Enhanced long-term nitrogen removal and its quantitative molecular mechanism in tidal flow constructed wetlands Wei Zhi,†,‡ Li Yuan,† Guodong Ji,*,† and Chunguang He*,§
†
Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of
Environmental Engineering, Peking University, Beijing, 100871, China ‡
John and Willie Leone Department of Energy and Mineral Engineering, The Pennsylvania
State University, University Park, Pennsylvania 16802, United States §
State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation
Restoration, Northeast Normal University, Changchun, 130024, China
*Author for correspondence, Guodong Ji (e-mail:
[email protected]; phone: +86 (010)-62755914) and Chunguang He (
[email protected]; phone: +86 (0431)-89165612)
Number of pages: 7 Number of tables: 1 Number of figures: 4
S1
SUPPORTING INFORMATION Table S1 Synthetic wastewater composition and operation strategy for tidal flow constructed wetlands. The hydraulic retention time (HRT) was 36 h with 24 h for “wet” phase and 12 h for “dry” phase. Figure S1 Schematic diagram of tidal flow constructed wetland system. Figure S2 The photo of one perforated PVC pipe (left) and three highly permeable columns (right) that were used for microbial sampling. In each CW, two perforated PVC pipes (L × D = 100 × 5 cm2) harboring a total of eight columns (filled with the same bed material of CWs) that wrapped up by highly permeable nylon mesh were pre-buried for microbial sampling. Figure S3 Nitrogen transformation rates in the tidal flow constructed wetlands: (a) T1, NH4+ and (b) T2, NO3-. The positive values of TN, NH4+, and NO3- indicate that they were transformed (reduced) in the systems, whereas the negative values of NO2- and NH4+ indicate that they accumulated (increased) in the systems. Figure S4 Nitrogen transformation pathways with functional genes in the tidal flow constructed wetlands.
S2
Table S1 Synthetic wastewater composition and operation strategy for tidal flow constructed wetlands. The hydraulic retention time (HRT) was 36 h with 24 h for “wet” phase and 12 h for “dry” phase. COD
NH4+ or NO3-
PO43-
HRT
HLR
(mg/L)
(mg/L)
(mg/L)
(h)
(m3/m2·d)
T1
200
30 (NH4+)
3
36
0.33
T2
200
30 (NO3-)
3
36
0.33
Treatment
HRT: hydraulic retention time. HLR: hydraulic loading rate.
S3
Figure S1 Schematic diagram of tidal flow constructed wetland system.
S4
Figure S2 The photo of one perforated PVC pipe (left) and three highly permeable columns (right) that were used for microbial sampling. In each CW, two perforated PVC pipes (L × D = 100 × 5 cm2) harboring a total of eight columns (filled with the same bed material of CWs) that wrapped up by highly permeable nylon mesh were pre-buried for microbial sampling.
S5
Transformation rates mg/L·d
30
(a)
25
TN TN NH4+ NH4+-N NO3NO3--N NO2NO2--N
20 15
10 5
0 0
50
-5
150
200
250
Time (d)
30
Transformation rates mg/L·d
100
(b)
25 20 TN TN NO3NO3--N NO2NO2--N NH4+-N NH4+
15 10 5 0
0
50
-5
100
150
200
250
Time (d)
Figure S3 Nitrogen transformation rates in the tidal flow constructed wetlands: (a) T1, NH4+ and (b) T2, NO3-.The positive values of TN, NH4+, and NO3- indicate that they were transformed (reduced) in the system, whereas the negative values of NO2- and NH4+ indicate that they accumulated (increased) in the systems.
S6
Figure S4 Nitrogen transformation pathways with functional genes in the tidal flow constructed wetlands.
S7
