Study On The Effect Of Antibiotics On Biofilm Reactor And Anaerobic Digestion System

Antibiotic wastewater is a kind of organic wastewater with high chroma andcontaining a large amount of refractory and biological toxic substances. Now the mainmethod for the treatment of antibiotic wastewater is biological treatment. In this paper,the effects of antibiotics on biofilm reactor and anaerobic digestion system werestudied in order to provide reference for the optimization of the biological treatmenteffect.First of all, five identical organic glass containers were numbered A、 B、C、D、E，and continuous inflow was adopted for test of biofilm formation after fiber ballsand sludge was added to every reactor. The efficiency of wastewater treatmentincreased continually during the biofilm formation and the average concentration ofsludge was increased to5581mg/L after reactors were running for32d. And at thistime we found that:(1)The biofilm reactor has relatively strong bearing capabilityagainst impact load and achieve complete nitrification of ammonia, of which about97%was changed to nitrate nitrogen and around3%to nitrite nitrogen; Both the removalof soluble SCOD (SCOD) and dissolved organic carbon (DOC) were more than85%;(2) The degradation of soluble starch is better than the degradation of cellulose in thisreaction system.(3) The analysis of microbial communities in five biofilm reactorsusing polymerase chain reaction-a gradient gel electrophoresis (PCR-DGGE)showed that the parallelism was good.Then, adding spiramycin, oxytetracycline, streptomycin and tigecycline to the B,C, D, E four reactors respectively with reactor A as a blank contrast to study theeffects of different antibiotics on biofilm reactor. The results show that:(1) Thespiramycin, oxytetracycline and streptomycin of0.1mg/L have little effect on systemand the removal of SCOD, DOC and ammonia nitrogen were stable at89%±2.5%,89%±2.5%and99.07%±0.5%respectively while the tigecycline has larger effect onsystem than the other three antibiotics and the removal of SCOD, DOC and ammonianitrogen were stable at87.38%±2.5%,87.38%±2.5%and96.95%±0.5%;(2)Antibiotics of0.1mg/L can activate soluble amylase and enhance the activity ofsoluble amylase but the promotion effect on activity of cellulose was weak;(3) Thebacterial communities in the A, B, C, D four reactors were similar and they were alldifferent from the E reactor, indicating that tigecycline of0.1mg/L has larger impacton system than spiramycin, oxytetracycline and streptomycin of0.1mg/L.Finally, aminoglycoside, macrolide and tetracycline antibiotics were added to the thermophilic anaerobic digestion system respectively to study the effects of differentantibiotics on thermophilic anaerobic digestion system. The results show that:(1)Theadding antibiotics had no or little effect on the hydrolysis acidification process buthad a certain inhibitory effect on the methanogenic bacteria;(2) The order of theinhibition of methanogens: macrolide> aminoglycoside> tetracycline, and theerythromycin macrolide antibiotic had better inhibitory effect on methanogens thanthat of spiramycin. As to aminoglycoside antibiotics, the inhibitory effect ofstreptomycin is better than Ribostamycin when they are all at low concentration andon the contrary when they are all at high concentration.