Acute Toxicity Evaluation Of Pharmaceutical Wastewater Using Luminescent Bacteria

Pharmaceutical wastewater contains drugs and drug intermediates residues and other toxic substances which are difficult to remove by conventional treatment process. Wastewater emissions may pose a potential ecological threat to the environment. In this paper, acute toxicity of influent and effluent wastewater from pharmaceutical wastewater treatment plants were tested by establishing acute toxicity testing method using Vibrio fischer..Vibrio fischer. was purchased from Marine microorganisms preservation management center in China, the strains number: 1 A02700. In the incubation time of 12 ~ 20 h, the strains can be used for testing. When acute toxicity were between 0.02 to 0.24 mg/L as mercuric chloride equivalent concentration, toxicity can be expressed as mercuric chloride concentration. When the toxicity of water samples exceeded 0.24 mg/L as mercuric chloride equivalent concentration, EC50 values should be used to represent acute toxicity.The pharmaceutical wastewater is highly toxic, and chemical synthetic pharmaceutical wastewater toxicity are significantly higher than the fermentative pharmaceutical wastewater. 7 pharmaceutical wastewater from the 10 pharmaceutical wastewater toxicities exceeded 0.24 mg/L as mercuric chloride equivalent concentration, should use EC50 values to represent. Toxicities of the 10 pharmaceutical wastewater treatment plants were significantly reduced after the whole treatment processes. 6 effluent acute toxicities could be reduced to less than 0.07 mg/LHg Cl2(emission standard).Toxicity reduction efficiency of each wastewater treatment unit varied greatly. During anaerobic treatment process, toxicities of some pharmaceutical wastewater were largely reduced, with the maximal reduction efficiency of 96.9 %, while toxicities of some pharmaceutical wastewater were enhanced on the contrary, with the maximal increasing rate of 97.3%. Toxicities of all the wastewater tested could be reduced in the aerobic treatment stage, but the degree of reduction is different between different treatment plants. Toxicities of some pharmaceutical wastewater were slightly reduced, the reduction efficiency of 9.3 %, while toxicities of some pharmaceutical wastewater were largely reduced, the reduction efficiency of 99.2 %. Physico-chemical treatment process can remove part of acute toxicities, and the maximum removal efficiencies of the flotation tank and flocculation mixing tank were 37.2 % and 33.3 %, respectively.