The Research On Zero Nitrogen And Phosphorus Discharge Technology For Pharmaceutical Wastewater

The wholly-owned foreign pharmaceutical enterprise in Suzhou intended to extend Centrum series and Caltrate series tablets production line in Wuzhong District Economic and Technological Development Zone,Suzhou.The formulations of both these two tablets contained a little nitrogen and phosphorus compounds,so the process wastewater（mainly the equipments cleaning water and floor flushing water）inevitably contained a little nitrogen and phosphorus pollutants.However,according to the Taihu pollution control and prevent regulations of Jiangsu province（revised in 2012）and the relevant regulations of the Suzhou Municipal Environmental Protection Bureau,the new-built and extended enterprises or projects which contained nitrogen and phosphorus pollutants must implement zero liquid discharge or zero nitrogen and phosphorus discharge.The wastewater from these enterprises or projects after advanced treatment can not be reused in the production（such as the pharmaceutical enterprises or projects which passed GMP certification）,these enterprises or projects must implement zero nitrogen and phosphorus discharge,and other enterprises or projects implemented zero liquid discharge.The wholly-owned foreign pharmaceutical enterprise in Suzhou passed GMP certification.According to the approval of construction project environmental impact assessment report,the project intended to expand by the enterprise must implement zero nitrogen and phosphorus discharge.The existing advanced wastewater treatment technology can achieve zero liquid discharge,but there were no any researches or reports about zero nitrogen and phosphorus discharge.This thesis consigned by a wholly-owned foreign pharmaceutical companies in Suzhou,carried out the research of zero nitrogen and phosphorus discharge technology for pharmaceutical wastewater.Firstly,through the laboratory tests,the feasibility of zero nitrogen and phosphorus discharge for pharmaceutical wastewater by the combined process of coagulation pretreatment,biological treatment,and ultrafiltration-reverse osmosis（UF-RO）advanced treatment was studied.Then a set of pilot device was designed on the basis of laboratory tests,the purpose was to validate the laboratory results through the pilot test,on the other hand,was also to provide more reliable technical parameters for engineering design.The laboratory and pilot tests results showed as follows.Using FeCl₃ as the coagulant for coagulation pretreatment,there was no need to adjust the wastewater pH value.When the dosage of FeCl₃ was 150～200 mg/L,about 95%turbidity and phosphates could be removed.The effluent of coagulation pretreatment was treated by A/O biological process,the COD,NH₃-N,TN and TP could be removed about 72%,86%,58%and 53%,respectively.The effluent of biological treatment unit was advanced treated with UF-RO process.When the water recovery of first-pass RO was less than 33%,the NH₃-N,TN and TP in the permeate water were all undetected.When the water recovery of first-pass RO was about 50%,the NH₃-N and TP in the permeate water were undetected,but TN was detected.When the water recovery of first-pass RO was about 67%,the TP in the permeate water was still undetected,but both NH₃-N and TN were detected.With the two-pass RO modules for advanced treatment of the biological unit effluent,the NH₃-N,TN and TP in the permeate water of second-pass RO were all undetected as water recovery of both first-pass RO and second-pass RO were about 67%,and the permeate water quality met requirement of zero nitrogen and phosphorus discharge.The RO concentrate was treated with evaporation and the evaporator condensate contained a little nitrogen and phosphorus which failed to meet requirement of zero nitrogen and phosphorus discharge.So the evaporation condensate should be returned to the RO unit for further treatment.