Construction Of Compound Microorganism Bacterium Agent And Its Bioaugmentation Efficiency In The Constructed Wetland At Low Temperature

Constructed Wetlands (CWs) are engineered environmental technologies, withadvantages of low investment, low operation cost and high pollutant removal efficiency.CWs have been widely used in southern China, while the development in northernChina is limited by the low temperature in cool winter. Bioaugmentation can be used toenhance the pollutant removal of biological systems at low temperature, but there havebeen few studies on the effect of bioaugmention on pollutant removal of CWs. In thispaper, compound microorganism bacterium agent at low temperature (CMBALT) wasconstructed based on the principles of niche separation, substrate selection andbiochemical cooperation, the effect of bioaugmentation on CWs at low temperature wasinvestigated in terms of organic matter, nitrogen and phosphorus removal and thedynamic succession of bacterial community was analyzed before and afterbioaugmentation was analyzed using pyrosequencing.Two bacterial strains with feature of degrading organic matter (ORS) and onebacterial strain with feature of removing phosphorus (PRS) were isolated from the soilof CWs. These three strains and the nitrogen removal bacterium agent (NRS) stored inour laboratory were combined to construct CMBALT. The optimal volumetricproportion of ORS, NRS and PRS was10:0.5:0.5.The effect of bioaugmention on pollutant removal of CWs at low temperature wasinvestigated from the angles of start-up time, hydraulic retention time (HRT) andbacterial agent dose (BAD). During the start-up stage, when HRT was4days and BADwas0.25%, adopting bioaugmention could reduce the startup time. With the decrease ofHRT to2days, the chemical oxygen demand (COD), ammonia nitrogen (NH4+-N) andtotal nitrogen (TN) concentration in the effluent of experimental group (bioaugmention)achieved the GB18918-2002standard (China) for Class I-B guideline (Class I-B), whilethe control group (no bioaugmention) did not. When HRT was reduced to1day andBAD was increased to0.5%, the COD concentration in effluent of the experimentalgroup maintained Class I-B, and the NH4+-N and TN achieved Class I-A.The dynamic succession of bacterial community was analyzed before and afterbioaugmentation using pyrosequencing. After bioaugmentation, the abundance ofbacteria with feature of removing nitrogen was increased, including Nitrosomonas, Nitrobacter and Aeromonas. The abundance of bacteria with feature of removingorganic matter was increased, incluing Bacillus.