Characteristics of nutrient release from sediments under different flow conditions

Figures & data

Figure 1. Schematic diagram of the experimental device.

Figure 2. TDP concentration variation with time under different flow velocity. (A) flow velocities of 0.05 and 0.1 m/s; (B) flow velocities of 0.15 and 02 m/s; (C) flow velocities of 0.25 and 0.3 m/s.

Figure 3. TDN concentration variation with time under different flow velocity. (A) flow velocities of 0.05 and 0.1 m/s; (B) flow velocities of 0.15 and 02 m/s; (C) flow velocities of 0.25 and 0.3 m/s.

Figure 4. Released amount of TDN and TDP from sediment under different flow velocity.

Figure 5. Equilibrium concentration of dissolved phosphorus and nitrogen in overlying water different flow rate conditions.

Table 1. Parameters of the model.

v (m/s)	D (10^−9 m^2/s)	Ct (g/m^3)	Cs (g/m^3)	vr (10^−4 m/s)	vd (10^−4 m/s)	k2
0.05	1	2818.7	10	1.08	−0.01	1.2
0.1	2.2	5641.0	23	4.33	−0.001	1.2
0.15	4.3	8467.1	38	9.74	−0.001	1.2
0.2	5.7	11296.8	90	17.33	−0.001	1.2
0.25	7.4	14130.2	120	27.10	−0.001	1.2
0.3	10	16967.3	130	38.80	−0.001	1.2

Table 2. Value of parameter k₁ under different flow velocity and time (TDP).

Time	v (m/s)
	0.05	0.1	0.15	0.2	0.25	0.30
10	0.2	0.9	0.4	0.1	0.08	0.05
20	0.6	0.6	0.08	0.05	0.01	0.006
30	0.5	0.03	0.002	0.0005	0.005	0.004
40	0.2	0.1	0.01	0.001	0.001	0.002
60	0.3	0.1	0.01	0.001	0.001	0.002
90	0.01	0.05	0.005	0.005	0.001	0.002
120	0.02	0.1	0.01	0.005	0.001	0.001
180	0.16	0.01	0.001	0.0001	0.001	0.0005

Table 3. Value of parameter k₁ under different flow velocity and time (TDN).

Time	v (m/s)
	0.05	0.1	0.15	0.2	0.25	0.3
10	0.008	0.005	0.001	0.0005	0.0002	0.0002
20	0.001	0.003	0.0001	0.0001	0.00001	0.00004
30	0.01	0.002	0.0006	0.0001	0.00001	0.00001
40	0.01	0.002	0.0001	0.00001	0.00001	0.000002
60	0.004	0.001	0.0001	0.00001	0.00001	0.000002
90	0.002	0.0002	0.0001	0.00001	0.00001	0.000005
120	0.002	0.0002	0.00006	0.00003	0.000001	0.000005
180	0.002	0.0002	0.00001	0.00001	0.000001	0.000005

Table 4. Deterministic coefficient of the modeling result.

V (m/s)	0.05	0.1	0.15	0.2	0.25	0.30
DC(TDP)	0.76	0.91	0.94	0.94	0.94	0.71
DC(TDN)	0.81	0.96	0.74	0.86	0.90	0.86