Title : Spatio-temporal assessment of industrial wastewater quality and pollution dynamics in Kano Metropolis, Northwestern Nigeria: Implications for sustainable water resource management
Abstract:
Industrial wastewater constitutes a significant environmental challenge where inadequate treatment and uncontrolled discharge can compromise receiving water bodies and threaten sustainable water-resource management. This study presents a spatio-temporal assessment of the physicochemical quality and pollution dynamics of industrial wastewater generated by selected industries in Kano Metropolis, Northwestern Nigeria, with emphasis on seasonal variations and compliance with World Health Organization (WHO) guideline values. Wastewater samples were evaluated during dry and wet seasons across 2020 and 2021 using key physicochemical indicators, including pH, electrical conductivity (EC), total dissolved solids (TDS), temperature, salinity, sulphate, phosphate, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), alkalinity, turbidity, nitrate and total hardness. The resulting dataset provides an integrated basis for characterizing wastewater quality and identifying parameters of potential environmental concern. The findings revealed considerable spatial and temporal variability among the investigated industries. Wastewater pH remained generally within the WHO permissible range of 6–9, while temperature, TDS, sulphate, phosphate, nitrate, salinity and total hardness were broadly within their respective guideline limits. However, electrical conductivity frequently exceeded the WHO reference value of 1000 µS/cm, indicating elevated dissolved ionic content and possible industrial contribution to wastewater mineralization.
Turbidity also demonstrated pronounced elevation, particularly during the 2021 dry and wet seasons, suggesting substantial particulate loading. COD showed marked inter-industrial variation, with values generally below the reported WHO limit but substantially higher in some industrial discharges, reflecting differences in organic and oxidizable pollutant loads. BOD and DO values further demonstrated variations in the organic pollution and oxygen-demand characteristics of the wastewater. Overall, the study establishes that industrial wastewater quality in Kano Metropolis is characterized by distinct spatial and seasonal signatures, with conductivity and turbidity emerging as important indicators of deteriorating wastewater quality. The findings underscore the need for strengthened industrial effluent monitoring, effective wastewater treatment, regulatory compliance and continuous water-quality surveillance to protect receiving environments and advance sustainable water-resource management in Kano Metropolis.
Key Words: Industrial Effluents, Water Quality Monitoring, Seasonal Variation, Environmental Pollution, Wastewater Management.
