Figure 3 should be here
3.3 Hydrogeological methods for denitriding
Fig. 4 showed the concentration distribution
of O2, NO3- and DOC at
typical moments of water level fluctuation
under different K . When the hydrological connectivity was
enhanced, the AR and DN reaction areas were significantly enlarged,
which was corroborated by that all the solute plumes increased with the
increasing K at any moment during the water level cycle. In
Table 5, the corresponding denitriding amounts under different Kwere shown, which quantitatively indicated that the larger K was,
the greater the denitriding capacity was. This was because the better
hydrological connectivity could increase the maximum
aquifer water storage (Q max) (Table 5). AndM in-NO3 has positive
correlation with Q max (e.g., Gu et al., 2012).
During the water level cycle, when the K increased
from 43.2m/d to 129.6m/d, M in-NO3 increased from
40.90g to 66.75g, the range of reaction (lateral coordinate) increased
from x =10m to x =12m, M rem-NO3 increased from
6.34g to 8.46g, the maximum denitriding rate increased from 1.58g/d
to 2.57g/d, while N rem-NO3 decreased from 15.5%
to 12.7% (Table 5).
By comparing case 13, 14 and 15, the range of each solute plume
increased with the increase of i . During the water level
regression period, each solute plume did not shrink, but continued
expanding (concentration distribution picture was omitted), which
indicated that the consumption of solute through chemical reactions was
smaller than solute being carried from the river induced by the
hydraulic gradient between surface water and groundwater. During the
water level cycle, the range of reaction (lateral coordinate) increased
from x =10m to x =16m,M rem-NO3 increased from 6.34g to 35.89g, the
maximum denitriding rate increased from 1.58g/d to 2.18g/d, whileN rem-NO3 reduced from 5.5%
to 13.6% (Table 5 ). It could be found that the maximum denitriding
rate had no significant change with the change of i , and the
influence of i onM in-NO3 , M rem-NO3 and the
reaction range were much greater than that of K on them.