Evaluation of Long-Term Wastewater Treatment Performances in Multi-Soil-Layering Systems in Small Rural Communities
Table 2
Mass balances of BOD, COD, T-N, and T-P from July 2012 to June 2013.
Index
BOD
COD
T-N
T-P
SITE 1
SITE 2
SITE 3
SITE 1
SITE 2
SITE 3
SITE 1
SITE 2
SITE 3
SITE 1
SITE 2
SITE 3
Total load (from wastewater)
159.1 (100)
172.4 (100)
223.5 (100)
363.3 (100)
330.9 (100)
427.5 (100)
77.6 (100)
63.0 (100)
113.8 (100)
10.5 (100)
6.6 (100)
11.7 (100)
Removal in BCAE
75.6 (48)
125.0 (72)
171.9 (77)
196.0 (54)
216.5 (65)
286.0 (67)
15.8 (20)
13.1 (21)
19.9 (17)
3.0 (29)
0.6 (9)
1.8 (16)
Discharge from BCAE
83.5 (52)
47.4 (28)
51.7 (23)
167.3 (46)
114.4 (35)
141.5 (33)
61.7 (80)
49.8 (79)
93.9 (83)
7.4 (71)
6.1 (91)
9.8 (84)
Discharge into river from BCAE (Nov–Apr)
34.3 (22)
13.5 (8)
—
76.3 (21)
39.8 (12)
—
24.5 (32)
17.2 (27)
—
2.7 (26)
2.1 (31)
—
Load into MSL
49.2 (31)
33.9 (20)
51.7 (23)
91.1 (25)
74.6 (23)
141.5 (33)
37.3 (48)
32.6 (52)
93.9 (83)
4.7 (45)
4.0 (60)
9.8 (84)
Load per unit area in MSL (g·m−2)
248.0
243.5
299.5
459.3
535.8
819.6
188.0
234.1
543.9
23.7
28.7
56.8
Removal in MSL
40.6 (26)
31.2 (18)
49.3 (22)
71.8 (20)
57.8 (18)
121.3 (28)
19.4 (25)
24.1 (38)
88.4 (78)
3.7 (36)
1.4 (21)
9.1 (78)
Removal rate in MSL (%)a
82.4
92.0
95.3
78.8
77.5
85.8
52.2
73.8
94.2
80.0
35.2
93.0
Discharge from MSL
8.6 (5)
2.7 (2)
2.4 (1)
19.3 (5)
16.8 (5)
20.2 (5)
17.8 (23)
8.5 (14)
5.5 (5)
0.9 (9)
2.6 (39)
0.7 (6)
Total discharge
42.9 (27)
16.2 (9)
2.4 (1)
95.6 (26)
56.5 (17)
20.2 (5)
42.3 (55)
25.8 (41)
5.5 (5)
3.7 (35)
4.7 (70)
0.7 (6)
Unit = kg (the data in parenthesis are expressed as relative values to total loading amount from wastewater (%)). aRemoval rate in MSL (%) = removal in MSL/load into MSL from BCAE × 100.
