『Abstract
This research study used sewage sludge from urban wastewater
treatment plants to restore road embankments. The results have
been used to propose a series of basic principles for the application
of sludge in this context. In the study, six experimental plots
(each composed of one cut slope and one fill slope) were set up
on a highway located in the province of Jaen (Spain). The soil
and vegetation in the plots were restored by a conventional hydroseeding
process, with each plot receiving a different sludge dosage. A
control plot did not receive may treatment at all, whereas another
plot was hydroseeded, but without any sludge added to the slurry
mix. In the plots, soil evolution was controlled from the moment
that the embankment was created and hydroseeded until the present.
As part of the soil monitoring process, agronomic parameters and
the heavy metal content of the soil were analyzed in the laboratory.
Another parameter of analysis was the vegetation cover, which
was studied on the basis of on-site visual inspections and the
rasterization of images with a view to calculate the percentage
of vegetation cover on each plot. Results showed the effectiveness
of sewage sludge as an organic complement in the restoration of
road embankments. Its viability is enhanced by the fact that the
sludge can be applied with the same methods used in public highway
construction. The results also showed the optimal sludge dosage
to be used in the slurry mix during the hydroseeding process.
Keywords: Road slope; Sludge; Landscape restoration; Waste management』
1. Introduction
2. Materials and methods
2.1. Location of the area of the study
2.2. Climate data
2.3. Contribution of sludge to road embankments and hydroseeding
2.4. Initial characteristics of soil and sludge
2.5. Monitoring and control
2.5.1. Vegetation cover
2.5.2. Soil
3. Results and discussion
3.1. Estimate of the real amount of sludge applied to the
soil
3.2. Soil evolution over a 2-year period
3.3. Monitoring of vegetation cover and plant growth
4. Conclusions and recommendations
Acknowledgements
References