| Freshwater eutrophication will threat the safety of drinking water and exacerbate water crisis, causing huge economic losses and ecological environmental problems. Bloom is a typical problem in Freshwater water eutrophication. It was casued by cyanobacteria, algae, diatoms etc. algae. Once formed eutrophication water body would hardly be restored thoroughly. Effectively control exogenous pollution while cutting nitrogen, phosphorus and organic load can fundamentally solve eutrophication. Endogenous nutrients can be reduced mainly by method of physical, chemical and biological. In this research, we applied indigenous deprad microrganisms enriched and domesticated in eutrophic water in order to screening efficient and safe defitrification microbial preparation which was suitable for ecological rehabilitation eutrophic water in northern China especially Haihe River. For the microbial preparation can be effective only in a short period and there are also the loss of such microorganisms, we would add microbial agents to ecological restoration of wetlands to further improve the wetland.At the beginning three strains of heterotrophic nitrifiers were isolated from Beiyunhe sediment, i.e., HN1, HN2 and HN3 whose nitrogen source was NH4+-N and other three strains of heterotrophic nitrifiers, i.e., HN4, HN5 and HN6 whose nitrogen source was NO2--N. Based on sequence analysis of the bacterial 16s rDNA and fungal ITS sequence, and software DNAMAN as homology analysis tool, strain HN1 was initial identified as Williopsis sp., strain HN2 as Swine fecal bacterium, strain HN4 as Shigella, both strain HN5 and HN6 as Candida palmioleophila, strain HN3 needed to be further identified.Activated carbon and zeolite was selected as the adsorption material. Through static and dynamic adsorption experiments, activated carbon's and zeolite's adsorption properties of ammonia were studied. The results static experimental show that Freundlich isotherm can better reflect the activated carbon's and zeolite's adsorption characteristics, and the degrees of fitting were 0.9783 and 0.9303 respectively. Zeolite's ability of adsorption ammonia(1.27mg/g)was higher than that of activated carbon's(0.53mg/g)under 24h experiment. Dynamic experimental shows that the time of zeolite adsorption reached saturation(96h)was longer than that of activated carbon(10h)and zeolite's ammonia nitrogen concentration of effluent water(64.57 mg/L)was lower than that of activated carbon(96.56 mg/L)under 120h experiment under the same influent ammonia concentration(110mg/L). Zeolite showed the superiorities as ammonia nitrogen adsorbent. After 96h biological regeneration of these matrix materials with heterotrophic nitrification microorganisms, the average concentrations of ammonia nitrogen in effluent water was decreased by 17.31 mg/L and 8.32 mg/L in active carbon and zeolite respectively, and the biomembrane on the surface of active carbon and zeolite were formed. The results suggested that it was feasible to decrease the concentration of the ammonia nitrogen in eutrophication water with the microbial enhanced matrix material.A bacterial strain AD1 screened from Beiyunhe sediment was found capable of aerobic denitrification.According to the morphological observation, physiological biochemical test and sequence analysis of the 16S rDNA, strain AD1 was identified as Pseudomonas sp.And the phylogentic position of the strain was performed based on the phylogenetic tree.The denitrifying capability of the strain was studied in batch culture under aerobic condition.The results showed that the nitrate in the culture could be efficiently removed by strain AD1 and the TN and NO3--N removal percentage were 63.82% and 84.83% in 24h;the TN and NO3--N removal percentage were 68.21% and 92.28% in 60h. |
