Chemical processing of pharmaceutical wastewater for pollution control

The present research investigation was aimed at determining the behavior of TSS, BOD5, COD, Oil and grease, phenols and ammonia of pharmaceutical wastewater under varied concentrations of polymers (alum and chlorine), in order to determine the effectiveness of polymers as coagulant aids. Wastewater samples were collected from the holding tank in plastic containers. Total suspended solids were removed from the wastewater by alum treatment and it was found that alum dose of 200 mg L-1 was sufficient to remove TSS from 458 to 23 mg L-1 (95 % removal). Similarly BOD bas 5 was also readily removed by the alum treatment, showing that alum dose of 300 mg L-1 was optimum, in achieving 89 per cent removal. Although removal of COD was not easily obtained due to the complex chemical composition of the wastewater. Therefore, variable results in terms of COD removal were obtained. It was observed that COD removal efficiency was as low as 13-46 per cent for 100 mg L-1 and for 200 mg L-1 it was between 26-77 per cent and for 300 mg L-1 it was found out to be 28-88 per cent. Different volumes of chlorine (diluted bleach, 50:50, 25:75 and 15:85) were used in order to find out the optimum chlorine dose for further reduction of COD. The residual COD removal efficiency of 15 per cent bleach at 30 mill 00 ml dose was found to be 71 per cent. Similarly for 25 per cent and 50 per cent bleach it was found out to be 89 per cent and 86 per cent respectively (Based on average of six results). Similarly alum dose of 300 mg L-1 was sufficient to remove 65 per cent phenol within a contact time of 30 minutes depending upon the phenol concentration in the original sample. Similarly the effect of chlorine on alum treated wastewater was observed for residual phenol and ammonia removal and it was found that 25 per cent bleach at 10 ml, 20 ml and 30 ml was effective in bringing phenol level down to acceptable level of.0.1 mg L-1 or less.