This study investigated the concentration of heavy metals in oil field produced water
from Niger Delta, before and after treatment with locally sourced agricultural
wastes. Two produced water samples were investigated for different metal ions such
as; Lead, Nickel, Cadmium, Copper, Iron, Magnesium, Chromium, Zinc,
Manganese, Calcium, Arsenic, Boron, Tin and Barium. The produced water samples
were treated with four different adsorbents which are; Orange peels, Banana peels,
Palm Kernel Fiber and Luffa Cylindrica. These adsorbents were used at different
particle sizes of 63 and 150 microns. Ten of these metals were analyzed using the
atomic absorption spectrophotometer (AAS) and the remaining four were analyzed
using the UV-Visible spectrophotometer. The analysis was carried out (in line with
the industrial standard) in order to determine the concentration of the metals in the
produced water samples.
The results obtained from the analysis showed that the concentration of the metal
ions investigated reduced drastically after treating. For example, the concentration
of lead, iron and zinc reduced from 0.095ppm, 0.045ppm, 0.108ppm to 0.018ppm,
0.001ppm and 0.002ppm respectively in sample X. The physical and chemical
properties as well as other contaminants of the produced water samples such as
chloride content, total dissolved solids and density were also determined before and
after treatment. There were reductions in the concentrations of these properties.
This showed that the produced water from the oil and gas activities should be treated
for metal ions present that may have concentrations higher than standard limits set
by regulatory bodies before disposal and/or re-use due to their negative effects to
man and its environment.