AWWA ACE71015

The overall objective of this study was to investigate the feasibility of coal combustion ash aggregates(CAA)-amended refill for open pit restoration. Specific objectives were to: assess the potential risksin relation to contamination of soil and groundwater associated with the use of the industrial byproductCAA; and, evaluate the phyto-viability of the land after restoration as the site is plannedto be used for agricultural purposes. The experimental approach included conducting laboratory feasibility tests for groundwater quality and phyto-viability assessments. Results showed that statisticallyhigher pH values (~8.5) were observed for the reactors with low-level rainfall intensities and small-sizedCAAs (P < 0.05). Turbidity was statistically higher for the reactors with low-level rainfall intensities, moreCAAs ratio, and smaller size CAAs. However, all systems produced turbidity of 0.5 NTU or lower.Statistically higher hardness concentrations were monitored for the reactors with more CAAs ratio for half the length of the experiment. However, low-level rainfall intensity dominantly produced significantlyhigher concentrations of hardness in the later experiment. For phyto-viability, a layered refill mode with atop soil and the CAA showed better results than a mixed one. Regardless of the seed type (pumpkins andbeans), better results were observed with a greater depth of the top soil for a layered backfilling mode anda higher ratio of the top soil to the CAAs for a mixed mode. Both plants also showed better results whentheir seeds were planted into the system that had more top soils than the CAAs. Includes 2 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2009

Number of Pages:

13

File Size:

1 file , 1.4 MB