Start-up Of Carbon Nitrogen Sulfur Removal Process System For Pharmaceutical Wastewater Treatment

Pharmaceutical wastewater contains high concentration of COD, sulfate andammonia, and the pH range from11to13.5. The conventional biological treatment hassome disadvantages, such as high sulfide in the effluent, long process flow. For theseproblems, an innovative integrated technology for desulfurization and denitrification(SDD) was developed, which is composed of Sulfate reduction&carbon removal (SR)unit, denitrifying sulfide removal (DSR) unit and Ammonia nitrification (AN) unit. Thetechnology can realize the simultaneous removal of organic carbon, sulfate, andammonia. The sulfate is converted into sulfur, and the resourcezation of waste water isbecoming possible using the technology.The study focused on the start-up of the system of the simultaneous removal oforganic carbon, sulfate, and ammonia treating the7-ACA production wastewater. Firstly,the start-up of each unit in the system was investigated. Then after the three units werechained in order, the impact of the influent pH was discussed. The result of theexperiments provided support for the practical engineering.For the SR unit, the reactor was EGSB, inoculated the mixture of sulfate reductionsludge and secondary sedimentation sludge. The influent was the dilute wastewateradding sodium lactate. It took25days to start up the SR unit, and the removal rate ofCOD and sulfide was78%and82%, respectively. For the DSR reactor, the equipmentwas EGSB, too. The seed sludge was sulfate reduction sludge. The influent was theeffluent of the SR unit. After the startup of DSR unit, the the removal rate of sulfide andCOD was100%and41%, respectively. Potassium nitrate was added into the influent asthe nitrogen source. For the AN reactor, the first, the secondary sediment sludge wasaerated for14days; the second, the urban domestic sewage was used to cultivate thenitrobacteria; the last, the effluent of DSR unit was bumped to the AN unit. The removalrate of ammonia and COD was93%and50%, respectively.At different pH (6.5-8.5), the processing of the SR unit was investigated using thebatch experiment, the optimal pH was8.5, at which the removal of sulfate and thespecific production rate was the highest. During the start-up of the system，the volatilityof the pH had little impact on the removal of the nitrogen. At the influent pH of5, theconversation rate of sulfur was the highest, the rate of DSR and AN unit was61%and40%, respectively. According to the data, the sulfur recovery unit should be located after the DSR unit. At the4kg COD m-3d-1,1kg SO42-m-3d-1,0.4kg NH4+-N m-3d-1,4kgCOD m-3d-1, the optimal influent pH is8.5, the removal of COD, sulfate, ammonia, totalnitrogen was89%，41%，93%，71%, respectively. At the influent pH of8.5,domesticating the activitated sludge of each unit in order, the startup of the system wasachieved for the treatment of rhe pharmaceutical wastewater and the treatment costs wasreduced.