Effect Of Sulfaquinoxaline Sodium On Production Of Methane And VFA Under Thermophilic Anaerobic Digestion And Nitrogen And Phosphorus Removal In SBR Reactors

Sulfaquinoxaline sodium is an anti-coccidial medicine widely used inbroiler industry as drug additive. They do not degrade in animal body, andwould be present in animal wastewater, finally they go into the aquaculturewastewater and environment, bring some ecological risks. In this study, weinvestigate the removal of sulfaquinoxaline sodium on thermophilic anaerobicdigestion and in SBR reactors and its effect on the two treatment processes.The main conclusions are listed as follows:(1) Sulfaquinoxaline sodium had no effect on the production of VFA, buthad an inhibition effect on the production of methane in thermophilicanaerobic digestion, and the inhibition increased with the increase ofsulfaquinoxaline sodium concentration. Sulfaquinoxaline sodium was difficultto degradate in thermophilic anaerobic digestion process, the conversion rateis about20%. The measured data for each group had a high degree of fittingGompertz equation, but had a lower degree of fitting with first-order kinetics,so this study using the modified Gompertz equation to model the experimentalgroups per g of sucrose cumulative production of methane.(2) The short-term adding of sulfaquinoxaline sodium in SBR reactorsexhibited inhibitory effect on COD removal. The COD removal rate of thegroup of200mg/L was only about31%compared to the control group; itsshort-term adding also had an inhibition effect on ammonia removal, theammonia removal rate of the group of200mg/L was about65%compared to thecontrol group; The adding of sulfaquinoxaline sodium inhibited nitrateproduction in nitrification stage, while inhibiting the decreasing of nitrateconcentrations in denitrification stage; The adding of sulfaquinoxaline sodiuminhibited sedimentary phosphorus in aerobic stage, while inhibiting thereleasing of phosphorus in anaerobic stage;(3) Under long-term effects of sulfaquinoxalinum sodium on SBR reactors,the COD removal rate of group20mg/L was more than95%, the group of100mg/L final COD removal rate stabilized at around80%, while group200mg/L stabilized at around56%; The group of adding sulfaquinoxalinumsodium ammonia removal rate were lower than the control group, and addedthe higher concentration, the lower ammonia removal rate; The group of 200mg/L final removal rate was about41%after long-term reaction in theSBR reactor;100mg/L group after long-term reaction the final removal ratewas about52%in the SBR reactor;20mg/L group after long-term reactionthe final removal rate was about78%in the SBR reactor. Microorganismswere easier to adapt to the environment of having a low concentration of toxic,high concentration of sulfaquinoxalinum sodium had a greater inhibition onmicroorganisms, which were still not to adapt in a long time. Highconcentration of sulfaquinoxalinum sodium had a strong toxic effects onprotozoa in the SBR reactor.