长/短HRT交替培养同步硝化反硝化除磷颗粒

Cultivation of simultaneous nitrification and denitrification phosphorus removal granular sludge with alternating long/short HRT

为快速实现颗粒化同时富集反硝化聚磷菌(denitrifying phosphate accumulating organisms,DPAOs),在接种絮状活性污泥和长期低温储存的颗粒污泥后,以人工配水为处理对象,分别以恒定水力停留时间(hydraulic retention time,HRT,t_(HR))和不同比的长/短HRT交替模式运行4组序批式活性污泥反应器(sequencing batch reactor,SBR),探究长/短HRT交替运行下的饥饿作用对于富集DPAOs和造粒等方面的影响。结果表明,长/短HRT交替运行下的颗粒污泥均具有更高的DPAOs占比和脱氮除磷率,沉降性能良好且颗粒致密。其中,在12 h/6 h的长/短HRT交替模式下,同步硝化反硝化除磷颗粒的污染物去除性能最好,其长周期内COD、TN和TP的去除率分别达93%、96%和98%,短周期内的去除率为95%、90%和93%,这主要是大粒径颗粒内形成的缺氧区、饥饿条件下胞外聚合物的分泌以及反硝化菌对可溶性微生物产物(soluble microbial products,SMP)的利用等因素综合作用的结果;当HRT比提高至13.5 h/4.5 h时,过高水平的SMP积累和过短的厌氧时间会使得出水COD和TP质量浓度超标;而当HRT比降低至10.5 h/7.5 h时,反硝化聚磷菌的占比下降了18%,出水TN去除率也有所下降,表明12 h/6 h是采用长/短HRT交替运行的可参考值。

For the rapid granulation and enrichment of denitrifying phosphate accumulating organisms(DPAOs),taking flocculent activated sludge and granular sludge stored at low temperature as inoculated sludge and synthetic water as treatment object,four groups of SBR were operated under constant hydraulic retention time(HRT)mode and alternating long/short HRT mode with different ratios.The impact of starvation under the alternating long/short HRT mode on DPAOs enrichment and granulation was explored.Results showed that the granular sludge under alternating long/short HRT mode had higher DPAOs proportion,better nitrogen and phosphorus removal capacity,better sedimentation capacity,and dense structure.The pollutant removal capacity of simultaneous nitrificationdenitrification and phosphorus removal(SNDPR)particles was the best when the ratio of alternating long/short HRT mode was 12 h/6 h.The removal rates of COD,TN,and TP reached 93%,96%,and 98%in the long cycle,and 95%,90%,and 93%in the short cycle,which was mainly due to the comprehensive effect of anoxic zone formed in large size particles,the secretion of EPS under starvation,and the utilization of soluble microbial products(SMP)by denitrifying bacteria.When the ratio of HRT increased to 13.5 h/4.5 h,too high a level of SMP accumulation and too short anaerobic time led the effluent COD and TP concentrations to exceed the standard;when the ratio of HRT decreased to 10.5 h/7.5 h,the proportion of DPAOs decreased by 18%,and the TN removal rate of effluent also reduced,which indicated that 12 h/6 h was a reference value for the operation of alternating long/short HRT mode.