Study On Process Techniques For Hypersaline Pharmaceutical Wastewater With Electrolysis-SBR

Systematic analysis of the varieties and characteristics of the pharmaceutical wastewater was conducted. Based on the experience of practical projects, we found that it was unfeasible to treat the pharmaceutical wastewater only with biological methods, it even caused the death of sludge. Considering high COD, complex composition and recalcitrant organic compounds in pharmaceutical wastewater and effectiveness and ease in operation of electrolysis, an schemes of electrolysis-SBR was established.Experiments were conducted to study the changes in chromaticity, COD and the biodegradability of pharmaceutical wastewater. The objective of this paper is to advance the knowledge of the influence of residence time, polar distance, initial reaction temperature, initial wastewater concentration, voltage, pH and electrolyte , electrode sort, switching frequency of anode and cathode, polar coupling type on the electrolysis efficiency. Chloride is widely presented in many wastewater, so it's worth studying the increase of chromaticity and COD removal by anode indirect oxidation without filling in any other electrolyte. Compared with the effects of Na2SO4, NaNO3 on the electrolysis efficiency, the results of the experiment showed that the COD removal can be mainly attributed to the indirect oxidation effect of NaCl in electrolysis process. The results indicate that the presence of Cl-can achieve higher COD removal because of anode indirect oxidation.As the wastewater used in this experiment was rich in chloride, electrolysis anode indirect oxidation occurred without filling in NaCl. The results showed that the use of electrolysis technology could remove about 96.9% of chromaticity and 41.4% of COD and improve the biodegradability of pharmaceutical wastewater from 0.17 to 0.34. volts d.c. of 30 voltages, 7.5 of pH value and a retention time of 60 minutes were recommended for the process design of electrolysis. This was verified ulteriorly by chromatogram-mass spectrum.Acclimation procedures are of utmost importance when high salinity wastewater was to be treated with SBR treatment. While the process was affected slightly, proper acclimation methods minimize negative effects and the process would yield a good quality effluent. Compared with confined movement way of SBR process, unconfmed way played a more important role in the good removal efficiency of COD.At present, there are some problems in the study of DO and ORP as control parameters, because the researches are usually developed in the invariable temperature. However, environmental temperature is changing in the wastewater treatment. The effect of environmental temperature on and ORP as control parameter was studied specially in some experiments carried on a sequencing batch reactor(SBR) fed with pharmaceutical wastewater in this paper. It was carried out in the invariable temperature and in the variable temperature, respectively. Results showed that DO as control parameter is valid in the invariable temperature, and the law of variation in DO during organism removal were influenced with the environmental temperature, at different experiment condition of aeration intensity, MLSS concentration or inflow nutrition concentration, but the variation in ORP were not influenced with it. The reason that the DO was influenced was also discussed. This paper brought forward that the control parameter using ORP was accurate and reliable when environmental temperature changed. In addition, inflow COD concentration and the time that ORP concave value appeared was connected, and the speed that ORP in curve ascended related with the COD concentration during the degradation. So it can be made on-line control of aeration intensity and aeration time.After the pre-treatment of pharmaceutical wastewater with electrolysis, the supernatant was neutralized and diluted and then was added to SBR reactor. Compared with the pharmaceutical wastewater without electrolysis, results showed that the average CODcr value of SBR effluent was 230mg/L, after flocculent sedimentation, CODcr reduced to le...