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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ftleedsuniv:oai:eprints.whiterose.ac.uk:117783 2023-05-15T15:52:45+02:00 Hydraulic and biotic impacts on neutralisation of high-pH waters Gomes, HI Rogerson, M Burke, IT Stewart, DI Mayes, WM 2017-12-01 text https://eprints.whiterose.ac.uk/117783/ https://eprints.whiterose.ac.uk/117783/1/1-s2.0-S0048969717313566-main.pdf en eng Elsevier https://eprints.whiterose.ac.uk/117783/1/1-s2.0-S0048969717313566-main.pdf Gomes, HI, Rogerson, M, Burke, IT et al. (2 more authors) (2017) Hydraulic and biotic impacts on neutralisation of high-pH waters. Science of the Total Environment, 601-60. pp. 1271-1279. ISSN 0048-9697 Article NonPeerReviewed 2017 ftleedsuniv 2023-01-30T21:55:56Z 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 White Rose Research Online (Universities of Leeds, Sheffield & York) |
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White Rose Research Online (Universities of Leeds, Sheffield & York) |
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ftleedsuniv |
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English |
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, HI Rogerson, M Burke, IT Stewart, DI Mayes, WM |
spellingShingle |
Gomes, HI Rogerson, M Burke, IT Stewart, DI Mayes, WM Hydraulic and biotic impacts on neutralisation of high-pH waters |
author_facet |
Gomes, HI Rogerson, M Burke, IT Stewart, DI Mayes, WM |
author_sort |
Gomes, HI |
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://eprints.whiterose.ac.uk/117783/ https://eprints.whiterose.ac.uk/117783/1/1-s2.0-S0048969717313566-main.pdf |
genre |
Carbonic acid |
genre_facet |
Carbonic acid |
op_relation |
https://eprints.whiterose.ac.uk/117783/1/1-s2.0-S0048969717313566-main.pdf Gomes, HI, Rogerson, M, Burke, IT et al. (2 more authors) (2017) Hydraulic and biotic impacts on neutralisation of high-pH waters. Science of the Total Environment, 601-60. pp. 1271-1279. ISSN 0048-9697 |
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1766387853320781824 |