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Assessment of Physicochemical Characteristics of Produced Water from Terminals of Some Oil Industry Facilities in Nigeria
OBUNWO, C.C. & CHUKWUDI, C.
Abstract
This study evaluated the physico-chemical characteristics, total hydrocarbon
concentration (THC) and some heavy metal levels of produced water from terminals of two oil
industry facilities in Nigeria, using standard methods. Appropriate sample bottles were used in
the collection of samples for analyses of BOD, other physico-chemical characteristics, total
hydrocarbon and heavy metals. The samples were preserved accordingly and transported to the
laboratory in ice - packed coolers. The levels of the physico-chemical properties of produced
water in the two locations, showed that mean temperature, pH, TDS, TSS, salinity and turbidity
levels were: 24.40± 0.35°C – 25.50 ± 0.35°C; 7.49 ± 0.28 – 7.89 ± 0.30; 8428 ±2332mg/l –
9205 ± 2100mg/l; 8.50 ± 3.40mg/l – 14.30 ± 5.10mg/l; 6108± 1250mg/l – 7422 ± 2280mg/l
and 16.00 ± 5.00 NTU – 37.00 ± 9.60 NTU respectively. DO and BOD levels were
respectively 3.07 ± 0.40mg/l – 3.29 ± 0.40mg/l and 1.46 ± 0.38mg/l – 1.72 ± 0.48mg/l. COD
levels did not vary between the two locations. Mean TOC levels ranged between 0.05 ±
0.02mg/l and 0.06 ± 0.02mg/l while mean THC ranged between 4.72 ± 1.59mg/l and 36.90 ±
3.03mg/l. The levels of the nutrient characteristics of nitrate, phosphate and sulphate ranged as
follows: NO3- (1.90 ± 1.16mg/l – 2.50 ± 0.26mg/l); PO43- (0.52 ± 0.12mg/l – 1.07 ± 0.12mg/l)
and SO42- (14.40 ± 4.57mg/l – 21.70 ± 2.75mg/l). Levels of trace metals ( Pb, Ni, V, Cd, Hg
and Cr) were below detection limits. However, the concentration of Fe ranged between 0.53 ±
0.11mg/l 1.06 ± 0.26mg/l. With the exception of salinity, TDS and TSS, the levels of other
physico- chemical characteristics including the trace metals were within the permissible limits
set out by Nigeria’s Department of Petroleum Resources (DPR).
Keywords
Physico- chemical characteristics; Produced water; oil terminals; Heavy metals; oil industry facility
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