An assessment model for the risk of wastewater of pharmaceutical manufacturers (mixing and formulation) taking methane-oxidizing bacteria as an indicator

In order to assess the environmental risk of water pollutants, a fitting function of the dose-effective relationship among microbial indicator and pollutants was reached. The microbial fauna in the microcosm of the pharmaceutical manufacturers of mixing and formulation were measured. The correlationship among different concentrations of artificial composed water and the mass growth of target microbial was calculated to set a fitting function. The methane-oxidizing bacteria was selected as the indicator owing to its better reactivity of mass growth, the highest correlationship(r=−0.968) along with the change of the waste-water concentrations and the coefficient of fitting function as R²=1. The fitting function equation was y=−1.63x⁴+2.908x³−1.783x²+0.299x+0.276; Thus, different risk levels were divided: No risk(OD600≥0.276), Low risk(0.276< OD600<0.138), Medium risk (0.138≤OD600<0.000), High risk (OD600≤0.000). The sensitivity of microbial indicator incresaes the precision of warning and the time of crisis response with very strong practicability.