Addition of an organic amendment and/or residue mud to bauxite residue sand in order to improve its properties as a growth medium

The effects of addition of carbonated residue mud (RMC) or seawater neutralized residue mud (RMS), at two rates, in the presence or absence of added green waste compost, on the chemical, physical and microbial properties of gypsum-treated bauxite residue sand were studied in a laboratory incubation...

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Bibliographic Details
Published in:Journal of environmental management 2012-03, Vol.95 (1), p.29-38
Main Authors: Jones, B.E.H., Haynes, R.J., Phillips, I.R.
Format: Article
Language:English
Subjects:
Acacia - growth & development
Acacia saligna
Aluminum base alloys
Aluminum Oxide
Animal, plant and microbial ecology
Applied ecology
Bauxite processing sand
Biological and medical sciences
Biomass
Chemical compounds
Compost
Composting
Conservation, protection and management of environment and wildlife
Environmental management
Environmental science
Fundamental and applied biological sciences. Psychology
General aspects
Germination
Growth
Laboratory
Lolium - growth & development
Lolium rigidum
Magnesium
Microorganisms
Mud
Organic Chemicals - analysis
Physical properties
Porosity
Red mud
Remediation
Residues
Sand
Sand & gravel
Soil - chemistry
Soil Microbiology
Waste
Water treatment
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Summary:The effects of addition of carbonated residue mud (RMC) or seawater neutralized residue mud (RMS), at two rates, in the presence or absence of added green waste compost, on the chemical, physical and microbial properties of gypsum-treated bauxite residue sand were studied in a laboratory incubation study. The growth of two species commonly used in revegetation of residue sand ( Lolium rigidum and Acacia saligna) in the treatments was then studied in a 18-week greenhouse study. Addition of green waste-based compost increased ammonium acetate-extractable (exchangeable) Mg, K and Na. Addition of residue mud at 5 and 10% w/w reduced exchangeable Ca but increased that of Mg and Na (and K for RMS). Concentrations of K, Na, Mg and level of EC in saturation paste extracts were increased by residue mud additions. Concentrations of cations in water extracts were considerably higher than those in saturation paste extracts but trends with treatment were broadly similar. Addition of both compost and residue mud caused a significant decrease in macroporosity with a concomitant increase in mesoporosity and microporosity, available water holding capacity and the quantity of water held at field capacity. Increasing rates of added residue mud reduced the percentage of sample present as discrete sand particles and increased that in aggregated form (particularly in the 1–2 and >10 mm diameter ranges). Organic C content, C/N ratio, soluble organic C, microbial biomass C and basal respiration were increased by compost additions. Where compost was added, residue mud additions caused a substantial increase in microbial biomass and basal respiration. L. rigidum grew satisfactorily in all treatments although yields tended to be reduced by additions of mud (especially RMC) particularly in the absence of added compost. Growth of A. saligna was poor in sand alone and mud-amended sand and was greatly promoted by additions of compost. However, in the presence of compost, addition of carbonated mud had a marked depressive effect on both top and root growth. The significant positive effect of compost was attributed to substantial inputs of K and marked reductions in the Na/K ratio in soil solution while the depressive effect of RMC was attributed to its greater alkalinity and consequently higher concentrations of HCO 3 − in solution. ► We added residue mud and compost to bauxite residue sand. ► Residue mud addition increased available water holding capacity of sand. ► Compost increased av
ISSN:0301-4797
1095-8630
DOI:10.1016/j.jenvman.2011.09.014