of an active microbial biofilm resulted in significantly more pH reduction in ponds (pH 11.2 → 9.5), but had a small impact on the cascade systems (pH 11.2 → 9.4). The pH variation in biofilm colonized systems shows a diurnal cycle of 1 to 1.5 pH units due to CO2 uptake and release associated with respiration and photosynthesis. The results demonstrate that, where gradient permits, aeration via stepped cascades are the best option for neutralisation of steel slag leachates, and where feasible, the development of biofilm communities can also help reduce alkalinity. |
format |
Article in Journal/Newspaper |
author |
Gomes, Helena I. Rogerson, Michael Burke, Ian T. Stewart, Douglas I. Mayes, William M. |
author_facet |
Gomes, Helena I. Rogerson, Michael Burke, Ian T. Stewart, Douglas I. Mayes, William M. |
author_sort |
Gomes, Helena I. |
title |
Hydraulic and biotic impacts on neutralisation of high-pH waters |
title_short |
Hydraulic and biotic impacts on neutralisation of high-pH waters |
title_full |
Hydraulic and biotic impacts on neutralisation of high-pH waters |
title_fullStr |
Hydraulic and biotic impacts on neutralisation of high-pH waters |
title_full_unstemmed |
Hydraulic and biotic impacts on neutralisation of high-pH waters |
title_sort |
hydraulic and biotic impacts on neutralisation of high-ph waters |
publisher |
Elsevier |
publishDate |
2017 |
url |
https://nrl.northumbria.ac.uk/id/eprint/43370/ https://doi.org/10.1016/j.scitotenv.2017.05.248 https://nrl.northumbria.ac.uk/id/eprint/43370/1/45_Gomes_flumes_STOTEN.pdf |
genre |
Carbonic acid |
genre_facet |
Carbonic acid |
op_relation |
https://nrl.northumbria.ac.uk/id/eprint/43370/1/45_Gomes_flumes_STOTEN.pdf Gomes, Helena I., Rogerson, Michael, Burke, Ian T., Stewart, Douglas I. and Mayes, William M. (2017) Hydraulic and biotic impacts on neutralisation of high-pH waters. Science of the Total Environment, 601-2. pp. 1271-1279. ISSN 0048-9697 |
op_rights |
cc_by_4_0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.scitotenv.2017.05.248 |
container_title |
Science of The Total Environment |
container_volume |
601-602 |
container_start_page |
1271 |
op_container_end_page |
1279 |
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1766387857644060672 |