Characteristics of Effluent from a Chemical Fertilizer Industry in Southern Nigeria

Abstract

A study was conducted on the characteristics of effluents emanating from a chemical fertilizer industry in Nigeria with the objective of proffering effective management strategies. A 24hour monitoring of the outfall effluent was carried out. A total of 98 effluent samples from different process streams were collected in addition to 8 samples of the domestic wastewater (sewage), which was also generated in the Plant. Samples collected were analyzed for temperature, pH, DO, TSS, TDS, BOD, Urea, residual chlorine, PO4, NO3, P, K, Fe, and Zn using appropriate standard methods. The flow rate of the effluent was 252 m3/hr. Data from the 24-hour effluent monitoring indicated high values for conductivity (1888.6± 952.2μs) and free ammonia (27.1 ±17.8 mg/l). The results indicated that the Urea and NPK Plants were the most incriminating plants, which contributed immensely to the high pollution loads of the effluent. This resulted in its non-compliance with National guidelines set by the Federal Environmental Protection Agency (FEPA). Urea Plant produced the highest ammonia level of 1381.3 ± 78.2 and 1479.7± 649.8 mg/l for morning and evening samples while NPK recorded the highest Urea level of 2684.5 ± 1336.6 mg/l and 2726.8 ± 411.4 mg/ l and Zn 4.87 ± 1.76 mg/l and 3.43 ± 1.23 mg/l for both morning and evening samples respectively. Among the effluent channels, the West Drain Before (WDB) recorded the highest level of phosphate (148.6 ± 62.8 mg/l and 202.1± 47.5 mg/l) for both morning and evening samples respectively. The characteristics of the effluent provided a basis for instituting appropriate effluent management by the industry.

Key words: Fertilizer Industry, Effluent characteristics, Pollution, Nigeria