Quality of Wastewaters from Selected Laboratories in a Tertiary Institution, Nigeria

Abstract

The compositions of laboratory wastewaters are so complex and similar to industrial wastewaters, thus may require more than a conventional biological treatment. In this paper, grab and composite samples of wastewaters from all identifiable and accessible discharge points emanating from the laboratories in Ahmadu Bello University (ABU), Zaria were collected over a period of four weeks.  The wastewaters collected were analyzed and compared with FEPA (1991) and WHO (1989) standards to ascertain if they can be completely treated by the existing waste stabilization ponds, with particular attention to some biological and physicochemical parameters as well as some heavy metals. The study revealed the average pH as 3.9 – 9.5, BOD₅ 33.50 – 120 mg/L, COD 72.50 – 277.50 mg/L, Nitrate 6.13 – 31.55 mg/L, Phosphate 15.19 – 51.78 mg/L, Oil and grease 0.07 – 14.50 mg/L and three heavy metals (Cr, Cd and Pb) were from 0.111 mg/L up to as high as 37.89 mgL. Lead values ranged from as low as 0.0026 to  0.026 mg/l which were all within the stipulated standard. The coefficient of variation (CV) of all the parameters studied in the various laboratories ranged from 0.02 to 0.99. This suggests that there are variations in the compositions of wastewaters generated. The study revealed that the characteristics of the laboratory wastewaters from ABU suggest that they are biodegradable based on their chemical oxygen demand/biological oxygen demand ratio and shows good indication for biological treatment except for wastewaters generated from Pharmacy laboratories.