Effect of sewage sludge treatment on soil
farmed with wheat studied to test its role on
the growth and productivity of wheat.
Cyanobacteria species were used as a
biological bioremediating agent for this soil.
The results showed an increase in the soil
contents of macro- and micronutrient elements
and heavy metals by the treatments with
cyanobacteria and sewage sludge. Soil electric
conductivity and organic matter were also
increased. The increase in all parameters
(macro- and micronutrient elements and heavy
metals) of the studied soil in response to the
different treatments was significant. Addition of
cyanobacteria to sewage sludge in the soil
caused slight reduction in the content of
micronutrients and heavy metals of the soil if
compared with the soil treated only with
sewage sludge. In the treated soil, the wheat
grains and straw acquired greater contents of
N, P and K. Heavy metals were mostly greater
in wheat straw than in grains. The enrichment
of soil with mixed treatment of cyanobacteria
and sewage sludge caused an increase in
wheat plant growth (plant height) and yield
parameters as straw yield, number of grains
per spike, weight of 100 grains and grain yield.
Cyanobacteria decreased the levels of
micronutrients and heavy metals of the grains
of wheat plants grown in the soil treated with
the low levels of sewage sludge to a below
level of the recommended critical value for
human consumption.
Key words: Cyanobacteria, wheat plant, sewage sludge,
heavy metals, micro - and macronutrients.
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