Performance Of Biological Phosphorus Removal System In Presence Of Roxarsone

Roxarsone have been widely used in chicken and swine feeding as additive,which do not degrade in animal body, and would be present in animal wastewater,challenging the biological phosphorus removal processes. In this study, weinvestigate the performance of biological phosphorus removal system in thepresence of roxarsone, and the consequencing biotransformation of roxarsone. Themain conclusions are:(1) Short-term experiments show that roxarsone exhibitsinhibitory effect on biological phosphorus removal process, especially for thephosphorus uptake processes. When roxarsone concentration is higher than80mgL-1, the reactor failed to accomplish phosphorus removal; By inhibiting model ofPO43--P release and PO43--P uptake were analyzed, and discover that when roxarsoneconcentration less than40mg L-1, roxarsone on the inhibitory effect of PO43--P release ratewas bigger, and when the concentration more than40mg L-1, inhibitory effect on PO43--Puptake is bigger.(2) Long-term experiments show that roxarsone inhibit thebiological phosphorus removal process, resulting the increasing of sludge particlesize, sedimentation rate, compactness, gray and complexity increase. No significanteffect on the morphology of protozoan could be observed.(3) Roxarsone in the SBRreactor first biotransformated for HAPA, and then converted to inorganic arsenic; The staticexperiments results show that roxarsone had no biological degradation with in6h, and itsdegradation model is consistent with a first-order kinetic model, degradation productsHAPA generation model and degradation model conforms to the linear and first-orderkinetics model respectively.