Changes to a soil on irrigation with a sanitary landfill leachate
1982
Chan, K.Y. (State Pollution Control Commissions, Lidcombe, NSW (Australia))
A detailed soil column leaching experiment was set up to investigate the changes in properties to a soil as a result of irrigation with an alkaline sanitary landfill leachate (pH 10.3). Chemistry of the soil was drastically altered as a consequence of the interaction. The soil was titrated from pH 5 to pH 10 and was changed from an exchangeable Mg dominated soil to an exchangeable Ca dominated soil. Magnesium was displaced by ion exchange reaction at acid pH, but at pH 10, 14.2 meq 100/g of Mg, i.e. up to three times the cation exchange capacity of Mg, was adsorbed in non-exchangeable forms at the immediate surface of the soil column by specific adsorption reactions. The leachate-treated soil was not stable on distilled water leaching. Structural breakdown led to clay dispersion and reduction in pore space, resulting in a 64 times reduction in hydraulic conductivity, 1.6 x 10('-4) to 2.5 x 10('-6) cm/s. The structural breakdown could be explained in term of the increase in Na adsorption ratio of the treated soil and the subsequent reduction in electrolyte concentration following the distilled water treatment.
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