Physicochemical Characterization and the Effect of Flow-Distance on Correlation between Chemical and Biochemical Oxygen Demands of Industrial Wastewaters | Chapter 05 | Advances in Applied Science and Technology Vol. 3
This work was carried out to establish
the effects of the activities of a cluster of industries in Jos-South Local
Government Area of Plateau State, Nigeria, on the environmental quality of the
industrial area. Some physicochemical parameters –temperature, pH, turbidity,
suspended solids (SS), total solids (TS), total hardness, alkalinity,
biological oxygen demand (BOD), chemical oxygen demand (COD), heavy metals (Cu²⁺, Co²⁺, Fe²⁺& Zn²⁺), phosphates, nitrates,
sulphates and chlorides –of
the wastewaters from the
various industries were
investigated using standard
protocols. Also, the influence of flow-distance on the
empirical correlation between biochemical oxygen demand (BOD) and chemical
oxygen demand (COD) of the wastewaters was investigated. Wastewater samples
were collected at point-sources and at 25, 50, 75 and 100m distances from the
point-sources. Sampling was done twice a week for a full seasonal cycle at peak
production period (morning and evening). The samples’ pH was adjusted to 7
using 0.5M acid for basic samples and 1.0M alkali for acidic samples,
de-chlorinated using 0.0125M Na₂S₂O₃ and seeded when necessary and then diluted
with de-ionized water. The ranges of the parameters were as follows: temperature:
22 –32°C, pH: 5.5 –10.4, SS: 0 –1,300
mg/L, TS: 200 –1.400
mg/L, sulphate: 0.37 –1.37
mg/L, nitrites: 0.10 –1.09
mg/L and phosphate: 14.80 –21.83
mg/L. The phosphate values, especially,
were in excess of the maximum contamination limit specified by Federal
Environmental Protection Agency (FEPA) and World Health Organization (WHO);
and are capable
of triggering eutrophication,which will
in turn increase BOD/COD values.
Concentrations of heavy
metals, determined by Atomic
Absorption Spectrophotometry (AAS), ranged as follows: 0.07 –2.01 mg/L
for Cu²⁺, 0.58 –3.27 mg/L for Fe²⁺, 0.01 –3.18 mg/L for Zn²⁺ and 0.11 –0.18
mg/L for Co²⁺ whose specified standard is not available. BOD₅ values ranged
between 5.34 –25.88 mg/L while COD values ranged from 727.30 –8,308.66
mg/L. Some BOD₅ values were in excess
of the allowable limit while all COD values were observed to be very high. This
implies an appreciable level of pollution exists here and recipient water
bodies of these wastewaters are at risk
of being polluted. COD and BOD₅ of the wastewaters from different sources highly
correlated with correlation
coefficients ranging 0.9396-0.9985. The
empirical correlation
between COD and
BOD₅ was generally maintained
despite the distance
of flow of the
wastewater from point-source and contributions of washings from farmlands
and other human activities i.e. the correlation between COD and BOD₅ for
wastewaters was not affected by flow distance. The correlation equations for
the industries may, therefore, be used to deduce rapid effluent quality from
chemical oxygen demand (COD) of sample from any point along the effluent flow
path.
Author(s) Details
O. M. Myina
Department of Chemical
Sciences, Bingham University, Karu, Nigeria.
A. O. Lawal
Department of Applied
Science, Kaduna Polytechnic, Kaduna, Nigeria.
B. M. Ajiga
Jehovah Nissi Boutique and
Accessories, Lagos, Nigeria.
A. Edah
Department of Chemistry,
University of Jos, Jos, Nigeria.
View Volume: https://doi.org/10.9734/bpi/aast/v3
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