Experimental Study On Treatment Of Traditional Chinese Medicine Wastewater By Hydrolytic Acidification-electrobioreactor Process

The composition of Chinese medicine wastewater is very complex,with poor biochemical properties,high concentrations of organic substances such as proteins,and high levels of bio-degradable substances.With changes in raw materials and pharmaceutical methods,wastewater may also contain anthraquinone,sterols,etc.These characteristics make it difficult to be easily degraded by ordinary munic ipal or industrial wastewater treatment processes.The research object of this subject is pharmaceutical wastewater discharged from a university pharmaceutical plant in Shaanxi.The author extensively consulted domestic and foreign literatures and finally adopted a combined process:hydrolysis acidif ication-electric bioreactor to study the treatment effect of traditional Chinese medicine wastewater.This experiment first studied the start-up characteristics of each unit reactor.After the startup is completed,the removal effect of COD by the hydrolytic acidif ication unit and the electro-biological treatment unit is about 25% and about 60%,respectively.Observed by biophase microscopy,the experiment found that the number of metazoans such as rotifers,ladybugs,oligochaetes,etc.in the biofilm of the electro-bioreactor is relatively large.Especially for rotifers,it has a large number,the body is relatively large and active.These phenomena indicate that the biofilm in the reactor grows well and has a good treatment effect.Then,an experiment was conducted to explore the optimal operating parameters of each processing unit.Experiments show that the optimal hydraulic retention time of the hydrolytic acidif ication unit is 10 h at room temperature,and the hydrolytic acidif ication effect is better when t he p H is in the range of 6.5～8.0.The average removal rates of COD and chroma of the hydrolytic acidif ication unit is 26.06%and 24.59%,respectively,and the average growth rate of ammonia nitrogen is 26.32%.The hydrolytic acidification reactor signif icantly improves the VFA and the B/C value of the influent.The optimal voltage of the applied electric field of the electrobioreactor is 6V,and the COD removal rate and ammonia nitrogen removal rate reach the best results when the HRT is 10h and 12h,respec tively.When the dissolved oxygen concentration（DO）is 2.0 mg/L and 2.5 mg/L,the COD removal rate and ammonia nitrogen removal rate of the electrobioreactor reach the highest values,respectively.Through orthogonal experiments on the combined process,the optimal dissolved oxygen concentration and optimal HRT of the electrobioreactor are 2.5mg/L and 12h,respectively.Under the optimal conditions,the combined process is in series and stable operation.The average removal rates of COD,ammonia nitrogen,TN and chroma of the combined process are 91.4%,80.1%,55.8%and 67.1%respectively.The content of toxic pollutants in the effluent has also been signif icantly reduced.The average biological toxicity in the final effluent was 0.072Hg Cl₂ toxicity equivalent,which achieved the expected effect of the effluent.Through the analysis of the environmental benefits of the combined process,After the project is implemented,it is expected that COD,ammonia nitrogen and TN discharged to the municipal pipe network will be reduced by 175.2 tons,2.6 tons and 4.1 tons each year.Effectively reduce the impact of the discharge of traditional Chinese medicine wastewater on municipal sewage treatment plants,so that the harmfulness of traditional Chinese medicine wastewater to the environment is effectively reduced.The process can better guarantee the relative stability of the microbial population structure in the secondary treatment unit of municipal sewage treatment plant.The experiment calculates the kinetic model of the electric bioreactor and calculates that the first-order reaction constant of the reactor is 0.3307,which is at a relatively high level.From this,it can be known that the electric bioreactor has a higher removal rate for organic matter.In the experiment,the parameters in the model are calculated by linear fitting to obtain the kinetic equation of the organic bioreactor for the degradation of organic matter in wastewater.The dynamic equation is:（?）...