The shortage of the organic carbon source in groundwater has limited the nitrogen removal of heterotrophic denitrification. In this paper, slow carbon releasing material was prepared by straw, polyvinyl alcohol (PVA), cellulose. And five different kinds of amylase were added to control carbon releasing velocity. The prepared material formed the interlocking/disperse-phase structure. PVA served as continuous phase and skeleton, whereas the straw performance as release component. the compressive strength, structural properties and carbon release properties of the material were studied. Then the carbon release material was added to an electrode biofilm reactor to establish the synergistic effect of autotrophic and heterotrophic denitrification to restore the nitrate polluted groundwater. Through the orthogonal test of the ratio of the material, The order of effective extent that effect the carbon releasing was tested and the kinetic equation of the carbon release can be expressed as . The autotrophic reaction and the system of synergistic heterotrophic—autotrophic denitrification was investigated, the influence on denitrification of current ,influent concentration and HRT were evaluated. NO3- -N removal rate increased first and then decreased with the increase of current intensity. At same time NO2-- N accumulation with NO3--N removal rate was studied. The result of synergistic heterotrophic—autotrophic denitrification showed that the optimum operation parameter was 8hours, 50mA and 30 degrees Celsius respectively. Microorganisms were sequenced using high throughput methods which was performed on two samples taken from the combination system. The results showed that the Coverage index of the two samples were all above 0.999 Shannon and Simpson index value demonstrated that heterotrophic-autotrophic denitrifying bacteria has more abundant bacteria diversity. 12 bacterial phyla were found on contact surface on the carbon materials sample. Among them, the percentage of Proteobacteria is the largest in the sample with 98% in abundance. Pseudomonadaceae and Sphingomonadaceae were the dominant bacteria, the proportion was 48.08% and 22.7% respectively. Pseudomonas have the maximum abundance in the genus which is up to 37.4%.

Research on remediation the NO3--N polluted groundwater by the synergistic effect of autotrophic and heterotrophic denitrification

255th National Meeting (2018)

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