Assessing the feasibility of land application of fly ash, sewage sludge and their mixtures
K.S. Sajwana, S. Paramasivama, A.K. Alvab,
D.C. Adrianoc, P.S. Hoodad
aCenter for Marine, Environmental Sciences Biotechnology Research,
Savannah State University, P. O. Box 20600, Savannah, GA 31404, USA
bUSDA-ARS-PWA, Vegetable and Forage Crops Research, 24106 N.
Bunn Road, Prossel; WA 99350, USA cSavannah River Ecology Laboratory,
University of Georgia, Drawer E, Aiken, SC 29802, USA
d Center for Earth and Environmental Science Research, Kingston
University, Kingston upon Thames, Surrey KT1 2EE, UK
Received 28 January 2002; accepted 5 August 2002
Abstract
Land disposal of fly ash (FA) and sewage sludge (SS) is a major problem
due largely to their potentially harmful constituents. Combined use of
FA and SS however may help reduce the associated pollution potential.
In this paper we summarize the results of several case studies designed
to assess the feasibility of land application of FA with and without SS.
A wide range of application rates was tested under laboratory, greenhouse
and field conditions. The leaching of metals from soil columns amended
with moderate rates of FA applications (8-16 Mg ha-1) generally
had no significant impact on the metal content of leachate or their downward
migration in the soil. The application of FA or SS at a much high rate
(74.1 Mg ha-1) significantly increased both leaching and downward
migration of metals. The use of 1: 1 FA + SS mixture at 148.2 Mg ha-1
reduced metal leaching compared to the combined metal quantities leached
when FA or SS applied at 74.1 Mg ha-1. The results indicate
that combined use of FA and SS at a rational rate of application should
not cause any significant effect on drainage water quality. Plant studies
conducted using FA and SS mixtures indicated that these materials could
be beneficial for biomass production, without contributing significant
metal uptake or leaching. The application of FA as high as 560 Mg ha-1
in a long-term field trial had no detectable deterioration in soil or
groundwater quality and no substantial increases in plant uptake of metals
and other trace elements were observed. Low to moderate rates of FA and
SS therefore could be successfully used as soil amendments, particularly
so when used as a mixture.
@ 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Biomass; Fly ash; Groundwater; Leaching; Metals;
Sewage sludge
SREL Reprint #2748
Sajwan, K. S., S. Paramasivam, A. K. Alva, D. C. Adriano and P. S. Hooda. 2003. Assessing the feasibility of land application of fly ash, sewage sludge and their mixtures. Advances in Environmental Research 8:77-91.
