Influence of organic waste and residue mud additions on chemical, physical and microbial properties of bauxite residue sand

Jones, Benjamin E. H., Haynes, Richard J. and Phillips, Ian R. (2011) Influence of organic waste and residue mud additions on chemical, physical and microbial properties of bauxite residue sand. Environmental Science and Pollution Research, 18 2: 199-211. doi:10.1007/s11356-010-0364-5


Author Jones, Benjamin E. H.
Haynes, Richard J.
Phillips, Ian R.
Title Influence of organic waste and residue mud additions on chemical, physical and microbial properties of bauxite residue sand
Journal name Environmental Science and Pollution Research   Check publisher's open access policy
ISSN 0944-1344
1614-7499
Publication date 2011-02-01
Year available 2010
Sub-type Article (original research)
DOI 10.1007/s11356-010-0364-5
Open Access Status
Volume 18
Issue 2
Start page 199
End page 211
Total pages 13
Place of publication Heidelberg, Germany
Publisher Springer
Language eng
Abstract In an alumina refinery, bauxite ore is treated with sodium hydroxide at high temperatures and pressures and for every tone of alumina produced, about 2 tones of alkaline, saline bauxite processing waste is also produced. At Alcoa, a dry stacking system of disposal is used, and it is the sand fraction of the processing waste that is rehabilitated. There is little information available regarding the most appropriate amendments to add to the processing sand to aid in revegetation. The purpose of this study was to investigate how the addition of organic wastes (biosolids and poultry manure), in the presence or absence of added residue mud, would affect the properties of the residue sand and its suitability for revegetation.

Samples of freshly deposited residue sand were collected from Alcoa's Kwinana refinery. Samples were treated with phosphogypsum (2% v/v), incubated, and leached. A laboratory experiment was then set up in which the two organic wastes were applied at 0 or the equivalent to 60 tones ha(-1) in combination with residue mud added at rates of 0%, 10% and 20% v/v. Samples were incubated for 8 weeks, after which, key chemical, physical and microbial properties of the residue sand were measured along with seed germination.

Additions of residue mud increased exchangeable Na(+), ESP and the pH, and HCO (3) (-) and Na(+) concentrations in saturation paste extracts. Additions of biosolids and poultry manure increased concentrations of extractable P, NH (4) (+) , K, Mg, Cu, Zn, Mn and Fe. Addition of residue mud, in combination with organic wastes, caused a marked decrease in macroporosity and a concomitant increase in mesoporosity, available water holding capacity and the quantity of water held at field capacity. With increasing residue mud additions, the percentage of sample present as sand particles (<1 mm diameter) decreased, and the percentage present in aggregated form (>2 mm diameter) increased; greatest aggregation occurred where a combination of residue mud and poultry manure were added. Stability of aggregates, as measured by wet sieving, was greatest where poultry manure was applied. Although total organic C and soluble organic C were greater in biosolids than poultry manure treatments, the reverse was the case for microbial biomass C and basal respiration. In the biosolids and poultry manure treatments, increasing residue mud additions tended to increase soluble C, microbial biomass C and basal respiration. Germination index of watercress was highest in control samples and reduced by additions of biosolids and poultry manure which was attributed to the high EC and possibly high extractable P and NH (4) (+) .

The concurrent addition of residue mud and organic wastes can improve chemical, microbial and particularly physical properties of residue sand. Future research should include neutralisation of the mud (e.g. with gypsum) and subsequent leaching to remove salts originating from both the mud and organic wastes.
Formatted abstract
Background, aim and scope: In an alumina refinery, bauxite ore is treated with sodium hydroxide at high temperatures and pressures and for every tonne of alumina produced, about 2 tonnes of alkaline, saline bauxite processing waste is also produced. At Alcoa, a dry stacking system of disposal is used, and it is the sand fraction of the processing waste that is rehabilitated. There is little information available regarding the most appropriate amendments to add to the processing sand to aid in revegetation. The purpose of this study was to investigate how the addition of organic wastes (biosolids and poultry manure), in the presence or absence of added residue mud, would affect the properties of the residue sand and its suitability for revegetation.
Materials and methods: Samples of freshly deposited residue sand were collected from Alcoa's Kwinana refinery. Samples were treated with phosphogypsum (2% v/v), incubated, and leached. A laboratory experiment was then set up in which the two organic wastes were applied at 0 or the equivalent to 60 tonnes ha-1 in combination with residue mud added at rates of 0%, 10% and 20% v/v. Samples were incubated for 8 weeks, after which, key chemical, physical and microbial properties of the residue sand were measured along with seed germination.
Results and discussion: Additions of residue mud increased exchangeable Na+, ESP and the pH, and HCO3- and Na+ concentrations in saturation paste extracts. Additions of biosolids and poultry manure increased concentrations of extractable P, NH4+, K, Mg, Cu, Zn, Mn and Fe. Addition of residue mud, in combination with organic wastes, caused a marked decrease in macroporosity and a concomitant increase in mesoporosity, available water holding capacity and the quantity of water held at field capacity. With increasing residue mud additions, the percentage of sample present as sand particles (<1 mm diameter) decreased, and the percentage present in aggregated form (>2 mm diameter) increased; greatest aggregation occurred where a combination of residue mud and poultry manure were added. Stability of aggregates, as measured by wet sieving, was greatest where poultry manure was applied. Although total organic C and soluble organic C were greater in biosolids than poultry manure treatments, the reverse was the case for microbial biomass C and basal respiration. In the biosolids and poultry manure treatments, increasing residue mud additions tended to increase soluble C, microbial biomass C and basal respiration. Germination index of watercress was highest in control samples and reduced by additions of biosolids and poultry manure which was attributed to the high EC and possibly high extractable P and NH4+.
Conclusions: The concurrent addition of residue mud and organic wastes can improve chemical, microbial and particularly physical properties of residue sand. Future research should include neutralisation of the mud (e. g. with gypsum) and subsequent leaching to remove salts originating from both the mud and organic wastes.
© 2010 Springer-Verlag.
Keyword Bauxite processing sand
Poultry manure
Biosolids
Aggregate stability
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online: 30 June 2010

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Agriculture and Food Sciences
 
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Created: Sun, 06 Mar 2011, 10:14:01 EST